Fate and contaminant transport model-driven probabilistic human health risk assessment of DNAPL-contaminated site
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RESEARCH ARTICLE
Fate and contaminant transport model-driven probabilistic human health risk assessment of DNAPL-contaminated site Abhay Guleria 1
&
Sumedha Chakma 1
Received: 25 August 2020 / Accepted: 10 November 2020 # Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract In this study, fate and contaminant transport model-driven human health risk indexes were calculated due to the presence of dense non-aqueous phase liquids (DNAPLs) in the subsurface environment of air force base area in Florida, USA. Source concentration data of DNAPLs was used for the calculation of transport model-driven health risk indexes for the children and adult subpopulation via direct oral ingestion and skin dermal contact exposure scenario using 10,000 Monte Carlo type simulations. The highest variation in the probability distribution of transformed DNAPL compound (cis-dichloroethene (cis-DCE) > vinyl chloride (VC)) was observed as compared to parent DNAPL (tetrachloroethene (PCE)) based on the 50-year simulation timespan. Transformed DNAPL compounds (VC, cis-DCE) posed the highest risk to human health for a longer duration (up to 15 years) in comparison to parent DNAPL (PCE), as non-carcinogenic hazard quotient varied from 400 to 1100. Carcinogenic health risks were observed as 3-order of magnitude higher than safe limit (HQSafe < 10−6) from 2nd to 5th year timespan and fall in the highrisk zone, indicating the need for a remediation plan for a contaminated site. Variance attribution analysis revealed that concentration, body weight, and exposure duration (contribution percentage – 70 to 95%) were the most important parameters, highlighting the impact of dispersivity and exposure model in the estimation of risk indexes. This approach can help decisionmakers when a contaminated site with partial data on hydrogeological properties and with higher uncertainty in model parameters is to be assessed for the formulation of remediation measures. Keywords Probabilistic human health risk assessment . DNAPLs . Groundwater . Model-driven risk index . Monte Carlo simulations
Introduction Contamination of the subsurface environment due to dense non-aqueous phase liquids (DNAPLs) is the major problem posing risk to human health (Pankow and Cherry 1996; USEPA 2004). Tetrachloroethene (PCE) and trichloroethene (TCE) are the synthetic chlorinated hydrocarbons which have been majorly used as solvents in industrial activities related to paint varnishes, fats, and rubbers and for dry cleaning and metal degreasing activities (Beamer et al. 2012). PCE and TCE are detected as the highest contributors to groundwater Responsible Editor: Marcus Schulz * Abhay Guleria [email protected] 1
Department of Civil Engineering, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
contamination due to volatile organic compounds (Moran et al. 2007; Huang et al. 2014). Due to the emanation of contaminants in the dissolved phase, chlorinated solvents (PCE and TCE) are considered a long-term source of subsurface contam
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