Citation:

Neale, A C. AND A M. Pitchford. PREDICTING PRESENCE OF NUTRIENTS AND PESTICIDES IN BASE FLOW CONDITIONS OF FIRST ORDER STREAMS IN THE MID-ATLANTIC COASTAL PLAIN. Presented at EPA Science Forum 2004, Washington, DC, June 1-3, 2004.

Impact/Purpose:

The primary objectives of this research are to:

Develop methodologies so that landscape indicator values generated from different sensors on different dates (but in the same areas) are comparable; differences in metric values result from landscape changes and not differences in the sensors;

Quantify relationships between landscape metrics generated from wall-to-wall spatial data and (1) specific parameters related to water resource conditions in different environmental settings across the US, including but not limited to nutrients, sediment, and benthic communities, and (2) multi-species habitat suitability;

Develop and validate multivariate models based on quantification studies;

Develop GIS/model assessment protocols and tools to characterize risk of nutrient and sediment TMDL exceedence;

Complete an initial draft (potentially web based) of a national landscape condition assessment.

This research directly supports long-term goals established in ORDs multiyear plans related to GPRA Goal 2 (Water) and GPRA Goal 4 (Healthy Communities and Ecosystems), although funding for this task comes from Goal 4. Relative to the GRPA Goal 2 multiyear plan, this research is intended to "provide tools to assess and diagnose impairment in aquatic systems and the sources of associated stressors." Relative to the Goal 4 Multiyear Plan this research is intended to (1) provide states and tribes with an ability to assess the condition of waterbodies in a scientifically defensible and representative way, while allowing for aggregation and assessment of trends at multiple scales, (2) assist Federal, State and Local managers in diagnosing the probable cause and forecasting future conditions in a scientifically defensible manner to protect and restore ecosystems, and (3) provide Federal, State and Local managers with a scientifically defensible way to assess current and future ecological conditions, and probable causes of impairments, and a way to evaluate alternative future management scenarios.

Description:

Excess nutrients and pesticides in the environment can cause a variety of ecological and human-health effects. When nutrients are unused by plants, or pesticides remain after use on their intended target, these compounds can be transported to streams, either directly through overland flow or through percolation through the soil, eventually contributing to ground-water discharge, sometimes termed "base flow," in a stream. Elevated concentrations of pesticides or nutrients can make water unfit for human consumption and can cause adverse effects on aquatic organisms (Briggs, 1992).

The Landscape Indicators for Pesticides Study in Mid-Atlantic Coastal Streams (LIPS-MACS) is a collaborative research effort between the U.S. Environmental Protection Agency's Office of Research and Development and the U.S. Geological Survey's National Water Quality Assessment Program. One of the objectives of the study was to develop models to relate land use, geology, and other geographic variables to water quality and aquatic ecology in small streams of the Mid-Atlantic Coastal Plain. A base network of 174 small (typically first-order) streams was selected across a gradient of hydrogeologic and land-use settings, from a population of 10,144 first-order watersheds in the region. Water samples were collected from all 174 streams and analyzed for selected pesticides, pesticide metabolites, nutrients, and major ions. Benthic-community and habitat assessments were also conducted at each stream. A data base of landscape metrics, computed from soils, land use, and topographic data for each sampled watershed, was compiled.

We used logistic regression to analyze the relationship between presence of pesticides and nutrients at various levels (dependent variables) and our suite of landscape metrics (independent variables). We will present our results for metolachlor, an herbicide, nitrate plus nitrite as total nitrogen, and total phosphorus. We were able to predict presence of metolachlor at levels above 0.06 g/L with an 87% concordance and at levels above 1 g/L with an 86% concordance. Nitrate plus nitrite was predicted at levels above 0.71 mg/L (ecoregional nutrient criteria) with a concordance of 78% and at levels above 1.5 mg/L with a concordance of 72%. Presence of total phosphorus at levels above 0.06 mg/L were predicted with a concordance of 67 %. From the models that we have developed, we will be able to predict presence of pesticides and nutrients at the levels above for most of our sample population of first-order watersheds. These models will enable managers to compare watersheds and make preliminary decisions about where to allocate resources for additional monitoring or remediation.

Record Details: