Benzene exposure: An overview of monitoring methods and their findings

Abstract

Benzene has been measured throughout the environment and is commonly emitted in several industrial and transportation settings leading to widespread environmental and occupational exposures. Inhalation is the most common exposure route but benzene rapidly penetrates the skin and can contaminant water and food resulting in dermal and ingestion exposures. While less toxic solvents have been substituted for benzene, it still is a component of petroleum products, including gasoline, and is a trace impurity in industrial products resulting in continued sub to low ppm occupational exposures, though higher exposures exist in small, uncontrolled workshops in developing countries. Emissions from gasoline/petrochemical industry are its main sources to the ambient air, but a person’s total inhalation exposure can be elevated from emissions from cigarettes, consumer products and gasoline powered engines/tools stored in garages attached to homes. Air samples are collected in canisters or on adsorbent with subsequent quantification by gas chromatography. Ambient air concentrations vary from sub-ppb range, low ppb, and tens of ppb in rural/suburban, urban, and source impacted areas, respectively. Short-term environmental exposures of ppm occur during vehicle fueling. Indoor air concentrations of tens of ppb occur in microenvironments containing indoor sources. Occupational and environmental exposures have declined where regulations limit benzene in gasoline (<1%) and cigarette smoking has been banned from public and work places. Similar controls should be implemented worldwide to reduce benzene exposure. Biomarkers of benzene used to estimate exposure and risk include: benzene in breath, blood and urine; its urinary metabolites: phenol, t,t-muconic acid (t,tMA) and S-phenylmercapturic acid (sPMA); and blood protein adducts. The biomarker studies suggest benzene environmental exposures are in the sub to low ppb range though non-benzene sources for urinary metabolites, differences in metabolic rates compared to occupational or animal doses, and the presence of polymorphisms need to be considered when evaluating risks from environmental exposures to individuals or potentially susceptible populations.

Hematologic Evaluation of Painting Hall Workers in an Automobile Manufacturing Company

“…Today, occupational exposure is normally below the regulatory standard of 1 ppm and is often below 0.1 ppm. However, identifying higher levels of exposure (> 10 ppm) in small and unregulated environments is an important step in bridging the information gap (9).…”

“…It is also present in cigarette smoke. Therefore, this compound, found in cigarette smoke and other products, may cause concerns for public health (7)(8)(9).…”

Electronic noses for monitoring benzene occupational exposure in biological samples of Egyptian workers

“…These observations are in line with findings of the present study, where both phenol and muconic acid were present in the blood and urine of Egyptian workers exposed to benzene in significant amounts as compared to non-exposed controls ( Table 1). The relative contribution of each benzene metabolite to the adverse health effects of benzene, both alone and in various combinations is still a subject of some debate [18]. Several studies have shown that benzene metabolites related to muconic acid and hydroquinone are more genotoxic than phenol or compounds related to catechol [3,21,22].…”

Discrimination and quantification of volatile organic compounds in the ppb-range with gas sensitive SiC-FETs using multivariate statistics

“…It was reported that ambient air concentrations vary from sub-ppb (approx. 1 µg/m 3 ) in rural areas to low ppb (5-20 µg/m 3 ) in urban areas, or even to tens of ppb in source impacted areas [8], [9]. Benzene is classified as carcinogenic to humans and according to the World Health Organization, WHO, there is no safe level of exposure.…”