Health Risk Assessment Of Chemicals Research Articles

Evaluating the impact of anatomical and physiological variability on human equivalent doses using PBPK models.

Addressing human anatomical and physiological variability is a crucial component of human health risk assessment of chemicals. Experts have recommended probabilistic chemical risk assessment paradigms in which distributional adjustment factors are used to account for various sources of uncertainty and variability, including variability in the pharmacokinetic behavior of a given substance in different humans. In practice, convenient assumptions about the distribution forms of adjustment factors and human equivalent doses (HEDs) are often used. Parameters such as tissue volumes and blood flows are likewise often assumed to be lognormally or normally distributed without evaluating empirical data for consistency with these forms. In this work, we performed dosimetric extrapolations using physiologically based pharmacokinetic (PBPK) models for dichloromethane (DCM) and chloroform that incorporate uncertainty and variability to determine if the HEDs associated with such extrapolations are approximately lognormal and how they depend on the underlying distribution shapes chosen to represent model parameters. We accounted for uncertainty and variability in PBPK model parameters by randomly drawing their values from a variety of distribution types. We then performed reverse dosimetry to calculate HEDs based on animal points of departure (PODs) for each set of sampled parameters. Corresponding samples of HEDs were tested to determine the impact of input parameter distributions on their central tendencies, extreme percentiles, and degree of conformance to lognormality. This work demonstrates that the measurable attributes of human variability should be considered more carefully and that generalized assumptions about parameter distribution shapes may lead to inaccurate estimates of extreme percentiles of HEDs.

A novel approach to assess the health risk of aryl hydrocarbon receptor-bound contaminants via inhalation exposure using CYP1A1 expression as a biomarker

Polycyclic aromatic hydrocarbons (PAHs) and dioxins are potential causes of multiple diseases by activating the aryl hydrocarbon receptor (AhR) pathway. Health risk assessment of chemicals primarily relies on the relative potency factor (RPF), although its accuracy may be limited when solely using EC50 values. The induction of cytochrome P4501A1 (CYP1A1) serves as a biomarker for AhR activation and is an integrator of dioxin-like toxicity. Here, we present a method for evaluating the risks associated with AhR activation using mathematical models of dose-CYP1A1 induction. The dose-effect curves for certain PAHs and dioxins, including Ant, BghiP, 1,2,3,4,7,8-HxCDD, and others, exhibited a non-classical S-shaped form. The toxic equivalent factor (TEF) profiles revealed a broad range of toxic equivalent factor values. The TEFs for PAHs ranged from approximately 0.01 to 6, with higher values being observed when the concentration was less than 10−10 M, with the exceptions of Ace, Phe, and BghiP. Most congeners of dioxins got the lowest TEF value at around 10−10 M, ranging from 0.04 to 1.00. The binding affinity of AhR to ligands did not display a strong correlation with the EC50 of CYP1A1 expression, suggesting that the AhR-mediated effects of PAHs and dioxins are not fixed but instead fluctuate with the dose. Air samples acquired from a parking area were used to compare the proficiency of RPF and our current approach. In the current method, naphthalene and chrysene were the primary contributors of PAHs to AhR-mediated risks in parking lots air samples, respectively. However, the contributions of naphthalene and chrysene could be disregarded in the RPF approach.

Chemical Health Risk Assessment and Evaluation of Risk toward Ototoxicants among Workers at Palm Oil Mills

Chemical Health Risk Assessment and Evaluation of Risk toward Ototoxicants among Workers at Palm Oil Mills

Risk Assessment of Inhalation Exposure to the Use of Chemicals in the Mineral Processing

Chemical exposure known as chemical hazards and toxic substances (CHTS), which occur through inhalation, ingestion, and skin contact, causes serious illness, irritation, corrosion, injury, and even death. The chemicals analyzed are limited to the reagents used in the mineral ore production process, in addition to dermal exposure. Data on hazard identification and exposure evaluation were collected. The utilization of CHTS will continue to increase in the coming years, thereby leading to health impacts on workers. Global data released by ILO showed a 270 million (62.8%) and 160 million (37.2%) rise in work accidents and illnesses, culminating in 430 million per year. Data on the number of workers who received benefits from the Work Accident Insurance program of the National Social Security Agency for Employment (known as BPJSTK), showed that 210,789 people (4,007 fatal) 221,740 people (3,410 fatal), and 234,370 people (6,552 fatal) experienced work-related accidents and illnesses in Indonesia. Therefore, this qualitative study aims to examine and analyze the health risks of mining workers exposed to CHTS through inhalation- using the observation method. The Chemical Health Risk Assessment (CHRA) method issued by the Malaysian Department of Safety and Health in 2018 was used to assess the inhalation exposure rate. The analyzed chemicals were limited to reagents used in production with data collected through the semi-quantitative method. The results showed that the inhalation exposure risk level is categorized as moderate and capable of causing health defects related to acute toxicity and specific target organ toxicity-single exposure (STOT-SE). Furthermore, 4 (four) out of 6 (six) reagents were identified as having significant inhalation exposure risk, hence, controls related to Occupational Health and Safety (OHS) in the mineral ore processing process must be increased.

Pregnancy-related maternal physiological adaptations and fetal chemical exposure

Prenatal life represents a susceptible window of development during which chemical exposures can permanently alter fetal development, leading to an increased likelihood of disease later in life. Therefore, it is essential to assess exposure in the fetus. However, direct assessment in human fetuses is challenging, so most research measures maternal exposure. Pregnancy induces a range of significant physiological changes in women that may affect chemical metabolism and responses. Moreover, placental function, fetal sex, and pregnancy complications may further modify these exposures. The purpose of this narrative review is to give an overview of major pregnancy-related physiological changes, including placental function and impacts of pregnancy complications, to summarize existing studies assessing chemical exposure in human fetal organs, and to discuss possible interactions between physiological changes and exposures. Our review reveals major knowledge gaps in factors affecting fetal chemical exposure, highlighting the need to develop more sophisticated tools for chemical health risk assessment in fetuses.

Chemical and radiological human health risk assessment from uranium and fluoride concentrations in tap water samples collected from Shiraz, Iran; Monte-Carlo simulation and sensitivity analysis

ABSTRACT Uranium is one of the most critical components in the nuclear field due to its chemical and radiological properties. Since few studies were conducted on uranium concentration in drinking water in Iranian cities, this study aimed to determine the concentration of uranium and flouridein the samples of drinking water collected from tap water in Shiraz, Fars province. Fifty samples were examined for uranium and fluoride presence using the ICP-MS and spectrophotometry methods. Hazard Quotient (HQ) and sensitivity analysis (SA) using the Monte Carlo Simulation technique with 10,000 iterations were applied to determine the human carcinogenic and non-carcinogenic effects of Uranium and Fluoride in three different groups (children, teenagers, and adults). The results showed that uranium and fluoride concentrations varied between 0.18–1.12 μg/L and 0.06–0.56 mg/L, respectively, which is less than the EPA recommendation for both elements. pH, EC, and TDS values were in accordance with the standard, and a positive correlation was observed between fluoride and total dissolved solids (TDS). The highest risk of carcinogenicity was found in the adult group with a value of 3.24E-9, lower than the allowable limit (1E-6). The highest hazard quotient (HQ) for uranium and fluoride was obtained in children with 0.13 and 0.66. Monte Carlo simulation results showed that the hazard quotient (HQ) for both elements in all groups was less than one and consistent with the values of the deterministic method. Also, water swallowing rate and contaminant concentration were the most influential parameters in the sensitivity analysis.

Experimental exposure assessment for in vitro cell-based bioassays in 96- and 384-well plates.

In vitro cell-based bioassays have great potential for applications in the human health risk assessment of chemicals. The quantification of freely dissolved concentrations (C free) in in vitro assays is essential to generate reliable data for in vitro-to-in vivo extrapolation. Existing methods for the quantification of C free are limited to low-throughput microtiter plates. The present study is a proof of principle for the applicability of a solid-phase microextraction (SPME) method for the determination of C free in the peroxisome proliferator-activated receptor gamma (PPARγ) bioassay run in 384-well plates with 80µL medium per well. The effect concentrations obtained from 384-well plates were compared with those obtained from 96-well plates in a previous study. Nominal effect concentrations obtained using 96- and 384-well plates agreed with each other within a factor of three, and freely dissolved effect concentrations agreed within a factor of 6.5. The good degree of agreement in the results from both plate formats proves the general applicability of the SPME method for the determination of C free for bioassays in 384-well plates, making the present study a first step toward exposure assessment in high-throughput bioassays.

Operational Risk Identification and Mitigation of the Chemical Production Process of PT. X Using Failure-Mode and Effect Analysis (FMEA) and Chemical Health Risk Assessment (CHRA) Methods

PT. X is a German-based multinational chemical company that produces surfactant as one of its products. As a chemical processing company, the operational activities of the production process in PT. X poses risks that could happen at any time. This research is conducted to identify, analyze, and propose mitigation plan for the risks in one of the plants operated by PT. X. Interviews are conducted to identify the risks using Fishbone diagram as the framework and the Ishikawa method to categorize the causes. There are 86 risks that are identified consisting of 51 operational risks and 35 risks of chemical exposure. To be more thorough, the identified operational risks are assessed using the Failure-Mode and Effect Analysis (FMEA) and the chemical exposure risks are assessed using the Chemical Health Risk Assessment (CHRA). From the 206 risk causes, 31% are caused by Man, 28% are caused by Machine, 22% are caused by Material, 15% are caused by Method, and 5% are caused by the Environment. The FMEA produces Risk Priority Number (RPN) which led to risk prioritizing using the Pareto diagram and risk mapping, resulting in 24 risks being prioritized that consists of 15 medium-level risks and 9 low-level risks with no high-level risk present. The CHRA produces Risk Rating (RR) and Level of Risk that resulted in 77 low-level and 19 moderate-level risks for risk for inhalation exposure, and 9 moderate-level risks and 86 high-level risks for the exposure through dermal contact. It produces the decision of 17 inadequate control measures for chemical exposures. These assessments are further processed to devise the appropriate contingency plan, mitigation plan, and action plan.

Identification of phthalate mixture exposure targets in the human and mouse ovary in vitro

Chemical health risk assessment is based on single chemicals, but humans and wildlife are exposed to extensive mixtures of industrial substances and pharmaceuticals. Such exposures are life-long and correlate with multiple morbidities, including infertility. How combinatorial effects of chemicals should be handled in hazard characterization and risk assessment are open questions. Further, test systems are missing for several relevant health outcomes including reproductive health and fertility in women. Here, our aim was to screen multiple ovarian cell models for phthalate induced effects to identify biomarkers of exposure. We used an epidemiological cohort study to define different phthalate mixtures for in vitro testing. The mixtures were then tested in five cell models representing ovarian granulosa or stromal cells, namely COV434, KGN, primary human granulosa cells, primary mouse granulosa cells, and primary human ovarian stromal cells. Exposures at epidemiologically relevant levels did not markedly elicit cytotoxicity or affect steroidogenesis in short 24-hour exposure. However, significant effects on gene expression were identified by RNA-sequencing. Altogether, the exposures changed the expression of 124 genes on the average (9–479 genes per exposure) in human cell models, without obvious concentration or mixture-dependent effects on gene numbers. The mixtures stimulated distinct changes in different cell models. Despite differences, our analyses suggest commonalities in responses towards phthalates, which forms a starting point for follow-up studies on identification and validation of candidate biomarkers that could be developed to novel assays for regulatory testing or even into clinical tests.

CHEMICAL HEALTH RISK ASSESSMENT IN THE METALLURGY DEPARTMENT OF A MINING COMPANY, INDONESIA : A CASE STUDY

ABSTRACT Background: Miners are routinely exposed to various hazardous chemicals entering the body through inhalation, dermal, and ingestion. Although, likely, the long-term health impacts of certain chemicals will only become evident in years to come, the utilization of hazardous chemicals will continue to increase in the coming years, leading to a higher disease burden. Therefore, effective controls for the sound management of chemicals at the workplace shall be implemented. Purpose: This study aimed to assess the chemicals used and analyze the health risks related to the use of the chemicals in the flotation process. Methods: This study was a descriptive case study conducted in Indonesia's gold and copper mining company. We ran the assessment using the Chemical Health Risk Assessment method published by the Department of Safety and Health, Malaysia, Year 2018. The chemicals analyzed were limited to the reagents used in the flotation process in the metallurgy department, which have two possible exposure, inhalation, and dermal routes. Results: The results show three out of seven chemicals have the potential to expose workers through inhalation, which is categorized under medium risk, where xanthate has the highest risk rating (RR=12), which potentially causes health effects related to acute toxicity, specific target organs, and reproductive toxicity. Meanwhile, five out of seven chemicals have the potential to expose workers through dermal, where three chemicals fell into the high-risk category: promoter, frother, and lime (H2), and two chemicals fell into the moderate-risk category: xanthate and solutrix (M2). Adverse health effects from chemical exposures to dermal include irritation, corrosion, and sensitization. Conclusion: The reagents used in the flotation plant exhibited a significant health risk of inhalation and dermal contact with hazardous chemical exposure. The company shall evaluate the hazard and risk from the hazardous chemicals used in the flotation plant and implement adequate controls, considering elimination, substitution, engineering, administrative, and personal protective equipment (PPE) controls to minimize the workers' inhalation and dermal exposure.

Human health risk assessment of 6:2 Cl-PFESA through quantitative in vitro to in vivo extrapolation by integrating cell-based assays, an epigenetic key event, and physiologically based pharmacokinetic modeling

Human health risk assessment of chemicals is essential but often relies on time-consuming and animal and labor-extensive procedures. Here, we develop a population-based, quantitative in vitro to in vivo extrapolation (QIVIVE) approach which depended on cellular effects monitored by in vitro assays, considered chemical internal concentration determined by LC-MS/MS, extrapolated into in vivo target tissue concentration through physiologically based pharmacokinetic (PBPK) modelling, and assessed populational health risk using in silico modelling. By applying this QIVIVE approach to 6:2 chlorinated polyfluorinated ether sulfonate (6:2 Cl-PFESA), as a representative of the emerging pollutants, we find that 6:2 Cl-PFESA disturbed lipid homeostasis in HepG2 cells through enhancement of lipid accumulation and fatty acid β-oxidation, during which miR-93-5p served as a key event towards toxicity and thus, could serve as an efficient toxicity marker for risk assessment; further, the disruption potency of lipid homeostasis of 6:2 Cl-PFESA for the most of studied populations in China might be of moderate concern. Together, our approach improved the reliability of QIVIVE during human health risk assessment, which can readily be used for other chemicals.

Occupational Pesticide Exposure and Respiratory Effects among Mosquito Control Workers in Kota Bharu and Bachok, Kelantan

Pesticides have been widely used in public health to control mosquito breeding, causing occupational exposures. A cross-sectional study was conducted to evaluate the relationship between pesticide exposure and respiratory health among 43 mosquito control workers in two vector control units in Kelantan by using purposive sampling. Pesticide risk assessment was based on the Chemical Health Risk Assessment (CHRA). A British Medical Research Questionnaire (BMRC) was used to assess respiratory symptoms and lung function was measured using a spirometer. The cumulative pesticide exposure of the individuals was calculated by taking the average number of fogging sessions per month. The risk level for all pesticides was moderate, except for Actellic 50EC. The most common respiratory symptoms were dyspnea (25.6%), cough (18.6%), phlegm (18.6%), and chest tightness (14.0%). Lung function was normal in 30%, restrictive in 45%, and obstructive in 25%. None of the reported respiratory symptoms and lung function values were associated with cumulative pesticide exposure (p>0.05). Past respiratory illness had a significant relationship with chest tightness (Adj OR=0.009, 95%CI: < 0.001 – 0.834). Age had a significant relationship with phlegm (Adj OR=1.259, 95% CI: 1.010 – 1.569). In conclusion, cumulative pesticide exposure did not relate to respiratory effects. However, mosquito control workers should be given proper training on pesticide handling and the effective usage of PPE to reduce occupational pesticide exposure.

Comparison of the chemical health risk assessment of exposure to metal fumes for the furnace operator of a foundry industry using quantitative and semi-quantitative methods

Heavy metals have several adverse effects on the workers' bodies due to their accumulation in the vital organs. Besides that, the current study aimed to assess the health risk of exposure to metal fumes for furnace operators working in a foundry industry based on the three different methods. The current sectional descriptive-analytical research conducted on a foundry industry in Isfahan (Iran) in 2022. Three common methods currently available, including the Semi-Quantitative Risk Assessment Method (SQRCA) and two methods provided based on the US-EPA provided technique, were used in this study. At first, the extent of people's exposure to metal fumes of Fe, Ni, Cr, and Mn was measured. Then, the chemical risk assessment of exposure to these metals' fumes was done using the three methods, and their results were compared. The SPSS Ver.25 has been used for data analysis and comparison in the current study. Results indicated that the furnace operator's exposure to all four metals was above the allowed limit of occupational exposure. The chemical risk assessment results also showed that in the first method (US-EPA-based), the risk of exposure for all workers was acceptable, while in the second method (SQCRA), the risk level of a majority of workers was medium, and in the third method (US-EPA-based), the risk level of a majority of workers was not acceptable. Comparing the methods showed that average risk scores in the first and second methods were significant compared to the exposure to fumes with equivalent concentration (Pvalue<0.05). The average score of carcinogenicity risk in method 3 was significant compared to the concentration of chromium and nickel (P-value < 0.05), but it was not significant for iron and manganese and the non-carcinogenic risk of chromium and nickel. Chemical exposure risk level for the furnace operator was approximately moderate in all three methods. In terms of complexity and information required to implement the method, all three methods were almost the same, with the difference that the results of the first method cannot be generalized to other people who have the same job conditions because individual information such as a person's weight is used to calculate its score.

Microbiota-mediated reactivation of triclosan oxidative metabolites in colon tissues

Triclosan (TCS) is a widespread antimicrobial agent that is associated with many adverse health outcomes. Its gut toxicity has been attributed to the molecular modifications mediated by commensal microbes, but microbial transformations of TCS derivatives in the gut lumen are still largely unknown. Aromatic hydroxylation is the predominant oxidative metabolism of TCS that linked to its toxicological effects in host tissues. Here, we aimed to reveal the biological fates of hydroxyl-TCS (OH-TCS) in the colon, where intestinal microbes mainly reside. Unlike the profiles generated via host metabolism, OH-TCS species remain unconjugated in human stools from a cohort study. Through tracking molecular compositions in mouse intestinal tract, elevated abundance of free-form OH-TCS while reduced abundance of conjugated forms was observed in the colon digesta and mucosa. Using antibiotic-treated and germ-free mice, as well as in vitro approaches, we demonstrate that gut microbiota-encoded enzymes efficiently convert glucuronide/sulfate-conjugated OH-TCS, which are generated from host metabolism, back to their bioactive free-forms in colon tissues. Thus, host-gut microbiota metabolic interactions of TCS derivatives were proposed. These results shed light on the crucial roles of microbial metabolism in TCS toxicity, and highlight the importance of incorporating gut microbial transformations in health risk assessment of environmental chemicals.

A Transformative Vision for an Omics-Based Regulatory Chemical Testing Paradigm.

Use of molecular data in human and ecological health risk assessments of industrial chemicals and agrochemicals has been anticipated by the scientific community for many years; however, these data are rarely used for risk assessment. Here, a logic framework is proposed to explore the feasibility and future development of transcriptomic methods to refine and replace the current apical endpoint-based regulatory toxicity testing paradigm. Four foundational principles are outlined and discussed that would need to be accepted by stakeholders prior to this transformative vision being realized. Well-supported by current knowledge, the first principle is that transcriptomics is a reliable tool for detecting alterations in gene expression that result from endogenous or exogenous influences on the test organism. The second principle states that alterations in gene expression are indicators of adverse or adaptive biological responses to stressors in an organism. Principle 3 is that transcriptomics can be employed to establish a benchmark dose-based point of departure (POD) from short-term, in vivo studies at a dose level below which a concerted molecular change (CMC) is not expected. Finally, Principle 4 states that the use of a transcriptomic POD (set at the CMC dose level) will support a human health-protective risk assessment. If all four principles are substantiated, this vision is expected to transform aspects of the industrial chemical and agrochemical risk assessment process that are focused on establishing safe exposure levels for mammals across numerous toxicological contexts resulting in a significant reduction in animal use while providing equal or greater protection of human health. Importantly, these principles and approaches are also generally applicable for ecological safety assessment.

Application of ARE-reporter systems in drug discovery and safety assessment

The human body is continuously exposed to xenobiotics and internal or external oxidants. The health risk assessment of exogenous chemicals remains a complex and challenging issue. Alternative toxicological test methods have become an essential strategy for health risk assessment. As a core regulator of constitutive and inducible expression of antioxidant response element (ARE)-dependent genes, nuclear factor erythroid 2-related factor 2 (Nrf2) plays a critical role in maintaining cellular redox homeostasis. Consistent with the properties of Nrf2-mediated antioxidant response, Nrf2-ARE activity is a direct indicator of oxidative stress and thus has been used to identify and characterize oxidative stressors and redox modulators. To screen and distinguish chemicals or environmental insults that affect the cellular antioxidant activity and/or induce oxidative stress, various in vitro cell models expressing distinct ARE reporters with high-throughput and high-content properties have been developed. These ARE-reporter systems are currently widely applied in drug discovery and safety assessment. In the present review, we provide an overview of the basic structures and applications of various ARE-reporter systems employed for discovering Nrf2-ARE modulators and characterizing oxidative stressors.

Advances in computational methods along the exposure to toxicological response paradigm

Human health risk assessment is a function of chemical toxicity, bioavailability to reach target biological tissues, and potential environmental exposure. These factors are complicated by many physiological, biochemical, physical and lifestyle factors. Furthermore, chemical health risk assessment is challenging in view of the large, and continually increasing, number of chemicals found in the environment. These challenges highlight the need to prioritize resources for the efficient and timely assessment of those environmental chemicals that pose greatest health risks. Computational methods, either predictive or investigative, are designed to assist in this prioritization in view of the lack of cost prohibitive in vivo experimental data. Computational methods provide specific and focused toxicity information using in vitro high throughput screening (HTS) assays. Information from the HTS assays can be converted to in vivo estimates of chemical levels in blood or target tissue, which in turn are converted to in vivo dose estimates that can be compared to exposure levels of the screened chemicals. This manuscript provides a review for the landscape of computational methods developed and used at the U.S. Environmental Protection Agency (EPA) highlighting their potentials and challenges.

The Compliance Status of Chemical Management among Industries in Malaysia: The USECHH after 20 years

Chemical management plays an important role in the protection of human health and environment. Malaysia through the Department of Occupational Safety and Health (DOSH) developed chemical related legislations under the Occupational Safety and Health Act (OSHA) 1994 upon tripartite and stakeholder consultation. Effective law enforcement by DOSH is important to ensure compliance to occupational health legislations in order to meet the objectives of OSHA 1994. This paper presents the status of chemical management compliance in Malaysia pertaining to compliance to the Occupational Safety and Health (Use and Standards of Exposure of Chemicals Hazardous to Health) (USECHH) Regulations 2000 among the industries in various economic sectors twenty years after its inception. This paper proposes four steps for investigating the compliance status. The four steps are overview of chemical legislations, enforcement strategies, data analysis and recommendations. There was a total of 9712 workplaces inspected by DOSH officers during the enforcement activities. About 54% workplaces received satisfactory grades while 46% were non satisfactory. USECHH operations for the last five years (2016-2020) revealed that 70% of the total workplaces inspected received satisfactory compliance while another 30% potrayed otherwise. These positive results show significant improvement in the status of compliance of chemical management as compared to the beginning of its introduction in year 2000 where majority of the grades are unsatisfactory. Analysis of each elements found that the worst compliance comes from elements such as medical surveillance, health surveillance, exposure monitoring and chemical health risk assessment The research also prescribes strategies and methods taken by DOSH Malaysia in ensuring chemical management compliance at the workplace. This paper shows an insight of chemical management in Malaysia briefly and provides suggestions and recommendations, measures and outcomes of enforcement. Future measures to be taken by DOSH is also suggested to boost compliance.

Implementation of Chemical Health, Safety, and Environmental Risk Assessment in Laboratories: A Case-Series Study.

IntroductionCharacterizing risks associated with laboratory activities in universities may improve health, safety, and environmental management and reduce work-related diseases and accidents. This study aimed to develop and implement a chemical risk assessment method to determine and prioritize more hazardous chemicals in the academic laboratories.MethodsA case-series study was conducted at five academic laboratories and research facilities of an Iranian medical sciences university in 2021. A risk assessment was developed and implemented in three phases to identify, evaluate, and classify potential risks and hazards. The approach provided an innovative tool for evaluating and prioritizing risks in chemical laboratories. Hazards were classified on a five-level scale. The technique reviewed both quantitative and qualitative data and pieces of evidence using Laboratory Safety Guidance (OSHA), Occupational Hazard Datasheet (ILO), the standards of the American Conference of Governmental Industrial Hygienists (ACGIH), International Agency for Research on Cancer (IARC), and National Fire Protection Agency (NFPA) codes.ResultsOverall, the frequency of risks rated from “moderate” to “very high” levels was determined for the health hazards (9.3%), environmental hazards (35.2%), and safety hazards (20.4%). Hydrochloric acid had a high consumption rate in laboratory operations and received the highest risk levels in terms of potential hazards to employees' health and the environment. Nitric acid, Sulfuric acid, Formaldehyde, and Sodium hydroxide were assessed as potential health hazards. Moreover, Ethanol and Sulfuric acid were recognized as safety hazards. We observed adequate security provisions and procedures in academic laboratory operations. However, the lack of awareness concerning health, safety, environmental chemical hazards, and inappropriate sewage disposal systems contributed to the increasing levels of laboratory risk.ConclusionsChemicals used in laboratory activities generate workplace and environmental hazards that must be assessed, managed, and risk mitigated. Developing a method of rating health, safety, and environmental risks related to laboratory chemicals may assist in defining and understanding potential hazards. Our assessment suggested the need for improving the risk perception of individuals involved in handling chemicals to prevent exposure from workplace duties and environmental pollution hazards.

Experimental models of animal chronic pathology in assessing health risks for sensitive population groups

The methodology for health risk assessment and hygienic standardization of chemicals often neglects such a vulnerable population group as people with chronic non-communicable diseases. According to the data provided by the WHO, the prevalence of such pathologies is high in many European countries; therefore, when a disease burden in a certain population is unaccounted for, this may result in lower accuracy of accomplished assessments. On the other hand, introduction of too conservative safe factors when hygienic standards are being developed for chemicals in various media leads to high uncertainty and excessive limitations. Our research goal was to provide scientific substantiation for a methodology for using experimental pathology models to improve reliability of hygienic standardization and accuracy of health risk assessments for sensitive population groups (people suffering from non-chronic communicable diseases) under exposure to naturally occurring chemicals. Another goal was to test this methodology by performing a case study on drinking water. The testing results indicate that a chronic 6-month exposure to model substances produced more apparent toxic effects on experimental animals with model pathologies (spontaneous hypertension and experimental histamine-induced nephropathy) in comparison with “healthy” animals. This allowed us to recommend using experimental models of congenital and induced animal pathology bearing in mind target organs for toxic effects produced by the analyzed chemicals to substantiate hygienic standards, health risks taken into account. This should be done at the stage when dose-dependent reactions are identified (determination of no-effect and / or threshold levels) in addition to studies performed on “healthy” animals. It is most appropriate to use this approach when the following conditions are met: 1) a research object is naturally occurring chemicals that are widely spread in the environment due to its natural formation; 2) pathologies of organs (systems) that are targets for biological effects produced by the tested chemicals are widely spread in a population (circulatory diseases, diseases of the excretory system, etc.).