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Manganese - A Water Pollution Indicator Or Natural Groundwater Chemistry

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This is a presentation that I gave to my UF Soil & Water Science Department, Geochemistry of Heavy Metals postgraduate class.

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Manganese - A Water Pollution Indicator Or Natural Groundwater Chemistry

  1. 1. CWR 6252 BIOGEOCHEMISTRY OF TRACE METALS MANGANESE – A GROUNDWATER POLLUTION INDICATOR OR NATURAL GROUNDWATER CHEMISTRY? 19 th April 2010 Padraic Mulroy
  2. 2. <ul><li>INTRODUCTION </li></ul><ul><li>ANTHROPOGENIC INPUT </li></ul><ul><li>AIR </li></ul><ul><li>SOIL & SEDIMENT </li></ul><ul><li>WATER </li></ul><ul><li>BIOCONCENTRATION IN BIOTA </li></ul><ul><li>HUMAN TOXICITY </li></ul><ul><li>INFLUENCE OF REDOX & pH </li></ul><ul><li>ELEVATED LEVELS IN POLLUTED GROUNDWATER </li></ul><ul><li>NATURAL ELEVATED LEVELS IN BEDROCK </li></ul><ul><li>CONCLUSIONS </li></ul>PRESENTATION OVERVIEW 1 Introduction 2 Anthropogenic Input 3 Air 4 Soil & sediment 5 Water 6 Bioconcentration 7 Human Toxicity 8 Influence of Redox & pH 9 Elevated levels in polluted groundwater 10 Natural elevated levels in bedrock 11 Conclusions
  3. 3. INTRODUCTION 1 Introduction 2 Anthropogenic Input 3 Air 4 Soil & sediment 5 Water 6 Bioconcentration 7 Human Toxicity 8 Influence of Redox & pH 9 Elevated levels in polluted groundwater 10 Natural elevated levels in bedrock 11 Conclusions <ul><li>Group 7 </li></ul><ul><li>Reddish grey/silver brittle element </li></ul><ul><li>Oxidation states of +1, +2, +3, +4, +6 and +7 </li></ul><ul><li>Omnipresent – 0.1% of Earth’s crust </li></ul><ul><li>12 th most abundant element (Iron more abundant) </li></ul>
  4. 4. INTRODUCTION 1 Introduction 2 Anthropogenic Input 3 Air 4 Soil & sediment 5 Water 6 Bioconcentration 7 Human Toxicity 8 Influence of Redox & pH 9 Elevated levels in polluted groundwater 10 Natural elevated levels in bedrock 11 Conclusions
  5. 5. INTRODUCTION 1 Introduction 2 Anthropogenic Input 3 Air 4 Soil & sediment 5 Water 6 Bioconcentration 7 Human Toxicity 8 Influence of Redox & pH 9 Elevated levels in polluted groundwater 10 Natural elevated levels in bedrock 11 Conclusions <ul><li>Principal ores – Pyrolusite (MnO 2 ) and Rhodocrosite (MnCO 3 ) </li></ul><ul><li>Large deposits in Cuyuna Range (Minnesota), Ukraine, Georgia, China </li></ul><ul><li>Common constituent of sedimentary rocks such as shales (southeast of Ireland) </li></ul>ACICULAR/RADIAL DENDRITIC
  6. 6. INTRODUCTION 1 Introduction 2 Anthropogenic Input 3 Air 4 Soil & sediment 5 Water 6 Bioconcentration 7 Human Toxicity 8 Influence of Redox & pH 9 Elevated levels in polluted groundwater 10 Natural elevated levels in bedrock 11 Conclusions <ul><li>Manganese nodules – rock concretions on sea bottom (concentric layers of Mn & Fe hydroxides) </li></ul><ul><li>Contain Mn (27-30%), </li></ul><ul><li>Fe (6%), Ni (1.25-1.5%), </li></ul><ul><li>copper (1-1.4%) </li></ul><ul><li>& cobalt (0.2-0.25%) </li></ul><ul><li>Possible future </li></ul><ul><li>mineral resource? </li></ul>OCEAN FLOOR CROSS-SECTION POSSIBLE HARVESTING?
  7. 7. ANTHROPOGENIC INPUT <ul><li>Municipal WWTP discharges to aquatic systems </li></ul><ul><li>Application of biosolids to land & marine dumping </li></ul><ul><li>Mining & mineral processing </li></ul><ul><li>Air emissions: </li></ul><ul><ul><li>alloy, steel & iron production, combustion of fossil fuels </li></ul></ul><ul><ul><li>Combustion of unleaded petrol with anti-knocking agent Methylcyclopentadienyl manganese tricarbyl (MMT) – </li></ul></ul><ul><ul><li>Canadian problem? </li></ul></ul>1 Introduction 2 Anthropogenic Input 3 Air 4 Soil & sediment 5 Water 6 Bioconcentration 7 Human Toxicity 8 Influence of Redox & pH 9 Elevated levels in polluted groundwater 10 Natural elevated levels in bedrock 11 Conclusions
  8. 8. AIR <ul><ul><li>Concentrations in air </li></ul></ul><ul><ul><ul><li>Remote: 0.5-14ng/m 3 </li></ul></ul></ul><ul><ul><ul><li>Rural: 40ng/m 3 </li></ul></ul></ul><ul><ul><ul><li>Urban: 65-166ng/m 3 </li></ul></ul></ul><ul><ul><li>Highest in source dominated areas – up to 8,000ng/m 3 </li></ul></ul><ul><ul><li>Annual averages near foundries 200-300ng/m 3 </li></ul></ul>1 Overview 2 Anthropogenic Input 3 Air 4 Soil & sediment 5 Water 6 Bioconcentration 7 Human Toxicity 8 Influence of Redox & pH 9 Elevated levels in polluted groundwater 10 Natural elevated levels in bedrock 11 Conclusions
  9. 9. SOIL & SEDIMENT <ul><li>Concentrations in soil </li></ul><ul><ul><li>Range <1-4,000mg/kg </li></ul></ul><ul><ul><li>Average 300-600mg/kg </li></ul></ul><ul><li>Sources: </li></ul><ul><ul><li>Crustal </li></ul></ul><ul><ul><li>Atmospheric deposition </li></ul></ul><ul><ul><li>Run-off from plant and other surfaces </li></ul></ul><ul><ul><li>Leaching from plant tissue </li></ul></ul><ul><ul><li>Leaves, dead plant </li></ul></ul><ul><ul><li>Animal material detritus & excrement </li></ul></ul><ul><li>Sources of Mn 2+ </li></ul><ul><ul><li>Anaerobic environment </li></ul></ul><ul><ul><li>Natural weathering of Mn 2+ minerals </li></ul></ul><ul><ul><li>Naturally acidic environments </li></ul></ul><ul><li>Sedimentation factors </li></ul><ul><ul><li>Oxygen concentration in overlying water column </li></ul></ul><ul><ul><li>Penetration of O 2 into sediment </li></ul></ul><ul><ul><li>Benthic organic carbon supply </li></ul></ul>1 Overview 2 Anthropogenic Input 3 Air 4 Soil & sediment 5 Water 6 Bioconcentration 7 Human Toxicity 8 Influence of Redox & pH 9 Elevated levels in polluted groundwater 10 Natural elevated levels in bedrock 11 Conclusions
  10. 10. WATER <ul><li>Concentrations in natural waters </li></ul><ul><ul><li>Range <1-10,000 μ g/litre </li></ul></ul><ul><ul><li>Average <200 μ g/litre </li></ul></ul><ul><li>Concentrations in unpolluted river sediments </li></ul><ul><ul><li>Range 410-6,700 μ g/litre </li></ul></ul><ul><li>Urban lake in vicinity of old mine tailings dump </li></ul><ul><ul><li>Sediment 13,400 m g/kg </li></ul></ul><ul><li>Intertidal mudflats </li></ul><ul><ul><li>Range 100-1,000 m g/kg </li></ul></ul><ul><ul><li>Unpolluted Dundalk mudflat 421 m g/kg </li></ul></ul><ul><li>Baltic Sea – Ferromanganese Nodule Area </li></ul><ul><ul><li>Range 3,550-8,960 m g/kg </li></ul></ul>1 Overview 2 Anthropogenic Input 3 Air 4 Soil & sediment 5 Water 6 Bioconcentration 7 Human Toxicity 8 Influence of Redox & pH 9 Elevated levels in polluted groundwater 10 Natural elevated levels in bedrock 11 Conclusions
  11. 11. BIOCONCENTRATION <ul><li>Bioconcentration at lower trophic levels </li></ul><ul><ul><li>BCF 2,000-20,000 for marine/freshwater plants </li></ul></ul><ul><ul><li>BCF 800-830 for intertidal mussels </li></ul></ul><ul><ul><li>BCF 35-930 for fish </li></ul></ul><ul><li>Uptake increases with increasing temperature but decreases with increasing pH </li></ul><ul><li>Dissolved O 2 – No effect </li></ul><ul><li>Concentration of Mn in fish flesh </li></ul><ul><ul><li>Range: <0.2-19mg/kg </li></ul></ul><ul><ul><li>Higher (i.e. >100mg/kg in polluted waters) </li></ul></ul><ul><li>Essential nutrient for terrestrial plants </li></ul><ul><ul><li>Requirements: 10-50mg/kg tissue </li></ul></ul><ul><ul><li>Members of Ericaceae family (includes blueberries) are recognized hyper-accumulators </li></ul></ul>1 Overview 2 Anthropogenic Input 3 Air 4 Soil & sediment 5 Water 6 Bioconcentration 7 Human Toxicity 8 Influence of Redox & pH 9 Elevated levels in polluted groundwater 10 Natural elevated levels in bedrock 11 Conclusions
  12. 12. HUMAN TOXICITY <ul><li>Adverse effects in humans via inhalation – neurotoxin causing ataxia, co-ordination impairment, anxiety, dementia, ‘mask-like’ face, involuntary movements, similar to Parkinson’s disease </li></ul><ul><li>Manganism or ‘Welder’s Disease’ – inhalation of toxic welding rod fumes – not age dependent </li></ul><ul><li>Mangasim found in farmers exposed to Manganese containing pesticides e.g. maneb (fungicide), rotenone (a insecticide) </li></ul><ul><li>Level of manganese found in groundwater supplies in Ireland/US far below average daily intake of manganese from food </li></ul><ul><li>Neurological effects were observed in the elderly within a group of families exposed to elevated manganese. No effect on youngest. </li></ul>1 Overview 2 Anthropogenic Input 3 Air 4 Soil & sediment 5 Water 6 Bioconcentration 7 Human Toxicity 8 Influence of Redox & pH 9 Elevated levels in polluted groundwater 10 Natural elevated levels in bedrock 11 Conclusions
  13. 13. INFLUENCE OF pH & REDOX 1 Overview 2 Anthropogenic Input 3 Air 4 Soil & sediment 5 Water 6 Bioconcentration 7 Human Toxicity 8 Influence of Redox & pH 9 Elevated levels in polluted groundwater 10 Natural elevated levels in bedrock 11 Conclusions <ul><li>MnO 2 (Pyrolusite) – stable compound at high redox regardless of pH </li></ul><ul><li>MnCO 3 (Rhodocrosite) – stable over a wide redox and pH range if carbonate is high </li></ul><ul><li>MnO 2 -CO 2 -H 2 O-S 2 -O 2 </li></ul>
  14. 14. INFLUENCE OF pH & REDOX 1 Overview 2 Anthropogenic Input 3 Air 4 Soil & sediment 5 Water 6 Bioconcentration 7 Human Toxicity 8 Influence of Redox & pH 9 Elevated levels in polluted groundwater 10 Natural elevated levels in bedrock 11 Conclusions <ul><li>H æmatite, iron(III) oxide (Fe 2 O 3 ) dominance shows Fe oxidises more readily in natural environment </li></ul><ul><li>H æmatite stable in presence of Mn 2+ over wide pH range </li></ul><ul><li>Precipitation of Mn 2+ will happened with increasing pH if carbonate or silica is present </li></ul><ul><li>If environmental becomes more oxidising, Mn will precipitate as one of oxides MnO 2 most stable </li></ul><ul><li>MnO 2 -CO 2 -H 2 O-S 2 -O 2 </li></ul>
  15. 15. ELEVATED LEVELS IN POLLUTED GROUNDWATER 1 Overview 2 Anthropogenic Input 3 Air 4 Soil & sediment 5 Water 6 Bioconcentration 7 Human Toxicity 8 Influence of Redox & pH 9 Elevated levels in polluted groundwater 10 Natural elevated levels in bedrock 11 Conclusions <ul><li>CASE STUDY A </li></ul><ul><li>Groundwater in vulnerable upland area polluted with septate from neighbour’s malfunctioning on-site WWTP </li></ul><ul><li>Introduction of carbon source will cause: </li></ul><ul><ul><li>Aerobic microbial consortia to use up all O 2 </li></ul></ul><ul><ul><li>Biofouling of borehole </li></ul></ul><ul><ul><li>Drop in Dissolved O 2 - Redox Potential drop </li></ul></ul><ul><ul><li>Anaerobic & facultative anaerobic consortia will take over & produce initially acid & fatty acid breakdown products </li></ul></ul><ul><ul><li>Increase in acidity -> pH drops </li></ul></ul><ul><ul><li>Reduction of Mn 4+ (solid MnO 2 ) -> Mn 2+ (soluble) </li></ul></ul><ul><ul><li>Solubilization of solid MnCO 3 -> Mn 2+ </li></ul></ul><ul><ul><li>Reduction of ferric Fe 3+ (solid haematite) -> </li></ul></ul><ul><ul><li>ferrous Fe 2+ (soluble) </li></ul></ul><ul><ul><li>Production of ammonia </li></ul></ul><ul><ul><li>Moving down the Redox Ladder </li></ul></ul>
  16. 16. ELEVATED LEVELS IN POLLUTED GROUNDWATER 1 Overview 2 Anthropogenic Input 3 Air 4 Soil & sediment 5 Water 6 Bioconcentration 7 Human Toxicity 8 Influence of Redox & pH 9 Elevated levels in polluted groundwater 10 Natural elevated levels in bedrock 11 Conclusions <ul><li>CASE STUDY A – NE IRELAND </li></ul>
  17. 17. ELEVATED LEVELS IN POLLUTED GROUNDWATER 1 Overview 2 Anthropogenic Input 3 Air 4 Soil & sediment 5 Water 6 Bioconcentration 7 Human Toxicity 8 Influence of Redox & pH 9 Elevated levels in polluted groundwater 10 Natural elevated levels in bedrock 11 Conclusions <ul><li>CASE STUDY A </li></ul><ul><li>OLD POLLUTED </li></ul><ul><li>BOREHOLE </li></ul><ul><li>NEW UNPOLLUTED </li></ul><ul><li>BOREHOLE </li></ul>
  18. 18. NATURAL ELEVATED LEVELS IN GROUNDWATER 1 Overview 2 Anthropogenic Input 3 Air 4 Soil & sediment 5 Water 6 Bioconcentration 7 Human Toxicity 8 Influence of Redox & pH 9 Elevated levels in polluted groundwater 10 Natural elevated levels in bedrock 11 Conclusions <ul><li>CASE STUDY B – COUNTY WEXFORD </li></ul><ul><li>83m deep water abstraction borehole drilled to </li></ul><ul><li>supply 19 residences </li></ul><ul><li>Grey shale bedrock becoming greyer with depth </li></ul><ul><li>Soft rock encountered at 81-83m bgl followed by large water strike </li></ul><ul><li>Pump tested over 72 hours - sustained yield of 30.2m 3 /day </li></ul><ul><li>3 sets of samples taken for laboratory analysis – 24, 48 & 72 hours </li></ul><ul><li>Elevated Mn levels - 1,140 to 670μg/litre – </li></ul><ul><li>Drinking Water Limit - 50μg/litre ( 10 times!) </li></ul><ul><li>Normal Fe levels 60 to 250μg/litre </li></ul><ul><li>No ammonia, nitrates or bacteria </li></ul><ul><li>Excellent clarity, no odour or taste </li></ul><ul><li>Flow cell Redox 129mV </li></ul>
  19. 19. NATURAL ELEVATED LEVELS IN GROUNDWATER 1 Overview 2 Anthropogenic Input 3 Air 4 Soil & sediment 5 Water 6 Bioconcentration 7 Human Toxicity 8 Influence of Redox & pH 9 Elevated levels in polluted groundwater 10 Natural elevated levels in bedrock 11 Conclusions <ul><li>CASE STUDY B </li></ul><ul><li>Ballylane Formation - laminated green, green grey and grey slaty mudstones and green or pale grey siltstones, with occasional greywacke sandstones and andesitic volcanics’ </li></ul><ul><li>Maulin Formation – dark phyllites, quartz rich siltstones which contain very small manganese-rich garnets </li></ul>
  20. 20. NATURAL ELEVATED LEVELS IN GROUNDWATER 1 Overview 2 Anthropogenic Input 3 Air 4 Soil & sediment 5 Water 6 Bioconcentration 7 Human Toxicity 8 Influence of Redox & pH 9 Elevated levels in polluted groundwater 10 Natural elevated levels in bedrock 11 Conclusions <ul><li>CASE STUDY B </li></ul>Mn 2+ - Rich Groundwater?
  21. 21. NATURAL ELEVATED LEVELS IN GROUNDWATER 1 Overview 2 Anthropogenic Input 3 Air 4 Soil & sediment 5 Water 6 Bioconcentration 7 Human Toxicity 8 Influence of Redox & pH 9 Elevated levels in polluted groundwater 10 Natural elevated levels in bedrock 11 Conclusions <ul><li>CASE STUDY B </li></ul><ul><li>CASE STUDY B – COUNTY WEXFORD </li></ul><ul><li>Where is the Mn coming from? </li></ul><ul><ul><li>Possibly went through Ballylane Formation into Maulin Formation at 81m bgl which is proven to have Mn-rich garnets or coticules </li></ul></ul><ul><ul><li>MnO 2 or MnCO 3 deposits within Ballylane Formation </li></ul></ul>
  22. 22. NATURAL ELEVATED LEVELS IN GROUNDWATER 1 Overview 2 Anthropogenic Input 3 Air 4 Soil & sediment 5 Water 6 Bioconcentration 7 Human Toxicity 8 Influence of Redox & pH 9 Elevated levels in polluted groundwater 10 Natural elevated levels in bedrock 11 Conclusions <ul><li>CASE STUDY B </li></ul><ul><li>CASE STUDY B – COUNTY WEXFORD </li></ul><ul><li>What is the solution? </li></ul><ul><ul><li>‘ Manganese Greensand’ is glauconite greensand (zeolite) impregnated with KMnO 4 </li></ul></ul><ul><ul><ul><ul><ul><li>Capable of reducing iron, manganese and hydrogen sulfide from water through oxidation and filtration. </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Soluble iron and manganese are oxidized and precipitated by contact with higher oxides of manganese on the greensand granules. </li></ul></ul></ul></ul></ul>
  23. 23. CONCLUSIONS 1 Overview 2 Anthropogenic Input 3 Air 4 Soil & sediment 5 Water 6 Bioconcentration 7 Human Toxicity 8 Influence of Redox & pH 9 Elevated levels in polluted groundwater 10 Natural elevated levels in bedrock 11 Conclusions <ul><li>SEDIMENTARY ROCK FORMATION </li></ul><ul><li>Mn deposits within shale result from 3 main processed: </li></ul><ul><ul><li>Concentration within seawater </li></ul></ul><ul><ul><li>Precipitation from seawater </li></ul></ul><ul><ul><li>Enrichment in the sediments </li></ul></ul><ul><li>Anoxic conditions are a basic factor for Mn concentration in seawater – weak oxic & alkaline conditions favourable for Mn carbonate precipitation with microbial activities playing a part </li></ul>
  24. 24. CONCLUSIONS 1 Overview 2 Anthropogenic Input 3 Air 4 Soil & sediment 5 Water 6 Bioconcentration 7 Human Toxicity 8 Influence of Redox & pH 9 Elevated levels in polluted groundwater 10 Natural elevated levels in bedrock 11 Conclusions <ul><li>GROUNDWATER QUALITY </li></ul><ul><li>Consensus in Ireland is that Drinking Water Standard for Mn (50μg/litre) is not health driven but down to aesthetic and organoleptic (i.e. taste) </li></ul><ul><li>EPA are aware of link with neurologic effects on elderly population – lack of research </li></ul><ul><li>Rural housing with on-site borehole in Mn-rich geological formation areas – elderly residents are at risk </li></ul><ul><li>Need for technical guidance and/or assistance with on-site water treatment systems </li></ul>
  25. 25. THANK YOU! 1 Overview 2 Anthropogenic Input 3 Air 4 Soil & sediment 5 Water 6 Bioconcentration 7 Human Toxicity 8 Influence of Redox & pH 9 Elevated levels in polluted groundwater 10 Natural elevated levels in bedrock 11 Conclusions Thanksgiving, Gainesville, 1995 (20 kilos lighter)

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