|dc.description.abstract||The objectives of this study were aimed to assess the human health risk of worker and residents near the petroleum hydrocarbons released site in central Taiwan in accordance with ASTM E1739-95, Standard Guide for Risk-Based Corrective Action (RBCA) Applied at Petroleum Release Site. Also, the major exposure pathways, analysis of sensitivity parameters and the risk of exposure regardless of correction were investigated in this study. Furthermore, values of the health risk were compared to the results from the Procedures for the Evaluation of Environmental Impact and Treatment Grading on the Definition of the Extent of Contaminants for Remediation Sites, announced by the Taiwan E.P.A. in 2003.
According to the study, for residents living outside the site, consuming vegetable, fruits and groundwater, and taking bath with groundwater, the risk of getting cancer is up to 1.0E-4. Even after the benzene concentration in the soil and groundwater has been significantly reduced, consuming of vegetable, fruit and groundwater brought the residents a risk of getting cancer up to 1.0E-7. Therefore, it is not recommendable to consume vegetable, fruits and groundwater from the site or its neighbor land.
Basement at organic contaminated site is one of the main pathways of exposure to the risk. The main risk for workers in the site is from inhalation of indoor air contaminated by pollutants volatilized from the soil and groundwater. The result of a sensitivity analysis indicated that the sensitivity parameter is gas exchange rate in closed space. Therefore, sufficient ventilation should be provided at basement to lower the risk.
Residents and pupils living outside the site are exposed to a considerable risk provided they drink groundwater or use it for bath. Thought a sensitivity analysis, it was concluded that the positive sensitivity parameter is hydraulic gradient, and the main negative sensitivity parameter is organic carbon content in the soil at the pathway of exposure. Therefore, restricting contaminated groundwater in the site from flowing to the neighbor land can effectively lower the risk outside the site, hydraulic control or construction of underground continuous walls are ways to stop the flow of groundwater to the neighbor land.
The result of an evaluation made with the Procedures for the Evaluation of Environmental Impact and Treatment Grading on the Definition of the Extent of Contaminants for Remediation Sites, announced by the Taiwan E.P.A. in 2003 showed that groundwater is the main contamination pathway, and the result of evaluation under ASTM 1739-95 also concluded that groundwater is a main contamination pathway. The results of these two evaluations are consistent. This is because the benzene concentration in the groundwater is much higher than that in the soil, and the main exposure pathways at the site are all related to the groundwater. Moreover, the physical and chemical properties of benzene, the hydrological and soil parameters of the site also contributed to the high score of groundwater in the evaluation. Thus, the groundwater is more important than the soil in the pathways of contamination.||en_US|