Water Resources Research Act Program

Details for Project ID 2018NC218B

Occurrence of pesticides in North Carolina private drinking water wells and identification of point-of-use treatment options

Institute: North Carolina
Year Established: 2018 Start Date: 2018-03-01 End Date: 2019-02-28
Total Federal Funds: $15,000 Total Non-Federal Funds: $52,800

Principal Investigators: Detlef Knappe, Francis de los Reyes, Catherine LePrevost

Abstract: Approximately 3.3 million North Carolinians (35% of the population) rely on private wells as their primary source of drinking water. Private wells are susceptible to contamination by chemicals applied to the land surface. Limited data from past studies as well as recent data from county health departments demonstrate that pesticide occurrence is a concern for the private well community in NC. Our first aim is to determine the occurrence of pesticides in private wells located in five NC counties. We will include in our analysis the nematicide 1,3- dichloropropene (1,3-D) and its legacy impurity 1,2,3-trichloropropane (TCP), a potent carcinogen. Based on the heavy use of 1,3-D in NC and TCP occurrence data from other states, we hypothesize that TCP commonly occurs in shallow private wells in the NC coastal plain. A second aim is to develop a framework for the selection of point-of-use (POU) filters that effectively control chemical and microbial risks posed by private well water. We hypothesize that POU filters containing activated carbon (AC) effectively remove esticides, but more advanced filtration devices are needed when pesticides co-occur with inorganic (e.g., nitrate or arsenic) and/or microbial contaminants (i.e., pathogens). The latter is of concern because AC filters are readily colonized by bacteria present in the drinking water source and filtration through biological AC increases microbial concentrations in filter effluent, a concern we will assess in this study. We will conduct community-based sampling in five NC counties, quantify pesticides, TCP, inorganics, and fecal indicator organisms in well water, and identify contamination patterns based on underlying aquifer geologies and well construction practices. Follow-up testing during year 2 will be conducted after 6 months at wells with detectable pesticides. We will also determine the efficacy of home filtration devices for controlling chemical and microbial risks in laboratory and field settings and will discuss home filtration options with residents whose water samples tested positive for pesticides, VOCs, or other constituents of concern in year 1. This research has the potential to yield clear public health benefit for the private well community in NC and across the US. The developed water quality data will support county health departments and the well water community to assure drinking water safety through (1) absence of pesticide detections or (2) identification of effective home filtration options.