Health risk assessment of exposure to benzene, toluene, ethyl benzene, and xylene in shoe industry-related workplaces.

Benzene, toluene, ethyl benzene, and xylene (BTEX) are prevalent pollutants in shoe industry-related workplaces. The aim of this study was to assess exposure to BTEX and their carcinogenic and non-carcinogenic risks in shoe-industry-related workplaces. This study was carried out at different shoe manufactures, small shoe workshop units, shoe markets, and shoe stores in Tabriz, Iran in 2021. Personal inhalation exposure to BTEX was measured using the National Institute for Occupational Safety and Health (NIOSH) 1501 method. Carcinogenic and non-carcinogenic risks due to inhalation exposure to BTEX were estimated by United States Environmental Protection Agency (U.S. EPA) method based on Mont Carlo simulation. Results showed that the concentrations of benzene and toluene were higher than the threshold limit value (TLV) in both gluing and non-gluing units of shoe manufactures. The total carcinogenic risk (TCR) due to exposure to benzene and ethyl benzene was considerable in all shoe industry-related workplaces. Also, the hazard index (HI) as a non-carcinogenic index was higher than standard levels in all shoe industry-related workplaces. Therefore, shoe industry-related workers are at cancer and non-cancer risks due to exposure to BTEX. Prevention measures need to be implemented to reduce the concentration of BTEX in shoe industry-related workplaces.

[Assessment of exposure to BTEX in vehicle filling stations in Rio de Janeiro, Brazil, and risks to workers' health]. / Avaliação da exposição a BTEX em postos de revenda de combustíveis no Rio de Janeiro, Brasil, e os riscos à saúde do trabalhador.

Gasoline is a complex mixture of substances, including aromatic hydrocarbons such as benzene, toluene, ethylbenzene, and xylenes (BTEX). These compounds are emitted into the air, with the special relevance of benzene since it is provenly carcinogenic. The study aimed to assess BTEX concentrations in filling stations in the city of Rio de Janeiro, Brazil, and to calculate the cancer risk associated with such exposures. Two types of sampling were performed (stationary and mobile), adapted from methodology n. 1,501 (U.S. National Institute for Occupational Safety and Health) for aromatic hydrocarbons, in six filling stations in the West Zone of Rio de Janeiro. Stationary sampling was done near the fuel pumps, while mobile sampling was done in the breathing zone of the workers (station attendants) as they moved around the station. The samples were analyzed with gas chromatography flame ionization detector. The sampling results were used to calculate the health risk, using the indicators Hazard quotient (HQ) and Cancer risk (CR) to assess the possible non-carcinogenic and carcinogenic effects, respectively, in filling station workers. Environmental concentrations for the most of the BTEX compounds were below the recommended limits, except for benzene, a carcinogenic compound, which displayed concentrations far above the limits, leading to high cancer risk values. The results showed that there are health risks for filling station attendants, especially the risk of developing cancer from excessive exposure to benzene.

A gasolina é uma mistura complexa de substâncias, dentre elas estão hidrocarbonetos como o benzeno, tolueno, etilbenzeno e xilenos (BTEX), sendo esses compostos emitidos para a atmosfera, com destaque ao benzeno, por ser comprovadamente carcinogênico. Objetivamos avaliar as concentrações de BTEX no ar de postos de revenda de combustíveis no Município do Rio de Janeiro, Brasil, e calcular o risco de câncer associado a estas exposições. Foram realizados dois tipos de amostragem (fixa e móvel) adaptadas da metodologia nº 1.501 do Instituto Nacional de Segurança e Saúde Ocupacional (Estados Unidos), em seis postos de revenda de combustíveis na Zona Oeste da cidade. A amostragem fixa foi feita próxima às bombas de combustível, enquanto a móvel foi realizada através da coleta do ar na zona respiratória dos trabalhadores (frentistas), conforme estes se deslocavam pelo posto. As amostras foram analisadas por cromatografia gasosa com detecção por ionização em chama. Com os resultados das amostragens foram feitos os cálculos de risco à saúde, usando os indicadores Quociente de perigo (HQ) e Risco de câncer (CR), para avaliar os possíveis efeitos não-carcinogênicos e carcinogênicos, respectivamente, nos trabalhadores dos postos de revenda de combustíveis. As concentrações ambientais para a maioria dos compostos BTEX foram abaixo dos limites preconizados, menos para o benzeno, um composto carcinogênico, que apresentou concentrações muito acima dos limites, levando a altos valores de risco de câncer. Os resultados demonstraram que há riscos à saúde dos trabalhadores de postos de revenda de combustíveis, principalmente o risco de desenvolver câncer, devido à exposição excessiva ao benzeno.

La gasolina es una mezcla compleja de sustancias, entre ellas existen hidrocarburos como el benceno, tolueno, etilbenceno y xilenos (BTEX), emitiéndose estos compuestos a la atmósfera, donde se destaca el benceno, al tratarse de un carcinogénico comprobado. Los objetivos fueron evaluar las concentraciones de BTEX en el aire de puestos de reventa de combustibles, en el municipio de Río de Janeiro, Brasil, así como calcular el riesgo de cáncer asociado a estas exposiciones. Se realizaron dos tipos de muestra (fija y movible), adaptadas de la metodología nº 1.501 del Instituto Nacional de Seguridad y Salud Laboral (EE.UU.), en seis puestos de reventa de combustibles de la zona oeste de la ciudad. La muestra fija se realizó cerca de las bombas de combustible, mientras que la móvil se hizo mediante tomas de aire en la zona respiratoria de los trabajadores (de la gasolinera), a medida que estos se desplazaban por el lugar de trabajo. Las muestras se analizaron por cromatografía gaseosa con detección por ionización en llama. Junto a los resultados de las muestras, se realizaron cálculos de riesgo para la salud, usando los indicadores Cociente de peligro (HQ) y Riesgo de cáncer (CR), con el fin de evaluar los posibles efectos no-carcinogénicos y carcinogénicos, respectivamente, en los trabajadores de los puestos de reventa de combustibles. Las concentraciones ambientales para la mayoría de los compuestos BTEX estuvieron por debajo de los limites preconizados, menos en el caso del benceno, un compuesto carcinogénico, que presentó concentraciones muy por encima de los límites, llevando a altos valores de riesgo de cáncer. Los resultados demostraron que existen riesgos para la salud de los trabajadores de puestos de reventa de combustibles, principalmente, riesgo de desarrollar cáncer, debido a la exposición excesiva al benceno.

[Characteristics of BTEX and Health Risk Assessment During Typical Pollution Episodes in Summer and Winter in Tianjin Urban Area].

Real-time BTEX(including benzene, toluene, ethylbenzene, m-, p-, and o-xylenes) were measured continuously in Tianjin urban site in July 2019 and January 2020 using a Syntech Spectras GC955 analyzer. The BTEX concentration levels, composition, and evolutionary mechanisms during typical pollution episodes were investigated. The potential sources of BTEX were analyzed qualitatively using the diagnostic ratios method. Finally, the BTEX health risk was evaluated by using the human exposure analysis and evaluation method according to US EPA. The averaged total mixing ratio of BTEX were 1.32×10-9 and 4.83×10-9 during ozone pollution and haze episodes, respectively. Benzene was the most abundant species, followed by toluene. The mixing ratio of BTEX was largely affected by short southwestern distance transportation in January, while local emissions in July. In addition, the BTEX mixing ratio depended on the influence of temperature and relative humidity(RH) in July, while the concentration was more sensitive to changes in RH when the temperature was low in January. Diagnostic ratios and source implications suggested that the BTEX was affected mainly by biomass/biofuel/coal burning during haze episodes. The traffic related emissions also had an impact except for the influence of biomass/biofuel/coal burning in July. The averaged hazard quotient(HQ) values were 0.072 and 0.29 during ozone pollution and haze episodes, respectively, which were in the upper safety range limit recommended by the US EPA. The carcinogenic risk posed by benzene in both cleaning and pollution processes was higher than the safety threshold set by the US EPA, which should be monitored carefully.

Mutagenicity Assessment to Pesticide Adjuvants of Toluene, Chloroform, and Trichloroethylene by Ames Test.

Pesticide adjuvants (PAs) denote the general term for auxiliaries in pesticide preparations except for the active components. Toluene, chloroform, and trichloroethylene are the three most commonly used PAs as organic solvents. The residues of the three chemicals in the process of production and application of pesticides may endanger the ecosystem. In the present study, the mutagenicity of toluene, chloroform, and trichloroethylene as well the mixture of the three chemicals was tested by the Salmonella typhimurium reverse mutation test (Ames test) with TA97, TA98, TA100, and TA102 strains in the system with and without rat liver microsomal preparations (S9). The four tester strains have been used for more than 40 years to detect mutagenic compounds in chemicals, cosmetics, and environmental samples. The mutagenicity was detected on tester strains in the separated experiment from the three chemicals. The addition of S9 decreased the mutation ratios of toluene to four strains, except for the TA100 strain, but increased the mutation ratios of chloroform to four strains except for the TA98 strain. Trichloroethylene caused positive mutagenicity to become negative on the TA102 strain. In the mixed experiment, positive effects were detected only on the TA102 strain in the absence of S9. The addition of S9 increased the mutagenicity except for the TA102 strain. The mixture of toluene, chloroform, and trichloroethylene showed antagonism in mutagenicity to tester strains, except for the TA102 strain without S9. However, the mixture showed a synergistic effect to tester strains after adding S9 except for the TA98 strain.

Estimation of toluene exposure in air from BMA (S-benzylmercapturic acid) urinary measures using a reverse dosimetry approach based on physiologically pharmacokinetic modeling.

This study aimed to use a reverse dosimetry PBPK modeling approach to estimate toluene atmospheric exposure from urinary measurements of S-benzylmercapturic acid (BMA) in a small group of individuals and to evaluate the uncertainty associated to urinary spot-sampling compared to 24-h collected urine samples. Each exposure assessment technique was developed namely to estimate toluene air exposure from BMA measurements in 24-h urine samples (24-h-BMA) and from distributions of daily urinary BMA spot measurements (DUBSM). Model physiological parameters were described based upon age, weight, size and sex. Monte Carlo simulations with the PBPK model allowed converting DUBSM distribution (and 24-h-BMA) into toluene air levels. For the approach relying on DUBSM distribution, the ratio between the 95% probability of predicted toluene concentration and its 50% probability in each individual varied between 1.2 and 1.4, while that based on 24-h-BMA varied between 1.0 and 1.1. This suggests more variability in estimated exposure from spot measurements. Thus, estimating toluene exposure based on DUBSM distribution generated about 20% more uncertainty. Toluene levels estimated (0.0078-0.0138 ppm) are well below Health Canada's maximum chronic air guidelines. PBPK modeling and reverse dosimetry may be combined to interpret urinary metabolites data of VOCs and assess related uncertainties.

Avaliação da exposição a BTEX em postos de revenda de combustíveis no Rio de Janeiro, Brasil, e os riscos à saúde do trabalhador / Assessment of exposure to BTEX in vehicle filling stations in Rio de Janeiro, Brazil, and risks to workers' health / Evaluación de la exposición a BTEX en puestos de reventa de combustibles, en Río de Janeiro, Brasil, y riesgos para la salud del trabajador

A gasolina é uma mistura complexa de substâncias, dentre elas estão hidrocarbonetos como o benzeno, tolueno, etilbenzeno e xilenos (BTEX), sendo esses compostos emitidos para a atmosfera, com destaque ao benzeno, por ser comprovadamente carcinogênico. Objetivamos avaliar as concentrações de BTEX no ar de postos de revenda de combustíveis no Município do Rio de Janeiro, Brasil, e calcular o risco de câncer associado a estas exposições. Foram realizados dois tipos de amostragem (fixa e móvel) adaptadas da metodologia nº 1.501 do Instituto Nacional de Segurança e Saúde Ocupacional (Estados Unidos), em seis postos de revenda de combustíveis na Zona Oeste da cidade. A amostragem fixa foi feita próxima às bombas de combustível, enquanto a móvel foi realizada através da coleta do ar na zona respiratória dos trabalhadores (frentistas), conforme estes se deslocavam pelo posto. As amostras foram analisadas por cromatografia gasosa com detecção por ionização em chama. Com os resultados das amostragens foram feitos os cálculos de risco à saúde, usando os indicadores Quociente de perigo (HQ) e Risco de câncer (CR), para avaliar os possíveis efeitos não-carcinogênicos e carcinogênicos, respectivamente, nos trabalhadores dos postos de revenda de combustíveis. As concentrações ambientais para a maioria dos compostos BTEX foram abaixo dos limites preconizados, menos para o benzeno, um composto carcinogênico, que apresentou concentrações muito acima dos limites, levando a altos valores de risco de câncer. Os resultados demonstraram que há riscos à saúde dos trabalhadores de postos de revenda de combustíveis, principalmente o risco de desenvolver câncer, devido à exposição excessiva ao benzeno.

Gasoline is a complex mixture of substances, including aromatic hydrocarbons such as benzene, toluene, ethylbenzene, and xylenes (BTEX). These compounds are emitted into the air, with the special relevance of benzene since it is provenly carcinogenic. The study aimed to assess BTEX concentrations in filling stations in the city of Rio de Janeiro, Brazil, and to calculate the cancer risk associated with such exposures. Two types of sampling were performed (stationary and mobile), adapted from methodology n. 1,501 (U.S. National Institute for Occupational Safety and Health) for aromatic hydrocarbons, in six filling stations in the West Zone of Rio de Janeiro. Stationary sampling was done near the fuel pumps, while mobile sampling was done in the breathing zone of the workers (station attendants) as they moved around the station. The samples were analyzed with gas chromatography flame ionization detector. The sampling results were used to calculate the health risk, using the indicators Hazard quotient (HQ) and Cancer risk (CR) to assess the possible non-carcinogenic and carcinogenic effects, respectively, in filling station workers. Environmental concentrations for the most of the BTEX compounds were below the recommended limits, except for benzene, a carcinogenic compound, which displayed concentrations far above the limits, leading to high cancer risk values. The results showed that there are health risks for filling station attendants, especially the risk of developing cancer from excessive exposure to benzene.

La gasolina es una mezcla compleja de sustancias, entre ellas existen hidrocarburos como el benceno, tolueno, etilbenceno y xilenos (BTEX), emitiéndose estos compuestos a la atmósfera, donde se destaca el benceno, al tratarse de un carcinogénico comprobado. Los objetivos fueron evaluar las concentraciones de BTEX en el aire de puestos de reventa de combustibles, en el municipio de Río de Janeiro, Brasil, así como calcular el riesgo de cáncer asociado a estas exposiciones. Se realizaron dos tipos de muestra (fija y movible), adaptadas de la metodología nº 1.501 del Instituto Nacional de Seguridad y Salud Laboral (EE.UU.), en seis puestos de reventa de combustibles de la zona oeste de la ciudad. La muestra fija se realizó cerca de las bombas de combustible, mientras que la móvil se hizo mediante tomas de aire en la zona respiratoria de los trabajadores (de la gasolinera), a medida que estos se desplazaban por el lugar de trabajo. Las muestras se analizaron por cromatografía gaseosa con detección por ionización en llama. Junto a los resultados de las muestras, se realizaron cálculos de riesgo para la salud, usando los indicadores Cociente de peligro (HQ) y Riesgo de cáncer (CR), con el fin de evaluar los posibles efectos no-carcinogénicos y carcinogénicos, respectivamente, en los trabajadores de los puestos de reventa de combustibles. Las concentraciones ambientales para la mayoría de los compuestos BTEX estuvieron por debajo de los limites preconizados, menos en el caso del benceno, un compuesto carcinogénico, que presentó concentraciones muy por encima de los límites, llevando a altos valores de riesgo de cáncer. Los resultados demostraron que existen riesgos para la salud de los trabajadores de puestos de reventa de combustibles, principalmente, riesgo de desarrollar cáncer, debido a la exposición excesiva al benceno.

The concentration of BTEX compounds and health risk assessment in municipal solid waste facilities and urban areas.

In this study, human exposure to benzene, toluene, ethylbenzene, xylenes (BTEX), along with their respective risk assessment is studied in four major units (n = 14-point sources) of the largest municipal solid waste management facilities (MSWF) in Iran. The results were compared with four urban sites in Tehran, capital of Iran. Workers at the pre-processing unit are exposed to the highest total BTEX (151 µg m-3). In specific, they were exposed to benzene concentrations of 11 µg m-3. Moreover, the total BTEX (t-BTEX) concentrations measured over the conveyor belt was 198 µg m-3 at most, followed by trommel (104), and active landfills (43). The mean concentration of ambient t-BTEX in Tehran is 100 µg m-3. On average, xylenes and toluene have the highest concentrations in both on-site and urban environments, with mean values of 24 and 21, and 41 and 37 µg m-3, respectively. Even though the non-carcinogenic risk of occupational exposure is negligible, BTEX is likely to increase the chance of carcinogenic risks (1.7E-05) for workers at the pre-processing unit. A definite carcinogenic risk of 1.3E-04, and non-carcinogenic effect, of HI = 1.6 were observed in one urban site. With the exception of the pre-processing unit, the citizens of Tehran had higher exposure to BTEX. Overall, BTEX concentrations in the largest MSWF of Iran remains an issue of public health concern.

Genotoxicity Assessment of Volatile Organic Compounds in Landfill Gas Emission Using Comet Assay in Higher Terrestrial Plant.

Genotoxicity model is developed to assess the individual subacute toxicity of benzene, toluene, ethylbenzene, and xylene (BTEX) at very low levels as in a landfill gas. Golden Pothos (Epipremnum aureum), a higher plant, was tested under variation of benzene 54-5656 ng/L, toluene 10-4362 ng/L, ethylbenzene 28-4997 ng/L, xylene 53-4845 ng/L, for 96 h. DNA fragmentation in plant leaves were investigated via comet assay. The results show that DNA migration ratio increased with the BTEX concentrations, but at different rates. The 50% effective concentration (EC50) of DNA fragmentation from the dose-response relationships indicated toluene has the highest EC50 value and followed by benzene, xylene and ethylbenzene. Alternatively, ethylbenzene has the highest toxicity unit and followed by xylene, benzene and toluene as described by toxicity unit (TU). In conclusion, comet assay of Pothos can be used in differentiating DNA fragmentation against very low levels of BTEX in the atmosphere. Pothos is recommended for genotoxicity assessment of a low BTEX contaminated atmosphere.

Screening-level human health risk assessment of toluene and dibutyl phthalate in nail lacquers.

Toluene and dibutyl phthalate (DBP) are found in many consumer products, including cosmetics, synthetic fragrances, and nail polish. In 2012, the California Environmental Protection Agency evaluated 25 nail products and found that 83% of the products that claimed to be toluene-free contained toluene at concentrations ranging up to 190,000 ppm, and 14% of the products that claimed to be DBP-free contained DBP at concentrations ranging up to 88,000 ppm. We conducted a preliminary, screening-level analysis of the potential toluene and DBP-related health risks to consumers and professionals based on the medium and maximum concentrations of toluene and DBP presented in the 2012 report and evaluated dermal and inhalation exposure to a salon patron, nail technician, and home user. We concluded that the maximum toluene concentration for the technician and home user scenarios exceeded the California MADL, but the estimated air concentrations did not exceed the Federal or Cal OSHA PEL. The MADL for DBP was exceeded for all user scenarios at both the median and maximum concentrations. Using these highly conservative assumptions, exposures above regulatory limits could possibly occur during routine use of nail products; further research is needed in order to evaluate potential human health risks.

Assessing human variability in kinetics for exposures to multiple environmental chemicals: a physiologically based pharmacokinetic modeling case study with dichloromethane, benzene, toluene, ethylbenzene, and m-xylene.

The objective of this study was to compare the magnitude of interindividual variability in internal dose for inhalation exposure to single versus multiple chemicals. Physiologically based pharmacokinetic models for adults (AD), neonates (NEO), toddlers (TODD), and pregnant women (PW) were used to simulate inhalation exposure to "low" (RfC-like) or "high" (AEGL-like) air concentrations of benzene (Bz) or dichloromethane (DCM), along with various levels of toluene alone or toluene with ethylbenzene and xylene. Monte Carlo simulations were performed and distributions of relevant internal dose metrics of either Bz or DCM were computed. Area under the blood concentration of parent compound versus time curve (AUC)-based variability in AD, TODD, and PW rose for Bz when concomitant "low" exposure to mixtures of increasing complexities occurred (coefficient of variation (CV) = 16-24%, vs. 12-15% for Bz alone), but remained unchanged considering DCM. Conversely, AUC-based CV in NEO fell (15 to 5% for Bz; 12 to 6% for DCM). Comparable trends were observed considering production of metabolites (AMET), except for NEO's CYP2E1-mediated metabolites of Bz, where an increased CV was observed (20 to 71%). For "high" exposure scenarios, Cmax-based variability of Bz and DCM remained unchanged in AD and PW, but decreased in NEO (CV= 11-16% to 2-6%) and TODD (CV= 12-13% to 7-9%). Conversely, AMET-based variability for both substrates rose in every subpopulation. This study analyzed for the first time the impact of multiple exposures on interindividual variability in toxicokinetics. Evidence indicates that this impact depends upon chemical concentrations and biochemical properties, as well as the subpopulation and internal dose metrics considered.

Risk assessment of volatile organic compounds benzene, toluene, ethylbenzene, and xylene (BTEX) in consumer products.

Exposure and risk assessment was performed by evaluating levels of volatile organic compounds (VOC) benzene, toluene, ethylbenzene, and xylene (BTEX) in 207 consumer products. The products were categorized into 30 different items, consisting of products of different brands. Samples were analyzed for BTEX by headspace-gas chromatography/mass spectrometry (headspace-GC/MS) with limit of detection (LOD) of 1 ppm. BTEX were detected in 59 consumer products from 18 item types. Benzene was detected in whiteout (ranging from not detected [ND] to 3170 ppm), glue (1486 ppm), oil-based ballpoint pens (47 ppm), and permanent (marking) pens (2 ppm). Toluene was detected in a leather cleaning product (6071 ppm), glue (5078 ppm), whiteout (1130 ppm), self-adhesive wallpaper (15-1012 ppm), shoe polish (806 ppm), permanent pen (609 ppm), wig adhesive (372 ppm), tapes (2-360 ppm), oil-based ballpoint pen (201 ppm), duplex wallpaper (12-52 ppm), shoes (27 ppm), and air freshener (13 ppm). High levels of ethylbenzene were detected in permanent pen (ND-345,065 ppm), shoe polish (ND-277,928 ppm), leather cleaner (42,223 ppm), whiteout (ND-2,770 ppm), and glue (ND-792 ppm). Xylene was detected in permanent pen (ND-285,132 ppm), shoe polish (ND-87,298 ppm), leather cleaner (12,266 ppm), glue (ND-3,124 ppm), and whiteout (ND-1,400 ppm). Exposure assessment showed that the exposure to ethylbenzene from permanent pens ranged from 0 to 3.11 mg/kg/d (men) and 0 to 3.75 mg/kg/d (women), while for xylene, the exposure ranges were 0-2.57 mg/kg/d and 0-3.1 mg/kg/d in men and women, respectively. The exposure of women to benzene from whiteout ranged from 0 to 0.00059 mg/kg/d. Hazard index (HI), defined as a ratio of exposure to reference dose (RfD), for ethylbenzene was 31.1 (3.11 mg/kg/d/0.1 mg/kg/d) and for xylene (2.57 mg/kg/d/0.2 mg/kg/d) was 12.85, exceeding 1 for both compounds. Cancer risk for benzene was calculated to be 3.2 × 10(-5) based on (0.00059 mg/kg/d × 0.055 mg/kg-d(-1), cancer potency factor), assuming that 100% of detected levels in some products such as permanent pens and whiteouts were exposed in a worst-case scenario. These data suggest that exposure to VOC via some consumer products exceeded the safe limits and needs to be reduced.

Adjustment factors for toluene, styrene and methyl chloride by population modeling of toxicokinetic variability.

The availability of experimental data suitable as a basis to quantify human variability in response to chemical exposure has increased in recent years. It has enabled scientifically based, data driven adjustment factors (AF) to be deployed in the risk assessment process. As part of this development, we derive AF for human toxicokinetic variability (HK) for three lipophilic organic solvents; toluene, styrene and methyl chloride using physiologically based pharmacokinetic (PBPK) models in a population framework. The Monte Carlo simulations cover the influence of age and gender on toxicokinetic variability in the general population, as well as workplace ventilation rates and fluctuations in exposure level and workload in adult male and female workers. The derived AFHK are below 2.2 (95th percentile) for all subpopulations, exposure scenarios and chemicals, except for markers of acute effects in workers, where the factors are up to 5.0.

Indoor exposure to toluene from printed matter matters: complementary views from life cycle assessment and risk assessment.

A pronounced presence of toluene from rotogravure printed matter has been frequently observed indoors. However, its consequences to human health in the life cycle of magazines are poorly known. Therefore, we quantified human-health risks in indoor environments with Risk Assessment (RA) and impacts relative to the total impact of toxic releases occurring in the life cycle of a magazine with Life Cycle Assessment (LCA). We used a one-box indoor model to estimate toluene concentrations in printing facilities, newsstands, and residences in a best, average, and worst-case scenario. The modeled concentrations are in the range of the values measured in on-site campaigns. Toluene concentrations can be close or even surpass the occupational legal thresholds in printing facilities in realistic worst-case scenarios. The concentrations in homes can surpass the US EPA reference dose (69 µg/kg/day) in worst-case scenarios, but are still at least 1 order of magnitude lower than in press rooms or newsstands. However, toluene inhaled at home becomes the dominant contribution to the total potential human toxicity impacts of toluene from printed matter when assessed with LCA, using the USEtox method complemented with indoor characterization factors for toluene. The significant contribution (44%) of toluene exposure in production, retail, and use in households, to the total life cycle impact of a magazine in the category of human toxicity, demonstrates that the indoor compartment requires particular attention in LCA. While RA works with threshold levels, LCA assumes that every toxic emission causes an incremental change to the total impact. Here, the combination of the two paradigms provides valuable information on the life cycle stages of printed matter.

A weight of evidence approach for the assessment of the ototoxic potential of industrial chemicals.

There is accumulating epidemiological evidence that exposure to some solvents, metals, asphyxiants and other substances in humans is associated with an increased risk of acquiring hearing loss. Furthermore, simultaneous and successive exposure to certain chemicals along with noise can increase the susceptibility to noise-induced hearing loss. There are no regulations that require hearing monitoring of workers who are employed at locations in which occupational exposure to potentially ototoxic chemicals occurs in the absence of noise exposure. This project was undertaken to develop a toxicological database allowing the identification of possible ototoxic substances present in the work environment alone or in combination with noise exposure. Critical toxicological data were compiled for chemical substances included in the Quebec occupational health regulation. The data were evaluated only for noise exposure levels that can be encountered in the workplace and for realistic exposure concentrations up to the short-term exposure limit or ceiling value (CV) or 5 times the 8-h time-weighted average occupational exposure limit (TWA OEL) for human data and up to 100 times the 8-h TWA OEL or CV for animal studies. In total, 224 studies (in 150 articles of which 44 evaluated the combined exposure to noise and a chemical) covering 29 substances were evaluated using a weight of evidence approach. For the majority of cases where potential ototoxicity was previously proposed, there is a paucity of toxicological data in the primary literature. Human and animal studies indicate that lead, styrene, toluene and trichloroethylene are ototoxic and ethyl benzene, n-hexane and p-xylene are possibly ototoxic at concentrations that are relevant to the occupational setting. Carbon monoxide appears to exacerbate noise-induced hearing dysfunction. Toluene interacts with noise to induce more severe hearing losses than the noise alone.

Toxic effects of Hydrilla verticillata exposed to toluene, ethylbenzene and xylene and safety assessment for protecting aquatic macrophytes.

Little information is available about the toxicity of toluene, ethylbenzene and xylene acting on macrophytes, and their toxicity data are rarely used in regulation and criteria decisions. The results extended the knowledge on toxic effects of toluene, ethylbenzene and xylene on aquatic plants. The responses of Hydrilla verticillata to these pollutants were investigated. Chlorophyll levels, lipid peroxidation, and antioxidant enzymes (superoxide dismutase and guaiacol peroxidase) showed diverse responses at different concentrations of toluene, ethylbenzene and xylene. The linear regression analyses were performed respectively, suggesting the concentrations of toluene, ethylbenzene and xylene expected to protect aquatic macrophytes were 7.30 mg L⁻¹, 1.15 mg L⁻¹ and 2.36 mg L⁻¹, respectively. This study emphasized that aquatic plants are also sensitive to organic pollutants as fishes and zooplanktons, indicating that macrophytes could be helpful in predicting the toxicity of these pollutants and should be considered in regulation and criteria decisions for aquatic environment protection.

A mechanistic modeling framework for predicting metabolic interactions in complex mixtures.

BACKGROUND: Computational modeling of the absorption, distribution, metabolism, and excretion of chemicals is now theoretically able to describe metabolic interactions in realistic mixtures of tens to hundreds of substances. That framework awaits validation. OBJECTIVES: Our objectives were to a) evaluate the conditions of application of such a framework, b) confront the predictions of a physiologically integrated model of benzene, toluene, ethylbenzene, and m-xylene (BTEX) interactions with observed kinetics data on these substances in mixtures and, c) assess whether improving the mechanistic description has the potential to lead to better predictions of interactions. METHODS: We developed three joint models of BTEX toxicokinetics and metabolism and calibrated them using Markov chain Monte Carlo simulations and single-substance exposure data. We then checked their predictive capabilities for metabolic interactions by comparison with mixture kinetic data. RESULTS: The simplest joint model (BTEX interacting competitively for cytochrome P450 2E1 access) gives qualitatively correct and quantitatively acceptable predictions (with at most 50% deviations from the data). More complex models with two pathways or back-competition with metabolites have the potential to further improve predictions for BTEX mixtures. CONCLUSIONS: A systems biology approach to large-scale prediction of metabolic interactions is advantageous on several counts and technically feasible. However, ways to obtain the required parameters need to be further explored.

An assessment of indoor air concentrations and health risks of volatile organic compounds in three primary schools.

Concentrations of volatile organic compounds (VOCs), including formaldehyde, in classrooms, kindergartens, and outdoor playgrounds of three primary schools were measured in spring, winter, and fall terms in Izmir, Turkey. A health-risk assessment was conducted for odor detection, sensory irritation, chronic toxic effects, and cancer. Active sampling was applied for VOCs and formaldehyde on Tenax TA and DNPH tubes, respectively. VOCs were analyzed in a thermal desorption-GC-MS system. Formaldehyde analysis was performed using an HPLC instrument. Benzene, toluene, and formaldehyde were the most abundant compounds with 95th percentile indoor air concentrations of 29, 87, and 106 µg/m(3), respectively. Naphthalene and xylenes followed them with an order of magnitude lower concentrations. Two isomers of dichlorobenzene (1,3 and 1,4) were the other notable compounds. The concentrations were utilized to classify the indoor air pollutants with respect to potential health effects. In addition, carcinogenic and chronic toxic risks were estimated using Monte-Carlo simulation. Formaldehyde appears to be the most concerning pollutant with high chronic toxic and carcinogenic risk levels according to the health assessment followed by naphthalene, benzene, and toluene due to their chronic effects.