VOCs, Pesticides, Nitrate, and Their Mixtures in Groundwater Used for Drinking Water in the United States

Abstract

Samples of untreated groundwater from 1255 domestic drinking-water wells and 242 public supply wells were analyzed as part of the National Water-Quality Assessment Program of the U.S. Geological Survey between 1992 and 1999. Wells were sampled to define the regional quality of the groundwater resource and, thus, were distributed geographically across large aquifers, primarily in rural areas. For each sample, as many as 60 volatile organic compounds (VOCs), 83 pesticides, and nitrate were analyzed. On the basis of previous studies, nitrate concentrations as nitrogen g3 mg/L were considered to have an anthropogenic origin. VOCs were detected more frequently (44%) than pesticides (38%) or anthropogenic nitrate (28%). Seventy percent of the samples contained at least one VOC, pesticide, or anthropogenic nitrate; 47% contained at least two compounds; and 33% contained at least three compounds. The combined concentrations of VOCs and pesticides ranged from about 0.001 to 100 µg/L, with a median of 0.02 µg/L. Water from about 12% of the wells contained one or more compounds that exceeded U.S. Environmental Protection Agency drinking-water standards or human health criteria, primarily because of nitrate concentrations exceeding the maximum contaminant level in domestic wells. A mixture is defined as a unique combination of two or more particular compounds, regardless of the presence of other compounds that may occur in the same sample. There were 100 mixtures (significantly associated with agricultural land use) that had a detection frequency between 2% and 19%. There were 302 mixtures (significantly associated with urban land use) that had a detection frequency between 1% and <2%. Only 14 compounds (seven VOCs, six pesticides, and nitrate) contributed over 95% of the detections in these 402 mixtures; however, most samples with these mixtures also contain a variety of other compounds.

Applying a statewide geospatial leaching tool for assessing soil vulnerability ratings for agrochemicals across the contiguous United States

“…Groundwater in the United States (US) was found to be vulnerable to a mixture of various contaminants, such as nitrate, pesticides, and volatile organic compounds (VOCs) (Nolan and Hitt, 2006;Squillace et al, 2002). Soil and groundwater contamination occurred from intensive human activities in both urban and agricultural areas, e.g., industrial discharges, landfills, hazardous waste dumps, septic tanks, and fertilizer applications (USEPA, 1997;Zogorski et al, 2006).…”

Degradation of methiocarb by monochloramine in water treatment: Kinetics and pathways

“…It has been frequently detected in groundwater in various countries at concentrations ranging from 0.03 to 5.40 mg L À1 (Barcelo et al, 1996;Garcia de Llasera and Bernal-Gonzalez, 2001;Squillace et al, 2002;APVMA, 2005). Although the detected concentrations of MC in natural waters are generally low, it poses a serious health threat to aquatic life and human considering its high toxicity.…”

Correlação entre uso da terra e qualidade da água subterrânea

“…Essa influência pode ser avaliada de diversas formas, como, por exemplo, usando-se um raio fixo em torno do poço SQUILLACE et al, 2002). Nos trabalhos feitos por Nolan et al (2002) e Squillace et al (2002), a degradação da qualidade da água subterrânea foi classificada e avaliada utilizando-se um círculo com raio de 500 m, centrado no poço.…”