Geology topics

Patrick J. Phillips

Publications and source records attributed to Patrick J. Phillips.

44 records · Page 3Linked to original sources

USGS2000

Pesticides and their metabolites in three small public water-supply reservoir systems, western New York, 1998-99

Twenty five pesticides or pesticide metabolites were detected in samples collected from May, 1998 through January, 1999 in three small public-supply reservoirs in western New York. Samples were collected at tributaries and reservoir outlets for comparison with samples from the water-supply intakes. No samples from public-water-supply intakes exceeded any Federal or State water-quality standards, although some samples from tributaries did exceed a few standards. The maximum concentrations of the most frequently detected pesticides in water-supply intake samples were between 10 and 50 percent of the lowest applicable water quality standard. Pesticides that exceeded water-quality standards at the tributary sites were the herbicides atrazine, alachlor, and cyanazine, and the insecticide p,p’ -DDE. Land use in the watersheds that surround these reservoirs is largely agricultural; thus, the results do not necessarily represent conditions in other water-supply reservoirs in New York State. The most frequently detected pesticides or pesticide metabolites were the corn herbicides atrazine and metolachlor, and two metabolites of metolachlor - metolachlor ethanesulfonic acid (ESA) and metolachlor oxanilic acid (OA). More than half of the samples from the three water-supply intake sites contained at least one of these compounds at concentrations greater than 0.2 µg/L (micrograms per liter); the concentrations ranged from 0.01 to nearly 10 µg/L. Many samples contained metabolites of other commonly used herbicides at concentrations greater than those of their parent compounds. Only two insecticides or insecticide metabolites were detected (carbofuran and p,p’ -DDE and concentrations of these compounds were less than 0.1 µg/L. The total concentration of pesticides and metabolites at the three water-supply intake sites are correlated with land use. The highest concentrations were in the watershed with the greatest percentage of row-crop land use,and the lowest concentrations were in the watershed with the smallest amount of row-crop land use. Total median concentration of all pesticides and metabolites at the water-supply- intake sites (median sum of detected pesticide and metabolite concentrations in all samples) was 10.0 µg/L for the LeRoy intake (25 percent row-crop land use), 2.99 µg/L for the Perry intake (21 percent row-crop land use), and 1.28 µg/L for the Hornell intake (12 percent row-crop land use). The decline in concentrations and numbers of pesticides and metabolites detected after the first storm runoff following pesticide application (the spring flush) was generally much greater in the tributaries than at the water-supply intakes, particularly for the LeRoy site. The lower variability at the intake sites is attributed to storage within the reservoir and may also be the result of sustained release of pesticides and metabolites from ground water that discharges to the reservoirs.

New York↗

USGS1999

Recommendations for Cycle II of National Water-Quality Assessment (NAWQA) Program

The Planning Team for the U.S. Geological Survey (USGS) National Water-Quality Assessment (NAWQA) Program defines a successful NAWQA Program as one that makes a balanced contribution to study-unit issues, national issues, and to the pursuit of scientific knowledge. Using this criterion, NAWQA has been a success. The program has provided important new knowledge and understanding of scientific processes, and insights into the occurrence and distribution of contaminants that have been key to local and national policy decisions. Most of the basic design characteristics of NAWQA's first decade (1991-2000), hereafter called cycle I) remain appropriate as the program enters its second decade (cycle II) in 2001. In cycle II, the program has the opportunity to build on its successful base and to evolve to take advantage of the knowledge generated in cycle I. In addition to this expected evolution, NAWQA must also make some changes to compensate for the fact that program funding has not kept pace with inflation. An important theme for the second cycle of NAWQA will be the integration of knowledge across scales and across disciplines. The question that drove the NAWQA design in the first cycle was "How is water quality related to land use?" Cycle II will build upon what was learned in cycle I and use land-use and water-quality gradients to identify and understand potential sources of various constituents and the processes affecting transport and fate of those constituents and their effects on receptors. The understanding we gain from applying this approach will be relevant to the interests of policymakers, regulatory agencies, and resource managers.

Open-File Report↗

USGS1999

Pesticides and their metabolites in wells of Suffolk County, New York, 1998

Five insecticide residues and 20 herbicide residues were detected in water samples collected from 50 shallow wells screened in the surficial sand and gravel aquifer in Suffolk County, Long Island in areas with known or suspected residues. Laboratory analytical methods with extremely low detection limits - from 0.001 to 0.2 ?g/L (micrograms per liter) - were used to analyze the samples for 60 pesticide residues. Forty-four of the samples contained at least one pesticide residue, and some samples contained as many as 11 different pesticides or pesticide metabolites. Only four water- quality standards were exceeded in the samples collected in this study. Dieldrin exceeded the New York State Class GA standard (0.004 ?g/L) in samples from eight wells. The Federal and New York State Maximum Contaminant Level for simazine (4 ?g/L) was exceeded in samples from two wells, and the State Class GA standard for simazine (0.5 ?g/L) was exceeded in samples from six wells. Federal water-quality standards have not been established for many of the compounds detected in this study, including herbicide metabolites. Maximum concentrations of four herbicide metabolites -metolachlor ESA (ethanesulfonic acid), metolachlor OA (oxanilic acid), and the alachlor metabolites alachlor ESA and alachlor OA -exceeded 20 ?g/L. The maximum concentration of one herbicide (tebuthiuron) exceeded 10 ?g/L, and the maximum concentration of three herbicides (simazine, metolachlor, and atrazine) and one herbicide metabolite (deisopropylatrazine) ranged from 1 to 10 ?g/L. The herbicide metolachlor, which is used on potato fields in Suffolk County, and its metabolites (metolachlor ESA and metolachlor OA) were most frequently detected in samples from agricultural areas. The herbicides simazine and tebuthiuron, which were used in utility rights-of-way, and the simazine metabolite deisopropylatrazine were detected at concentrations greater than 0.05 ?g/L most frequently in samples from residential and mixed land-use areas. The results of this investigation are not necessarily representative of conditions throughout the remainder of Long Island, because these samples were collected in areas of known or suspected residues.

Water-Resources Investigations Report↗

USGS1998

Isotopes as indicators of environmental change

In addition to providing an understanding of processes within a catchment system, isotopic techniques have been instrumental in providing reconstructions of catchment climate and other environmental indicators at various time scales. Many recent changes are a direct consequence of anthropogenic activities. Isotopic analysis serves as a valuable tool for distinguishing between natural variations in long-term climatic patterns and anthropogenic effects, yielding improved understanding of natural feedback mechanisms and the development of realistic remediation strategies. This chapter discusses the examples of isotopic techniques that have been applied to understand several types of ongoing and recent environmental changes, and in paleo-environmental studies. It discusses isotope geochemistry, hydrology, and climatology to look at new ways of applying isotopic tracing techniques to provide information on environmental change. It also gives an overview on how isotopic indicators are being applied in investigations of environmental change in continental settings.

Book chapter↗

USGS1998