Second moment method for evaluating human health risks from groundwater contaminated by trichloroethylene.

Abstract

Pollutants in groundwater aquifers may constitute a significant human health risk. A large variation in response may result among human populations experiencing the same level and duration of exposure to pollutants. Variability in response, as a result of exposure to a carcinogenic contaminant such as trichloroethylene (TCE), can be represented by a distribution function of safe doses. Spatial variability in aquifer characteristics and contaminant transport parameters requires the use of stochastic transport models to quantify variability in exposure concentrations. A second moment method is used to evaluate the probability of exceeding safe dose levels for a contaminated aquifer. The name of this method stems from the fact that the formulation is based on the first and second moments of the random variables. With this method, the probability is a function of the variability of contaminant concentration (which incorporates variability in hydrogeologic parameters such as hydraulic conductivity) and the variability in response in the human population. In this manner, the severity of the health risk posed by a contaminated aquifer and the evaluation of appropriate strategies and technologies for aquifer remediation are a function of contaminant concentrations and human health risks. The applicability and limitations of this method are demonstrated with data on groundwater contaminated by TCE at Hill Air Force Base, Utah. Images Figure 1. Figure 2. Figure 3. Figure 4.

Evaluation of health risks for contaminated aquifers.

“…Letting fr(r) and fc(c) define the distribution of safe doses and the distribution of contaminant concentrations, respectively, the probability of the remediation method not achieving reductions in contaminant concentrations that are below the prescribed low cancer risk is defined by the convolution integral as (132) 00 Pf = JF7(C)f,(C)dc 0 [27] where Fr(C) is the cumulative distribution function of fr(R) evaluated at C. Equation incorporate exposure information into health risk assessment. The second moment method was used to calculate cancer risk contours for a contaminated aquifer at Hill Air Force Base, Utah (133). In this study, contaminant plume concentrations for trichloroethylene were incorporated into the risk assessment process to produce cancer risk contours for the contaminated aquifer.…”

Synthesis, characterisation and application of an exfoliated graphite–diamond composite electrode in the electrochemical degradation of trichloroethylene

“…5 Due to its toxicity and carcinogenic effect, exposure to TCE may result in adverse health effects. [6][7][8][9] For example, acute exposures to TCE at doses exceeding 250 ppm can impair the central nervous system, whilst long-term exposure is thought to induce hepatotoxicity, nephrotoxicity and neurotoxicity. 10 Psychomotor impairment was noticed aer inhalation exposure to 5400 mg m À3 (1000 ppm) for 2 h in work place conditions.…”

Electrochemical Detection of Trichloroethylene with an Electrodeposited Pb-Modified Electrode

“…8 Furthermore, TCE was confirmed to be a carcinogenic material in many medical investigations. [9][10][11] Therefore, to detect and monitor TCE concentration in order to protect people health is very important in the working environment.…”