Pesticide-monitoring program of surface water in the State of Hawaiʻi
Summary
Problem Potential offsite impacts to public and ecosystem health from exposure to current-use pesticides and other organic contaminants are a growing concern in Hawaiʻi. In response to these concerns, the U.S. Geological Survey (USGS), in cooperation with the State of Hawaiʻi Department of Agriculture (HDOA), initiated a comprehensive pesticide-monitoring program of surface water in Hawaiʻi in 2016. The State of Hawaiʻi Department of Health (HDOH) is collaborating by providing technical and scientific assistance. Objectives The objectives of the Hawaiʻi pesticide-monitoring program include (1) documenting the occurrence and distribution of current-use pesticides in surface water of geographically distinct agricultural and developed [...]
Summary
Problem
Potential offsite impacts to public and ecosystem health from exposure to current-use pesticides and other organic contaminants are a growing concern in Hawaiʻi. In response to these concerns, the U.S. Geological Survey (USGS), in cooperation with the State of Hawaiʻi Department of Agriculture (HDOA), initiated a comprehensive pesticide-monitoring program of surface water in Hawaiʻi in 2016. The State of Hawaiʻi Department of Health (HDOH) is collaborating by providing technical and scientific assistance.
Objectives
The objectives of the Hawaiʻi pesticide-monitoring program include (1) documenting the occurrence and distribution of current-use pesticides in surface water of geographically distinct agricultural and developed areas and (2) comparing concentrations of pesticide compounds found in the environment with water-quality standards, criteria, and benchmarks.
Approach
The Hawaiʻi pesticide-monitoring program will collect surface-water samples in Hawaiʻi and analyze these samples for current-use pesticides. The pesticide-monitoring program builds upon the efforts and findings of a previous project, the 2013–14 State-Wide Pesticide-Sampling Pilot Project (State of Hawaiʻi Department of Health, 2014), by sampling under both high-flow and low-flow conditions, broadening the number of sample sites, and expanding the publicly available database of impartial and reliable pesticide data in the State. This program will provide information on the occurrence and distribution of pesticides as well as variations in pesticide concentrations under different flow conditions for surface waters near agricultural and developed lands. The concentrations of pesticides detected in the water samples will be compared with water-quality standards, criteria, and benchmarks. Results may be useful for evaluating possible links between pesticide concentrations in surface waters and pesticide-application practices in Hawaiʻi.
Studies of pesticides in Hawaiian streams during storms that cause high-flow conditions can be challenging because such periods are commonly infrequent and brief– especially in the relatively dry and flat lowland regions of the State where agricultural activities occur. Hence, the collection of water samples during high-flow conditions is difficult without complex stream-gaging stations that are properly located and that have automatic-pump samplers. USGS stream-gaging stations with automatic-pump samplers adequate for this program are currently (March 2018) established at sites on Oʻahu only. A subset of these existing stations with automatic-pump samplers will be used to collect high-flow samples at selected stream sites on Oʻahu only. Relatively simple and inexpensive stage-level samplers, which automatically collect stream water without powered pumps, will be used at selected stream and ditch sites on Oʻahu first, and then will be considered for use at additional sites on Oʻahu and neighboring islands. Low-flow samples will be collected at perennial streams and water bodies, and these samples may provide insight on the impacts of pesticides on groundwater in areas where surface water and groundwater interact. Passive, accumulation-type samplers will be deployed in perennial streams and water bodies for several weeks and will provide a time-weighted average assessment of contaminants in surface waters, which is critical for understanding the consequences of prolonged exposure to pesticides in water.
The monitoring strategies described above– as well as site selection, sampling frequency, and types of pesticides considered– will be evaluated by USGS in collaboration with HDOA and HDOH throughout the duration of the program, with adjustments to the strategies to be made as appropriate. Most samples likely will be analyzed for more than 200 current-use pesticides at the USGS National Water Quality Laboratory in Colorado, using the analytical method described in Sandstrom and others (2015). Pesticide results that meet quality-control objectives will be made available in the USGS National Water Information System database accessible at https://doi.org/10.5066/F7P55KJN. In addition, these pesticide results will be summarized and released periodically on this ScienceBase page (see Child Items below).
References cited
Sandstrom, M.W., Kanagy, L.K., Anderson, C.A., Kanagy, C.J., 2015, Determination of pesticides and pesticide degradates in filtered water by direct aqueous-injection liquid chromatography-tandem mass spectrometry: U.S. Geological Survey Techniques and Methods, book 5, chap. B11, 54 p., https://doi.org/10.3133/tm5B11.
State of Hawaiʻi Department of Health, 2014, 2013-14 State wide pesticide sampling pilot project water quality findings, Hazard Evaluation and Emergency Response Office, available at: https://eha-web.doh.hawaii.gov/eha-cma/documents/7fb9412b-9b2f-401e-992a-92bf729b3159.
