Identifying Nutrient Pollution Sources with Stable Isotopes to Improve Water Quality
James Herrin, Source Molecular Corporation, [email protected]
Abstract
Nutrient source tracking is a method used to determine the sources of nutrient pollution in the environment. There are many potential sources of nutrients in the water -- manure and animal waste, atmospheric deposition, chemical fertilizers, urban runoff and wastewater treatment plant discharge. Millions of dollars have been spent to reduce nutrients but they continue to be a leading cause of impairment. Thus, stakeholders need to gain a better understanding of the sources of nutrient pollution. Specifically, where did the nitrogen that's causing excessive nutrient loading come from? Nitrogen isotopes are effective tracers of nutrient source identification. Different sources of nutrients have distinctive isotope ratios and these serve as unique markers in order to trace them. Crafting a nitrogen source tracking plan begins with developing an initial hypothesis for the nitrogen source. Next, sampling sites must be identified. Samples must be collected at nitrogen hotspots and must represent the watershed's spatial variability. They must also be collected in wet and dry weather. There should be a substantial number of sampling events to represent temporal variability. Samples should be tested for anthropogenic sources and for the most likely natural sources.
1. Keyword
nutrients
2. Keyword
pollution sources
3. Keyword
stable isotopes
4. Additional Keyword
nutrient source tracking
5. Additional Keyword
water quality
6. Additional Keyword
nitrogen isotopes