Health Risk Assessment of Chlorobenzenes in the Air of Residential Houses Using Probabilistic Techniques

Abstract

A human health risk assessment was performed to evaluate the risks due to chlorobenzenes in the air of residential houses. Chlorobenzenes found in the air in the toilets, rooms, and outdoors of three houses in Brisbane, Australia, were sampled by trapping on Tenax TA and analyzed using an automated thermal desorption (ATD)-gas chromatography/mass spectrometry (GC/MS) method. Concentrations of 1,4-dichlorobenzene (1,4-DCB) in the rooms, toilets, and outdoors were used as the exposure concentrations (E), while those in the toilets (microg/m3) were used as the high-exposure concentrations (HE). The exposure concentrations were transformed into exposure doses (EXD(E) and EXD(HE)). Dose-response data from the literature for a range of adverse effects in animals were obtained and exposure doses were expressed as human equivalent dose (HED). The HED values were higher than the EXD(E) and EXD(HE) values for all adverse effects, and a hazard quotient was calculated that indicated a low level of risk with the high-exposure environment. The lifetime average daily doses (LADDs) for a wide range of adverse effects observed in human case studies were estimated and compared to the doses in the high-exposure (HE) situation. Using the Monte Carlo simulation technique the probabilities of risk quotients higher than unity ranged from 0.02 to 0.26. This evaluation indicated that 1,4-DCB posed low risks to general residents; however, for individuals with susceptible characteristics and exposure to elevated 1,4-DCB, the probability of adverse responses was moderate to high.

Rhizosphere mediated biodegradation of 1,4-dichlorobenzene by plant growth promoting rhizobacteria of Jatropha curcas

“…1,4-dichlorobenzene is widely used as industrial solvent, a commonly used volatile disinfectant and deodorizer (Djohan et al, 2007). It is well established that chlorobenzene, 1,2-dichlorobenzene, and 1,4-dichlorobenzene undergo aerobic biodegradation (Haigler et al, 1988;Spain and Nishino, 1987) but are more resistant to biodegradation under anaerobic conditions (Spain and Nishino, 1987;Dilmeghani and Zahir, 2001;Fung et al, 2009).…”

Effects of occupational exposure to 1,4-dichlorobenzene on hematologic, kidney, and liver functions

“…Exposure to 1,4-DCB by inhalation has been extensively evaluated in homes, factories, and new buildings (Saijo et al 2004;Djohan et al 2007;Dodson et al 2007). People who inhale 1,4-DCB excrete 2,5-dichlorophenol (2,5-DCP), the major metabolite of 1,4-DCB, in urine.…”

An overall risk probability-based method for quantification of synergistic and antagonistic effects in health risk assessment for mixtures: theoretical concepts

“…In this method, a large number of HQ values are calculated by randomly selecting values from the two cumulative probability curves. From these HQ values, the probability distribution of HQ values can be calculated and plotted out (eg Djohan et al 2007). Effectively, this method transforms the two cumulative probability charts of exposure and effects into a new probability distribution of HQ values.…”