Ecological Geochemistry Of Heavy Metals And Remediation Of Contaminated Soil Using Chemical Immobilization Method In Western Shenyang

Distributions of heavy metals in river waters, groundwater, surface sediments, soils, farm products, domestic poultry, fish, and human scalp hair were studied. Using multiple assessment and GIS methods, the pollution levels, potential risk, and sources were evaluated. The following conclutions can be made.(1) The single pollution index and Nemero index of six heavy metals in the Hun and Pu River were all less than 1.0. The water of the Irrigation Channel of Shenyang and Fushun were both slightly polluted by Cr and Cd. The Cd and Cr pollution in shallow groundwater adjacent to the Xi River were more serious at medium pollution level. The deep groundwater and rice field water adjacent to the Xi River were classified as clean. The Pu River and Hun sediments ranked as at low potential ecological risk for seven heavy metals. Cd in the Xi River sediments was ranked as very high level risk and Cu as medium-level risk.(2) Supported by Geographic information system (GIS), the pollution situation of seven heavy metals in top soils from the farmland adjacent to the Pu, Hun, Xi River and the Shenyang-Fushun Irrigation Channel were studied using the multiple evaluation methods. The Hg, Cd, Zn, As, Cr, Cu, and Pb contents were all higher than the background value of Liaoning Porovince soil. The farmland soils nearby the Xi River were seriously polluted. The pollution sources could be waste water discharge and solid waste; utilization of phosphorous fertilizers and manure; metallurgical, electro-plating and stainless steel industries. The GIS method proved to be feasible, effective and direct for pollution evaluation and source identification.(3) Pollution status of heavy metals in crops, vegetables, poultry, and fish from some villages near the Xi River were investigated. Cadmium contents in rice seeds exceeded the national standard by 33.3%, showing an enrichement relative to soils.. Arsenic, cadmium, and chromium in part of poultry samples exceeded the national standard. Mercury and arsenic in fish samples from the junction of the Xi River and Hun River exceeded the national standard.(4) Concentrations and geographic distribution of heavy metals in human hairs from the residents in the villages near the Xi River were investigated, which were significantly dependent on sex and age, and possibly related with the industrial pollution in the river watershed. Zn and Cr in the hair samples were high but Pb, Cd, Hg were at a normal level.(5) According to the local people’s dietary habit, the potential human health risks posed by heavy metals via diet were estimated. The uptake of arsenic was 44.3% of the Reference Dose value (RfD) 3.0 mg/kg body weight/d suggested by USEPA. The symdrom of skin desease occurred in some residents linving near the Xi River may coused by chonic poison via a long-term accumulation of arsenic in human body.(6) The pollution of Mn and Br, which are not the routine environmental monitoring objects in China, in the Xi River watershed area were abnormaly high. Concentrations in groundwater from several villages in the Xi River watershed exceeded the national standard for Level IV waters. The Mn contents in crops and vegetables were dependent on species and possibly caused by shallow groundwater irrigation.(7) An in situ field experiment was carried out in a farmland near the Xi River, western Shenyang, using several P-containing agents for various vegetables unde rthe irrigation of sub-shallow groundwater contaminated by heavy metals to som extent. The amendment by phosphorite was more effective than P fertiliser, and after remediation, the heavy metal contents in the vegetables were greatly reduced to be within the restriction values of the national standrad.