| Organic contamination detection results from 69 cities of 31 provinces show that at least one organic matter was detected in 383 samples among 791 samples detected, with the detection ratio of 48.42%. Single organic pollutant exceeds the standard in 18 samples, and the over-limit of carbon tetrachloride, benzene, chloroform, 1,2-dichloroethane, trichloroethylene, 1,1,2-trichloroethane, 1,2-dichloropropane, and benzo(a) pyrene is 0.75%, 0.5%, 0.25%, 0.25%, 0.13%, 0.13%, 0.13% and 0.13% respectively. Most sampling wells are agricultural, industrial and domestic wells, and some of them are water supply wells. Concentrations of organic pollutants in the wells of the water resource area are lower than those of the drinking water standard. Detection indicators are 38 substances that cause abnormality, cancer and mutation, and harmful and toxic and hazardous substances, comprising 15 halohydrocarbons, 5 chlorobenzenes, 6 monocyclic aromatic hydrocarbons, 11 organochlorine pesticides and 1 polycyclic aromatic hydrocarbon. The analytical results show that, although the over-limit ratio is relatively low, the detection ratio is relatively high for organic matter in groundwater in main cities of China. Some organic matters were detected with relatively high detection ratios. The detection ratio of chloroform, benzo(a) pyrene, total HCH, β-HCH, tetrachloroethylene, 1,2-dichloroethane, 1,2-dichloropropane, carbon tetrachloride, trichloroethylene, dichloromethane, and benzene is 20.23%, 16.21%, 6.03%, 5.65%, 5.03%, 4.4%, 4.15%, 3.89%, 3.77%, 3.64% and 2.01% respectively, whereas that of other substances is lower than 2%. |