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Toxic Elements in Aquatic Sediments: Distinguishing Natural Variability from Anthropogenic Effects
Aixin Hou1, Ronald D DeLaune1, MeiHuey Tan1
1Department of Environmental Sciences, School of the Coast and Environment, 1255 Energy, Coast and Environment Bldg., Baton Rouge, LA 70803, USA.
Water, Air, and Soil Pollution
|June 23, 2016
Summary
This study used aluminum as a reference to differentiate natural elemental variations from human-caused pollution in Louisiana freshwater sediments. Model II regression successfully identified anthropogenic impacts, distinguishing them from natural background levels.
Area of Science:
- Environmental Chemistry
- Geochemistry
- Aquatic Science
Background:
- Anthropogenic pollution can elevate concentrations of potentially toxic elements in freshwater sediments.
- Distinguishing natural elemental variability from human impacts is crucial for accurate environmental assessment.
- Aluminum content in sediments often reflects natural geochemical processes and can serve as a reference element.
Purpose of the Study:
- To differentiate natural variability from anthropogenic pollution in Louisiana freshwater sediments using aluminum as a reference.
- To assess concentrations of potentially toxic elements against screening effects levels.
- To evaluate the effectiveness of geometric mean model II regression for identifying human impacts.
Main Methods:
- Analysis of potentially toxic elements in freshwater sediments from Louisiana.
- Application of geometric mean model II regression to analyze aluminum-geochemistry relationships.
- Comparison of elemental concentrations with threshold effects levels to identify pollution.
Main Results:
- Aluminum content explained over 50% of the natural variability in most sediment samples.
- Most cadmium concentrations exceeded threshold effects levels without evidence of anthropogenic impact.
- Anthropogenic pollution was identified in Bayou Trepagnier (Cr, Cu, Pb, Ni, Zn) and Capitol Lake (Pb) linked to specific sources.
Conclusions:
- Geometric mean model II regression is essential for accurately identifying anthropogenic impacts by filtering natural variability.
- Aluminum serves as a reliable indicator for natural variability in freshwater sediments.
- This approach allows for the correct attribution of elemental contamination, avoiding misclassification of natural occurrences as pollution.
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