Study On The Distribution Of Arsenic In Groundwater And Its Transport In Farmland Soil In Kuitun，Xinjiang

High arsenic groundwater is common in arid region, and such phenomenon has strong negative effect on the agriculture and human health. Kuitun Farming Area in Xinjiang is the first area with endemic arsenic poisoning disease identified in China. Although arsenic related diseases have been under control by alterative drinking water supply, however, for agricultural irrigation it is still a common practice. This paper focused on the distribution of As in groundwater through field investigation and sampling as well as lab test and analysis. Transport and accumulation of arsenic in soils under high As water irrigation were studied by using the soil column experiment, adsorption experiment, simulated leaching experiment, respectively, for providing the theoretical basis of reasonable utilization of groundwater resources in arid region. The main conclusions were as follows:(1)The concentration of As in the groundwater ranged between 2.29-400.68μg·L-1.The mean value was 87.34μg·L-1 and it was 9 times standard for drinking water quality.There were 32% samples the concentration of As had beyond the agricultural irrigation request. As and altitude had a significant negative correlation and the correlation coefficient was-0.550**.The concentration of As in the Kuitun area increased gradually from south to north.The groundwater quality in water supply meeted standard for drinking water quality. The quality in well irrigation area meeted standard for irrigation water quality.The quality in non well irrigation area exceed standard for irrigation water quality as it can not directly agricultural irrigation.(2) Isothermal adsorption of As can be fitted by Langmuir and Freundlich equation. Formland soil in Kuitun had strong adsorption capacity of As. The smaller solid-to-liquid ratio was, the stronger the adsorption capacity was. The soil had the biggest amount of As sorption on the p H=5. As sorption mostly increased with p H fluctuate on the p H﹥5.(3) After leached in the soil column, As was mainly concentrated in the first 0-2 cm and As concentration gradually decreased with soil depth.As was mainly existed in O-As and Al-As while H2O-As and A-As is a little less in soil. The O-As was most in 0-2cm soil and Al-As t is most in 2-20 cm. O-As,Fe-As and H2O-As was gradually decreased. The HYDRUS-1D model can predict transport of As in the farmland soil and the correlate coefficient is 0.985.According to the prediction modes, As concentration would exceed standards for groundwater quality(Ⅲ)when irrigation time last more than12 years and the environment and groundwater would be suffered a certain risk of contamination.