Pollution In Surface Soil Of HCHs And DDTs In Heilongjiang River Basin, China

This thesis in an effort to characterize the distrubuting of contamination of organochlorine pesticides which have been widely used as active inseticide in the history of China and are a few used now, including HCHs and DDTs in Heilongjiang River Basin (HRB) (China) where agriculture and industry at a higher level, besides HRB (China) used more organochlorine pesticides. And make a study of the usage、discharge、residues and influence on the entironment. In order to study the source and transport behavior of organochorine pesticdes, we samplinged from the Basin for monitoring the residue level, contact with the usage and residue inventories.The soil samples were collected from HRB (China) and analyzed the HCHs and DDTs, get the muster of usage, discharge and residues of HCHs and DDTs in HRB (China), moreover, forecasting and evaluation.Establish the analyse method of HCHs and DDTs, and detected and analyzed the soil samples which collected from HRB (China). The residue relves of HCHs range from 0.0037×10-3mg/kg to 9.82×10-3mg/kg with the average level of 1.057×10-3mg/kg which is lower than the levels of Yangtse River Delta、Guangzhou and Tianjin, and the residue relves of DDTs range from 0×10-3mg/kg ~6.11×10-3mg/kg with the average level of 0.87×10-3mg/kg. The HCHs in soil may come from the residues and the usage of lindane because there is no use of HCHs in HRB (China) at present. The concentrations ofβ-HCH and DDTs is undetected at B01, it is indicated that HCHs and DDTs haven’t been used in this area.The gridded maps of different croplands have also been used as surrogate in this study. Digital maps for rice, wheat, soybean, maize, sorghum, and orchard with 1/6°latitude by 1/4°longitude (12km×12km) resolution have been created for Heilongjiang River Basin (China). All these cropland datasets were compiled using an advanced high resolution radiometer (AVHRR) global land database, then a gridded inventory for total technical HCHs and DDTs usage was created. Between 1952 and 1984 total usege of technical HCHs was 108 900 t and between 1951 and 1984 total usege of DDTs was 4900 t in HRB (China). Heilongjiang province made the highest contributions in the use of these HCHs and DDTs in this basin, next is Jilin province and the lowest is the Inner Mongolia Municipality because the main farmland is Songnen Campagna and Sanjian Campagna where use more pesticide in the Heilongjiang River Basin.HRB (China) HCHs and DDTs emission inventories bases on the material diffusion in soil model and runoff model. The data of inventories is original data, then by VB program get HCHs and DDTs emission data which add the data of HCHs and DDTs is the total HCHs and DDTs.The results of emissions inventory indecated that the amount of HCHs and DDTs in soil in 2005 is much lower than 1985 the time of stop use of HCHs and DDTs in HRB (China), which is mainly in the Songnen Campagna, Sanjian Campagna and other region nearby. Except individual districts, the emission of the norther and southeastern mountainous area are almost zero. According to the data of the grid, the rate ofβ-HCH andα-HCH is higher than the previous, in the soil the concentration ofβ-HCH is more thanα-HCH, and the concentration ofβ-HCH was increased. This is indicated that there is no new contaminated source of HCHs in the basin during this period. According to the data of the grid, the emission amount rate of p,p’-DDE together with p,p’-DDD and p,p’-DDT is higer, while the concention of p,p’-DDE and p,p’-DDD was increased, which indicated that there is no new contaminated source of DDTs in the basin during this period.The concentration of HCHs and DDTs is decreased significantly in soil becacuse of degradation and emission to the surrounding environment. Only a very few areas have the low concentration residues of HCHs and DDTs in the northern and southeaste mountainous areas. The residues of HCHs and DDTs are mainly in the Songnen Campagna, Sanjian Campagna and other region nearby. The residues of HCHs and DDTs in soil are sill more in Nenjiang Basin and the area along the Songhua river, this is accord with the high density of farmland in the area.