Pesticides Detected in Urban Streams During Rainstorms and Relations to Retail Sales of Pesticides in King County, Washington

Abstract

Twenty-three pesticides were detected in water from urban streams during rainstorms, and the concentrations of five of these pesticides exceeded limits set to protect aquatic life. During rainstorms, 23 of 98 pesticides sampled for were detected in water samples from 12 study sites in 10 urban watersheds. Concentrations of five insecticides exceeded recommended maximum concentrations set by the National Academy of Sciences and National Academy of Engineering (NAS/NAE) (1973). In a few samples, concentrations of Diazinon, carbaryl, and Lindane exceeded U.S. Environmental Protection Agency (USEPA) and other chronic aquatic-life criteria. Pesticides used on lawns and gardens contribute to the occurrence of several pesticides in urban streams. According to 1997 sales data from home and garden stores, of the pesticides sampled for, Diazinon, 2,4-D, and MCPP are the most frequently purchased pesticides by residents of King County. MCPP and 2,4-D are also among those pesticides used by professional applicators for pest control in residential, recreational, and industrial areas. The presence of these pesticides in water samples from all of the 12 study sites shows that their widespread application impacts water quality in urban streams. Also, residents purchased and applied four of the five pesticides that exceeded recommended maximum concentrations set by the NAS/NAE (Diazinon, carbaryl, Malathion, and chlorpyrifos). Many pesticides found in urban streams might be the result of nonresidential applications. Almost half of the 23 pesticides detected in stream water had no retail sales according to a 1997 survey of pesticides sales from home and garden stores in King County. Two of these pesticides (atrazine and simazine) were found at more than 60 percent of the study sites. This indicates that these pesticides are being applied to nonresidential areas in urban watersheds such as rights-of-way, parks, and recreational areas.

Growth and survival of pacific coho salmon smolts exposed as juveniles to pesticides within urban streams in western Washington, USA

“…Previously, King and colleagues [18] compared the maximum reported concentrations of the pesticides within our cocktail with effects thresholds for aquatic life used by Wilson et al [50] for a subset of the streams in western Washington that formed the basis for the present study [16]. Anderson et al [15] compared concentrations of pesticides detected in Thornton Creek, 1 of the urban creeks included in the 2 previous USGS studies [14,16], with existing water quality criteria after more intensive sampling in 2003. Anderson et al [15] compared concentrations of pesticides detected in Thornton Creek, 1 of the urban creeks included in the 2 previous USGS studies [14,16], with existing water quality criteria after more intensive sampling in 2003.…”

“…Our pesticide cocktail was based on data for urban streams in western Washington collected between 1998 and 2003 [16]. Comparison of these data with results of monitoring in 1997 [14], 2003 [15], and 2007 [17] suggest that the pesticides most frequently detected have changed and concentrations have declined [18]. Most notably, diazinon was no longer registered for homeowner use as of 2003 [16].…”

“…Unfortunately, the potential for nonadditive toxicity within surface waters is relatively unknown [22]. Triazine herbicides are frequently detected in urban streams, likely associated with the use of lawn treatments [14,16]. For example, the addition of triazine herbicides to mixtures of some organophosphate pesticides resulted in synergistic toxicity in aquatic invertebrates [23].…”

“…Although pesticide inputs to surface waters are predominantly considered to be an agricultural concern, pesticides are detected in urban streams [13], including those in western Washington [7,[14][15][16][17]. Voss et al [14] detected 23 pesticides at 12 sites within 10 urban/suburban watersheds in western Washington after rainfall events and related the detections to retail sales of formulated products for garden and yard care by homeowners. In a more intensive study of many of the same creeks, Frans [16] detected 37 pesticides: 20 herbicides, 9 insecticides, 2 fungicides, and 6 transformation products.…”

“…For example, the addition of triazine herbicides to mixtures of some organophosphate pesticides resulted in synergistic toxicity in aquatic invertebrates [23]. Triazine herbicides are frequently detected in urban streams, likely associated with the use of lawn treatments [14,16].…”