Estimating Annual Cadmium Load

International Conference on Environmental and Hazardous Substance Management: Towards a Green Economy, Bangkok, Thailand.
May 21-23, 2013
Estimating Annual Cadmium Load
via Surface Runoff
into Songkhla Lake, Thailand
Kitipan Kitbamroong, Ph. D
G.Padmanabhan, Ph. D
Penjai Sompongchaiyakul, Ph. D

May 21-23, 2013
May 21-23, 2013
Problem
 Increasing agricultural activities in the
catchments of Songkhla Lake have the
potential to increase cadmium accumulation
in the lake.
 Cadmium was found in the lake sediments
 Cadmium is common in phosphate rocks
 Surface runoff and associated sediment flow
are the major mechanisms of transport of
non-point source pollutants

May 21-23, 2013
May 21-23, 2013
Research Objectives
 To develop a database for non-point source
cadmium transport modeling of the Lake
Basin from the surrounding drainage area.
 To carry out a scenarios analysis of the
cadmium transport to the lake from the
surrounding drainage areas to assist
environmental decision makers.

May 21-23, 2013
May 21-23, 2013
Methodology
 A spatially distributed cell-based model is
proposed.
 Data to be assembled from local sources on
landuse, soils, fertilizers, and practices.
 Meaningful scenarios will be constructed
 For each scenario, the model runs will be
analyzed.
 Results will be presented to the decision
makers.

May 21-23, 2013
May 21-23, 2013
Non-Point Source Models
 Available models:
 MIKE SHE
 SWAT
 BASINS
 TREX
 AnnAGNPS
 Criteria
 Predominant land use: agricultural
 Data input requirements: local
 Integration with GIS: Arcview
 Metals transport

May 21-23, 2013
May 21-23, 2013
Model and Scenarios Used
 Non point source pollution modeling of
cadmium
 TREX (Two-dimenstional Runoff, Erosion, and
eXport model)
 Scenarios
Three scenarios were tested:
 Significant increase and decrease of fertilizer
usage.
 Change in types of fertilizer applied.
 Change in the application rate of fertilizer for
certain crops.

May 21-23, 2013
May 21-23, 2013
TREX
 Two-dimensional Runoff, Erosion, and Export
model is a generalized rainfall-runoff watershed
model with a framework for modeling sediment
and contaminant transport.
 Based on the CASC2D watershed model with
chemical transport and fate processes from the
USEPA WASP and IPX series of stream water
quality models
 Three main components: 1) hydrology 2)sediment
transport, and 3) chemical transport and fate.

May 21-23, 2013
May 21-23, 2013
TREX

May 21-23, 2013
May 21-23, 2013
Research Activities Flow Diagram
Model
Source
Mgt Tools
SFA
Pre-Processing
Post-Processing
GIS

May 21-23, 2013
May 21-23, 2013
GIS
 The acquired information was compiled in a
Geographical Information System (GIS) –
ArcView.
 The TREX model was run and the result
presented within ArcView.
 Pre-processing of data and post processing
of the model results were done in the GIS
platform.

May 21-23, 2013
May 21-23, 2013
Watershed Delineation
Figure 3-7 Steps performed during watershed delineation

May 21-23, 2013
May 21-23, 2013
8 Watersheds

May 21-23, 2013
May 21-23, 2013
Model calibration
 The model parameters subject to the
calibration were
 hydraulic conductivity
 soil erodibility
 flow resistance
 crop management factor
 chemical distribution coefficients.

May 21-23, 2013
May 21-23, 2013
Model calibration
Chemical distribution coefficients – depending
on metal of interest

May 21-23, 2013
May 21-23, 2013
Model calibration
 Parameters of the model are perturbed until
an acceptable difference between measured
and model-generated output is obtained.

May 21-23, 2013
May 21-23, 2013
Model validation
 The model is run here with the calibrated
parameters to compare the performance of
the model with measured data (Suviboon,
2006; Leekpai, 2006).

May 21-23, 2013
May 21-23, 2013
Calibration
 20 Stations
 Precipitation runoff
 Sedimentation Loss
 Cd content in sediment
 Relative error between
5-20%

May 21-23, 2013
May 21-23, 2013
Verification
 220 sampling
points
 Precipitation runoff
 Sedimentation Loss
 Cd content in
sediment
 Relative error
between 10-30%

May 21-23, 2013
May 21-23, 2013
 hydraulic conductivity

May 21-23, 2013
May 21-23, 2013
 soil erodibility

May 21-23, 2013
May 21-23, 2013
 flow resistance

May 21-23, 2013
May 21-23, 2013
 crop management
factor

May 21-23, 2013
May 21-23, 2013
Cadmium
 Model Performance
 Calibration pts
 Validation pts

May 21-23, 2013
May 21-23, 2013
Scenario Analysis (1.1)
 Increase Fertilizer
usage by 10%

May 21-23, 2013
May 21-23, 2013
 Increase Fertilizer
usage by 50%

May 21-23, 2013
May 21-23, 2013
 Decrease usage by
10%

May 21-23, 2013
May 21-23, 2013
 Decrease usage by
50%

May 21-23, 2013
May 21-23, 2013
Scenario Analysis (2)
 changing types of
fertilizer
 7.19 mg/kg cadmium  7.27 mg/kg cadmium

May 21-23, 2013
May 21-23, 2013
 changing types of
fertilizer

May 21-23, 2013
May 21-23, 2013
 change of crops grown
in the area

May 21-23, 2013
May 21-23, 2013
Conclusion
 Substance Flux Analysis
 41,745 tons/year of phosphorus, and 273
kg/year of cadmium from phosphate fertilizer
were induced into SLB.
 The stock calculation for phosphorus and
cadmium were found to be 248.7 tons/year
and 62.8 tons/year respectively.

May 21-23, 2013
May 21-23, 2013
Conclusion
 TREX Modeling
 U-Tapao watershed had the highest potential of
phosphorous and cadmium transportation in the
sediment runoff.
 Factors promoting includes;
 run off – high runoff
 elevation – steep slope
 soil erodibility – high erosion
 organic matter – high
 pH –acidity
 crop management – horticultural crops
 clay – high percentage
 total metal – high

May 21-23, 2013
May 21-23, 2013
Conclusion
 Scenario Analysis
 A total of three scenarios were demonstrated
and tested in U-Tapao sub watershed.
 Alone by changing the fertilizer formula, from high
to low contaminated cadmium lead towards a
significant decrease of cadmium contribution to
the watershed.

May 21-23, 2013
May 21-23, 2013
Acknowledgements
 Asst. Prof. Dr. Chatchai Ratanachai (PSU)
 Dr. Manaskorn Rachakornkij (CU)
 Lecturers and staffs of NRC-EHWM

May 21-23, 2013
May 21-23, 2013
Q&A

Estimating Annual Cadmium Load

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