An Assessment of Occupational Exposure to Polycyclic Aromatic Hydrocarbons in the UK

Abstract

A cross-industry occupational hygiene survey was commissioned by the Health and Safety Executive (HSE) to determine the levels of polycyclic aromatic hydrocarbon (PAH) exposure in UK industry and to determine if one or more target analytes were suitable as markers for assessing total exposure to PAHs. There were no broadly applicable UK exposure standards for assessing total exposure to PAHs. Until 1993 a guidance value for assessing exposure in coke ovens only, where PAH exposure is known to be the highest, was based on gravimetric analysis of cyclohexane-soluble material. Biological monitoring based on urinary 1-hydroxypyrene (1-OHP) is widely reported to be an effective indicator of exposure by both dermal and inhalation routes but there was no UK guidance value. The survey involved an occupational hygiene study of 25 sites using both airborne monitoring of a total of 17 individual PAHs and biological monitoring. The results showed 8 h TWA levels of total PAH in air ranged from 0.4 to 1912.6 microg m(-3) with a GM of 15.8 microg m(-3). The profile of PAHs was dominated by naphthalene, the most volatile 2-ring PAH. Airborne benzo(a)pyrene (BaP) correlated well (r(2) = 0.971) with levels of carcinogenic 4-6 ring PAHs and was an effective marker of exposure for all industries where significant particle bound PAH levels were found and, in particular, for CTPV exposure. The 8 h TWA levels of BaP ranged from <0.01 to 6.21 microg m(-3) with a GM of 0.036 microg m(-3); 90% were <0.75 microg m(-3) and 95% were <2.0 microg m(-3). Two hundred and eighteen urine samples collected from different workers at the end of shift and 213 samples collected pre-shift next day were analysed for 1-OHP. Levels of 1-OHP in end-of-shift samples were generally higher than those in pre-shift-next-day samples and showed a good correlation (r(2) = 0.768) to airborne BaP levels if samples from workers using respiratory protection or with significant dermal exposure were excluded. Urinary 1-OHP in end-of-shift samples ranged from the limit of detection (0.5 micromol mol(-1) creatinine) to 60 micromol mol(-1) creatinine with a mean of 2.49 micromol mol(-1) and a 90th percentile value of 6.7 micromol mol(-1) creatinine. The highest 1-OHP levels were found in samples from workers impregnating timber with creosote where exposure was dominated by naphthalene. If the 11 samples from these workers were excluded from the dataset, the 90% value for end-of-shift urine samples was 4 micromol mol(-1) creatinine (n = 207) and this value has since been adopted by the HSE as a biological monitoring benchmark value.

Biological Monitoring of Blood Naphthalene Levels as a Marker of Occupational Exposure to PAHs among Auto-Mechanics and Spray Painters in Rawalpindi

“…Moreover, as it can exist in gas phase, this chemical can be used for air and biological monitoring of exposure to PAHs [8,9]. According to Unwin NAPH dominates the PAH profile at every site, being a representative of 50-90 percent of total PAHs [3]. The United State's EPA has declared NAPH as among the most hazardous of air pollutants [17].…”

“…Among the most common contaminants PAHs are of particular concern as they are comprised of a group of highly lipophilic, non-polar and persistent substances with remarkable mutagenic and carcinogenic properties. Exposure of PAHs can come from both occupational and environmental sources arising from use of coal tar, fires at oil wells, exposure to automotive exhaust gases, tobacco smoke and crude and mineral oils as well as incomplete combustion of fossil fuel and many other sources [2,3]. Among the attributes of PAHs that determine the bioavailability and toxicity of individual chemicals, molecular weight is the most important, as most of the higher molecular weight PAHs usually settled with particulate matter, and those with low molecular weight remain suspended in the air where they can become disseminated in the environment and inhaled by human [4,5].…”

Neurobehavioral Toxicity of a Repeated Exposure (14 Days) to the Airborne Polycyclic Aromatic Hydrocarbon Fluorene in Adult Wistar Male Rats

“…The daily exposure period was limited to 6 hours in order to respect the illuminated part of the circadian cycle and to allow the behavioral testing during the dark part of the cycle within the same day. Thus, considering this period of time and the air volume inhaled by the rats (12 L/hour), the lowest concentration of fluorene was calculated in order to reach in the animals similar levels of exposure to those observed in humans living in urban areas [1], [2] whereas the highest one was more characteristic of occupational exposure [4], [11]. At the end of the exposure period, 12 animals from each group were used for behavioral investigations whereas the remaining 6 rats were sacrificed for biological measurements.…”

“…Based on the findings of several studies [1], [2], the non-occupational levels of PAH exposure are comprised between 1 and 440 ng/m 3 depending on the location of the study, the location of the sampling sites, the season of sampling, the phase investigated (gas and/or particle phases), and the number of PAHs measured in air. PAHs are also well-known as a source of occupational exposure for significant groups of workers with levels that can reach several tens of µg/m 3 [3], [4].…”

Exposure to Polycyclic Aromatic Hydrocarbons Among Never Smokers in Golestan Province, Iran, an Area of High Incidence of Esophageal Cancer – a Cross-Sectional Study with Repeated Measurement of Urinary 1-OHPG in Two Seasons

“…The major sources of PAHs are tobacco smoking, some occupational exposures (such as coke oven working), air pollution, and diet, particularly charbroiled or fried foods (Unwin et al, 2006; Perello et al, 2008; Kamangar et al, 2009). The International Agency for Research on Cancer has classified benzo[ a ]pyrene, a prototype PAH, and exposures in several occupations with heavy exposure to PAHs as carcinogenic to humans (Baan et al, 2009).…”