Current-use pesticides in urban watersheds and receiving waters of western Lake Ontario measured using polar organic chemical integrative samplers (POCIS)

Abstract

Abstract Surface water contamination with current-use pesticides (CUPs) is usually associated with inputs from agriculture. However, there are several urban sources of these compounds, including pesticides used in public spaces, golf courses, and lawns and gardens; discharges of municipal wastewater containing fungicides from pharmaceuticals and personal care products (PPCPs); and runoff of biocides that are used in construction materials. Polar organic chemical integrative samplers (POCIS) were used to monitor the occurrence of fungicides and selected herbicides in surface waters in the densely populated urban area near Toronto, Canada. Samplers were deployed in five urban streams, one agriculturally dominated stream, and at five locations in the nearshore zone of western Lake Ontario adjacent to urban areas. Sampling rates for target compounds in POCIS determined in laboratory calibration experiments ranged between 0.03 and 0.65 L/day. For herbicides, atrazine was detected at all sites, and diuron, 2,4-D, and mecoprop were frequently detected. The fungicides carbendazim and thiophanate-methyl were detected at all sites, and a hydroxy-metabolite of the fungicide chlorothalonil was also widely detected. Fungicides used in PPCPs (e.g. fluconazole, climbazole) were primarily detected in POCIS deployed in locations impacted by municipal wastewater. Estimated time-weighted average (TWA) concentrations of iprodione and carbendazim in urban streams were consistent with the number of golf courses in the watershed. However, runoff of biocides from building materials may also be a source of these fungicides. Overall, these data indicate that urban environments, as indicated by the Toronto area, have several point and non-point sources of fungicides and other CUPs.