Integrated evaluation of solvent exposure in an occupational setting: air, dermal and bio-monitoring

Human exposure to BTEX emitted from a typical e-waste recycling industrial park: External and internal exposure levels, sources, and probabilistic risk implications

Benzene, toluene, ethylbenzene, and xylene (BTEX) can be released during extensive activities associated with the disposal of electronic waste (e-waste), which might pose deleterious health effects on workers. In this study, pollution profiles of BTEX in air and their urinary excretive profiles in occupational workers were investigated in a typical e-waste recycling industrial park. The results showed that the workers in the park were generally exposed to high levels of BTEX. The median levels of urinary metabolites were approximately 6-orders of magnitude higher than those of unmetabolized BTEX, indicating that pollutants efficiently metabolize at those occupational levels. The analytes presented differential profiles in external and internal exposure. Among the metabolites, significant correlation (p < 0.05) was observed between N-acetyl-S-benzyl-L-cysteine (S-BMA) concentration and atmospheric individual BTEX derived from the e-waste recycling area, suggesting that S-BMA is a potential marker for BTEX exposure to e-waste occupational workers. Notably, 95.2 % of all the workers showed a cumulative carcinogenic risk induced by BTEX exposure via inhalation, with 99.9 % of the carcinogenic risk distribution based on concentration of benzene metabolite (N-acetyl-S-(phenyl)-L-cysteine) exceeding 1.0E-6. This study holds potential in providing valuable inferences for the development of remediation strategies focusing on BTEX exposure reduction to protect workers' health at e-waste recycling industries.

An alternative method to assess permeation through disposable gloves

Previously, we have demonstrated the capability of activated charcoal cloth (ACC) to assess dermal exposure to VOCs. Here we investigated whether ACC patches can be used as an under-glove indicator to evaluate the ingress of toluene through disposable gloves in a controlled environment, and compared these results to the amount of toluene ingress determined from the standardized test methods for determining chemical permeation through PPE. In a test chamber, with plugs for air sampling, five to six ACC patches were placed on a mannequin hand underneath disposable gloves (latex, nitrile, neoprene, polymer laminate). Three work-exposure scenarios were simulated to assess toluene ingress through the different gloves: vapor exposure; spray exposure, and immersion. The standard permeation test, using a diffusion cell, was carried with glove material of the palm, with continuous contact conditions. In all of ACC test, the order of toluene ingress was latex > neoprene > nitrile > Barrier, but for the standardized testing, the order of the neoprene and nitrile was reversed, and nitrile had higher levels of toluene ingress. These results show the need to think beyond standard testing techniques for occupational exposure to hazardous substances, and the added value of "application style" testing.

Assessment of dermal exposure to N,N-dimethylacetamide in spray workers by combining personal exposure monitoring, biological monitoring, and glove permeation monitoring: A pilot study

OBJECTIVES

We assessed dermal exposure to N,N-dimethylacetamide (DMAC) in a spray worker by utilizing a combination of personal exposure monitoring, biological monitoring, and glove permeation monitoring. We also determined the protective effects of chemical protective gloves (CPGs).

METHODS

Surveys with and without CPG usage were performed on different days. In the survey with CPG usage, the worker had worn leather gloves over the CPG. Personal exposure monitoring and glove permeation monitoring were performed using 3M Organic Vapor Monitor 3500 and PERMEA-TEC Pads respectively. Urinary concentration of DMAC and its metabolites (N-methylacetamide [NMAC], N-hydroxymethyl-N-methylacetamide [DMAC-OH], S-(acetamidomethyl) mercapturic acid [AMMA]) were measured in the before-shift and end-of-shift samples collected from the worker.

RESULTS

Personal exposure DMAC concentration in the survey with CPG usage (0.32 ppm) was twice that in the survey without CPG usage (0.15 ppm). However, urinary concentrations of DMAC-OH and AMMA in the end-of-shift samples in the survey with CPG usage (DMAC-OH, 0.74 mg/g creatinine; AMMA, 0.10 mg/g creatinine) were lower than those in the survey without CPG usage (DMAC-OH, 1.27 mg/g creatinine; AMMA, 0.24 mg/g creatinine). Urinary concentrations of DMAC and NMAC were below the limit of detection in all samples. DMAC concentrations in PERMEA-TEC Pads that were used in the surveys with and without CPG usage were in the range of 0.3-2.1 µg/sample and 16.4-1985.2 µg/sample respectively.

CONCLUSIONS

The combination of CPG usage and leather gloves was effective in preventing dermal exposure to DMAC.

Assessment of the absorbed dose after exposure to surgical smoke in an operating room

Surgical smoke produced by electrosurgery contains various chemical substances such as volatile organic compounds (VOCs) and polycyclic aromatic hydrocarbons (PAHs). The aim of this study is to investigate airborne concentrations of VOCs and PAHs during electrosurgery in an operating room, in relation to metabolites in urine in order to assess the absorbed dose. A 5-day exposure study was set up in a general surgery operation room including surgeons, scrub assistants and circulation nurses (n = 15). Stationary and personal air sampling for VOCs and PAHs were carried out. Pre-, mid- and end-shift analysis of urinary S-phenylmercapturic acid (SPMA), o-cresol, mandelic acid and 1-hydroxypyrene was performed to assess the internal exposure to respectively benzene, toluene, styrene and PAHs. Several VOCs (styrene, ethyl benzene, benzene and toluene), ranging from 0.7 to 3.27 μg/m³ were detected in the air samples, along with one PAH (naphthalene, ranging from 0.012 to 0.39 μg/m³). There was no significant correlation between air monitoring and urinary biomonitoring. O-cresol levels were increased, especially among assistants and nurses at mid- and end-shift, exceeding current biological exposure indices several times. External and internal exposure for assistants and nurses was substantially more, compared to surgeons. This study confirms the presence of VOCs and PAHs in surgical smoke and shows the presence of their metabolites in urine, but the association is unclear. Urinary biomonitoring shows especially high concentrations of o-cresol.

Evaluation of potential health effects associated with occupational and environmental exposure to styrene - an update

The potential chronic health risks of occupational and environmental exposure to styrene were evaluated to update health hazard and exposure information developed since the Harvard Center for Risk Analysis risk assessment for styrene was performed in 2002. The updated hazard assessment of styrene's health effects indicates human cancers and ototoxicity remain potential concerns. However, mechanistic research on mouse lung tumors demonstrates these tumors are mouse-specific and of low relevance to human cancer risk. The updated toxicity database supports toxicity reference levels of 20 ppm (equates to 400 mg urinary metabolites mandelic acid + phenylglyoxylic acid/g creatinine) for worker inhalation exposure and 3.7 ppm and 2.5 mg/kg bw/day, respectively, for general population inhalation and oral exposure. No cancer risk value estimates are proposed given the established lack of relevance of mouse lung tumors and inconsistent epidemiology evidence. The updated exposure assessment supports inhalation and ingestion routes as important. The updated risk assessment found estimated risks within acceptable ranges for all age groups of the general population and workers with occupational exposures in non-fiber-reinforced polymer composites industries and fiber-reinforced polymer composites (FRP) workers using closed-mold operations or open-mold operations with respiratory protection. Only FRP workers using open-mold operations not using respiratory protection have risk exceedances for styrene and should be considered for risk management measures. In addition, given the reported interaction of styrene exposure with noise, noise reduction to sustain levels below 85 dB(A) needs be in place.