Styrene-associated health outcomes at a windblade manufacturing plant

Emission of volatile organic compounds during open fire cooking with wood biomass: Traditional three-stone open fire vs. gasifier cooking stove in rural Kenya

Cooking with wood biomass fuels releases hazardous air pollutants, including volatile organic compounds (VOCs), that often disproportionally affect women and children. This study, conducted in Kwale and Siaya counties in Kenya, employed thermal desorption gas chromatography - mass spectrometry to analyse VOC emissions from cooking with a wood biomass three-stone open fire vs. top-lit updraft gasifier stove. In kitchens with adequate ventilation, total VOC levels increased from 35-252 μg∙m-3 before cooking to 2235-5371 μg∙m-3 during open fire cooking, whereas use of a gasifier stove resulted in reduced emissions from cooking by 48-77 % (506-2778 μg∙m-3). However, in kitchens with poor ventilation, there was only a moderate difference in total VOC levels between the two methods of cooking (9034-9378 μg∙m-3 vs. 6727-8201 μg∙m-3 for the three-stone open fire vs. gasifier stove, respectively). Using a non-target screening approach revealed significantly increased levels of VOCs, particularly benzenoids, oxygenated and heterocyclic compounds, when cooking with the traditional open fire, especially in closed kitchens, highlighting the effects of poor ventilation. Key hazardous VOCs included benzene, naphthalene, phenols and furans, suggesting potential health risks from cooking. In kitchens with good ventilation, use of the gasifier stove markedly reduced emissions of these priority toxic VOCs compared to cooking with an open fire. Thus, substituting open fires with gasifier stoves could help to improve household air quality and alleviate health risks. The study revealed that VOCs were present prior to cooking, possibly originating from previously cooked food (buildup) or the outside environment. VOC emissions were also exacerbated by reduced air flow in high humidity during rainfall, suggesting an area for further research. The findings underscore the importance of adopting cleaner cooking technologies and enhancing kitchen ventilation to mitigate the impacts of VOCs in developing countries.

Impact of Epidemic Intelligence Service Training in Occupational Respiratory Epidemiology

The Centers for Disease Control and Prevention's Epidemic Intelligence Service (EIS) is a fellowship in applied epidemiology for physicians, veterinarians, nurses, scientists, and other health professionals. Each EIS fellow is assigned to a position at a federal, state, or local site for 2 years of on-the-job training in outbreak investigation, epidemiologic research, surveillance system evaluation, and scientific communication. Although the original focus of the program on the control of infectious diseases remains salient, positions are available for training in other areas of public health, including occupational respiratory disease. In this Perspective, we describe the EIS program, highlight three positions (one federal and two state-based) that provide training in occupational respiratory epidemiology, and summarize trainees' experiences in these positions over a 30-year period. For early-career health professionals interested in understanding and preventing occupational respiratory hazards and diseases, EIS offers a unique career development opportunity.

Effects of styrene monomer on a mouse model of atopic dermatitis

Aim: Styrene monomer (SM) is a basic chemical used as a raw material for polystyrene and unsaturated polyester resins and in the production of synthetic resins, synthetic rubbers, paints, and adhesives. To date, it is unclear whether SM is associated with the aggravation of atopic dermatitis. The aim was to investigate the effects of SM on atopic dermatitis-like skin lesions induced by mite allergen in NC/Nga mice.Methods: Male mice were injected intradermally with mite allergen on their right ears. In the presence of an allergen, SM (3.5 or 350 μg/animal/week) was administered by intraperitoneal injection. We evaluated clinical scores, ear thickening, histologic findings, and the protein expressions of cytokines and chemokines.Results: Macroscopic and microscopic examinations demonstrated that exposure to SM at a dose of 3.5 μg caused an exacerbation of atopic dermatitis-like skin lesions related to mite allergen. These changes were consistent with the level of histamine in the ear tissue as an overall trend. In contrast, 350-μg SM did not show significant enhancement effects.Conclusion: These results indicate that SM exacerbated atopic dermatitis-like skin lesions at hundred-fold lower levels than the level that causes no observed adverse effects as determined by histologic changes in rodent livers. SM could be at least partly responsible for the recent increase in atopic dermatitis.Impact statementStyrene monomer (SM) is classified as an International Agency for Research on Cancer group 2B carcinogen and includes neurotoxicity and respiratory disorders. However, the effects of SM as a chemical substance on existing allergic pathophysiology have not been elucidated yet. This study demonstrated that SM exacerbated murine atopic dermatitis-like skin lesions at hundred-fold lower levels than the level that causes no observed adverse effects as determined by histologic changes in rodent livers, which was concomitant with the local level of histamine. These data hasten a need for comprehensive research to clarify the chemical pollutants' effects of doses much lower than NOAEL on vulnerable pathophysiologies such as allergy/atopy.

Carcinogenic and health risk assessment of respiratory exposure to Acrylonitrile, 1,3-Butadiene and Styrene (ABS) in a Petrochemical Industry Using the United States Environmental Protection Agency (EPA) Method

PURPOSE

This study aimed to carcinogenic and health risk assessment of respiratory exposure to acrylonitrile, 1,3-butadiene, and styrene in the petrochemical industry.

MATERIALS AND METHODS

This cross-sectional study was conducted in a petrochemical plant producing acrylonitrile, butadiene, and styrene (ABS) copolymers. Respiratory exposure with acrylonitrile, 1,3-butadiene and styrene was measured using methods No. 1604, 1024, and 1501 of the National Institute of Occupational Safety and Health, respectively. The US Environmental Protection Agency method was used to assess carcinogenic and health risks.

RESULTS

The average occupational exposure to acrylonitrile, 1,3-butadiene, and styrene was 560.82 μg. m^-3 for 1,3-butadiene, 122.8 μg. m^-3 for acrylonitrile and 1.92 μg. m^-3 for styrene. The average lifetime cancer risk (LCR) in the present study was 2.71 ×10^-3 for 1,3-butadiene, 2.1 ×10^-3 for acrylonitrile, and 6.6 for styrene. Also, the mean non-cancer risk (HQ) among all participants for 1,3-butadiene, acrylonitrile, and styrene was 4.04 ± 6.93, 10.82 ± 14.76, and 0.19 ± 0.11, respectively.

CONCLUSION

The values of carcinogenic and health risks in the majority of the subjects were within the unacceptable risk levels due to exposure to 1,3-butadiene, acrylonitrile, and styrene vapors. Hence, corrective actions are required to protect the workers from non-cancer and cancer risks.

Styrene associated respiratory outcomes among reinforced plastic industry workers

The study aim was to determine whether styrene exposure was associated with respiratory outcomes in a dose-response manner in the fibreglass reinforcement industry. Workers (n=254) from a fibreglass reinforcement factory were subjected to a standardised interview, spirometry and styrene monitoring. Cumulative exposure was calculated across different jobs and levels of exposure. Logistic regression modelling estimated risk for symptoms, respiratory diseases and lung function change across exposure tertiles. The geometric means of styrene in the General Laminating and Fitting Departments were 48.2 mg/m³ (95% CI 36.3-64.1 mg/m³) and 20.7 mg/m³ (95% CI: 15.6-27.5 mg/m³), respectively. The cumulative exposure odds ratios for chronic cough, phlegm, wheezing and breathlessness for high exposure was 3.1 (95% CI 1.1-8.6), 5.3 (95% CI 1.7-16.6), 3.3 (95% CI 1.2-9.1) and 5.5 (95% CI 1.15-26.4), respectively. The cumulative exposure associated reduction in FEV₁/FVC ratio, percent predicted FEV₁ and FVC was 0.01, 0.04% and 0.05%, respectively. Styrene exposure increases the risk of respiratory symptoms and is associated with reduced lung function.

Respiratory health effects of the fiberglass-reinforced plastic lamination process in the yacht-building industry

Objectives:

Fiberglass-reinforced plastics (FRP) manufacturing has been related to cases of severe airway obstruction and elevated risk of respiratory mortality. But the specific job content risk is not clear. This study evaluated the respiratory health effects of the FRP lamination process.

Methods:

A questionnaire was used to evaluate respiratory symptoms of workers in two yacht-building plants. Pre-shift (07:30–08:30 hours) and post-shift (17:00–18:00 hours) lung function was measured, while post-shift induced sputum was collected on the first day of the week. The participants were grouped into FRP laminators and non-laminators. Linear and logistic regression was used to investigate the effects of the lamination process on lung function.

Results:

Laminators had a higher prevalence of chronic cough, lower pre-shift forced expiratory volume in first second (FEV1) and FEV1/force vital capacity (FVC) (-3.3% and -1.5%), lower post-shift FVC and FEV1 (-3.6% and -4.9%), and larger post-shift reduction of FVC (-2.1%) compared to non-laminators. The laminators also had higher risk of early obstructive and overall (obstructive plus restrictive) lung function impairment, and post-shift reduction of FVC >10% [odds ratio (OR) 5.98, 4.98, and 3.87, respectively). They also had higher percentages of neutrophils and lymphocytes in the induced sputum.

Conclusion:

Laminators should undergo regular check-ups of respiratory symptoms and lung function. Further toxicologic studies are warranted to identify the specific causal agent in the FRP lamination process.

Quercetin alleviates styrene oxide-induced cytotoxicity in cortical neurons in vitro via modulation of oxidative stress and apoptosis

Styrene 7,8-oxide (SO) is the principal metabolite of styrene, an industrial neurotoxic compound which causes various neurodegenerative disorders. The present study aimed to explore the mechanisms of SO cytotoxicity (0.5 - 4 mM) in primary cortical neurons and to evaluate the neuroprotective potential of quercetin (QUER). Our results showed that exposure to SO decreased viability of cortical neurons in a concentration-dependent manner. In the presence of QUER, cell viability was increased significantly. The neuroprotective effects of QUER were associated with the reduction of intracellular Reactive Oxygen Species (ROS), the decrease in calcium overload and the restoration of mitochondrial membrane depolarization caused by SO. Additionally, to evaluate neuronal death mechanisms triggered by SO, cells were incubated with Ac-DEVD-CHO, Calpeptin and Necrostatin-1, pharmacological inhibitors of caspase-3, calpains and necroptosis respectively. The data showed that the three inhibitors reduced cell death induced by SO and suggested the implication of apoptotic, necrotic and necroptotic pathways. However, western blot analysis showed that QUER attenuated the activation of caspase-3 but did not prevent calpain activity. Taken together, these data indicated that the cytotoxicity of SO was mediated by oxidative stress and apoptosis, necrosis and necroptosis mechanisms, while the neuroprotection provided by QUER against SO depended mainly on its anti-apoptotic activity.

Occupational Bronchiolitis: An Update

Occupational bronchiolitis is characterized by inflammation of the small airways, and represents a heterogeneous set of lung conditions that can occur following a range of inhalation exposures related to work. The most common clinical presentation includes insidious onset of exertional dyspnea and cough. Multiple reports in recent years have drawn attention to previously unrecognized risk factors for occupational bronchiolitis following exposures in several settings. Both current and past occupational exposures, including prior military deployment-related exposures, should be considered in patients undergoing evaluation for unexplained dyspnea. Diagnostic testing for potential bronchiolitis should include a thorough assessment of the small airways.

Effects of concomitant exposure to styrene and intense noise on rats' whole lung tissues. Biochemical and histopathological studies

Concurrent exposure to styrene (ST) and noise is common especially in industrial environments. The present study aims to determine the related oxidant-induced changes as the result of combined exposure to ST and noise. For this purpose, 24 male Wistar rats were used in four experimental groups (n = 6/groups): (1) control group, (2) the group exposed to an octave band of noise centered at 8 kHz (100 dB SPL) (6 h/day), (3) the group inhalationally exposed to ST (750 ppm) (6 h/day), (4) the group exposed to noise and ST simultaneously. The DNA damage was measured by assessing the concentration of 8-hydroxyl-2-deoxyguanosine (8-OHdG) using ELISA kit. Levels of lipid peroxidation (MDA), GSH and antioxidative activity of SOD and CAT were also determined in whole lung tissues. The results relatively indicated that sub-acute exposure to both noise and ST can lead to pathological damage in rat lung tissues. Furthermore, enhanced levels of 8-OHdG and MDA production were observed in lung tissues. In contrast, GSH, CAT and SOD were markedly reduced in co-exposed group. The results of the study verified additive interaction between noise and ST on accumulation of DNA oxidation products, progressive morphological damages as well as undermining the antioxidative defense system in the rat lung tissues.

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.

Lung disease associated with occupational styrene exposure

Despite reports of pulmonary toxicity due to styrene, guidelines on acceptable styrene exposure levels have been based on risk of cancer and central nervous system and liver toxicity and not on respiratory effects. Many reports have linked exposure to styrene vapor in occupational settings to various forms of non-malignant pulmonary disorders including bronchiolitis, hypersensitivity pneumonitis, and occupational asthma. We report two cases in which the same tasks performed in a single workplace resulted in exposure to styrene vapor with subsequent development of acute respiratory symptoms associated with impaired gas exchange and imaging and histopathologic findings consistent with bronchiolitis and organizing pneumonia. Both patients gradually recovered once their workplace exposure to styrene was terminated. Clinicians, employers, and insurers should be aware of the potential for pulmonary toxicity from exposure to styrene.

Draft Genome Sequence of Pseudomonas putida CA-3, a Bacterium Capable of Styrene Degradation and Medium-Chain-Length Polyhydroxyalkanoate Synthesis

Pseudomonas putida strain CA-3 is an industrial bioreactor isolate capable of synthesizing biodegradable polyhydroxyalkanoate polymers via the metabolism of styrene and other unrelated carbon sources. The pathways involved are subject to regulation by global cellular processes. The draft genome sequence is 6,177,154 bp long and contains 5,608 predicted coding sequences.

Occupational styrene exposure and acquired dyschromatopsia: A systematic review and meta-analysis

BACKGROUND

Styrene is a chemical used in the manufacture of plastic-based products worldwide. We systematically reviewed eligible studies of occupational styrene-induced dyschromatopsia, qualitatively synthesizing their findings and estimating the exposure effect through meta-analysis.

METHODS

PubMed, EMBASE, and Web of Science databases were queried for eligible studies. Using a random effects model, we compared measures of dyschromatopsia between exposed and non-exposed workers to calculate the standardized mean difference (Hedges'g). We also assessed between-study heterogeneity and publication bias.

RESULTS

Styrene-exposed subjects demonstrated poorer color vision than did the non-exposed (Hedges' g = 0.56; 95%CI: 0.37, 0.76; P < 0.0001). A non-significant Cochran's Q test result (Q = 23.2; P = 0.171) and an I² of 32.2% (0.0%, 69.9%) indicated low-to-moderate between-study heterogeneity. Funnel plot and trim-and-fill analyses suggested publication bias.

CONCLUSIONS

This review confirms the hypothesis of occupational styrene-induced dyschromatopsia, suggesting a modest effect size with mild heterogeneity between studies.

Effect of styrene exposure on plasma parameters, molecular mechanisms and gene expression in rat model islet cells

Styrene is an aromatic hydrocarbon compound present in the environment and have primary exposure through plastic industry. The current study was designed to evaluate styrene-induced toxicity parameters in rat plasma fasting blood glucose (FBG) level, oral glucose tolerance, insulin secretion, oxidative stress, and inflammatory cytokines in cellular and molecular levels. Styrene was dissolved in corn oil and administered at different doses (250, 500, 1000, 1500, 2000mg/kg/day and control) to each rat, for 42days. In treated groups, styrene significantly increased fasting blood glucose, plasma insulin (p<0.001) and glucose tolerance. Glucose tolerance, insulin resistance and hyperglycemia were found to be the main consequences correlating gene expression of islet cells. Styrene caused a significant enhancement of oxidative stress markers (p<0.001) and inflammatory cytokines in a dose and concentration-dependent manner in plasma (p<0.001). Moreover, the activities of caspase-3 and -9 of the islet cells were significantly up-regulated by this compound at 1500 and 2000mg/kg/day styrene administrated groups (p<0.001). The relative fold change of GLUD1 was downregulated (p<0.05) and upregulated at 1500 and 2000mg/kg, respectively (p<0.01). The relative fold changes of GLUT2 were down regulated at 250 and 1000mg/kg and up regulated in 500, 1500 and 2000mg/kg doses of styrene (p<0.01). The expression level of GCK indicated a significant upregulation at 250mg/kg and downregulation of relative fold changes in the remaining doses of styrene, except for no change at 2000mg/kg of styrene for GCK. Targeting genes (GLUD1, GLUT2 and GCK) of the pancreatic islet cells in styrene exposed groups, disrupted gluconeogenesis, glycogenolysis pathways and insulin secretory functions. The present study illustrated that fasting blood glucose, insulin pathway, oxidative balance, inflammatory cytokines, cell viability and responsible genes of glucose metabolism are susceptible to styrene, which consequently lead to other abnormalities in various organs.

Non-malignant respiratory disease among workers in industries using styrene-A review of the evidence

BACKGROUND

Asthma and obliterative bronchiolitis (OB) cases have occurred among styrene-exposed workers. We aimed to investigate styrene as a risk factor for non-malignant respiratory disease (NMRD).

METHODS

From a literature review, we identified case reports and assessed cross-sectional and mortality studies for strength of evidence of positive association (i.e., strong, intermediate, suggestive, none) between styrene exposure and NMRD-related morbidity and mortality.

RESULTS

We analyzed 55 articles and two unpublished case reports. Ten OB cases and eight asthma cases were identified. Six (75%) asthma cases had abnormal styrene inhalation challenges. Thirteen (87%) of 15 cross-sectional studies and 12 (50%) of 24 mortality studies provided at least suggestive evidence that styrene was associated with NMRD-related morbidity or mortality. Six (66%) of nine mortality studies assessing chronic obstructive pulmonary disease-related mortality indicated excess mortality.

CONCLUSIONS

Available evidence suggests styrene exposure is a potential risk factor for NMRD. Additional studies of styrene-exposed workers are warranted. Am. J. Ind. Med. 60:163-180, 2017. © 2016 Wiley Periodicals, Inc.