Investigation And Assessment Of Basic Groundwater Environment Situation In Qiqihar Urban Area

Groundwater pollution is increasingly serious with the development of economy, which urges both normative and systematic implementation of groundwater protection and pollution control management system. It is the strategic water source in Qiqihar area that the pollution situation of groundwater needs to be well investigated and effective protection and control measures needs to be proposed. This project adopted the Qiqihar urban area as the research area with landfills of Heihua Group, Hongxing and Liming as typical pollution fields. The status of groundwater near industrial pollutant sources and landfills were first investigated and evaluated, and further the assessment for groundwater pollution simulation and prediction, health risk, prevention and control area division and field restoration(pollution prevention and control)were conducted. In the end, a general overview of the status of groundwater pollution in Qiqihar area was obtained and adequate protection and preventing strategies were proposed accordingly.Utilizing the single component evaluation method and comprehensive evaluation method according to the Groundwater Quality Standards(GB/T 14848) and simultaneously referring the Surface Water Environmental Quality standards(GB 3838), this study carried out an quality assessment on the groundwater quality of the research area of Heihua Group, Hongxing and Liming. Pollution index Pki method was used to evaluate the pollution status of the three sites. The results demonstrated that groundwater quality of the five sites selected within the research area of Heihua tended to be “extremely poor” while the pollution situation had the same trajectory which were also “severely polluted”. On the other hand, the study result of six points in the Red Star landfill consisted of one “rather poor” and five “extremely poor” with the pollution status was “severely polluted”; The five points of Liming landfill showed one “rather poor” and four “extremely poor” while the pollution status was “severely polluted”.In the simulated prediction assessment for groundwater pollution, Visual MODFLOW software was utilized for construction the flow model concerning the groundwater of the research area of Heihua. The transport modeling of volatile phenols showed that its transport rate was high and its concentration in downstream Nenjiang River was estimated to exceed the type III groundwater quality standard in one year, threatening the security of the water environment in Nenjiang area.In health risk assessment of toxicity, harmfulness and exposure routes of the groundwater of the Heihua, Hongxing and Liming sites, human health risk value contributed by methylbenzene or ethylbenzene in the groundwater was calculated combining with the scene mode within the three sites. The assessment results showed that carcinogenic risk level due to ethylbenzene in Heihua site was unacceptable, corresponding remediation practices were needed to perform immediately. At that point, by using qualitative matrix method, the remediation approaches were initially proposed, including the Monitored Natural Attenuation(MNA), groundwater barrier, in-situ microbial remediation, in-situ chemical oxidation(ISCO), etc.In order to carry out assessment for appropriate districts where groundwater pollution prevention and control measures would perform in Qigihar City, a series of assessment conclusions, comprising pollution source load assessment, groundwater vulnerability assessment, functional value assessment, etc, were considered in general. The results showed that the risk value of groundwater source in most parts of Qiqihar urban area was relatively low. As a result, this zone was defined as a conservation area. The prevention and control risk value of partial water source areas in Fulaerji District was high and near the Heihua site. Accordingly, the health risk value was unacceptable and this area was suggested to be zoned as a remediation area. The other areas were zoned as general prevention and control area, important prevention and control area and prior prevention and control area according to corresponding risk value.