Probabilistic ecological risk assessment of 1,2,4-trichlorobenzene at a former industrial contaminated site.
ABSTRACT Measured concentrations of 1,2,4-trichlorobenzene (1,2,4-TCB) in soil and groundwater detected in an industrial contaminated site were used to test several probabilistic options for refining site-specific ecological risks assessment, ranging from comparison of single effects and exposure values through comparison of probabilistic distributions for exposure and effects to the use of distribution based quotients (DBQs) obtained through Monte Carlo simulations. The results of the deterministic approach, which suggest that risk exceeds a level of concern for soil organisms, were influenced mainly by the presence of hot spots reaching concentrations able to affect acutely a large proportion of species, while the large majority of the area presents 1,2,4-TCB concentrations below those reported as toxic. Ground-(pore)water concentrations were compared with aquatic ecotoxicity data in orderto obtain an estimation of the potential risk for aquifers and streams in the adjacent area as well as for soil-dwelling organisms exposed via pore water. In this case, the risk is distributed over a large proportion of the site, while the local risk of hot spots was low, showing that risk characterization based exclusively on soil concentrations might be insufficient.
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ABSTRACT: Endosulfan concentrations and its distribution in air, soil, sediment and foodstuffs in the area surrounding a production facility in Huai'an, China were investigated because of its threats to the environment and human health. Air concentrations for endosulfan Ι, endosulfan II and endosulfan sulfate measured in this study were several orders of magnitude higher than those reported previously for this region. Surface soil concentration ranges of endosulfan I, endosulfan II, and endosulfan sulfate were greater than in sediment. Endosulfan II was the greatest contributor to total endosulfan concentrations in both surface sediment and soil followed by endosulfan sulfate and endosulfan Ι. However, a different concentration profile was observed in fish and crop samples, with endosulfan sulfate having the highest concentration followed by endosulfan I and endosulfan II. The concentration of Σendosulfans (endosulfans Ι and II) in soil decreased rapidly with increasing distance from the plant by a factor of 10 within 45km. Trace amounts of Σendosulfans were observed in deep soil layers which implied that these compounds are transported through the leaching of pore water in soil. This demonstrated that emissions from the manufacturing facility can lead to ground water contamination in the area near the plant. A screening level human health risk assessment of Σendosulfans based on the worst-case scenario was performed for people living in the vicinity of the manufacturing facility. The hazard indices were at least 2 orders of magnitude of <1, indicating no adverse health effects are likely to occur at current exposure levels, and the risk to human health is generally acceptable.Science of The Total Environment 01/2014; · 3.16 Impact Factor
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ABSTRACT: 1,2,4-trichlorobenzene (1,2,4-TCB) is one of the most common pollutants in landfill leachate that impacts shallow drinking groundwater quality; accordingly, the transport mechanism and capacity for remediation of this compound are important to the management of local water resource. In this study, a series of indoor experiments and analytical predictions revealed that the transportation of 1,2,4-TCB in groundwater is similar in medium sand and fine sand. Specifically, the peak time increases with distance between monitoring points and the source point, but the peak relative concentrations decrease with distance, indicating that the concentration of 1,2,4-TCB in groundwater is controlled by adsorption and biodegradation. In addition, transportation of water in a fine sand column was lower than that in a medium sand column; therefore, the adsorption and biodegradation of 1,2,4-TCB in groundwater was lower in the medium sand column. These findings demonstrate that 1,2,4-TCB in groundwater could be removed by natural degradation after about 5 years, but that other methods (permeable reactive barriers, air sparging or biosparging) should be applied in the field to shorten the remediation period and enhance water supply safety around landfill.Environmental earth sciences 08/2014; 72(3):941-948. · 1.57 Impact Factor
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ABSTRACT: This article integrates a fractional fuzzy health risk approach with multi-objective analysis in consideration of multiple exposure pathways in order to assess human health risk in petroleum hydrocarbon (PH)–contaminated aquifers. A PH-contaminated groundwater aquifer located in the Pinggu District of Beijing, China, is then studied for demonstrating the applicability of the proposed approach. The results show that with more fuzzy parameters considered in the risk assessment procedure, the multi-parameter fuzzy (MPF) result is more accurate than that from the single-parameter fuzzy (SPF) model. The comparison results also indicate the advantage of the proposed fractional fuzzy approach in assessing parameter uncertainty. The non-carcinogenic risk assessment results imply that the contaminated groundwater in the study area is in the medium risk level, and remediation plans for soil and groundwater should be considered to ensure safe groundwater utilization.Human and Ecological Risk Assessment 02/2015; 21(2). · 1.08 Impact Factor