Use of Pesticides and Application of an Index for Assessing the Possibility of Groundwater Contamination in Golf Courses in Jeju

This study aimed to investigate pesticides used in golf courses in Jeju and evaluate the possibility of groundwater contamination by the used pesticides. In the recent past, the use of pesticides in golf courses at Jeju has increased every year. In 2020, the use of products in which pesticide was the main ingredient reached 9.58 kg/ha, which is 1.4 times higher than the national usage. The pesticides used in golf courses were ranked as follows by usage: fungicide > insecticide > herbicide, and by ingredient used: chlorothalonil > thiophanate-methyl > iprodione > tebuconazole > etridiazole. By monitoring the residual pesticides in golf courses, we detected a total of 11 ingredients from 2014 to 2020. Most of these included low toxic fungicides with a half-life of more than 30 days in soil. Based on the groundwater ubiquity score (GUS), the top 10 most-used pesticides in 2020 were found to have a low to moderate possibility of groundwater contamination. However, azoxystrobin and thifluzamide, which were detected every year via monitoring of pesticide residues, have a high possibility of groundwater contamination.