3 TYPES OF APPROACHES TO CONTROLLING NONPOINT-SOURCE POLLUTION OF AGROCHEMICALS FROM GOLF LINKS IN WATER-RESOURCES MANAGEMENT

In recent years Japan has had an opportunity to develop a strategy to control diffused pollution of agrochemicals in watersheds upstream of drinking water intakes. Three types of approaches to controlling proba ble pollution have been examined. These are (1) risk based assessment approach, (2) regulatory approach supported by standard setting and (3 ) planning based guide to land use. In this paper, based on the result s of pilot studies in several golf links the practical procedures of t hese approaches are systematically structured. First, risk-based asses sment approach includes typical exposure assessment and quantitative r isk assessment (QRA) coupled with fate analysis of runoff into reservo irs. The basic process of QRA of indicative herbicides, insecticides a nd fungicides, generated the result that additional cancer risk would be around minus 5-6 order of life time risk for citizens to drink wate r from reservoirs receiving contaminated river water. Second, appropri ate standard setting enhances a reasonable regulatory approach. In 199 0, concentration of twenty agrochemicals in effluents from golf links and rivers at receiving outlets from golf links were evaluated in a na tion-wide program in terms of the ratios of samples having higher conc entrations than the tentative quality standard. Both seasonal change o f observed concentration in dry weather and high concentration in rain fall events are evaluated. Concerning a planning based guide to land u se, zoning of forest conservation districts for water resources conser vation would be responsible for appropriate land use management and wa ter quality control. The author proposed the skeleton of a water resou rces conservation plan for safe drinking water supply for a local gove rnment as a client, especially emphasizing land use suitability mappin g, development guides and mitigation techniques.