Fluoride analysis of drinking water in endemic fluorosis areas in Shandong province from 2005 to 2007

Objective To investigate the distribution of water-borne fluoride and the current status of water defluoridation project by improving drinking water quality in endemic fluorosis areas in Shandong province,and to provide scientific basis for making strategies in prevention and control of the disease. Methods According to "the National Technical Scheme for Endemic Disease Control in 2004, 2005 and 2006", 113 endemic fluorosis diseased counties(cities, and districts) of the province's 17 cities were screened in order to investigate the fluoride level in drinking water in fluorosis villages, recheck the fluoride level after implementing the water defluoridation project, and investigate the current status of the water defluoridation project. The fluoride level in drinking water was determined by F-ion selective electrode. Results There were a total of 5816 water defluoridation projects in the province. Most of them were carried out by drilling a deep well to get under-ground water. The wells still in good condition were accounted for 72.80% (4234/5816). Intermittent operated wells were accounted for 3.11% (181/5816). Abandoned wells were accounted for 24.09%(1401/5816). Level of water fluoride was determined in 6940samples from fluorosis villages(villages that not carry out the water defluoridation project as well as villages carried out the water defluoridation project with abandoned wells were included) and the value that lower or equal to 1.00mg/L was determined in 2987 villages which accounted for 43.04% (2987/6940). Level of water fluoride that over 1.00 mg/L was found in 3953 villages which accounted for 56.96% (3593/6940), and the highest level of water fluoride was 11.33 mg/L. Level of water fluoride were determined in 4415 samples from water defluoridation project and the value lower or equal to 1.00 mg/L was in 2983 wells which accounted for 65.53%(2983/4415). The value over 1.00 mg/L was in 1522 wells which accounted for 34.47%(1522/4415), the highest value of water fluoride was 9.71 mg/L. Conclusions Level of water fluoride in up to 1/2 of the villages and 1/3 of the projects, is still higher than the standard in Shandong province. Nearly 1/4 of the project has been abandoned. The current situation for endemic fluorosis control is still not good in the province, countermeasures for endemic fluorosis must be carried out as soon as possible and surveillance of water defluoridation project must be strengthened. Key words: Endemic diseases; Fluoride poisoning; Water defluoridation project