1. Analyzed research of groundwater pollution by sulfometuron methyl X.Yi, W.H.Feng Changan University, College of Environmental Science and Engineering China Introduction Sulfometuron Methyl is a new-typed, low toxic, super-high-efficient, non-farmland used, non- selective, broad spectrum herbicide. It may transfer from soil into groundwater easily, and its biological activities are enhanced under the situation of increasing of soil water capability. When farmland is irrigated by polluted groundwater, agricultural products are harmed and productions are declined. Methods Investigating plants injured symptoms; By simulating experiment to rule out related other organic pollutants; By tracing and analyzing on pollutant in the groundwater, and calculating influence radius of well to clarify the situation of groundwater pollution. Results and discussion There are 3 kinds of organic matter for experiment ( table 1). Contrasted with CK, biological outputs of chinese cabbages that are treated by carbon bisulfide, ethylenduamine and sulfometuron methyl respectively, are all decreased significantly. Compared vegetable injured symptom between field and pot experiments, which are irrigated by ground- water and sulfometuron methyl treatments respectively, are the same exactly. It is Table 1 The influences of different treatments on growth of Chinese cabbage deduced that there be exist relationship between sulfometuron methyl and groundwater polluted. Analyzing groundwater sample in polluted and non- polluted area, concentration of sulfometuron methyl in polluted area is between 0.16 to 2.32μg/l. Several samples can be detected out sulfometuron methyl fragment ion peak. In the un-pollution area sulfometuron methyl is not detected in phreatic water. Analyzing hydrogeological conditions on groundwater pollution Under conditions of the exploitation flow field, ground-water depression cone will be formed when single well is exploited. It will be formed 2 small-scale exploitation flow fields when group wells are exploited (figure 1), in which one of groundwater depression cone, named A area, that is consisted of 6 wells, including well 04, 05, 06, 07, 08 and 11, is located in the south of pipeline leaking spot, and the other one, named B area, that is formed by well 01, 02, 03, 13, 14 and 15, is located in the north of pipeline leaking spot.

2. Legend: 1 building 2 polluted well 3 normal well 4 waste water pipeline 5 pipeline leaking spot 6 pollution area 7 trail 8 contour 9 enclosing wall of factory 10 road In the A area, if single well is exploited, the groundwater table of any well that is located in the south of pollution source will be fallen down, and the direction of groundwater flow will also be changed to the center of groundwater depress cone. So pollutant migrates against the direction of groundwater to A area. When group wells are exploited, if only water table falls 3m, well 04, 05, 06, 07, 08 and 11 will be polluted all. Only all wells in A area are not exploited, and lowering groundwater table recover to original table, groundwater flow field transfers to natural state, pollutant will be migrated along the direction of N30°W groundwater. Conclution In the pollution area, no matter crops and weeds, if they are irrigated by groundwater, all appear injury symptoms. By total analyzing phreatic groundwater, the results correspond to the national standard of agricultural irrigation. The possibility that inorganic pollutants is ruled out. By simulation experiment, it is confirmed initially that polluted phreatic groundwater is related with sulfometuron methyl. By contrasting concentrations of sulfometuron methyl in water samples between pollution area and un-pollution area, it is proved further that groundwater is polluted by sulfometuron methyl. By analyzing hydrogeological conditions of pollution area, when groups wells are exploited, the state of migration and distribution of pollutant in groundwater corresponds totally to actual situation. The influence radius of single or group wells are calculated in A area and B area respectively by the related formula (Table 2). Table 2 Influence radius of single well and group wells at different decreased values of water table (m) From table 2 and figure 1, the results are reached that no matter single well or group wells are exploited in the B area, if the distance between well and pollution source is smaller than influence radius, pollutants will be migrated quickly towards this well or group wells and contaminated groundwater. Fig. 1 Sketch map of the scope of pollution area