Study On Risk Assessment Of Groundwater Contamination And The Design And Development Of Software System

With the dynamics strength of environmental protection and the confirmation of strategy "people-oriented" and "harmonious development of economy, society, environment" of our country, it has already been upgraded to a very important position to protect the health of human being and to keep the sustainable development of human society. Health risk assessment (HRA) is an important method to quantitatively determinate the relationship between pollution and human health. HRA not only can make scientific evaluation about the possibility and the degree of contamination's damage to human health, but also can offer dependable warrant for pollution management and pollution repair.Based on the way of physical intakes and mechanism of contaminants, the relationship between contaminants exposure dose and physical health response, the groundwater contaminated risk assessment method was discussed and risk assessment software was designed and developed in this paper, the main contents of the research are as follows:(1) The paper briefly introduced the background, researching purpose and signification, main research problems and technical courses of the research which had established a basis for carrying out the research smoothly. In summary of the references, the current domestic and international research situation have been analyzed, characteristics and existing problems that domestic and international research came crossed have been summarized, which provided an effective and directive functions to choose research methods and assessment modes.(2) The principia of risk assessment was analyzed. The basic concept of risk assessment, mechanism of physical intakes of contaminants, carcinogenicity and non-carcinogenicity virulence of contamination were generally expounded. Compared of several commonly used risk assessment methods, their merits and faults have been summarized. Finally, NAS method of USA Country Sciences Academy has been chosen as the basic assessment method.(3) Health risk assessment of groundwater contamination was discussed, it includes data collection, dose-response assessment, exposure assessment and risk characteristics. It confirmed a proper exposure way, ten assessment modes of exposure dose computation and two modes of risk characteristics computation. The computation method of exposure dose of contaminants has been improved, which added some parameters, such as gastrointestinal absorption factor, skin absorption factor and skin permeability coefficient. The index system of health risk assessment has been established, which includes indices of risk assessment and exposure assessment.(4) Based on the principle of exposure assessment computation and risk characteristics computation models and interface design, use software of risk assessment of groundwater contamination with MATLAB, which has prominently interactive functions and amicably interfaced to achieve computation of exposure assessment and risk characteristics of health risk assessment.(5) It confirmed that trichloroethylene as the main contamination of the research area through investigation and tests for groundwater monitoring place. Aimed at computation of exposure assessment and risk characteristics for the truthful monitoring data of groundwater contamination in 2003～2006, exposure dose, risk of carcinogenicity and risk exponent of non-carcinogenicity indices has been found out, which applied the risk assessment software, through four ways as drinking exposure, breathing air exposure, touching water exposure and touching air exposure. The assessment result indicated that groundwater of research area has been contaminated by trichloroethylene, the carcinogenicity risk is much higher than normal standard and non-carcinogenicity risk is less than 1.0. Compared with the bar diagram of non-carcinogenicity risk, breathing air and drinking exposure are the main factors of carcinogenicity risk, the carcinogenicity risk caused by touching water and air exposure could be ignored. Based on the assessment results, some valid advices have been put forward to the local government and denizen.The main innovations of the research are as follows:(1) Summarized the research findings of many domestic and international references, developed an index system of risk assessment for groundwater contamination and it could provide scientific basis for groundwater contamination risk assessment.(2) Improved and perfected the related mode of exposure assessment and risk characteristics in the process of groundwater contamination risk assessment, which offered an integrated mathematics model for groundwater contamination risk assessment.(3) Used the MATLAB software to compile the risk assessment software for the first time, provided a high-eflfect, reliable and practical assessment tool for groundwater contamination risk assessment.