Health hazards of xylene: a literature review

Product labeling accuracy and contamination analysis of commercially available cannabidiol product samples

Background and objective: Commercially available cannabidiol (CBD) products are increasingly being used for medicinal purposes, including for the treatment of various neurological conditions, but there are growing concerns around adherence to quality control measures that protect consumers. This study was conducted to assess the purity and label accuracy of commercially available CBD products. Methods: Commercially available CBD products were chosen from the open stream of commerce in the United States based on formulations as a tincture, gummy, vape, or topical product. Cannabinoid concentrations were analyzed to verify label accuracy including "full spectrum," "broad spectrum," and "CBD isolate" claims on the product label. Analysis for the presence of contaminants included evaluation for heavy metals, pesticides, and residual solvents. Labeled and actual total amounts of CBD and levels of impurities such as heavy metals, residual solvents, and pesticides were measured. Results: A total of 202 CBD products (100 tinctures, 48 gummies, 34 vape products, and 20 topicals) were chosen to represent a broad sample in the United States. Of the products tested (full spectrum, n = 84; broad spectrum, n = 28; CBD isolate, n = 37), 26% did not meet the definition for product type claimed on the packaging. The majority of products (74%) deviated from their label claim of CBD potency by at least 10%. Heavy metals were detected 52 times across 44 of the 202 products tested, with lead being the most prevalent heavy metal. Residual solvents were detected 446 times across 181 of 202 products, with the highest concentrations reported for hexane, m/p-xylene, methanol, and o-xylene. Of 232 pesticides tested, 26 were found 55 times across 30 products. A total of 3% of heavy metals, 1% of residual solvents, and 1% of pesticides violated >1 regulatory threshold. Discussion: This study demonstrated that the majority of commercially available CBD products tested within the current study are inaccurately labeled. Heavy metals, residual solvents, and pesticides were found in several products, some of which violated regulatory thresholds. Thus, uniform compliance with CBD quality control measures is lacking and raises consumer protection concerns. Improved regulatory oversight of this industry is recommended.

Biorenewable Solvents for High-Performance Organic Solar Cells

With the advent of nonfullerene acceptors (NFAs), organic photovoltaic (OPV) devices are now achieving high enough power conversion efficiencies (PCEs) for commercialization. However, these high performances rely on active layers processed from petroleum-based and toxic solvents, which are undesirable for mass manufacturing. Here, we demonstrate the use of biorenewable 2-methyltetrahydrofuran (2MeTHF) and cyclopentyl methyl ether (CPME) solvents to process donor: NFA-based OPVs with no additional additives in the active layer. Furthermore, to reduce the overall carbon footprint of the manufacturing cycle of the OPVs, we use polymeric donors that require a few synthetic steps for their synthesis, namely, PTQ10 and FO6-T, which are blended with the Y-series NFA Y12. High performance was achieved using 2MeTHF as the processing solvent, reaching PCEs of 14.5% and 11.4% for PTQ10:Y12 and FO6-T:Y12 blends, respectively. This work demonstrates the potential of using biorenewable solvents without additives for the processing of OPV active layers, opening the door to large-scale and green manufacturing of organic solar cells.

Case Report: Long segmental lesions of the spinal cord caused by exposure to xylene

Xylene has the potential to cause nervous system disturbances since it is a lipophilic substance with high affinity for lipid-rich tissue, such as the brain. Involvement in the spinal cord, especially long segmental spinal cord lesions that permeate almost the entire cervical and thoracic spinal cord, is extremely rare. We report two cases of occupational exposure to excessive xylene, both of which presented with severe and rapidly progressive numbness and weakness in the limbs that, more importantly, led to poor outcomes: one died and the other was left severely disabled. In both, spinal magnetic resonance imaging showed long segmental lesions in the cervicothoracic spinal cord. These findings may provide some insights into the effects of xylene as an isolated agent on the spinal cord injury.

Haemato-biochemical, mutagenic, and histopathological changes in Oreochromis niloticus exposed to BTX

The study of the DNA damage response in erythrocytes after exposure to volatile organic compounds (VOCs) can present evidence for its potential effect as genotoxic- biomarkers for environmental pollution. Although VOCs are dangerous pollutants, still little is known about hemotoxic, cytotoxic, and genotoxic effects of such pollutants on fish. We optimized an assay method for apoptosis and DNA damage in erythrocytes of adult tilapia fish after 15 days exposure to benzene (0.762 ng/L), toluene (26.614 ng/L), and xylene (89.403 ng/L). The highest level of apoptosis and DNA damage were recorded in benzene-exposed fish, as was the highest level of histopathological alterations in gills, liver, and kidney. The imbalance of the antioxidants profile explained the stress-case reported in exposed fish. These results suggest that hemotoxic, cytotoxic, genotoxic, and tissue damage were recorded after exposure to BTX in Oreochromis niloticus.

Exposure to Crude Oil-Related Volatile Organic Compounds Associated with Lung Function Decline in a Longitudinal Panel of Children

BACKGROUND

Children in the affected area were exposed to large amounts of volatile organic compounds (VOCs) from the Hebei Spirit oil spill accident.

OBJECTIVES

We investigated the lung function loss from the exposure to VOCs in a longitudinal panel of 224 children 1, 3, and 5 years after the VOC exposure event.

METHODS

Atmospheric estimated concentration of total VOCs (TVOCs), benzene, toluene, ethylbenzene, and xylene for 4 days immediately after the accident were calculated for each village (n = 83) using a modeling technique. Forced expiratory volume in 1 s (FEV₁) as an indicator of airway status was measured 1, 3, and 5 years after the exposure in 224 children 4~9 years of age at the exposure to the oil spill. Multiple linear regression and linear mixed models were used to evaluate the associations, with adjustment for smoking and second-hand smoke at home.

RESULTS

Among the TVOCs (geometric mean: 1319.5 mg/m³·4 d), xylene (9.4), toluene (8.5), ethylbenzene (5.2), and benzene (2.0) were dominant in the order of air concentration level. In 224 children, percent predicted FEV₁ (ppFEV₁), adjusted for smoking and second-hand smoke at home, was 100.7% after 1 year, 96.2% after 3 years, and 94.6% after 5 years, and the loss over the period was significant (p < 0.0001). After 1 and 3 years, TVOCs, xylene, toluene, and ethylbenzene were significantly associated with ppFEV₁. After 5 years, the associations were not significant. Throughout the 5 years' repeated measurements in the panel, TVOCs, xylene, toluene, and ethylbenzene were significantly associated with ppFEV₁.

CONCLUSIONS

Exposure to VOCs from the oil spill resulted in lung function loss among children, which remained significant up to 5 years after the exposure.

Toxicological Effects of Technical Xylene Mixtures on the Female Reproductive System: A Systematic Review

Technical xylene is a compound of massive production that is used in applications such as petrochemical and healthcare laboratories. Exposure to xylene can cause acute and chronic effects in humans and animals. Currently available studies regarding xylene’s adverse effects with credible designs were dated almost twenty years ago. This systematic review summarizes the findings regarding the detrimental effects of technical xylene from human, animal, and in vitro studies. It recapitulated available studies with respect to the effects of xylene on the female reproductive system to stress the need for updating the current data and guidelines. Based on pre-specified criteria, 22 studies from journal databases exploring the toxic effects of xylene on menstruation, endocrine endpoints, fetal development, and reproductive functions were included for the review. It was found that related studies with a specific focus on the effects of technical xylene on the female reproductive system were insufficient. Therefore, further studies are necessary to update the existing data, thus improving the quality and reliability of risk assessment of exposure to xylene in pregnant women

Examination of xylene exposure in the U.S. Population through biomonitoring: NHANES 2005-2006, 2011-2016

Aim: Xylenes are aromatic hydrocarbons used for industrial applications such as the production of petrochemicals and plastics. Acute xylene exposures can negatively impact health through neurotoxicity and irritation of respiratory and dermal tissues. We quantified urinary biomarkers of xylene exposure [2-methylhippuric acid (2MHA) and a mixture of 3- and 4-methylhippuric acids (34MH)] in a representative sample of the U.S. population. Methods: Spot urine obtained during the National Health and Nutrition Examination Survey 2005-2006 and 2011-2016 was analysed using ultra-high-performance liquid chromatography/tandem mass spectrometry. Exclusive smokers were distinguished from non-users using a combination of self-report and serum cotinine data. Results: The median 2MHA and 34MH levels were higher for exclusive smokers (100 µg/g and 748 µg/g creatinine, respectively) than for non-users (27.4 µg/g and 168 µg/g creatinine, respectively). Participants who smoked cigarettes had significantly higher 2MHA and 34MH levels (p < 0.0001) than unexposed participants. Smoking 1-10, 11-20, and >20 cigarettes per day (CPD) was significantly associated with 181%, 339% and 393% higher 2MHA levels, respectively. For 34MH, smoking 1-10, 11-20, and >20 CPD was significantly associated with 201%, 398%, and 471% higher 34MH levels, respectively. Conclusion: We confirm that tobacco smoke is a significant source of xylene exposure as measured by urinary 2MHA and 34MH levels.

Quantitative differences between common occupational health risk assessment models

Objectives

Methodological studies on occupational health risk assessment (OHRA) models are rarely reported. This study aimed to explore the quantitative differences between common OHRA models.

Methods

The risk ratios (RRs) in five typical industries (leather, wooden furniture manufacturing, printing and dyeing, printing, and garment manufacturing) were investigated using six OHRA models, namely the models from the US Environmental Protection Agency (EPA), Singapore, the Control of Substances Hazardous to Health (COSHH), Australia, Romania, and International Council on Mining and Metals (ICMM). The consistency, correlation, and reliability were evaluated for quantitative differences between the models.

Results

The order of the RRs obtained from the EPA, Singaporean, and COSHH models in the five industries was consistent with the order of the inherent risk levels in those industries. The EPA and Singaporean models could effectively distinguish the inherent risk levels of risk factors like xylene and ethyl acetate. The order of RR between the six models was: RR _EPA > RR _COSHH > RR _Singaporean > RR _Australian > RR _Romanian and RR _ICMM (P < .05). The EPA model had the weakest correlations with other models. The Singaporean model had positive correlations in RRs with the other models (P＜0.01).

Conclusions

The EPA and Singaporean models exhibited good reliability since they could distinguish the inherent risk of the industry or risk factor and tended to get higher risk levels. The EPA model was independent and the Singaporean model had a good correlation with other models. More studies on OHRA methodology are needed.

Biofriendly Substitutes for Xylene in Deparaffinization

Background

Xylene is an aromatic hydrocarbon that is routinely used in histopathological laboratories. It is biohazardous and produces many toxic effects like carcinogenesis. A safer substitute for xylene is necessary to minimize its usage.

Aim

The aim of this study was to evaluate the effectiveness of 1.7% dishwashing solution, 95% lemon water, and 100% coconut oil when compared to xylene as a deparaffinizing agent during hematoxylin and eosin (H&E) staining.

Materials and Methods

Fifteen paraffin-embedded tissue blocks were selected. Four sections were made from each block. One section was stained with conventional H&E method using xylene (group A) as deparaffinizing agent and other three sections were stained with xylene-free H&E method using 1.7% dishwashing solution (group B), 95% lemon water (group C), and 100% coconut oil (group D), respectively. Slides were scored blindly by a single pathologist considering the parameters such as nuclear and cytoplasmic staining; uniformity, clarity, and crispness of staining; and presence or absence of wax retention.

Results

Adequate nuclear staining was noted in 100% of sections of groups A, B, C, and D (P < 0.001), whereas adequate cytoplasmic staining was noted in 93.33% each in groups A, C, and D when compared with 100% in group B (P > 0.05). Uniform staining was present in 80% of groups A and B and in 73.33% of groups C and D (P > 0.05). Clarity of staining was present in 86.66% of groups A and B and in 80% of groups C and D (P > 0.05), whereas crispness of staining was seen in 73.33% of groups A and D, 86.66% of group B, and 80% of group C (P > 0.05). Wax retention was noted in 20% of groups A and B, and 26.66% of groups C and D (P > 0.05). Adequate staining for diagnosis was noted in 100% of group A sections followed by 93.33% in group B, 86.66% in group C, and 80% in group D as compared with 90% in group B (P > 0.05).

Conclusion

Dishwashing solution, lemon water, and coconut oil can be used as safer and cost-effective substitutes to xylene for deparaffinization in H&E staining procedure.

Alternative to xylene as a clearing agent in histopathology

INTRODUCTION:

Clearing is an essential step in processing tissue for light microscopy. Xylene is the clearing agent used most commonly worldwide. Xylene is toxic and therefore a threat to personnel working in histopathology laboratories. We evaluated a safer alternative clearing agent for use in the histopathology laboratory.

MATERIALS AND METHODS:

We used 230 formalin-fixed, paraffin-embedded tissue blocks from 19 different tissues. Half of the specimens were processed using xylene and half were processed using UltraClear™. Tissues were evaluated for eight parameters: sectioning, nuclear staining, cytoplasmic staining, overall cell morphology, clarity of staining, uniformity of staining, quality of immunohistochemistry (IHC), and cost.

RESULTS:

Both UltraClear™ and xylene processed sections scored 100% for IHC. Sections processed using UltraClear™ were easy to cut (81.7%) as were xylene processed sections (96.5%). UltraClear™ processed sections showed 67%, 60.9%, 52.2%, 63.5%, and 67% for nuclear staining, cytoplasmic staining, cell morphology, clarity of staining, and uniformity of staining, respectively. UltraClear™ is twice as expensive as xylene. We found that tissues processed using UltraClear™ were easy to cut and worked well for both hematoxylin and eosin and IHC staining.

CONCLUSION:

UltraClear™ is less toxic, less flammable, friendlier to the environment, and easy to handle, but it is two times expensive than xylene. The findings of this study recommend the use of UltraClear™ solution as a routine clearing agent in histopathology laboratories. However, further studies are required.

Assessment of the chemical hazard awareness of petrol tanker driver: A case study

Understanding the tanker driver hazard awareness on chemical exposure is important to ensure that they are fortified with the appropriate information regarding the risk of their occupation. This present study was conducted to determine the awareness of the petrol tanker driver on the chemical exposure during transportation petroleum product. The assessment on hazardous awareness of the petrol tank driver was conducted through questionnaire survey. Wherein, the questionnaire was designed with considering the variables of age of the driver, working experience, working hours in a day and knowledge on chemical hazard presence in the petroleum oil. A reliability test of Cronbach's Alpha was performed to validate the questionnaire and the Chi-Square test was conducted to determine the correlation among the studied variables. The findings of the present study revealed that the drivers who are frequently come into direct contact with petrol cannot identify the spillage had occurred during working. The study identified that there is an urgency to conduct training on safe handling of petroleum oil in order to eliminate the risk of chemical hazards exposure to the tanker driver.

Toxicity of xylene in occupationally exposed workers: A high-performance liquid chromatography analysis

Background:

Xylene is one of the most commonly used solvents in industrial and medical technologies. Several health hazards of xylene have been documented in literature. Workers in certain forces appear to have the greatest potential for exposure to high concentrations of xylene – histopathology technicians and painters are two such groups. This study was undertaken with the aim to determine the level of xylene exposure and the various systemic health effects among these groups.

Methodology:

The study was performed by analyzing the urine samples of the participants for methylhippuric acid, the established biomarker of xylene with the aid of high-performance liquid chromatography.

Results and Conclusion:

The work hours per week of the occupationally exposed participants were statistically analyzed with that of the excretory values of the metabolites of xylene, and the P value was found to be highly significant. Various side effects of xylene including respiratory, dermatological, neurological and gastrointestinal symptoms were observed among the study groups.

Exhaled breath analysis for gastric cancer diagnosis in Colombian patients

We present here the first study that directly correlates gastric cancer (GC) with specific biomarkers in the exhaled breath composition on a South American population, which registers one of the highest global incidence rates of gastric affections. Moreover, we demonstrate a novel solid state sensor that predicts correct GC diagnosis with 97% accuracy. Alveolar breath samples of 30 volunteers (patients diagnosed with gastric cancer and a controls group formed of patients diagnosed with other gastric diseases) were collected and analyzed by gas-chromatography/mass-spectrometry (GC-MS) and with an innovative chemical gas sensor based on gold nanoparticles (AuNP) functionalized with octadecylamine ligands. Our GC-MS analyses identified 6 volatile organic compounds that showed statistically significant differences between the cancer patients and the controls group. These compounds were different from those identified in previous studied performed on other populations with high incidence rates of this malady, such as China (representative for Eastern Asia region) and Latvia (representative for Baltic States), attributable to lifestyle, alimentation and genetics differences. A classification model based on principal component analysis of our sensor data responses to the breath samples yielded 97% accuracy, 100% sensitivity and 93% specificity. Our results suggest a new and non-intrusive methodology for early diagnosis of gastric cancer that may be deployed in regions lacking well-developed health care systems as a prediagnosis test for selecting the patients that should undergo deeper investigations (e.g., endoscopy and biopsy).

Characteristic of the acute drug intoxication conveyed by Kanagawa helicopter emergency medical service

Aim

Various critical cases have been transported since the use of the Kanagawa Helicopter Emergency Medical Service (HEMS) started at Tokai University Hospital (Isehara, Japan) in 2002, including cases of acute poisoning. We analyzed the characteristics of acute poisoning cases conveyed by the HEMS.

Methods

Kanagawa HEMS conveyed 3,814 cases from July 2002 to March 2013, and acute drug and poison intoxication was diagnosed in 131 of these cases. We undertook a descriptive statistical study of these cases.

Results

The causative agent was found to be psychiatric prescription drugs in 39.7% of cases, pesticides in 29.7%, alcohol in 8.4%, analgesics in 5.3%, detergent or bleach in 6.1%, oil, natural gas, or thinner in 4.6%, and others in 6.1%. At HEMS contact, systolic blood pressure was less than 90 mmHg in 18.3% of cases, and 40.2% were in coma. Endotracheal intubation was carried out in 44.5% of cases, and 6.9% died within 24 h of hospital admission. The cases of poisoning that we transported in the HEMS were often in shock and/or coma on arrival at the field, and rapid endotracheal intubation was required in nearly half of them, as many were in a serious condition.

Conclusion

We believe that outcomes were more likely to be improved by appropriate early treatment by the HEMS. It will be necessary to further compare the ambulance service with the HEMS to evaluate their efficacy in the future.

Bio-Friendly Alternatives for Xylene - Carrot oil, Olive oil, Pine oil, Rose oil

BACKGROUND

Xylene is a flammable liquid with characteristic petroleum or aromatic odours, it is miscible with most of the organic solvents and paraffin wax. Xylene clears tissues rapidly and renders transparency, facilitating clearing endpoint determination, this made it to be used as a clearing agent in routine histopathological techniques. Even though it is a good clearing agent, it causes damage to the tissues by its hardening effect particularly those fixed in non-protein coagulant fixatives. Apart from these tissue effects, it has severe, long lasting ill effects on health of technicians and pathologists when exposed to longer duration. Hence in order to overcome these effects and replace xylene with a safe alternative agent, the present study was carried out to assess the clearing ability and bio-friendly nature of four different natural oils i.e., Carrot oil, Olive oil, Pine oil and Rose oil in comparison with that of Xylene. According to Bernoulli's principle of fluid dynamics, to decrease viscosity of these oils and increase penetration into tissues for rapid clearing hot-air oven technique was used.

AIMS

To assess:1) Clearing ability and bio-friendly nature of four different oils i.e., Carrot oil, Olive oil, Pine oil, Rose oil in comparison with that of xylene, 2) Application of Bernoulli's principle of fluid dynamics in rapid clearing of tissues by using hot-air oven.

MATERIALS AND METHODS

Forty different formalin fixed tissue samples were taken. Each sample of tissue was cut into 5 bits (40x5=200 total bits) which were subjected for dehydration in differential alcohol gradients. Later, each bit is kept in 4 different oils such as Carrot oil, Olive oil, Pine oil, Rose oil and xylene and transferred into hot-air oven. Further routine steps of processing, sectioning and staining were done. Individual sections cleared in four different oils were assessed for cellular architecture, staining quality and a comparison was done between them.

RESULTS

Results showed that all the four oils had ability to clear the tissues similar to that of xylene. Pine oil was superior in its physical and clearing properties, which also maintained good cellular architecture and distinct staining quality, when compared with other oils and xylene.

CONCLUSION

Carrot oil, Olive oil, Pine oil, Rose oil, are not only bio friendly and economical but can also be used as clearing agent instead of xylene. In this study stability and longetivity of haematoxyllin and eosin staining was evaluated for over a period of one year and no significant difference in staining quality were observed.