This document presents a simple method for quantifying dissolved nitrous oxide (N2O) in tile drainage water. Modified 10 mL volumetric pipettes placed inside standard 1 L water sampling bottles are used to collect tile drainage water samples while minimizing the water-atmosphere interface and reducing N2O exchange. Water is extracted from the pipettes using syringes for measurement of dissolved N2O concentration via headspace analysis using gas chromatography. Laboratory trials showed that retaining water samples in the pipettes reduced N2O degassing such that concentrations did not significantly decrease in the first 24 hours, allowing for automated collection and preservation of dissolved gas concentrations in drainage water.
This document provides an introduction to physical-chemical water treatment. It discusses the instructor, Hans van Leeuwen, and his background and research interests in wastewater treatment and bioengineering. It then covers various topics related to water treatment including ozone applications, exotic species in ports, human technological development, pollution, waterborne diseases, dissolved oxygen, biochemical oxygen demand, oxygen depletion in streams, and uses the Streeter-Phelps model to analyze an example of oxygen sag in a river.
The document summarizes an investigation into the quality of groundwater in an area of Sri Lanka around a university and garbage dumping site. 96 domestic wells were sampled and tested for 14 physical, chemical and biological parameters. The results found that over 95% of wells had pH levels making the water unsuitable for drinking. Other parameters like turbidity, total solids and nitrite levels were also found to negatively impact water quality. Statistical analysis found significant differences in nitrate, nitrite and other contaminant levels between different areas. The study concludes the groundwater in the area is generally not suitable for drinking due to contamination from human activities. Recommendations are made to improve waste management and further study groundwater quality variations.
This study analyzed greenhouse gas fluxes from soils in seasonal wetlands in the Mekong River Delta. Soil, gas, and water samples were collected and analyzed for greenhouse gases, porewater chemistry, and soil moisture under controlled flooding simulations. The results showed that soil moisture is a primary controller of gas emissions. Upon draining of wetland soils, methane and carbon dioxide effluxes increased, with methane showing a short-lived pulse and carbon dioxide increasing for an extended period. The study found that greenhouse gas emissions from soils in the Mekong Delta are regulated by changes in soil moisture levels.
This document summarizes a student group's experiment to determine the biochemical oxygen demand (BOD) of various water samples using a data logger. They tested pond water, drain water, distilled water, aquarium water, and pipe water. The drain water had the highest BOD value at 0.963 mg/L, indicating it was the most polluted sample. The distilled water had the lowest BOD at 0.412 mg/L, showing it was the least polluted. Over five days, the BOD levels of all samples generally increased as bacteria broke down more organic matter over time.
International Journal of Mathematics and Statistics Invention (IJMSI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJMSI publishes research articles and reviews within the whole field Mathematics and Statistics, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
This document presents a project proposal for analyzing the biological components of groundwater in selected industrial and residential areas in Chinhoyi, Zimbabwe. It introduces the significance of groundwater and issues of contamination from human and other activities. Key water quality parameters that will be analyzed include microbiological (total coliform, E. coli), chemical (COD, BOD), and physical properties. Methodologies for sample collection, handling, and analyzing COD, BOD and total coliform are described, including calculations. Health risks of coliform contamination are also discussed. The analysis will assess water quality and identify sources of pollution to inform water management.
Nitrogen Use & Climate Change Mitigation - Liz Baggs (University of Aberdeen)Farming Futures
The document discusses nitrous oxide (N2O) emissions from soil and opportunities for mitigation. It notes that N2O concentrations have increased 20% over the last 100 years. Soil is a major source, producing 10.2 Tg N per year. The primary controls of N2O production from soil are nitrogen application, aeration/water content, temperature, and available carbon. Understanding these controls is key for modeling emissions and developing mitigation strategies like improved fertilizer management and planting techniques. New opportunities for mitigation may include manipulating rhizosphere microbes and chemistry to maximize N2O reduction to nitrogen gas.
1. The document describes an experiment to determine the biochemical oxygen demand (BOD) of various water samples using data loggers.
2. Samples of pond water, drain water, distilled water, aquarium water, and pipe water were tested by recording the initial and final dissolved oxygen concentrations over 5 days.
3. The BOD value, which indicates how polluted the water is, was calculated using the difference between initial and final dissolved oxygen levels. The higher the BOD value, the more polluted the water sample.
This document provides an introduction to physical-chemical water treatment. It discusses the instructor, Hans van Leeuwen, and his background and research interests in wastewater treatment and bioengineering. It then covers various topics related to water treatment including ozone applications, exotic species in ports, human technological development, pollution, waterborne diseases, dissolved oxygen, biochemical oxygen demand, oxygen depletion in streams, and uses the Streeter-Phelps model to analyze an example of oxygen sag in a river.
The document summarizes an investigation into the quality of groundwater in an area of Sri Lanka around a university and garbage dumping site. 96 domestic wells were sampled and tested for 14 physical, chemical and biological parameters. The results found that over 95% of wells had pH levels making the water unsuitable for drinking. Other parameters like turbidity, total solids and nitrite levels were also found to negatively impact water quality. Statistical analysis found significant differences in nitrate, nitrite and other contaminant levels between different areas. The study concludes the groundwater in the area is generally not suitable for drinking due to contamination from human activities. Recommendations are made to improve waste management and further study groundwater quality variations.
This study analyzed greenhouse gas fluxes from soils in seasonal wetlands in the Mekong River Delta. Soil, gas, and water samples were collected and analyzed for greenhouse gases, porewater chemistry, and soil moisture under controlled flooding simulations. The results showed that soil moisture is a primary controller of gas emissions. Upon draining of wetland soils, methane and carbon dioxide effluxes increased, with methane showing a short-lived pulse and carbon dioxide increasing for an extended period. The study found that greenhouse gas emissions from soils in the Mekong Delta are regulated by changes in soil moisture levels.
This document summarizes a student group's experiment to determine the biochemical oxygen demand (BOD) of various water samples using a data logger. They tested pond water, drain water, distilled water, aquarium water, and pipe water. The drain water had the highest BOD value at 0.963 mg/L, indicating it was the most polluted sample. The distilled water had the lowest BOD at 0.412 mg/L, showing it was the least polluted. Over five days, the BOD levels of all samples generally increased as bacteria broke down more organic matter over time.
International Journal of Mathematics and Statistics Invention (IJMSI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJMSI publishes research articles and reviews within the whole field Mathematics and Statistics, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
This document presents a project proposal for analyzing the biological components of groundwater in selected industrial and residential areas in Chinhoyi, Zimbabwe. It introduces the significance of groundwater and issues of contamination from human and other activities. Key water quality parameters that will be analyzed include microbiological (total coliform, E. coli), chemical (COD, BOD), and physical properties. Methodologies for sample collection, handling, and analyzing COD, BOD and total coliform are described, including calculations. Health risks of coliform contamination are also discussed. The analysis will assess water quality and identify sources of pollution to inform water management.
Nitrogen Use & Climate Change Mitigation - Liz Baggs (University of Aberdeen)Farming Futures
The document discusses nitrous oxide (N2O) emissions from soil and opportunities for mitigation. It notes that N2O concentrations have increased 20% over the last 100 years. Soil is a major source, producing 10.2 Tg N per year. The primary controls of N2O production from soil are nitrogen application, aeration/water content, temperature, and available carbon. Understanding these controls is key for modeling emissions and developing mitigation strategies like improved fertilizer management and planting techniques. New opportunities for mitigation may include manipulating rhizosphere microbes and chemistry to maximize N2O reduction to nitrogen gas.
1. The document describes an experiment to determine the biochemical oxygen demand (BOD) of various water samples using data loggers.
2. Samples of pond water, drain water, distilled water, aquarium water, and pipe water were tested by recording the initial and final dissolved oxygen concentrations over 5 days.
3. The BOD value, which indicates how polluted the water is, was calculated using the difference between initial and final dissolved oxygen levels. The higher the BOD value, the more polluted the water sample.
This document discusses dissolved oxygen (DO) in aquatic environments. It provides background on DO including its importance to aquatic organisms and factors that affect its concentration. Methods are described for measuring DO directly in water or from samples. Key points include:
- DO is vital for aquatic life and its concentration indicates water quality. Higher DO supports more diversity.
- Factors like temperature, aquatic plants, decaying matter, and human activities influence DO levels.
- DO can be measured on site or from stored samples. Proper collection and storage methods are outlined.
This study analyzed the relationship between land use and water quality in 4 lakes near West Milford, NJ: Greenwood Lake (heavily residential), Upper Greenwood Lake (also heavily residential), Wawayanda Lake (forested and protected), and Surprise Lake (remote and glacial, used as a control). Water samples from each lake were tested for dissolved oxygen, conductivity, pH, temperature, turbidity, phosphates, nitrates, trace metals, and bacteria. Results showed the residential lakes had higher levels of phosphates, nitrates, and some metals, likely due to runoff from septic systems and impervious surfaces. Buffer zones near lakes generally had the best water quality. The study suggests land use impacts water chemistry
Samples were collected from four stations along the Rhode Island coast with varying depths and nutrient inputs. The Providence River estuary station exhibited the highest mean concentrations of organic matter and chlorophyll a, while Rhode Island Sound exhibited the lowest. Concentrations differed significantly between stations. Additionally, chlorophyll a and organic matter concentrations in Rhode Island Sound and Block Island Sound were higher than values from other nearby studies. The abundance of these variables in sediments relates to primary production levels in the overlying waters.
The chemical investigation on water pollution of kurnool district by water qu...Avishkaarsgrowup
1) The document analyzes water quality parameters like pH, conductivity, turbidity, nutrients and heavy metals in drinking water samples from 10 locations in the Nandyal region of Kurnool district, India.
2) Testing found the pH, conductivity, fluoride and heavy metal levels were within WHO guidelines for most locations, but some had higher turbidity and nutrients like nitrates.
3) The highest levels of parameters like copper, iron and manganese were found in samples from locations like Maddur and Kowlur.
The document discusses the self-purification process of streams. It defines self-purification as the automatic purification of polluted water over time by the stream itself. The key factors that support self-purification are dilution, current, sedimentation, temperature, sunlight, oxidation, and reduction. As the polluted water travels downstream, it progresses through four zones: the degradation zone near the discharge, the active decomposition zone, the recovery zone where water quality improves, and finally the clear water zone where the stream returns to its natural state.
This document discusses measuring biochemical oxygen demand (BOD) to determine water quality. BOD measures the amount of dissolved oxygen needed by aerobic bacteria to decompose organic waste in water. Higher BOD means less dissolved oxygen is available for aquatic life. A student group measured BOD in two rivers near their university. One river contained polluted water with high BOD and few fish, while the other river had clean water with low BOD and many fish. The students took water samples from both rivers to study and compare their oxygen content in the lab.
Evaluation and and comparison of of water qualityparameters from from fresh ...Alexander Decker
This document summarizes a study that evaluated water quality parameters from freshwater streams and hand-dug wells in Isiokpo Community, Rivers State, Nigeria. Water samples from 6 streams and 4 wells were analyzed for physicochemical characteristics and heavy metal levels. The results showed that pH levels in both water sources were lower than national and international standards. Cobalt levels exceeded limits in 2 streams, and manganese levels exceeded limits in 3 wells. Overall, the surface water was determined to be suitable for drinking but the well water should be treated due to higher manganese levels, which can pose health risks with prolonged exposure. The study provides baseline water quality data for the community.
The document discusses how students from UPSI measured the biochemical oxygen demand (BOD) of different water samples, finding that drain water had the highest BOD level indicating it was most polluted while distilled water had the lowest. A high BOD means less dissolved oxygen is available for aquatic life since bacteria use it to break down organic waste. The experiment demonstrated how BOD testing can evaluate water quality and pollution levels.
Trace Metals Concentration in Shallow Well Water in Enugu Metropolispaperpublications3
Abstract: This work assesses the concentration of heavy metals in Enugu Municipal well-water considering the fact that some Enugu inhabitants depend on well-water as their major source of water supply. Water from twenty four (24) different hand dug wells from six locations were investigated for Zn, Cu, Pb, Mn, Cd, and Fe using Atomic Absorption Spectroscopy (AAS). The result of the study expressed as the means and standard deviations were compared to WHO and EU standards for drinking water, and it was found that well waters from Iva-Valley and Uwani areas suffer from Cd and Mn pollution. The remaining four locations (Emene, Asata, Abakpa Nike and Achara Layout) were all free from Cd and Mn pollution. Cu, Zn, Fe and Pb concentrations were either completely absent or below world threshold limits at all the locations.
Assessment of impact of climatic change on groundwater quality around igbokod...Alexander Decker
This document summarizes a study that assessed the impact of coastal saltwater on groundwater quality in Igbokoda, Nigeria. Hydrochemical analysis of 39 groundwater samples found higher concentrations of sodium and chloride ions compared to other ions, indicating influence from saltwater intrusion. While most ion concentrations met drinking water standards, iron and manganese exceeded guidelines in some samples. Ratios of ions like magnesium to calcium and chloride to bicarbonate suggested transformation of fresh groundwater to brackish water in parts of the aquifer due to saltwater mixing. The dominant groundwater type was characterized as sodium-chloride, reflecting saltwater influence, along with some calcium-bicarbonate freshwater sources.
1. Water sampling is the process of taking water samples for analysis to check water quality.
2. There are two main types of water sampling: grab sampling, which collects discrete samples at a point in time, and composite sampling, which mixes multiple grab samples.
3. The water sampling procedure involves identifying sampling points, collecting samples using proper containers and labels, and transporting samples to a laboratory for testing of various physical, chemical, and bacteriological parameters.
This document summarizes a university student's investigation into desalination and its brine waste. It provides background on desalination processes like reverse osmosis and multi-stage flash distillation. These produce brine waste that is more concentrated than seawater and can harm coastal ecosystems if discharged untreated. The document examines environmental impacts like altered ecosystems and erosion from brine discharge. It then evaluates potential solutions like precipitating silver chloride from brine or electrolyzing sodium chloride to produce useful byproducts. The student concludes electrolysis of sodium chloride is the best option as the gases produced could be sold to offset costs while lowering brine chlorine levels and fossil fuel use.
This document discusses standards and criteria for drinking water, irrigation water, and water used in industry. It defines that standards refer to definite levels of quality achieved, while criteria are properties used to judge quality. For drinking water, it lists chemical, physical, and biological characteristics that serve as criteria, such as dissolved oxygen, pH, turbidity, and coliform. For irrigation water, criteria mentioned include pH, salinity, sodium, and nutrients. Industry water criteria vary depending on use, such as feed water characteristics for boilers. The document also notes that countries have their own water quality standards that specify parameters, sampling methods, and analytical quality control.
J. Sequeira Ocean Acidification SoA ReviewJohn Sequeira
This document summarizes research on ocean acidification and its effects. It discusses how increased CO2 absorption by oceans leads to acidification, affecting calcium carbonate availability and organisms that use it in shells and skeletons. While most research focuses on single species responses, one study found increased calcification in coccolithophores during winter when pH is lowest, contradicting hypotheses. Experts agree ocean acidification due to CO2 emissions will continue for centuries and exceed past rates, but have less consensus on specific biogeochemical issues.
IRJET- Analysis of Physico Chemical Parameters of Underground Water Sample fr...IRJET Journal
This document analyzes the physico-chemical parameters of underground water samples from selected areas of Satna District in Madhya Pradesh, India. Water samples were collected from 9 locations and tested for various parameters including temperature, pH, alkalinity, hardness, TDS, EC, DO, BOD, and COD. The results found that most parameters were within permissible limits but the water quality was not suitable for drinking due to higher levels of certain parameters. While the water quality needs improvement, most parameters met groundwater quality standards. The analysis helps communicate the current water quality to citizens and policymakers.
The International Journal of Engineering and Science (IJES)theijes
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
This document discusses using advanced analytical chemistry and hydrogeological modeling to identify and quantify the relative risk of groundwater contamination. It outlines methods used including gas chromatography-mass spectrometry to detect over 70 chemicals and metals, as well as analyzing physical properties like pH, dissolved solids and oxygen levels. The methods have found elevated levels of arsenic, barium and other chemicals near gas drilling sites compared to non-drilling areas and historical levels. Further monitoring is needed over time to better understand contamination risks from drilling activities and improve practices.
This document summarizes a study that evaluated two water quality labs at the University of Arkansas to determine if there were significant differences in their measurement of nitrate concentrations in surface water samples. Standards with nitrate concentrations ranging from 0.01 to 10 mg/L NO3-N were tested in each lab to examine precision and accuracy. Environmental samples from streams and lakes across Arkansas were also tested to evaluate performance over a broad range of concentrations. The goal was to ensure the labs could accurately measure nitrate levels near thresholds important for algal growth in surface waters.
This document summarizes a study that compared the nitrate removal rates, efficiencies, and potential for pollution swapping of different organic carbon media in laboratory denitrification bioreactors. The media tested included lodgepole pine woodchips, cardboard, lodgepole pine needles, barley straw, and a soil control. Results showed nitrate removal was consistently over 99% for all media. However, when considering pollution swapping through the production of other nitrogen species and leaching of contaminants, removal efficiencies ranged from 67% to 95%. Phosphorus releases from the bioreactors exceeded thresholds for eutrophication. Greenhouse gas emissions were dominated by carbon dioxide and methane, with little nitrous oxide. Compar
Nitrous Oxide Emissions from aLarge, Impounded River The Oh.docxcurwenmichaela
Nitrous Oxide Emissions from a
Large, Impounded River: The Ohio
River
J . J . B E A U L I E U , * W . D . S H U S T E R , A N D
J . A . R E B H O L Z
National Risk Management Research Laboratory, Office of
Research and Development, U.S. Environmental Protection
Agency, 26 West Martin Luther King Drive, Cincinnati,
Ohio 45268
Received May 17, 2010. Revised manuscript received
August 9, 2010. Accepted August 10, 2010.
Models suggest that microbial activity in streams and rivers
is a globally significant source of anthropogenic nitrous oxide
(N2O), a potent greenhouse gas, and the leading cause of
stratospheric ozone destruction. However, model estimates of
N2O emissions are poorly constrained due to a lack of
direct measurements of microbial N2O production and consequent
emissions, particularly from large rivers. We report the first
N2O budget for a large, nitrogen enriched river, based on direct
measurements of N2O emissions from the water surface and
N2O production in the sediments and water column. Maximum
N2O emissions occurred downstream from Cincinnati, Ohio,
a major urban center on the river, due to direct inputs of N2O
from wastewater treatment plant effluent and higher rates
of in situ production. Microbial activity in the water column
and sediments was a source of N2O, and water column production
rates were nearly double those of the sediments. Emissions
exhibited strong seasonality with the highest rates observed
during the summer and lowest during the winter. Our results
indicate N2O dynamics in large temperate rivers may be
characterized by strong seasonal cycles and production in the
pelagic zone.
Introduction
Atmospheric concentrations of nitrous oxide (N2O), a potent
greenhouse gas with a global warming potential nearly 300
times that of carbon dioxide (1) and the leading cause of
stratospheric ozone destruction (2), are rising by 0.26% per
year (1). The primary anthropogenic source of N2O is the
biological conversion of nitrogen (N) to N2O in terrestrial
and aquatic ecosystems (3). Nitrous oxide production in
agricultural soils has been well studied with over 1000
published measurements and is a relatively well constrained
component of the global N2O budget (4). Anthropogenic N2O
production in rivers which receive anthropogenic N in runoff
and sewage inputs may be as large as 1.7 Tg N y-1 or 25%
of the global N2O budget (1, 5). However, this estimate is
uncertain, partially due to a lack of N2O emission measure-
ments from large rivers made over annual temporal scales.
In this study we measured the production and emission
of N2O from the Markland Pool of the Ohio River, which is
ranked by annual discharge as the third largest river in North
America. Nitrous oxide emission rates were measured
biweekly for 13 months at one site and along a transect of
the pool during two successive summer surveys. We quanti-
fied several sources of N2O to the river including wastewater
treatment plant (WWTP) effluent and microbial N2O pro-
...
The document summarizes research on the ozonolysis of 2,3-dimethyl-2-butene. Ozonolysis of volatile organic compounds produces Criegee intermediates that have short lifetimes and undergo reactions or rearrangements. The research used cavity ring-down spectroscopy to analyze the spectra of products from ozonolysis experiments with and without scavengers like hexafluoroacetone and sulfur dioxide. Scavenging revealed additional spectral contributions that could be from secondary organic aerosols or rearrangement products. Measuring the sulfur dioxide consumed during scavenging allowed indirectly measuring Criegee intermediate yields, which increased with pressure. Future work aims to further study Criegee intermediate yields and identify reaction
This document discusses dissolved oxygen (DO) in aquatic environments. It provides background on DO including its importance to aquatic organisms and factors that affect its concentration. Methods are described for measuring DO directly in water or from samples. Key points include:
- DO is vital for aquatic life and its concentration indicates water quality. Higher DO supports more diversity.
- Factors like temperature, aquatic plants, decaying matter, and human activities influence DO levels.
- DO can be measured on site or from stored samples. Proper collection and storage methods are outlined.
This study analyzed the relationship between land use and water quality in 4 lakes near West Milford, NJ: Greenwood Lake (heavily residential), Upper Greenwood Lake (also heavily residential), Wawayanda Lake (forested and protected), and Surprise Lake (remote and glacial, used as a control). Water samples from each lake were tested for dissolved oxygen, conductivity, pH, temperature, turbidity, phosphates, nitrates, trace metals, and bacteria. Results showed the residential lakes had higher levels of phosphates, nitrates, and some metals, likely due to runoff from septic systems and impervious surfaces. Buffer zones near lakes generally had the best water quality. The study suggests land use impacts water chemistry
Samples were collected from four stations along the Rhode Island coast with varying depths and nutrient inputs. The Providence River estuary station exhibited the highest mean concentrations of organic matter and chlorophyll a, while Rhode Island Sound exhibited the lowest. Concentrations differed significantly between stations. Additionally, chlorophyll a and organic matter concentrations in Rhode Island Sound and Block Island Sound were higher than values from other nearby studies. The abundance of these variables in sediments relates to primary production levels in the overlying waters.
The chemical investigation on water pollution of kurnool district by water qu...Avishkaarsgrowup
1) The document analyzes water quality parameters like pH, conductivity, turbidity, nutrients and heavy metals in drinking water samples from 10 locations in the Nandyal region of Kurnool district, India.
2) Testing found the pH, conductivity, fluoride and heavy metal levels were within WHO guidelines for most locations, but some had higher turbidity and nutrients like nitrates.
3) The highest levels of parameters like copper, iron and manganese were found in samples from locations like Maddur and Kowlur.
The document discusses the self-purification process of streams. It defines self-purification as the automatic purification of polluted water over time by the stream itself. The key factors that support self-purification are dilution, current, sedimentation, temperature, sunlight, oxidation, and reduction. As the polluted water travels downstream, it progresses through four zones: the degradation zone near the discharge, the active decomposition zone, the recovery zone where water quality improves, and finally the clear water zone where the stream returns to its natural state.
This document discusses measuring biochemical oxygen demand (BOD) to determine water quality. BOD measures the amount of dissolved oxygen needed by aerobic bacteria to decompose organic waste in water. Higher BOD means less dissolved oxygen is available for aquatic life. A student group measured BOD in two rivers near their university. One river contained polluted water with high BOD and few fish, while the other river had clean water with low BOD and many fish. The students took water samples from both rivers to study and compare their oxygen content in the lab.
Evaluation and and comparison of of water qualityparameters from from fresh ...Alexander Decker
This document summarizes a study that evaluated water quality parameters from freshwater streams and hand-dug wells in Isiokpo Community, Rivers State, Nigeria. Water samples from 6 streams and 4 wells were analyzed for physicochemical characteristics and heavy metal levels. The results showed that pH levels in both water sources were lower than national and international standards. Cobalt levels exceeded limits in 2 streams, and manganese levels exceeded limits in 3 wells. Overall, the surface water was determined to be suitable for drinking but the well water should be treated due to higher manganese levels, which can pose health risks with prolonged exposure. The study provides baseline water quality data for the community.
The document discusses how students from UPSI measured the biochemical oxygen demand (BOD) of different water samples, finding that drain water had the highest BOD level indicating it was most polluted while distilled water had the lowest. A high BOD means less dissolved oxygen is available for aquatic life since bacteria use it to break down organic waste. The experiment demonstrated how BOD testing can evaluate water quality and pollution levels.
Trace Metals Concentration in Shallow Well Water in Enugu Metropolispaperpublications3
Abstract: This work assesses the concentration of heavy metals in Enugu Municipal well-water considering the fact that some Enugu inhabitants depend on well-water as their major source of water supply. Water from twenty four (24) different hand dug wells from six locations were investigated for Zn, Cu, Pb, Mn, Cd, and Fe using Atomic Absorption Spectroscopy (AAS). The result of the study expressed as the means and standard deviations were compared to WHO and EU standards for drinking water, and it was found that well waters from Iva-Valley and Uwani areas suffer from Cd and Mn pollution. The remaining four locations (Emene, Asata, Abakpa Nike and Achara Layout) were all free from Cd and Mn pollution. Cu, Zn, Fe and Pb concentrations were either completely absent or below world threshold limits at all the locations.
Assessment of impact of climatic change on groundwater quality around igbokod...Alexander Decker
This document summarizes a study that assessed the impact of coastal saltwater on groundwater quality in Igbokoda, Nigeria. Hydrochemical analysis of 39 groundwater samples found higher concentrations of sodium and chloride ions compared to other ions, indicating influence from saltwater intrusion. While most ion concentrations met drinking water standards, iron and manganese exceeded guidelines in some samples. Ratios of ions like magnesium to calcium and chloride to bicarbonate suggested transformation of fresh groundwater to brackish water in parts of the aquifer due to saltwater mixing. The dominant groundwater type was characterized as sodium-chloride, reflecting saltwater influence, along with some calcium-bicarbonate freshwater sources.
1. Water sampling is the process of taking water samples for analysis to check water quality.
2. There are two main types of water sampling: grab sampling, which collects discrete samples at a point in time, and composite sampling, which mixes multiple grab samples.
3. The water sampling procedure involves identifying sampling points, collecting samples using proper containers and labels, and transporting samples to a laboratory for testing of various physical, chemical, and bacteriological parameters.
This document summarizes a university student's investigation into desalination and its brine waste. It provides background on desalination processes like reverse osmosis and multi-stage flash distillation. These produce brine waste that is more concentrated than seawater and can harm coastal ecosystems if discharged untreated. The document examines environmental impacts like altered ecosystems and erosion from brine discharge. It then evaluates potential solutions like precipitating silver chloride from brine or electrolyzing sodium chloride to produce useful byproducts. The student concludes electrolysis of sodium chloride is the best option as the gases produced could be sold to offset costs while lowering brine chlorine levels and fossil fuel use.
This document discusses standards and criteria for drinking water, irrigation water, and water used in industry. It defines that standards refer to definite levels of quality achieved, while criteria are properties used to judge quality. For drinking water, it lists chemical, physical, and biological characteristics that serve as criteria, such as dissolved oxygen, pH, turbidity, and coliform. For irrigation water, criteria mentioned include pH, salinity, sodium, and nutrients. Industry water criteria vary depending on use, such as feed water characteristics for boilers. The document also notes that countries have their own water quality standards that specify parameters, sampling methods, and analytical quality control.
J. Sequeira Ocean Acidification SoA ReviewJohn Sequeira
This document summarizes research on ocean acidification and its effects. It discusses how increased CO2 absorption by oceans leads to acidification, affecting calcium carbonate availability and organisms that use it in shells and skeletons. While most research focuses on single species responses, one study found increased calcification in coccolithophores during winter when pH is lowest, contradicting hypotheses. Experts agree ocean acidification due to CO2 emissions will continue for centuries and exceed past rates, but have less consensus on specific biogeochemical issues.
IRJET- Analysis of Physico Chemical Parameters of Underground Water Sample fr...IRJET Journal
This document analyzes the physico-chemical parameters of underground water samples from selected areas of Satna District in Madhya Pradesh, India. Water samples were collected from 9 locations and tested for various parameters including temperature, pH, alkalinity, hardness, TDS, EC, DO, BOD, and COD. The results found that most parameters were within permissible limits but the water quality was not suitable for drinking due to higher levels of certain parameters. While the water quality needs improvement, most parameters met groundwater quality standards. The analysis helps communicate the current water quality to citizens and policymakers.
The International Journal of Engineering and Science (IJES)theijes
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
This document discusses using advanced analytical chemistry and hydrogeological modeling to identify and quantify the relative risk of groundwater contamination. It outlines methods used including gas chromatography-mass spectrometry to detect over 70 chemicals and metals, as well as analyzing physical properties like pH, dissolved solids and oxygen levels. The methods have found elevated levels of arsenic, barium and other chemicals near gas drilling sites compared to non-drilling areas and historical levels. Further monitoring is needed over time to better understand contamination risks from drilling activities and improve practices.
This document summarizes a study that evaluated two water quality labs at the University of Arkansas to determine if there were significant differences in their measurement of nitrate concentrations in surface water samples. Standards with nitrate concentrations ranging from 0.01 to 10 mg/L NO3-N were tested in each lab to examine precision and accuracy. Environmental samples from streams and lakes across Arkansas were also tested to evaluate performance over a broad range of concentrations. The goal was to ensure the labs could accurately measure nitrate levels near thresholds important for algal growth in surface waters.
This document summarizes a study that compared the nitrate removal rates, efficiencies, and potential for pollution swapping of different organic carbon media in laboratory denitrification bioreactors. The media tested included lodgepole pine woodchips, cardboard, lodgepole pine needles, barley straw, and a soil control. Results showed nitrate removal was consistently over 99% for all media. However, when considering pollution swapping through the production of other nitrogen species and leaching of contaminants, removal efficiencies ranged from 67% to 95%. Phosphorus releases from the bioreactors exceeded thresholds for eutrophication. Greenhouse gas emissions were dominated by carbon dioxide and methane, with little nitrous oxide. Compar
Nitrous Oxide Emissions from aLarge, Impounded River The Oh.docxcurwenmichaela
Nitrous Oxide Emissions from a
Large, Impounded River: The Ohio
River
J . J . B E A U L I E U , * W . D . S H U S T E R , A N D
J . A . R E B H O L Z
National Risk Management Research Laboratory, Office of
Research and Development, U.S. Environmental Protection
Agency, 26 West Martin Luther King Drive, Cincinnati,
Ohio 45268
Received May 17, 2010. Revised manuscript received
August 9, 2010. Accepted August 10, 2010.
Models suggest that microbial activity in streams and rivers
is a globally significant source of anthropogenic nitrous oxide
(N2O), a potent greenhouse gas, and the leading cause of
stratospheric ozone destruction. However, model estimates of
N2O emissions are poorly constrained due to a lack of
direct measurements of microbial N2O production and consequent
emissions, particularly from large rivers. We report the first
N2O budget for a large, nitrogen enriched river, based on direct
measurements of N2O emissions from the water surface and
N2O production in the sediments and water column. Maximum
N2O emissions occurred downstream from Cincinnati, Ohio,
a major urban center on the river, due to direct inputs of N2O
from wastewater treatment plant effluent and higher rates
of in situ production. Microbial activity in the water column
and sediments was a source of N2O, and water column production
rates were nearly double those of the sediments. Emissions
exhibited strong seasonality with the highest rates observed
during the summer and lowest during the winter. Our results
indicate N2O dynamics in large temperate rivers may be
characterized by strong seasonal cycles and production in the
pelagic zone.
Introduction
Atmospheric concentrations of nitrous oxide (N2O), a potent
greenhouse gas with a global warming potential nearly 300
times that of carbon dioxide (1) and the leading cause of
stratospheric ozone destruction (2), are rising by 0.26% per
year (1). The primary anthropogenic source of N2O is the
biological conversion of nitrogen (N) to N2O in terrestrial
and aquatic ecosystems (3). Nitrous oxide production in
agricultural soils has been well studied with over 1000
published measurements and is a relatively well constrained
component of the global N2O budget (4). Anthropogenic N2O
production in rivers which receive anthropogenic N in runoff
and sewage inputs may be as large as 1.7 Tg N y-1 or 25%
of the global N2O budget (1, 5). However, this estimate is
uncertain, partially due to a lack of N2O emission measure-
ments from large rivers made over annual temporal scales.
In this study we measured the production and emission
of N2O from the Markland Pool of the Ohio River, which is
ranked by annual discharge as the third largest river in North
America. Nitrous oxide emission rates were measured
biweekly for 13 months at one site and along a transect of
the pool during two successive summer surveys. We quanti-
fied several sources of N2O to the river including wastewater
treatment plant (WWTP) effluent and microbial N2O pro-
...
The document summarizes research on the ozonolysis of 2,3-dimethyl-2-butene. Ozonolysis of volatile organic compounds produces Criegee intermediates that have short lifetimes and undergo reactions or rearrangements. The research used cavity ring-down spectroscopy to analyze the spectra of products from ozonolysis experiments with and without scavengers like hexafluoroacetone and sulfur dioxide. Scavenging revealed additional spectral contributions that could be from secondary organic aerosols or rearrangement products. Measuring the sulfur dioxide consumed during scavenging allowed indirectly measuring Criegee intermediate yields, which increased with pressure. Future work aims to further study Criegee intermediate yields and identify reaction
This document summarizes research on using sewage sludge in engineered dry covers to remediate sulphide mine tailings. It describes six research papers that evaluated applying sewage sludge as a sealing layer, vegetation substrate, and in combination with fly ash in pilot and field-scale experiments. The research found that a sewage sludge sealing layer was effective at preventing oxygen diffusion but degraded over 8 years, releasing constituents. Applying sludge as a vegetation substrate released nitrate that oxidized pyrite, while sludge-borne metals accumulated in tailings over 2-6 years. Combining sludge and fly ash prevented oxygen diffusion and trapped metals in the fly ash layer.
Isotope hydrology uses stable and radioactive isotopes as tracers to study hydrological processes. Stable isotopes of oxygen (18O) and hydrogen (deuterium) are fractionated during evaporation and condensation, allowing precipitation to be distinguished from evaporated waters. Global and local meteoric water lines relate the 18O and deuterium compositions in precipitation. Radioactive isotopes like tritium (3H), with a half-life of 12.3 years, and its daughter product helium-3 (3He) are used to directly date groundwaters up to 55 years old. Beyond this, radiocarbon dating is applied to date waters from 300 to 55,000 years before present.
Groundwater and soil pollution with nitrate nitrogen by land disposal of wastewater, and a trial measure against the issues.
Tomio Suzuki (Non Profit Organization, Institute of Ecological Engineering, Japan)
Yutaro Anzai (Shinshu-University, Japan)
Akito Matsumoto (Shinshu-University, Japan)
Soma Sekhar Sriadibhatla presented on the effects of increasing carbon dioxide levels in the environment and methods of sequestering carbon dioxide. The presentation discussed how rising CO2 levels are leading to global warming and ocean acidification. Testing of water samples from Visakhapatnam, India found decreasing pH levels and carbonate ion concentrations over time, indicating ongoing ocean acidification. The presentation proposed carbon dioxide sequestration techniques including reversible adsorption and discussed using captured CO2 for commercial purposes like enhanced oil recovery. It concluded more must be done to regulate CO2 emissions and deal with issues like global warming and ocean acidification.
This presentation focuses, how carbon dioxide plays dirty role in Ocean Acidification and Global Warming. I have analyzed data and presented it with some real samples collected from Visakhapatnam, India. Thank you!
This document summarizes research on the reduction of nitrate leaching under conservation tillage. The research was conducted at a micro-catchment scale in Michigan and compared conventional tillage (CT) to no-till (NT). Automated water sampling of tile drainage was used to measure nitrate loads. Soil samples were also taken to analyze health and nitrogen levels. Results showed that NT had lower nitrate loads in soybean years and similar loads as CT in corn years. Soil health indicators like respiration and nitrogen levels were higher under NT, indicating better nutrient retention and reduced leaching compared to CT.
"INVESTIGATION STUDY OF HEAVY METALS POLLUTION IN SOIL AND WATER IN AND AROUN...IRJET Journal
This document summarizes a study investigating heavy metal pollution in soil and water samples collected from Avaragolla village in Davangere District, Karnataka, India. Soil and water samples were collected from 8 directions around the village in May and June. Atomic absorption spectrophotometry was used to measure concentrations of cadmium, chromium, copper, zinc, and lead in the samples. On average, zinc had the highest concentration in soil and water followed by lead, chromium, copper, and cadmium. All sample concentrations were within WHO and agricultural standards. Geoaccumulation, contamination factor, and pollution load indices indicated the soil was uncontaminated with less contamination. Agricultural activities and waste disposal were likely responsible for
woodchip bioreactots for nitrate removal in agricultural land drainageMEHRAJ U DIN DAR
Wood chip bioreactors can be used to remove nitrate from agricultural drainage water. They work by routing drainage water through trenches filled with wood chips that provide carbon as a food source for denitrifying bacteria. These bacteria convert nitrate into harmless nitrogen gas. Key factors that affect the performance of bioreactors include hydraulic retention time, influent nitrate concentration, temperature, and available carbon sources within the wood chips. Pilot and field-scale studies have shown that bioreactors can effectively remove 30-80% of nitrate from drainage areas of 30-120 acres. While requiring some management, bioreactors provide a cost-effective solution to nitrate contamination compared to other options such as wetlands or changing fertil
This document describes research on nitrogen transformations in aquaponic systems. The objectives were to quantify the impact of physical and chemical variables on nitrogen transformations, evaluate transformations of different nitrogen forms under various conditions, examine ecologically important species, and investigate greenhouse gas emissions. Experiments were conducted with different hydraulic loading rates, pH levels, plant species, and sediment draining frequencies. The results showed that nitrate accumulation was affected by loading rate, pH, and plant uptake rate, while nitrogen loss occurred through denitrification. Microbial analyses provided insight into nitrifying bacteria populations and their role in the nitrogen cycle.
Influence of hydrological connectivity of riverine wetlandso.docxjaggernaoma
Influence of hydrological connectivity of riverine wetlands
on nitrogen removal via denitrification
E. Racchetti • Marco Bartoli • E. Soana •
D. Longhi • R. R. Christian • M. Pinardi •
P. Viaroli
Received: 30 April 2009 / Accepted: 25 May 2010 / Published online: 17 June 2010
� Springer Science+Business Media B.V. 2010
Abstract Wetland ecosystems in agricultural areas
often become progressively more isolated from main
water bodies. Stagnation favors the accumulation of
organic matter as the supply of electron acceptors
with water renewal is limited. In this context it is
expected that nitrogen recycling prevails over nitro-
gen dissipation. To test this hypothesis, denitrifica-
tion rates, fluxes of dissolved oxygen (SOD),
inorganic carbon (DIC) and nitrogen and sediment
features were measured in winter and summer 2007
on 22 shallow riverine wetlands in the Po River Plain
(Northern Italy). Fluxes were determined from incu-
bations of intact cores by measurement of concen-
tration changes or isotope pairing in the case of
denitrification. Sampled sites were eutrophic to
hypertrophic; 10 were connected and 12 were
isolated from the adjacent rivers, resulting in large
differences in nitrate concentrations in the water
column (from \5 to 1,133 lM). Benthic metabolism
and denitrification rates were investigated by two
overarching factors: season and hydrological
connectivity. SOD and DIC fluxes resulted in respi-
ratory quotients greater than one at most sampling
sites. Sediment respiration was coupled to both
ammonium efflux, which increased from winter
to summer, and nitrate consumption, with higher
rates in river-connected wetlands. Denitrification
rates measured in river-connected wetlands (35–
1,888 lmol N m-2 h-1) were up to two orders of
magnitude higher than rates measured in isolated
wetlands (2–231 lmol N m-2 h-1), suggesting a
strong regulation of the process by nitrate availabil-
ity. These rates were also significantly higher in
summer (9–1,888 lmol N m-2 h-1) than in winter
(2–365 lmol N m-2 h-1). Denitrification supported
by water column nitrate (DW) accounted for 60–
100% of total denitrification (Dtot); denitrification
coupled to nitrification (DN) was probably controlled
by limited oxygen availability within sediments.
Denitrification efficiency, calculated as the ratio
between N removal via denitrification and N regen-
eration, and the relative role of denitrification for
organic matter oxidation, were high in connected
wetlands but not in isolated sites. This study confirms
the importance of restoring hydraulic connectivity of
riverine wetlands for the maintenance of important
biogeochemical functions such as nitrogen removal
via denitrification.
Keywords Denitrification � Benthic respiration �
N-regeneration � Hydrological connectivity �
Riverine wetlands
E. Racchetti � M. Bartoli (&) � E. Soana �
D. Longhi � M. Pinardi � P. Viaroli
Department of Environmental Sciences, Univers.
This document discusses carbon fluxes along the land-water continuum from land to sea. It summarizes previous literature on carbon cycling in inland waters like lakes and rivers. Some key points made in the document include:
- Inland waters cover a small percentage of the Earth's surface but play an important role in the global carbon cycle as sinks and sources of carbon.
- Dissolved organic carbon imported from surrounding landscapes makes up a large portion of the carbon in many inland waters.
- Carbon is transformed in inland waters through processes like flocculation, microbial mineralization, and photochemical mineralization.
- Sediment burial is an important fate of carbon in inland waters, with flocculation of dissolved organic carbon accounting
This document summarizes a study on the effects of shear stress and oxygen levels on the toxicity of contaminated sediment and overlying water. Gust chambers were used to subject sediment cores to different shear stresses and oxygen concentrations. Testing found that oxygen had a greater effect than shear stress on the release of metals like copper from sediments. Under oxygenated conditions, more metal sulfides dissolved, releasing metals into the water. While toxicity was low under experimental conditions, substantial metal release occurred even at low shear stresses. The presence of oxygen significantly increased metal release from sediments.
Monitored Natural Attenuation Of Groundwater NitrateVicMadrid
The document summarizes a presentation about using various analytical tools and methods to characterize natural attenuation of groundwater nitrate contamination through denitrification. Specifically, it discusses analyzing nitrate isotopic composition and measuring excess nitrogen in groundwater to identify denitrification and determine its rate and extent. It provides an example case study of using these methods to monitor natural attenuation at a contaminated site.
This study measured greenhouse gas (GHG) emissions and concentrations at a wastewater treatment plant (WWTP) that was upgraded to use integrated fixed film activated sludge biological nitrogen removal (IFAS BNR). The study found:
1) Nitrous oxide (N2O) gas emissions were highest from the re-aeration zone but dissolved N2O concentrations were high in the aerated and post-anoxic zones.
2) Methane (CH4) gas emissions were greatest from the aerated and re-aeration zones, but dissolved CH4 concentrations were highest in inflow water, suggesting CH4 is produced upstream and stripped out in aerated zones.
3)
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Winkler's method is used to determine the dissolved oxygen (DO) content of water. It involves adding potassium iodide and manganese sulfate to the water sample, which oxidizes to form iodine in the presence of oxygen. The liberated iodine is then titrated with sodium thiosulfate using starch indicator. The amount of thiosulfate used corresponds to the amount of dissolved oxygen originally present. Biological oxygen demand (BOD) and chemical oxygen demand (COD) are also described as important water quality parameters. BOD measures the amount of oxygen used by microorganisms to break down organic matter over 5 days. COD determines the oxygen required to chemically oxidize organic compounds and is generally
Similar to A simple method for quantifying dissolved nitrous (20)
ESR spectroscopy in liquid food and beverages.pptxPRIYANKA PATEL
With increasing population, people need to rely on packaged food stuffs. Packaging of food materials requires the preservation of food. There are various methods for the treatment of food to preserve them and irradiation treatment of food is one of them. It is the most common and the most harmless method for the food preservation as it does not alter the necessary micronutrients of food materials. Although irradiated food doesn’t cause any harm to the human health but still the quality assessment of food is required to provide consumers with necessary information about the food. ESR spectroscopy is the most sophisticated way to investigate the quality of the food and the free radicals induced during the processing of the food. ESR spin trapping technique is useful for the detection of highly unstable radicals in the food. The antioxidant capability of liquid food and beverages in mainly performed by spin trapping technique.
Phenomics assisted breeding in crop improvementIshaGoswami9
As the population is increasing and will reach about 9 billion upto 2050. Also due to climate change, it is difficult to meet the food requirement of such a large population. Facing the challenges presented by resource shortages, climate
change, and increasing global population, crop yield and quality need to be improved in a sustainable way over the coming decades. Genetic improvement by breeding is the best way to increase crop productivity. With the rapid progression of functional
genomics, an increasing number of crop genomes have been sequenced and dozens of genes influencing key agronomic traits have been identified. However, current genome sequence information has not been adequately exploited for understanding
the complex characteristics of multiple gene, owing to a lack of crop phenotypic data. Efficient, automatic, and accurate technologies and platforms that can capture phenotypic data that can
be linked to genomics information for crop improvement at all growth stages have become as important as genotyping. Thus,
high-throughput phenotyping has become the major bottleneck restricting crop breeding. Plant phenomics has been defined as the high-throughput, accurate acquisition and analysis of multi-dimensional phenotypes
during crop growing stages at the organism level, including the cell, tissue, organ, individual plant, plot, and field levels. With the rapid development of novel sensors, imaging technology,
and analysis methods, numerous infrastructure platforms have been developed for phenotyping.
ESA/ACT Science Coffee: Diego Blas - Gravitational wave detection with orbita...Advanced-Concepts-Team
Presentation in the Science Coffee of the Advanced Concepts Team of the European Space Agency on the 07.06.2024.
Speaker: Diego Blas (IFAE/ICREA)
Title: Gravitational wave detection with orbital motion of Moon and artificial
Abstract:
In this talk I will describe some recent ideas to find gravitational waves from supermassive black holes or of primordial origin by studying their secular effect on the orbital motion of the Moon or satellites that are laser ranged.
The technology uses reclaimed CO₂ as the dyeing medium in a closed loop process. When pressurized, CO₂ becomes supercritical (SC-CO₂). In this state CO₂ has a very high solvent power, allowing the dye to dissolve easily.
When I was asked to give a companion lecture in support of ‘The Philosophy of Science’ (https://shorturl.at/4pUXz) I decided not to walk through the detail of the many methodologies in order of use. Instead, I chose to employ a long standing, and ongoing, scientific development as an exemplar. And so, I chose the ever evolving story of Thermodynamics as a scientific investigation at its best.
Conducted over a period of >200 years, Thermodynamics R&D, and application, benefitted from the highest levels of professionalism, collaboration, and technical thoroughness. New layers of application, methodology, and practice were made possible by the progressive advance of technology. In turn, this has seen measurement and modelling accuracy continually improved at a micro and macro level.
Perhaps most importantly, Thermodynamics rapidly became a primary tool in the advance of applied science/engineering/technology, spanning micro-tech, to aerospace and cosmology. I can think of no better a story to illustrate the breadth of scientific methodologies and applications at their best.
The binding of cosmological structures by massless topological defectsSérgio Sacani
Assuming spherical symmetry and weak field, it is shown that if one solves the Poisson equation or the Einstein field
equations sourced by a topological defect, i.e. a singularity of a very specific form, the result is a localized gravitational
field capable of driving flat rotation (i.e. Keplerian circular orbits at a constant speed for all radii) of test masses on a thin
spherical shell without any underlying mass. Moreover, a large-scale structure which exploits this solution by assembling
concentrically a number of such topological defects can establish a flat stellar or galactic rotation curve, and can also deflect
light in the same manner as an equipotential (isothermal) sphere. Thus, the need for dark matter or modified gravity theory is
mitigated, at least in part.
Describing and Interpreting an Immersive Learning Case with the Immersion Cub...Leonel Morgado
Current descriptions of immersive learning cases are often difficult or impossible to compare. This is due to a myriad of different options on what details to include, which aspects are relevant, and on the descriptive approaches employed. Also, these aspects often combine very specific details with more general guidelines or indicate intents and rationales without clarifying their implementation. In this paper we provide a method to describe immersive learning cases that is structured to enable comparisons, yet flexible enough to allow researchers and practitioners to decide which aspects to include. This method leverages a taxonomy that classifies educational aspects at three levels (uses, practices, and strategies) and then utilizes two frameworks, the Immersive Learning Brain and the Immersion Cube, to enable a structured description and interpretation of immersive learning cases. The method is then demonstrated on a published immersive learning case on training for wind turbine maintenance using virtual reality. Applying the method results in a structured artifact, the Immersive Learning Case Sheet, that tags the case with its proximal uses, practices, and strategies, and refines the free text case description to ensure that matching details are included. This contribution is thus a case description method in support of future comparative research of immersive learning cases. We then discuss how the resulting description and interpretation can be leveraged to change immersion learning cases, by enriching them (considering low-effort changes or additions) or innovating (exploring more challenging avenues of transformation). The method holds significant promise to support better-grounded research in immersive learning.
Authoring a personal GPT for your research and practice: How we created the Q...Leonel Morgado
Thematic analysis in qualitative research is a time-consuming and systematic task, typically done using teams. Team members must ground their activities on common understandings of the major concepts underlying the thematic analysis, and define criteria for its development. However, conceptual misunderstandings, equivocations, and lack of adherence to criteria are challenges to the quality and speed of this process. Given the distributed and uncertain nature of this process, we wondered if the tasks in thematic analysis could be supported by readily available artificial intelligence chatbots. Our early efforts point to potential benefits: not just saving time in the coding process but better adherence to criteria and grounding, by increasing triangulation between humans and artificial intelligence. This tutorial will provide a description and demonstration of the process we followed, as two academic researchers, to develop a custom ChatGPT to assist with qualitative coding in the thematic data analysis process of immersive learning accounts in a survey of the academic literature: QUAL-E Immersive Learning Thematic Analysis Helper. In the hands-on time, participants will try out QUAL-E and develop their ideas for their own qualitative coding ChatGPT. Participants that have the paid ChatGPT Plus subscription can create a draft of their assistants. The organizers will provide course materials and slide deck that participants will be able to utilize to continue development of their custom GPT. The paid subscription to ChatGPT Plus is not required to participate in this workshop, just for trying out personal GPTs during it.
ESPP presentation to EU Waste Water Network, 4th June 2024 “EU policies driving nutrient removal and recycling
and the revised UWWTD (Urban Waste Water Treatment Directive)”
EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...Sérgio Sacani
Context. With a mass exceeding several 104 M⊙ and a rich and dense population of massive stars, supermassive young star clusters
represent the most massive star-forming environment that is dominated by the feedback from massive stars and gravitational interactions
among stars.
Aims. In this paper we present the Extended Westerlund 1 and 2 Open Clusters Survey (EWOCS) project, which aims to investigate
the influence of the starburst environment on the formation of stars and planets, and on the evolution of both low and high mass stars.
The primary targets of this project are Westerlund 1 and 2, the closest supermassive star clusters to the Sun.
Methods. The project is based primarily on recent observations conducted with the Chandra and JWST observatories. Specifically,
the Chandra survey of Westerlund 1 consists of 36 new ACIS-I observations, nearly co-pointed, for a total exposure time of 1 Msec.
Additionally, we included 8 archival Chandra/ACIS-S observations. This paper presents the resulting catalog of X-ray sources within
and around Westerlund 1. Sources were detected by combining various existing methods, and photon extraction and source validation
were carried out using the ACIS-Extract software.
Results. The EWOCS X-ray catalog comprises 5963 validated sources out of the 9420 initially provided to ACIS-Extract, reaching a
photon flux threshold of approximately 2 × 10−8 photons cm−2
s
−1
. The X-ray sources exhibit a highly concentrated spatial distribution,
with 1075 sources located within the central 1 arcmin. We have successfully detected X-ray emissions from 126 out of the 166 known
massive stars of the cluster, and we have collected over 71 000 photons from the magnetar CXO J164710.20-455217.
The debris of the ‘last major merger’ is dynamically youngSérgio Sacani
The Milky Way’s (MW) inner stellar halo contains an [Fe/H]-rich component with highly eccentric orbits, often referred to as the
‘last major merger.’ Hypotheses for the origin of this component include Gaia-Sausage/Enceladus (GSE), where the progenitor
collided with the MW proto-disc 8–11 Gyr ago, and the Virgo Radial Merger (VRM), where the progenitor collided with the
MW disc within the last 3 Gyr. These two scenarios make different predictions about observable structure in local phase space,
because the morphology of debris depends on how long it has had to phase mix. The recently identified phase-space folds in Gaia
DR3 have positive caustic velocities, making them fundamentally different than the phase-mixed chevrons found in simulations
at late times. Roughly 20 per cent of the stars in the prograde local stellar halo are associated with the observed caustics. Based
on a simple phase-mixing model, the observed number of caustics are consistent with a merger that occurred 1–2 Gyr ago.
We also compare the observed phase-space distribution to FIRE-2 Latte simulations of GSE-like mergers, using a quantitative
measurement of phase mixing (2D causticality). The observed local phase-space distribution best matches the simulated data
1–2 Gyr after collision, and certainly not later than 3 Gyr. This is further evidence that the progenitor of the ‘last major merger’
did not collide with the MW proto-disc at early times, as is thought for the GSE, but instead collided with the MW disc within
the last few Gyr, consistent with the body of work surrounding the VRM.
1. SHORT COMMUNICATION
A simple method for quantifying dissolved nitrous
oxide in tile drainage water
Jennifer D. Roper1
, David L. Burton1,3
, Ali Madani2
, and Glenn W. Stratton1
1
Department of Environmental Sciences, Dalhousie University, Truro, Nova Scotia, Canada B2N 5E3; and
2
Department of Engineering, Dalhousie University, Truro, Nova Scotia, Canada B2N 5E3.
Received 7 March 2012, accepted 6 November 2012.
Roper, J. D., Burton, D. L., Madani, A. and Stratton, G. W. 2013. A simple method for quantifying dissolved nitrous oxide
in tile drainage water. Can. J. Soil Sci. 93: 59Á64. It is often assumed that the N2O produced from nitrification and
denitrification in soil systems is lost primarily as a gas from the soil surface. However, the dissolution and eventual
degassing of N2O in water leaching through, and draining from, agricultural fields is also a significant loss pathway. The
quantification of this pathway of N2O loss has been limited by available methodologies for measuring dissolved gases in
drainage water. Here a simple method is presented, which allows for the collection of tile drainage water samples using
standard automated water sampling equipment that maintains the dissolved gases. Tile drainage water was collected in 1 L
ISCOTM
water sampling bottles outfitted with modified 10 mL volumetric pipettes. The pipettes provide a means of
reducing the water:atmosphere interface for water held within the pipette thus reducing the N2O exchange with the
atmosphere. The water samples are removed from the pipette using long slender needles attached to a 20-mL syringe,
drawing 5 mL of water from within the bulb of the pipette. The dissolved N2O in the water samples was measured by
headspace analysis using a gas chromatograph. A laboratory trial determined that retaining the water in the pipette bulbs
resulted reduced N2O degassing such that N2O concentration did not decrease significantly in the first 24 h after filling of
the bottle.
Key words: Dissolved gas measurement, nitrous oxide, drainage water, greenhouse gas
Roper, J. D., Burton, D. L., Madani, A. et Stratton, G. W. 2013. Simple me´ thode pour doser l’oxyde nitreux dissous dans
l’eau draine´ e par des tuiles. Can. J. Soil Sci. 93: 59Á64. On pre´ sume souvent que le N2O re´ sultant de la nitrification et de la
de´ nitrification dans le sol se perd essentiellement sous forme de gaz qui s’e´ chappe a` la surface du sol. Cependant, la
dissolution du N2O dans l’eau puis le de´ gazage de cette dernie` re quand elle s’infiltre dans le sol par lixiviation ou drainage
des champs agricoles peut aussi entraıˆner des pertes importantes de ce gaz. Jusqu’a` pre´ sent, les me´ thodes existantes qui
recueillent automatiquement les e´ chantillons d’eau servant a` doser le volume des gaz dissous dans l’eau de drainage
restreignaient la quantification de ces pertes. Les auteurs proposent une me´ thode simple permettant de recueillir l’eau
draine´ e par des tuiles avec du mate´ riel standard d’e´ chantillonnage automatique tout en re´ duisant les pertes de gaz dissous.
L’eau draine´ e est recueillie dans des bouteilles ISCOMC
d’un litre pourvue a` l’exte´ rieur d’une pipette volume´ trique de
10 mL modifie´ e. La pipette diminue l’interface entre l’eau qu’elle contient et l’atmosphe` re, ce qui re´ duit les e´ changes de
N2O. L’eau e´ chantillonne´ e est retire´ e de la pipette avec une longue aiguille fixe´ e a` une seringue de 20 mL. On pre´ le` ve ainsi
5 mL d’eau de l’ampoule de la pipette, puis on mesure la quantite´ de N2O dissous en analysant l’espace libre par
chromatographie gazeuse. Un essai en laboratoire a e´ tabli que garder l’eau dans l’ampoule de la pipette atte´ nue le de´ gazage
du N2O au point que la concentration de ce gaz ne diminue pas de manie` re significative durant les 24 heures qui suivent le
remplissage de la bouteille.
Mots cle´s: Doser le volume de gaz dissous, oxyde nitreux, l’eau draine´ e, gaz a` effet de serre
Studies of the fate of N in soil often assume that surface
flux emissions adequately estimate the soil N2O produc-
tion, overlooking emissions associated with water leach-
ing from the soil profile (van Bochove et al. 2001;
Grandy et al. 2006; Phillips 2007; Reay et al. 2009). To
fully quantify N2O emissions associated with agricul-
tural activities, an effort has to be made to measure
losses of dissolved N2O in water draining from
agricultural landscapes (Dowdell et al. 1979; Minami
and Fukushi 1984; Haag and Kaupenjohann 2001;
Reay et al. 2009). The degassing of N2O dissolved in
agricultural drainage water has been shown to contri-
bute to N2O emissions to the atmosphere (Reay et al.
2003) and may exceed surface emissions (Minamikawa
3
Corresponding author (e-mail: dburton@dal.ca).
Abbreviations: ECD, electron capture detector; HgCl2, mercuric
chloride; HS, headspace; K, solubility; NO3
-N, nitrate nitrogen;
NH4
-N, ammonium nitrogen; N2O, nitrous oxide; TCD, thermal
conductivity detector
Can. J. Soil Sci. (2013) 93: 59Á64 doi:10.4141/CJSS2012-021 59
Can.J.Soil.Sci.Downloadedfrompubs.aic.cabyUSPUNIVERSIDADEDESAOPAULOon02/16/15
Forpersonaluseonly.
2. et al. 2010). The N2O produced in the soil profile
dissolves in the soil solution and is transported to
subsurface and, where drainage systems are present, is
discharged to surface waters, where the N2O rapidly
degasses from solution and is released to the atmosphere
(Bowden and Bormann 1986; van Bochove et al. 2001;
Sawamoto et al. 2005). This indirect source of N2O
is easily overlooked, in that it is often temporally
and spatially displaced from the expected site of
production and its quantification is difficult (Hasegawa
et al. 2000).
Subsurface drainage is a management practice in
agricultural fields used to remove excess water from
the landscape in order to increase trafficability and
enhance crop productivity (Drury et al. 1993). It has
been shown to be a highly beneficial practice in Atlantic
Canada, which receives approximately 1200 mm of
precipitation annually, primarily in the fall and spring
(Madani and Brenton 1995). The addition of fertilizer
(organic and inorganic) to agricultural lands in sub-
humid regions contributes to the production of N2O
(Minami and Fukushi 1984). Ronen et al. (1988) state
that approximately 30% of the N applied to agricultural
soils can be lost through leaching. Similarly, guidelines
for the reporting of dissolved N2O associated with
drainage water are included as EF5g in the Intergovern-
mental Panel on Climate Change (IPCC) guidelines for
indirect N2O emissions assume the fraction of applied N
that leaches (FracLeach) from the root zone in humid
regions is 0.30 (IPCC 2006; Rochette et al. 2008).
Soluble C compounds and NO(
3 -N applied to the
soil surface can leach downward, supplying substrate
(electron donors) and terminal electron acceptors for
denitrification to occur at depth within the soil. The
N2O produced at depth can easily be dissolved in soil
water or groundwater (Sawamoto et al. 2005). Tile
drainage expedites the movement of water from the
field, reducing the opportunity for biochemical reduc-
tion of dissolved N2O in the soil profile (Mehnert et al.
2007).
Nitrous oxide is highly soluble in water (at 58C 1.0
mL N2O-N mL(1
water00.0425 mols N2O L(1
water)
(Dowdell et al. 1979; Davidson and Swank 1990;
Heincke 2001), with its solubility increasing as tempera-
ture decreases (Weiss and Price 1980; Heincke and
Kaupenjohann 1999). During the winter period in
northern latitudes, there is the potential for the forma-
tion of continuous ice layers that can restrict the
diffusion of N2O to the atmosphere, trapping N2O at
a depth where it can dissolve in cold water (Davidson
and Swank 1990; Burton and Beauchamp 1994).
Although it has been recognized as a component of
N2O emissions from agricultural systems, dissolved N2O
in drainage water is still poorly understood and seldom
quantified. In particular, we do not adequately under-
stand the impact of land management decisions, such as
the choice of tillage system, which could affect water
movement, profile N dynamics and the potential for
N2O emissions in tile drainage water during the non-
growing period. One of the major limitations to
quantification of this source is a practical, reliable,
and automated means of collecting water samples in a
manner that preserves dissolved gas concentrations.
This paper describes a simple method that allows for
the collection of drainage water samples using standard
automated water sampling equipment that maintains the
dissolved gases and thereby allows automated collection
of water sampled for determination of dissolved N2O in
agricultural drainage waters.
MATERIALS AND METHODS
Sampling Apparatus
Tile water is commonly collected in 1-L ISCOTM
water
sampling bottles using an automated sampler (ISCO
6700 Portable Sampler, ISCO Inc., Lincoln, NE). The
configuration of this type of sample container allows
exposure of the sample to the atmosphere and degassing
of dissolved gasses. To maintain the integrity of the
water sample for dissolved N2O quantification, the
potential for the sample to degas must be minimized.
To accomplish this in a simple, cost-effective manner, a
10-mL volumetric pipette, cut at the fill line to ensure
that water fills the pipette beyond the bulb, was placed
inverted in each of the sampling bottles in the auto-
sampler. A portion of the glass was cut from the upper
part of the pipette to insure the pipette fit completely
within the bottle and there was no interference with the
workings of the autosampler and to ensure the water
filled to the narrow portion of the pipette (Fig. 1). The
pipette was inverted for three reasons: the pipette can
be modified by simply cutting it; to speed the rate
of filling; and to minimize turbulence during filling.
Fig. 1. Diagram of modified volumetric pipette within an
ISCOTM
water sample container, illustrating the retrieval of
water from within the bulb of the pipette using a syringe. The
internal diameter of the pipette stem at the water line is 0.13
cm2
and the pipette contains approximately 10 mL of water.
60 CANADIAN JOURNAL OF SOIL SCIENCE
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3. The approximately 9 mL of water contained in the
pipette has a significantly reduced the surface area (0.13
cm2
) compared with the larger sample container (Fig. 1).
The water samples were extracted from the pipettes
using a 20-mL syringe fitted with a 20-gauge 30.5-cm
Popper†
deflected noncoring septum penetration needle
(Fisher Scientific), drawing 5 mL of water from within
the bulb of each of the pipettes. Care was taken to
slowly withdraw the water sample to minimize degas-
sing. Four millilitres of the sample was injected into a
12-mL exetainer (Labco International, UK), which had
previously been evacuated and brought to atmospheric
pressure with ultrapure grade helium. Prior to evacua-
tion, 50 mL of 0.02 M mercuric chloride (HgCl2) solution
was added to the exetainers to inactivate microbial
function and thus prevent further gas production or
consumption in the water sample following injection
into the vial (Elkin 1980; Ueda et al. 1993; Reay et al.
2003). The biostatic agent HgCl2 was chosen as it
inhibits microbial activity in water samples (Reay
et al. 2004), does not alter the physical and chemical
characteristics of the solution (Trevors 1996), and does
not contain N.
The dissolved N2O in the tile drainage water sample
contained in the exetainer was measured by a headspace
method. Vials containing water samples were equili-
brated at room temperature (228C) before being ana-
lyzed by gas chromatography, as noted below. The
laboratory temperature was recorded during the analysis
of dissolved N2O concentration. The value for the
N2O solubility (K0) was adjusted for temperature
according to the procedure presented by Weiss and
Price (1980).
Gas Analysis
Gas analysis was performed using a Varian Star 3800
Gas Chromatograph (Varian, Walnut Creek, CA) fitted
with an electron capture detector (ECD), thermal
conductivity detector (TCD) and a Combi-PAL Auto-
sampler (CTC Analytics, Zwingen, Switzerland). The
Combi-PAL injects 2.5 mL into the gas chromatograph
to fill two 0.5-mL sampling loops that load gas onto
ECD and TCD/FID flow streams. The ECD was
operated at 3808C, 90% Ar, 10% CH4 carrier gas at
20 mL min(1
, Haysep N 80/100 pre-column (0.32 cm
diameter)50 cm length) and Haysep D 80/100 mesh
analytical columns (0.32 cm diameter)200 cm length)
in a column oven operated at 708C. The pre-column was
used in combination with a four-port valve to remove
water from samples. The TCD was operated at 1308C,
pre-purified He carrier gas at 30 mL min(1
, Haysep N
80/100 mesh (0.32 cm diameter)50 cm length) pre-
column followed by a Porapak QS 80/100 mesh (0.32 cm
diameter)200 cm length) analytical column maintained
at 708C. Nitrous oxide was quantified based on ECD
response for concentrations up to 50 mL N2O-N L(1
and on TCD response for concentrations greater than 50
mL N2O-N L(1
.
Calculations
The calculation of total dissolved N2O in tile drainage
waters was achieved by first determining the N2O in the
headspace (N2OHS) of the ExetainerTM
in equilibrium
with the water sample (headspace analysis). This num-
ber was used to calculate the concentration of N2O
dissolved (N2ODIS) in the sampled water assuming
equilibrium. The sum of these two amounts (N2OHS'
N2ODIS) represents total dissolved N2O (N2OTOT) con-
tained in the original water sample. The calculations
were modified from Weiss and Price (1980).
Step 1 Á Calculate the N2O (mol) in the Headspace
The amount of N2O in the pressurized headspace (HS)
was calculated according to the equation:
N2OHS 0
Psample ) x0
N2O ) VHS
R ) T
(1)
where N2OHS is the amount of N2O in exetainer
headspace (mol), Psample is the pressure of the head-
space (atm), x0
N2O is the molar volume of N2O in the
headspace (L N2O-N L(1
air), VHS is the volume of
headspace (L), R is the ideal gas constant (0.08214 L
atm mol(1
8K(1
), and T is the laboratory temperature
(8K).
The sample pressure (Psample) was calculated as a ratio
of the volume of the initial headspace at atmospheric
pressure to the volume of the headspace remaining after
the injection of water (0.012/0.008 atm).
Step 2 Á Calculate the Amount of N2O (mol)
Dissolved in Water (N2ODIS)
The method of Weiss and Price (1980) was modified and
used to calculate the number of moles of N2O dissolved
in the aqueous phase (N2ODIS). To predict phase
equilibria between the aquatic and gaseous phase at
pressures above atmospheric, deviations from the ideal
gas law may need to be taken into account. Under
standard conditions 1 mole of N2O occupies 0.7%
less volume than 1 mole of idea gas (Weiss and Price
1980) and therefore, depending on the desired precision,
correction for non-ideal behavior may be required. This
is done using the temperature-dependent virial coeffi-
cients (B, d) that account for the imperfect conditions at
gas-water interface (Hayden and O’Connell 1975).
N2ODIS 0x0
)F )VH2O (2)
F 0K0 )(P(pH2O))exp
P)
B ' 2d
R ) T
(3)
B0(905:95'4:1685)T-0:0052734)T2
(4)
d065:0(0:1338)T (5)
where N2ODIS is the amount of N2O dissolved (mol
N2O), F is function F (mol air L(1
), VH2O is the volume
of water in exetainer (L), x0
is the molar volume of N2O
in dry air (mol N2O mol(1
air), K0 is the equilibrium
ROPER ET AL. * NITROUS OXIDE IN TILE DRAINAGE WATER 61
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4. constant (mol L(1
atm(1
), P is the total barometric
pressure (atm), pH2O is the vapour pressure of water
(atm), B is the second virial coefficient (cm3
mol(1
), d is
the cross virial coefficient (cm3
mol(1
), R is the gas
constant (0.08214 L atm mol(1
8K(1
), and T is the
absolute temperature (8K).
The value for N2O solubility (K0) was adjusted for
temperature according to the procedure presented by
Weiss and Price (1980). Therefore, the adjusted values in
Eq. 3 are calculated using Eqs. 6 through 8.
K0 0(0:0000299)T2
)((0:00214)T)'0:0591 (6)
In pH2O024:4543(67:4509)
100
T
(4:8489
)ln
T
100
(7)
(B ' 2d)
R ) T
0
(9:4563
T
'0:04759(6:427)10(5
T (8)
Step 3 Á Combine Headspace and Dissolved N2O and
Express as a Function of the Volume of the Water
Sample
Total N2O dissolved in the water sample (mol) is the
sum of N2O in the headspace (N2OHS) determined using
Eq. 1 and N2O dissolved in the water at equilibrium
(N2ODIS) calculated from Eqs. 2 through 8. The final
sum was expressed as a concentration (N2OTOT; mol
N2O L(1
) by dividing the moles of N2O by the volume
of the sample.
N2OTOT 0
N2ODIS ' N2OHS
VH2O
(9)
Eight-day Laboratory Study
To determine the relative rate of degassing from the
water contained in the modified pipette relative to bulk
water, an 8-d laboratory study was conducted using
15 L of water collected from tile drains from a nearby
experimental site and placed in a 20-L glass carboy. The
concentration of dissolved N2O was increased by intro-
ducing 5 mL of 100% N2O into the headspace and
allowing to equilibrate at 48C for a 2-d period. The water
was then transferred to bottles with and without 0.25
mmol HgCl2 L(1
to determine whether microbial con-
sumption of N2O was occurring. Six pipettes were placed
in each bottle. At each sampling time a 4-mL aliquot of
water was collected from within the pipette and a second
4-mL aliquot of water sampled was collected directly
from the water in the open bottle. There were five
replicates for each measurement. The pipette that was
sampled was removed from the bottle after sampling.
Samples were collected immediately upon the water’s
addition (t00) to the apparatus and at 0.5, 1, 2, 4 and 8 d
after addition. The 4-mL water samples were injected
in 12-mL exetainers containing HgCl2 as described
above, and headspace analysis was performed by gas
chromatography at the end of experiment after at least
24 h of equilibration for all samples.
Statistical Methods
The experiment was set up as a two-factor completely
randomized design with the factors being sampling
location (bulk water vs. pipet bulb), (9) biostatic agent
in bulk water with repeated measures (storage times).
Exponential curve fits were performed on averages from
each sampling time. Statistical analysis was performed
using JMP 10 (SAS Institute, Inc., Cary, NC).
RESULTS AND DISCUSSION
Over the 8-d storage period, the concentration of N2O
dissolved in the water decreased significantly (P5
0.001). The rate of decrease was significantly (P50.01)
different depending on the sampling location, but was
not significantly influenced by the addition of HgCl2 to
the water (Fig. 2). Water contained in the pipette lost
dissolved N2O at a rate of 2% d(1
(k00.02 d(1
) as
compared with 7% d(1
(k00.07 d(1
) for the bulk
water (Fig. 2). For the first 24 h of storage there was no
significant change in the concentration of dissolved N2O
in samples stored in the pipette. The average N2O
concentration on the first day from the pipettes and
the bulk water contained in the bottles were 0.1089
0.003 and 0.10390.001 mmol N2O L(1
water, relative
to 0.11490.002 at the time of filling. After 8 d of
storage the average N2O concentration was 0.0979
0.004 mmol N2O L(1
(16% loss), while the concentra-
tion in the bulk water had dropped to an average of
0.06390.004 mmol N2O L(1
(45% loss). There was
significantly (P00.001) less loss of N2O from water
contained in the pipette when compared with water
contained in the open bottle.
These findings indicate that the rate of degassing of
dissolved N2O can be significantly reduced by minimiz-
ing the sample:atmosphere interface using a modified
pipette enclosure. Loss still occurs, but at a reduced rate,
providing the opportunity for delaying the collection of
sample for up to 24 h without significant change in
dissolved N2O concentration. The addition of a biostatic
agent to the bulk water had no effect on the rate to
decrease in dissolved N2O suggesting that loss was
primarily the result of desorption and biological con-
sumption was not part of the decrease. Further exam-
ination of the rate of loss as a function of temperature
and dissolved N2O concentration may result in a
predictable rate of loss allowing for the opportunity to
further delay sample collection.
There are several potential sources of error that need to
considered. Leakage of gas from the vial can result not
only in a loss of N2O, but also in an error in the assumed
pressure of the headspace. Leakage from ExetainersTM
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5. has been shown to be small (Glatzel and Well 2008);
however, direct measurement of vial pressure or the use
of an internal standard to correct for the mass of the gas
in the headspace would provide a more direct means of
correcting for this error, but would result in a more
complex method and/or analytical requirement. This
error can be minimized by limited reuse of exetainers
caps (Bfive punctures) and minimizing the time of
storage in the Exetainers. The volume of water injected
into the vial is also of importance and should be done as
accurately as possible. Caution also needs to be exercised
in the handling and disposal of HgCl2; appropriate safety
documentation should be consulted. The use of a less
toxic biostatic agent should also be considered.
SUMMARY
The method presented offers a simple, reproducible, and
reliable method for measuring dissolved N2O that is
compatible with automated water-sampling systems. The
apparatus described is simple to assemble from readily
available materials. The use of this apparatus provides a
practical means of collecting samples using an automated
water-sampling device without the need for immediate
recovery for dissolved gas analysis. The availability
of simple, practical means of collecting representative
samples of tile drainage water should allow researchers to
obtain better data on this important yet poorly docu-
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