Setting Risk-Based Occupational Exposure Limits for No-Threshold Carcinogens

Several regulators have recently issued so-called risk-based occupational exposure limits for carcinogenic substances, and also reported estimates of the risk of fatality that exposure to the limit value would give rise to. This practice provides an opportunity to study how differences in the exposure limits set by different regulators are influenced by differences in the scientific judgment (what is the risk at different levels?) and in the policy judgment (how should large risks be accepted?). Based on a broad search, a list was compiled of exposure limits for carcinogens that the respective regulator associates with a numerical risk estimate. For benzene, such data was available from six regulators. The differences in estimates of the risk/exposure relationship and in risk tolerance were about equal in size for benzene, while the range for acceptability was somewhat wider. A similar pattern was observed, although less clearly, for substances with data from only two or three regulators. It is concluded that the science factor and the policy factor both contribute to differences in exposure limits for carcinogens. It was not possible to judge which of these two factors has the larger influence.     

Effect of Variability in Pharmacokinetic Parameters on the Derivation of Exposure Limits for Pharmaceutical Compounds

The purpose of this study was to investigate how variability in pharmacokinetic parameters influences the determination of occupational exposure limits (OEL) for pharmaceutical compounds in potentially susceptible subpopulations. A compartmental pharmacokinetic model for quinidine was applied to derive OELs based on target blood concentrations in humans but relied on pharmacokinetic parameters in subjects with cirrhosis rather than normal subjects. Quinidine was used as the sample compound as this was used in the development of the methodology. The intent was not to set an OEL for quinidine for a particular population but rather to use the methodology to investigate how factors, which may influence susceptibility, could be incorporated into the analysis. The model was used to simulate exposure concentrations that would result in levels below those that cause undesirable pharmacological effects taking into account variability in parameters through incorporation of Monte Carlo sampling. Results indicate that cirrhotic patients did not require additional protection from occupational exposure to quinidine. These results cannot be extrapolated to other compounds, as the effects of variability in pharmacokinetics on systemic exposure are compound specific. However, this methodology does provide a framework for addressing issues related to the contribution of pharmacokinetics to susceptibility from occupational exposure to pharmaceutical compounds.     

医务人员艾滋病职业暴露危险因素评估与防护现况调查

医务人员艾滋病职业暴露是关系到公众及医务人员身体健康和生命安全的公共卫生问题。保护医务人员免受艾滋病职业暴露的威胁已日益成为艾滋病防治的关键,北京市东城区疾病控制中心率先在北京市医务人员中开展艾滋病执业暴露危险因素及防护现状的调查,旨在了解和掌握医务人员艾滋病职业暴露危险因素及防护现况,为医务人员艾滋病职业暴露防护对策提供科学依据。     

Evaluation of Potential Exposure to Metals in Laundered Shop Towels

We reported in 2003 that exposure to metals on laundered shop towels (LSTs) could exceed toxicity criteria. New data from LSTs used by workers in North America document the continued presence of metals in freshly laundered towels. We assessed potential exposure to metals based on concentrations of metals on the LSTs, estimates of LST usage by employees, and the transfer of metals from LST-to-hand, hand-to-mouth, and LST-to-lip, under average- or high-exposure scenarios. Exposure estimates were compared to toxicity criteria. Under an average-exposure scenario (excluding metals’ data outliers), exceedances of the California Environmental Protection Agency, U.S. Environmental Protection Agency, and the Agency for Toxic Substances and Disease Registry toxicity criteria may occur for aluminum, cadmium, cobalt, copper, iron, and lead. Calculated intakes for these metals were up to more than 400-fold higher (lead) than their respective toxicity criterion. For the high-exposure scenario, additional exceedances may occur, and high-exposure intakes were up to 1,170-fold higher (lead) than their respective toxicity criterion. A sensitivity analysis indicated that alternate plausible assumptions could increase or decrease the magnitude of exceedances, but were unlikely to eliminate certain exceedances, particularly for lead.     

Occupational hazard exposures and health risks at wooden toys industry in Southern Thailand

Abstract

The paper aims to examine occupational hazard exposures and health risks in wooden toys processing industry in the Southern Thailand. A walk-through survey was conducted as well as environmental and personal dust sampling measurements were performed during June 2015–January 2016. A cross-sectional study was conducted among 704 workers. Environmental and personal noise and wood dust samplings (NIOSH method 0500 and 0600) were conducted. The workers were exposed to wood dust at levels of 0.4581?mg/m³ for total dust (SD = 0.4391) and 1.111?mg/m³ for respirable dust (SD = 0.3450), respectively. The pulmonary defects among male had higher prevalence than female the (OR = 1.49; 95%CI = 0.97–2.29). Aged group <25 years old had significant lower than aged group >40 years old for almost twice (OR = 0.48). Male workers were significantly at lower risk for noise-induced hearing loss (NIHL) than females (OR = 0.54; 95%CI = 0.34–0.84). This study provides evidence that pulmonary defects among aged group <25 years old had significant lower than aged group >40 years old (p?=?.026). Male workers were significantly at lower risk for NIHL than females (p?=?.006).     

Limits in soil ingestion data: The potential for imputing data when soil ingestion estimates are below the detection limit

The formation of a soil ingestion distribution based on pooling data from current soil ingestion studies is appealing. An important issue in forming such a distribution is what to do with negative soil ingestion estimates for particular subjects, because they comprise approximately 10 to 40% of the total soil ingestion estimates. A method of correcting for the negative estimates of soil ingestion is to make use of the “soil ingestion detection limit”;. An appropriate methodology for forming estimates of such detection limits is available in the literature. This paper discusses appropriate use of the existing soil ingestion detection limit methodology in forming a pooled database using current soil ingestion study data. The discussion focuses attention on the current limitations of children's soil ingestion data and potential pitfalls in applying the detection limit model when generating a soil ingestion distribution. In summary, currently available soil ingestion data are not sufficiently reliable to impute individual soil ingestion estimates below the detection limit. Research directed toward identifying and quantifying individual error in soil ingestion estimates is needed to overcome this limitation.     

The Concept of Data Utility in Health Risk Assessment: A Multi-Disciplinary Perspective

Human and ecological health risk assessments and the decisions that stem from them require the acquisition and analysis of data. In agencies that are responsible for health risk decision-making, data (and/or opinions/judgments) are obtained from sources such as scientific literature, analytical and process measurements, expert elicitation, inspection findings, and public and private research institutions. Although the particulars of conducting health risk assessments of given disciplines may be dramatically different, a common concern is the subjective nature of judging data utility. Often risk assessors are limited to available data that may not be completely appropriate to address the question being asked. Data utility refers to the ability of available data to support a risk-based decision for a particular risk assessment. This article familiarizes the audience with the concept of data utility and is intended to raise the awareness of data collectors (e.g., researchers), risk assessors, and risk managers to data utility issues in health risk assessments so data collection and use will be improved. In order to emphasize the cross-cutting nature of data utility, the discussion has not been organized into a classical partitioning of risk assessment concerns as being either human health- or ecological health-oriented, as per the U.S. Environmental Protection Agency's Superfund Program.     

Risk Assessment for Dermal Exposure of Organochlorine Pesticides for Local Fishermen in the Rangsit Agricultural Area,Central Thailand

Organochlorine pesticides (OCPs) used in agriculture and for public health purposes were banned in Thailand over the past decade; however, their persistent residues have been found in several agricultural areas of the country. This may result in adverse effects to human populations. This study investigated the concentration of organochlorine pesticides residues (OCPRs) in surface water and evaluated the potential cancer risk associated with dermal contact of the local fisherman fishing in the Khlong 7 canal, Rangsit agricultural area, central Thailand. Water samples were extracted using liquid-liquid extraction (LLE) and then analyzed by gas chromatography with microelectron capture detector (μ -ECD). The results show that low concentrations of OCPRs were detected in parts per billion (ppb or ng/ml) levels, that is, ∑ Endosulfan (α -, β -, and -sulfate) 0.082 ng/ml > DDT and derivatives 0.019 ng/ml > ∑ HCH (α -, γ -, β -, and δ -HCH) 0.014 ng/ml > aldrin and dieldrin 0.007 ng/ml > heptachlor and heptachlor epoxide 0.0068 ng/ml > endrin and endrin aldehyde 0.005 ng/ml > methoxychlor 0.001 ng/ml, respectively. Using the worst-case scenario defined as the reasonable maximum exposure (RME) to assess the potential cancer risk, five OCPs (dieldrin, 4,4′ -DDT, β -HCH, heptachlor, and heptachlor epoxide) may pose a risk of concern on a lifetime human carcinogenesis greater than one in a million.     

Health risk assessment of occupational exposure to styrene depending on the type of industry: Data from the Workplace Environmental Monitoring Program in Korea

Data from the Workplace Environmental Monitoring Program was used to evaluate the concentrations and risk of occupational exposure to styrene in different industries to identify which industries should be prioritized for styrene exposure management. Risk assessments were conducted for the five industries with several workplaces that mostly use styrene: motor vehicle and motorcycle maintenance and repair services, other chemical product manufacturing, ship and boat building, basic chemical manufacturing, and plastic products manufacturing. The highest central tendency exposure was found in the plastic products manufacturing industry (10.14 mg/m³). In addition, the hazard quotient (HQ) for central tendency exposure exceeded 1 only in the plastic products manufacturing industry. Almost two-thirds (62.2%) of workplaces in the plastic products manufacturing industry have an HQ exceeding 1. We conclude that workers in the plastic products manufacturing industry are at the highest risk for styrene exposure, and those in motor vehicle and motorcycle maintenance and repair service and basic chemical manufacturing are at the lowest risk. These results show that styrene exposure could be most effectively managed by prioritizing control measures in the plastic products manufacturing industry.     

Human body burdens of chemicals used in plastic manufacture

In the last decades, the availability of sophisticated analytical chemistry techniques has facilitated measuring trace levels of multiple environmental chemicals in human biological matrices (i.e. biomonitoring) with a high degree of accuracy and precision. As biomonitoring data have become readily available, interest in their interpretation has increased. We present an overview on the use of biomonitoring in exposure and risk assessment using phthalates and bisphenol A as examples of chemicals used in the manufacture of plastic goods. We present and review the most relevant research on biomarkers of exposure for phthalates and bisphenol A, including novel and most comprehensive biomonitoring data from Germany and the United States. We discuss several factors relevant for interpreting and understanding biomonitoring data, including selection of both biomarkers of exposure and human matrices, and toxicokinetic information.     

Data Fusion Methods for Human Health Risk Assessment: Review and Application

The improved accessibility to data that can be used in human health risk assessment (HHRA) necessitates advanced methods to optimally incorporate them in HHRA analyses. This article investigates the application of data fusion methods to handling multiple sources of data in HHRA and its components. This application can be performed at two levels, first, as an integrative framework that incorporates various pieces of information with knowledge bases to build an improved knowledge about an entity and its behavior, and second, in a more specific manner, to combine multiple values for a state of a certain feature or variable (e.g., toxicity) into a single estimation. This work first reviews data fusion formalisms in terms of architectures and techniques that correspond to each of the two mentioned levels. Then, by handling several data fusion problems related to HHRA components, it illustrates the benefits and challenges in their application.     

The Ethical Conduct of Studies Involving Controlled Human Exposure to Environmental Pollutants

In recent years, the concern for human research subject protection has increased markedly in the United States. The nature of research subject participation in controlled-exposure environmental health research is such that the individual subject bears the risk of participation, while the benefits of such research accrue to society. Therefore, particular attention must be paid when designing studies to protect the health and safety of human research subject. This paper outlines principles for the appropriate selection of pollutants to which humans can be exposed, and the principles that should be used to protect the health and safety of human research subject.     

Ecological Risk Assessment of Radiological Exposure to Depleted Uranium in Soils at a Weapons Testing Facility

The potential for unacceptable risks to biota from radiological exposure to depleted uranium (DU) in soils was evaluated at two sites where DU weapons testing had been conducted in the past. A screening risk assessment was conducted to determine if measured concentrations of DU-associated radionuclides in site soils exceed radionuclide levels considered protective of biota. While concentrations of individual radionuclides did not exceed acceptable levels, total radionuclide concentrations could result in potentially unacceptable doses to exposed biota. Thus, a receptor-specific assessment was conducted to estimate external and internal radiological doses to vegetation and wildlife known or expected to occur at the sites. Wildlife evaluated included herbivores, omnivores, and top-level predators. Internal dose estimates to wildlife considered exposure via fugitive dust inhalation and soil and food ingestion; root uptake was the primary exposure route evaluated for vegetation. Total doses were compared with acceptable dose levels of 1.0 and 0.1 rad/day for vegetation and wildlife, respectively, with potentially unacceptable risks indicated for doses exceeding these levels. All estimated doses were below or approximated acceptable levels, typically by an order of magnitude or more. These results indicate that current levels of DU in soils do not pose unacceptable radiological risks to biota at the sites evaluated.     

High-Throughput Exposure Assessment Tool (HEAT) for exposure-based prioritization of chemicals

Abstract

High-throughput methods are now routinely used to rapidly screen chemicals for potential hazard. However, hazard-based decision-making excludes important exposure considerations resulting in an incomplete estimation of chemical safety. Models to estimate exposure exist, but are generally unsuited to keep up with high-throughput demands. The High-Throughput Exposure Assessment Tool (HEAT) is designed to efficiently predict near-field exposure to consumers and workers via inhalation, oral and dermal routes. HEAT is based on well-known modeling algorithms and provides default model parameters to support reasonably conservative exposure estimates. Underlying chemical-specific data are uploaded or entered by the end user. HEAT’s main strength is the flexible tiered screening functionality, which enables exposure estimates for single or multiple chemicals simultaneously. Hypothetical case examples highlighting the application of HEAT to more complex exposure estimates for alternative and aggregate assessments are provided.     

Exposure risks to pesticide applicators posed by the use of electric backpack sprayers and stretcher-mounted sprayers in orchards

Abstract

The introduction of the pesticide registration system in pesticide risk assessments has promoted the scientific and safe use of pesticides, and the assessment of occupational exposure risk. In the present study, we performed an experiment in a citrus orchard subject to normal orchard management practices. By measuring the exposure of applicators’ (farmers and technicians) body parts to 45% malathion emulsifiable concentrate during its application using electric backpack sprayers (0.25?KPa) and stretcher-mounted sprayers (1.5?KPa), the unit exposure (UE) was determined. The risks of exposure for pesticide applicators who adopted five different protective measures (A: no personal protective equipment (PPE), i.e., no clothes, no gloves, no caps, and no socks; B: short-sleeved top and shorts; C: short-sleeved top, shorts, and a single pair of gloves; D: short-sleeved top, shorts, a single pair of gloves, and a cap; E: long-sleeved top, long pants, a single pair of gloves, and a cap) were also assessed. The results were as follows: 1) The total levels of exposure for pesticide applicators using electric backpack sprayers and stretcher-mounted sprayers were 3613.63?µg and 5654.28?µg, respectively. When electric backpack sprayers were used, the body parts that had the highest exposure were the head (13.8%), hands (19.9%) and back (14.0%), and when stretcher-mounted sprayers were used, the hands (32.5%) and lower legs (21.1%) had the highest level of exposure; 2) In the absence of PPE, the UE values for farmers who used electric backpack sprayers and farmers who used stretcher-mounted sprayers were significantly different. However, when PPE was used, the difference in UE values between the farmers using the two different types of sprayers was not significant; 3) When protective measure A was adopted, the risk quotient (RQ) values of the farmers and technicians who used electric backpack sprayers for the application of malathion were 1.44 and 0.54, respectively; the corresponding RQ values when protective measure B was adopted were 0.97 and 0.28, respectively. When stretcher-mounted sprayers were used for the application of chlorpyrifos, the RQ value of the farmers who adopted protective measure E was 0.43 while other types of PPE use resulted in RQ values greater than 1. In contrast, the RQ value for technicians was 1.62 when protective measure A was used and 1.02 when protective measure B was adopted, whereas other types of PPE use resulted in RQ values less than 1. Therefore, besides increasing the awareness of personal protection among pesticide applicators, improvement in the management of pesticide use and the enhancement of standard operations are of practical significance for controlling occupational exposure to pesticides.     

Assessing Risks of Plant-Based Pharmaceuticals: I. Human Dietary Exposure

Protein-based drugs are the fastest growing class of drugs for the treatment of disease in humans and other animals. However, the current method of producing proteins for pharmaceutical application is predicted to fall short because of population growth and demographic trends. This study characterized human dietary risks using quantitative risk assessment techniques for three pharmaceutical proteins produced in field-grown maize. The three proteins were aprotinin, gastric lipase, and Escherichia coli heat-labile enterotoxin B subunit (LT-B). The human dietary risks from the three proteins inadvertently occurring in food were evaluated using three different exposure scenarios so that potential risks could be compared. The three exposure scenarios ranged in conservatism to evaluate the range of risk between the proteins and scenarios. Risk quotients (RQs) were calculated for all three scenarios to integrate exposure and effect (toxicity). The risk assessments revealed that the most conservative scenario produced higher RQs than the other two scenarios. The dietary risks from scenario 1 for aprotinin were three orders of magnitude greater than for scenario 2, and four orders of magnitude greater than for scenario 3. This risk assessment revealed that dietary risks will vary dramatically and depend on factors such as the specific pharmaceutical protein, protein expression, and exposure scenarios. The assessment also reinforced the need for case-by-case assessments.     

The Role of Human Error Analysis in Occupational and Environmental Risk Assessment: A Serbian Experience

Human error analysis is certainly a challenge today for all involved in safety and environmental risk assessment. The risk assessment process should not ignore the role of humans in accidental events and the consequences that may derive from human error. This article presents a case study of the Success Likelihood Index Method (SLIM) applied to the Electric Power Company of Serbia (EPCS), with the aim to disclose the importance of human error analysis in risk assessment. A database on work-related injuries, accidents, and critical interventions that occurred over a 10-year period in the EPCS provided the basis for this study. The research comprised analysis of 1074 workplaces, with a total of 3997 employees. A detailed analysis identified 10 typical human errors, performance shaping factors (PSFs), and estimated human error probability (HEP). Based on the obtained research results one can conclude that PSF control remains crucial for human error reduction, and thus prevention of occupational injuries and fatalities (the number of injuries decreased from 58 in 2012 to 44 in 2013, no fatalities recorded). Furthermore, the case study performed at the EPCS confirmed that the SLIM is highly applicable for quantification of human errors, comprehensive, and easy to perform.     

Review of Information Resources to Support Human Exposure Assessment Models

Efforts to model human exposures to chemicals are growing more sophisticated and encompass increasingly complex exposure scenarios. The scope of such analyses has increased, growing from assessments of single exposure pathways to complex evaluations of aggregate or cumulative chemical exposures occurring within a variety of settings and scenarios. In addition, quantitative modeling techniques have evolved from simple deterministic analyses using single point estimates for each necessary input parameter to more detailed probabilistic analyses that can accommodate distributions of input parameters and assessment results. As part of an overall effort to guide development of a comprehensive framework for modeling human exposures to chemicals, available information resources needed to derive input parameters for human exposure assessment models were compiled and critically reviewed. Ongoing research in the area of exposure assessment parameters was also identified. The results of these efforts are summarized and other relevant information that will be needed to apply the available data in a comprehensive exposure model is discussed. Critical data gaps in the available information are also identified. Exposure assessment modeling and associated research would benefit from the collection of additional data as well as by enhancing the accessibility of existing and evolving information resources.     

Cadmium Exposure in the South Korean Population: Implications of Input Assumptions for Deterministic Dietary Assessment

Dietary exposure to Cadmium (Cd) is of increasing interest globally because of the adverse health effects of Cd arising from multiple sources. The assumptions used when undertaking deterministic assessment of Cd in global or regional diets have implications when applied to specific national cases representing local variation in food composition and consumption patterns different from global or regional norms. We have conducted deterministic dietary Cd exposure assessments for the South Korean population using a variety of schemes for point estimation. Consumption data from the Korean Nutrition Survey (2001 to 2003) and monitoring data from the Korea Food and Drug Administration were used as the basis for the exposure estimates. The average daily per capita Cd exposure was 14 μ g for the South Korean population, representing about 27% of tolerable daily intake (TDI) and is similar to that reported in other countries. The hazard index (HI, the ratio of total Cd exposure to the TDI) typically ranged from 0.3 to 0.9 depending on assumptions used in deterministic estimates of dietary exposure. Even though the current exposure of the South Korean population at large is found to be safe on the basis of these estimates, consideration of high-end patterns of Cd level and consumption suggests the need for continued vigilance in dietary Cd monitoring.