A survey of water quality in the nation's rivers, coastal areas and lakes showed little change in fiscal 1998 compared with the year before, according to a report released by the Environment Agency on Tuesday. In one portion of the annual study, 7,290 locations were checked to see whether water met government standards for protecting the environment and found that 77.9 percent of them did. The figure was 0.2 percentage point lower than the previous year. Nearly 74 percent of coastal waters, 81 percent of rivers and around 41 percent of lakes and reservoirs met the agency's environmental criteria, the survey showed. The figure for coastal waters was the lowest since fiscal 1976. The low compliance rate in lakes and other enclosed bodies of water was in part due to their tendency to remain polluted because of low water turnover rates, agency officials said. In addition, about 99.5 percent of the 5,409 sites studied to see whether standards for protecting human health had been met passed the test, according to the survey results. The survey highlights the need to improve water quality by pushing for stricter measures on waste water from homes and companies, according to the agency. The nation's five cleanest rivers were all in Hokkaido, while the most polluted river was Osaka's Kashi River, followed by the Benten River in Kagawa Prefecture and the Taniyagigawa in Hyogo Prefecture. Teganuma Lake, in Chiba Prefecture, retained the title of the lake or reservoir with the worst water quality, while the three cleanest lakes were also in Hokkaido. The condition of the nation's wells, however, is not much better. More than 60 percent of the approximately 1,800 wells previously found to be polluted continue to exceed environmental standards regarding volatile organic compounds and heavy metals, according to an Environment Agency report released Tuesday. Of the 1,800 wells, 1,188 are beyond permissible levels, 558 now clear environmental standards, and 54 can no longer be surveyed. The most commonly found pollutants were trichloroethylene, found in 610 wells, and tetrachloroethylene, found in 420 wells. Both are known carcinogens that are used in solvents for cleaning. The survey was based on groundwater contamination data taken between fiscal 1959 and fiscal 1998.