Simultaneous Analysis of 13 Pesticides in Groundwater and Evaluation of its Persistent Characteristics

Abstract

For this study, groundwater samples for 3 years from 2011 through 2013 were collected at 106 groundwater monitoring site in Korea. These groundwater samples were analyzed for 13 pesticides such as cabofuran, pentachlorobenzene, hexachlorobenzene, simazine, atrazine, lindane (gamma-HCH), alachlor, heptachlor, chlordane (total), endosulfan (1, 2), dieldrin, endrin, 4,4-DDT. The objectives of this study were to determine the detection frequency and their concentrations of 13 pesticides and evaluate the health risk level considering ingestion, inhalation, and skin contact using concentrations of 13 pesticides in groundwater samples. An analysis was used for the simultaneous determination for 13 pesticides using GC-MS. GC-MS was performed on HP-5ms, using helium (1 ml min-1) as carrier gas. The average recoveries of the pesticides were from 92.8% to 120.8%. The limits of detection (LODs) were between 0.004 µg L-1 and 0.118 µg L-1 and the limits of quantification (LOQs) were between 0.012 µg L-1 and 0.354 µg L-1. 106 groundwater wells were selected. 54 wells were from well to monitor background groundwater quality and 52 wells were from well to monitor groundwater quality in industrial or contamination source area. Eight pesticides including pentachlorobenzene, lindane (Gamma-HCH), heptachlor, chlordane (total), Endosulfan (1, 2), dieldrin, endrin, and 4,4-DDT were not detected in groundwater samples. The detection frequency for hexachlorobenzene, alachlor, carbofuran and simazine was 23.4%, 11.4%, 7.3%, and 1.0%, respectively. Atrazine was detected once in 2011. The average concentrations were 0.00423 µg L-1 for carbofuran, 0.000243 µg L-1 for alachlor, 0.00015 µg L-1 for simazine, and 0.00001 µg L-1 for hexachlorobenzene. The detection frequency of hexachlorobenzene was high, but the average concentration was low. In the contaminated groundwater, the detection frequency for hexachlorobenzene, alachlor, carbofuran, simazine and atrazine was 26.1%, 21.3%, 7.1%, 1.9% and 0.3%, respectively. In the uncontaminated groundwater, detection frequency for hexachlorobenzene, carbofuran and alachlor were 20.2%, 7.5%, and 1.9% respectively. Simazine and atrazine were not detected at uncontaminated groundwater wells. According to the purpose of groundwater use, atrazine was detected for agricultural groundwater use. Hexachlorobenzene showed high detection frequency at agricultural groundwater use area where the animal feeding area and golf course area were located. Alachlor showed more than 50% detection frequency at cropping area, pollution concern river area, and golf course area. Atrazine was detected in agricultural water use area. By land use, the maximum detection frequency of alachlor was found near an orchard. For human risk assessment, the cancer risk for the 5 pesticides was between 10-7 and 10-10, while the non-cancer risk (HQ value) was between 10-4 and 10-6. For conclusion, these monitoring study needs to continue because of the possibility of groundwater contamination based on various purpose of groundwater use. Detection frequency and average concentrations of pesticides near the sources of the contamination (S: Agricultural water use area, N: Crops area, O: Pollution concern river area, F: Industrial area, P: General waste landfill area, I: Designated waste landfill area, K: Metal mine area, B: Area near the manure treatment plant, J: Resident health survey area, U: Amusement park & Park area, G: Golf course area, C: Urban residential area, T: Storage tank area).