Health Risk Assessment On Groundwater Environment Of An Area In Chengdu

As one of the important water resource, groundwater is polluted worse and worseby high development. Contacting with pollutant is the key cause for influencinghealth. Part of Si Chuan treat Groundwater as drinking water. As once as it iscontaminated, residents health and society stability would be affected by contaminantthrough any ways. Basing on the above, making risk assessment on the groundwaterso as to establish the relationship between groundwater and human health means amatter of great significance to evaluate degree of damage on human health caused bygroundwater contamination.This thesis adopted four-steps put forward by NAS. Taking an area in the ChengDu as an example and modeling by pollutant exposure and health risk assessment, itmade health risk assessment on lots of contaminants in the groundwater. The mainconclusions are as below:(1) Evaluation by single factor pollution index showed that beryllium, nitrate andammonia nitrogen were key pollution factors. Factors as nitrite, manganese andsulfate could bring about potential harm.(2) In the risk assessment, analyzed the analytic hierarchy process to confirmpollutants which were harmful to human health. The screening and assessment systeminclude11index. The results showed that beryllium was the most harmful factor tohuman health, next to were barium and cuprum. Among them, sulfate, chlorides andiodides did least harm, so they were not taking into consideration in this assessment.(3) According to exposure assessment model of EPA, the exposure ofgroundwater pollutants was estimated. It showed that nitrate had the most even dailyexposure amount, next to it were fluorid ammonia, nitrogen, barium, iron and cuprum.It of manganese, zinc, iodides and nitrite were the least. As an arcinogenic pollutants,beryllium had an exposure amount between10-3and10-5a-1during wet season, whichcan’t be detected during drought period. Except for manganese and zinc, there waslittle difference among different sampling points of one element, which were in the same order. Through drinkingwater, even daily exposure amount of a child was thefour times than that of an adult.(4) Basing on the SF and RfD recommended by EPA, this thesis adopting healthrisk assessment model to evaluate carcinogen pollutant and non carcinogen pollutant.The research revealed that this area had polluted groundwater in this district. By theway of drinking exposure way, risk harm laying on a child was the four times thanthat of an adult. Meanwhile the human health risk lead by carcinogen pollutant ismore than that of non carcinogen pollutant. Beryllium risk for an adult had an averagevalue of8.09E-06during wet season, while that of a child was3.31E-05. As a result,the children health risk had over A small crowd acceptable risk value, which wasbetween10-5/a and10-4/a by EPA. Non carcinogen pollutants did more harm duringwet season than drought period. Among non carcinogen pollutants, barium could dothe most harm to human health, which was between10-8and10-9a-1. Although noncarcinogen pollutant would lead little health risk, it would make bad influence on thehuman health in long period. Total risk assessment during wet season was between10-5/a from10-6/a, which was above acceptable risk value set by EPA. Theunacceptable risk value should be paid high attention by some related departments.Total risk assessment during drought period was between10-7/a~10-8/a, which wasacceptable and leave little harm on human beings.(5) On account of the result, control and management plan should be drew on theexperience of. The specific measures should be taken by taking local economiccondition into consideration.