David Eckhardt - Academia.edu (original) (raw)

Papers by David Eckhardt

Scientific Investigations Report, 2010

Analyses of water samples collected from 64 streams and rivers across New York State in June 1997... more Analyses of water samples collected from 64 streams and rivers across New York State in June 1997 indicate that patterns of pesticide detection are largely related to the predominant upstream land use and pesticide-application patterns. Of the 47 pesticides for which the samples were analyzed, 25 were detected. Concentrations of most pesticides detected were low and generally did not exceed 0.1 flg/L (microgram per liter). Herbicides used on cornfields, including atrazine, metolachlor, cyanazine, alachlor, and the atrazine degradate deethylatrazine, were detected in samples from 41 to 97 percent of the 64 sites sampled. The highest concentrations (greater than 0.10 fJg/L) of these compounds were in streams in western New York State, where corn production is the greatest. Two insecticides carbaryl and diazinon were detected in 20 and 14 percent of the samples, respectively. Carbaryl was detected most frequently in streams whose drainage basins either contain extensive vineyards or orchards, or are widely urbanized. Diazinon was detected most frequently in streams that drain urban or residential watersheds. Concentrations of four insecticides azinphosmethyl, p,p'-DDE, diazinon, and dieldrin-and one herbicide-simazine exceeded some New York State water-quality criteria. Some Federal or State criteria were exceeded at 10 sites. These results represent an initial assessment of the status of pesticide concentrations in surface waters of New York State and, when combined with data collected in the future, will help water managers to assess the status, trends, and health impacts of pesticide contamination of ground and surface waters of New York State including Long Island. This information also will be useful to researchers and water managers who require such data to define the health and environmental effects of pesticide use in the State.

Scientific Investigations Report

The transport and fate of the herbicide metolachlor and its principal metabolites -metolachlor ES... more The transport and fate of the herbicide metolachlor and its principal metabolites -metolachlor ESA (ethanasulfonic acid) and metolachlor OA (oxanilic acid) -in ground water from Suffolk County, on Long Island, from tile drains in an agricultural area in central New York and in surface water from five streams in central and western New York, was evaluated in 1997-98. Comparison of (1) the ratio of metolachlor ESA to metolachlor (SAM ratio) and (2) the ratio of metolachlor ESA to metolachlor OA (SAO ratio) in well water from Suffolk County with these ratios in tile-drain runoff and in the five streams indicates that these ratios vary according to soil properties, hydrologic factors, and time since metolachlor application. Both ratios were lower in well-water samples from Suffolk County (which is dominated by coarse-grained soils), than in the tile-drain samples from central New York fields (which have finer grained soils). The lower SAM ratios for the Suffolk County well-water samples...

Analyses of stormflow samples collected from tributaries to Cayuga Lake in western New York short... more Analyses of stormflow samples collected from tributaries to Cayuga Lake in western New York shortly after application of atrazine and metolachlor to agricultural fields in June 1998 indicate that the highest concentrations, and the bulk of the loads of the two herbicides in the three tributaries was transported during peak flows. Concentrations of metolachlor metabolites remained high after the flow peaked as the soils drained. In contrast, deethylatrazine concentrations, which were generally low, increased only slightly during stormflow, apparently because the parent compound (atrazine) degrades at a much slower rate than metolachlor. Far more metolachlor-ESA (a degradation compound) was transported than any other pesticide or degradate; this indicates that it is relatively stable and mobile in the hydrologic environment. The ratios of a metabolite concentration to that of other metabolites and the parent compound in stream-water samples showed that base flow in the tributaries bef...