Health Risk Assessment Of Exposure Research Articles

Health risk assessment for exposure to nitrate and nitrite in drinking water in Iran: a systematic review and meta-analysis

Health risk assessment for exposure to nitrate and nitrite in drinking water in Iran: a systematic review and meta-analysis

A critical review of health risk assessments of exposure to emissions from coal-fired power stations in South Africa

Emissions from coal-fired power stations increase the incidence of respiratory, cardiovascular and cardiopulmonary diseases and contribute to premature deaths. Wildly varying estimates of the magnitude of these health impacts have been published, however. This paper investigates the reasons for the large discrepancies calculated in five comprehensive health risk assessments of South African coal-fired power station emissions. We review the approaches and input data used by the studies. We also evaluate the exposure-response functions (which relate the pollution concentration to which the population is exposed, to the increase in health risk) used by each study and pay specific attention to whether the exposure-response functions are relevant to the South African context. Health risks are under-estimated in studies that only consider impacts in industrialised areas, or assume high counterfactual concentrations. Health risks are probably over-estimated, however, in other studies which use linear or exponential exposure-response functions that are not applicable in areas where exposure levels are much higher (such as solid fuel-using communities). A more accurate estimate of health effects would be obtained by applying integrated exposure-response functions to quantify health risks at actual exposure levels, and then apportioning the health effects relative to the contribution made by each source to total exposure levels. A fair assessment of the health risk of South Africa’s older coal-fired power stations should also weigh the health costs of the emissions against the health benefits of electricity use in lower income households.

An occupational health risk assessment for exposure to BTEX: A case study of informal traders in a metro centre (taxi rank) in South Africa

An occupational health risk assessment for exposure to BTEX: A case study of informal traders in a metro centre (taxi rank) in South Africa

Health risk assessment of exposure to ambient concentrations of benzene, toluene and xylene in Pretoria West, South Africa

Benzene, toluene and xylene (BTX) are part of the volatile organic group of pollutants and are seen as international environmental priority air pollutants that can constitute a threat to public health. This study assessed the non-carcinogenic and carcinogenic risks of exposure to BTX in an industrial area located in Pretoria West, South Africa. The study comprised two parts, namely ambient air monitoring and the application of a Human Health Risk Assessment (HHRA) model. The study included sampling data for the 2014 calendar year (January – December). Sampling frequency were hourly samples of ambient concentrations of BTX. Estimate of the possible non-carcinogenic risk of BTX and carcinogenic risk of benzene were determined using the hazard quotient (HQ) and lifetime cancer risk (LCR) respectively. Annual average concentration (µg/m3) of BTX was 0.9 ± 0.9, 2.2 ± 2.5 and 0.8 ± 0.6, respectively, with higher concentrations during winter months. The HQ indicated no likelihood of adverse health effects on children and adults. The HQ of exposure to BTX were <1 for both children (0.094 µg/m3) and adults (0.38 µg/m3). The LCR of exposure to benzene among children (4.4 × 10−7) as well as adults (1.8 × 10−6) was lower than those stipulated by regulatory organizations.

Health risk assessment of exposure to the Middle-Eastern Dust storms in the Iranian megacity of Kermanshah

ObjectiveThis study assessed the effects of particulate matter (PM), equal or less than 10 μm in aerodynamic diameter (PM10), from the Middle-Eastern Dust events on public health in the megacity of Kermanshah (Iran). Study designThis study used epidemiological modeling and monitored ambient air quality data to estimate the potential PM10 impacts on public health. MethodsThe AirQ2.2.3 model was used to calculate mortality and morbidity attributed to PM10 as representative of dust events. Using Visual Basic for Applications, the programming language of Excel software, hourly PM10 concentrations obtained from the local agency were processed to prepare input files for the AirQ2.2.3 model. ResultsUsing baseline incidence, defined by the World Health Organization, the number of estimated excess cases for respiratory mortality, hospital admissions for chronic obstructive pulmonary disease, for respiratory diseases, and for cardiovascular diseases were 37, 39, 476, and 184 persons, respectively, from 21st March, 2014 to 20th March, 2015. Furthermore, 92% of mortality and morbidity cases occurred in days with PM10 concentrations lower than 150 μg/m3. The highest percentage of person-days occurred for daily concentrations range of 100–109 μg/m3, causing the maximum health end-points among the citizens of Kermanshah. ConclusionsCalculating the number of cumulative excess cases for mortality or morbidity attributed to PM10 provides a good tool for decision and policy-makers in the field of health care to compensate their shortcomings particularly at hospital and healthcare centers for combating dust storms. To diminish these effects, several immediate actions should be managed in the governmental scale to control dust such as spreading mulch and planting new species that are compatible to arid area.

Health risk assessment of exposure to heavy metals in dairy products collected from Bushehr, Iran

Background: Assessment of dairy products can identify the presence of heavy metals in them that poses a serious threat to human health and is a major concern on a global scale. Objective: The aim of this research was to evaluate the heavy metal concentrations in dairy products and their potential risks in urban areas in Bushehr city, Iran. Materials and Methods: A total of 71 dairy product samples (16 milk, 14 yoghurt, 15 cheeses, 13butter, 11 dough, and 12 creams) were collected randomly from dairy shops in Bushehr city, Iran and analyzed by using a flame atomic absorption spectrophotometer. Results: The results of this research showed that the concentrations of lead in cream and butter were significantly higher than in milk and yoghurt samples (P

Health risk assessment of exposures to a high molecular weight plasticizer present in automobile interiors

This study provides an exposure and risk assessment of diundecyl phthalate (DUP), a high molecular weight phthalate plasticizer present in automobile interiors. Total daily intake of DUP was calculated from DUP measured in wipe samples from vehicle seats from six automobiles. Four of the vehicles exhibited atypical visible surface residue on the seats. Two vehicles with no visible surface residue were sampled as a comparison. DUP was the predominant organic compound identified in each of the wipes from all seats. A risk assessment of DUP via oral, dermal, and inhalation routes resulting from contact with automobile seats was conducted. The mean, standard deviation, and maximum DUP concentrations on the seats with visible surface residue were 6983 ± 7823 μg/100 cm2 and 38300 μg/100 cm2, respectively. The mean and 95th percentile of the mean for daily cumulative dose of DUP for all exposure routes for the seats with no visible surface residue ranged from 7 × 10−4 to 4 × 10−3 mg/kg-day and from 8 × 10−4 to 5 × 10−3 mg/kg-day, respectively. For seats with visible surface residue, cumulative doses ranged from 2 × 10−3 to 2 × 10−2 mg/kg-day and from 4 × 10−3 to 2 × 10−2 mg/kg-day, respectively. The estimated daily intake (contact or absorbed dose) of DUP from automobile seats were far lower than the NOAELs reported in and derived from animal studies, and are well below the reported Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) Derived No Effect Levels (DNELs) for the general population. Based on this analysis, using virtually any benchmark for evaluating safety, exposure to DUP via automobile seat covers did not pose a measureable increased health-risk in any population under any reasonably plausible exposure scenario.

Microscale spatial distribution and health assessment of PM2.5-bound polycyclic aromatic hydrocarbons (PAHs) at nine communities in Xi'an, China

Spatial variability of polycyclic aromatic hydrocarbons (PAHs) associated with fine particulate matter (PM2.5) was investigated in Xi'an, China, in summer of 2013. Sixteen priority PAHs were quantified in 24-h integrated air samples collected simultaneously at nine urban and suburban communities. The total quantified PAHs mass concentrations ranged from 32.4 to 104.7 ng m−3, with an average value of 57.1 ± 23.0 ng m−3. PAHs were observed higher concentrations at suburban communities (average: 86.3 ng m−3) than at urban ones (average: 48.8 ng m−3) due to a better enforcement of the pollution control policies at the urban scale, and meanwhile the disorganized management of motor vehicles and massive building constructions in the suburbs. Elevated PAH levels were observed in the industrialized regions (west and northwest of Xi'an) from Kriging interpolation analysis. Satellite-based visual interpretations of land use were also applied for the supporting the spatial distribution of PAHs among the communities. The average benzo[a]pyrene-equivalent toxicity (Σ[BaP]eq) at the nine communities was 6.9 ± 2.2 ng m−3 during the sampling period, showing a generally similar spatial distribution to PAHs levels. On average, the excess inhalation lifetime cancer risk derived from Σ[BaP]eq indicated that eight persons per million of community residents would develop cancer due to PM2.5-bound PAHs exposure in Xi'an. The great in-city spatial variability of PAHs confirmed the importance of multiple points sampling to conduct exposure health risk assessment.

Health risk assessment for exposure to nitrate in drinking water from village wells in Semarang, Indonesia

The levels of nitrate in 52 drinking water wells in rural Central Java, Indonesia were evaluated in April 2014, and the results were used for a health risk assessment for the local populations by using probabilistic techniques. The concentrations of nitrate in drinking water had a range of 0.01–84 mg/L, a mean of 20 mg/L and a medium of 14 mg/L. Only two of the 52 samples exceeded the WHO guideline values of 50 mg/L for infant methaemoglobinaemia. The hazard quotient values as evaluated against the WHO guideline value at the 50 and 95 percentile points were HQ50 at 0.42 and HQ95 at 1.2, respectively. These indicated a low risk of infant methaemoglobinaemia for the whole population, but some risk for the sensitive portion of the population. The HQ50 and HQ95 values based on WHO acceptable daily intake dose for adult male and female were 0.35 and 1.0, respectively, indicating a generally a low level of risk. A risk characterisation linking birth defects to nitrate levels in water consumed during the first three months of pregnancy resulted in a HQ50/50 values of 1.5 and a HQ95/5 value of 65. These HQ values indicated an elevated risk for birth defects, in particular for the more sensitive population. A sanitation improvement program in the study area had a positive effect in reducing nitrate levels in wells and the corresponding risk for public health. For example, the birth defect HQ50/50 values for a subset of wells surveyed in both 2014 and 2015 was reduced from 1.1 to 0.71.

Public Health Risk Conditioned by Chemical Composition of Ground Water

The article studies the public health potential risk originated from water consumption and estimated on the basis of the groundwater chemical composition. We have processed the results of chemical groundwater analysis in different aquifers of Tomsk district (Tomsk Oblast, Russia). More than 8400 samples of chemical groundwater analyses were taken during long-term observation period. Human health risk assessment of exposure to contaminants in drinking water was performed in accordance with the risk assessment guidance for public health concerning chemical pollution of the environment (Russian reference number: 2.1.10.1920-04-M, 2004). Identified potential risks were estimated for consuming water of each aquifer. The comparative analysis of water quality of different aquifers was performed on the basis of the risk coefficient of the total non-carcinogenic effects. The non-carcinogenic risk for the health of the Tomsk district population due to groundwater consumption without prior sanitary treatment was admitted acceptable. A rather similar picture is observed for all aquifers, although deeper aquifers show lower hazard coefficients.

Classification and Health Risk Assessment for Borehole Water Contaminated by Metals in Selected Households in Southwest Nigeria

Samples of borehole water were randomly collected from twenty households in the Lagos-Ogun axis of southwestern Nigeria. The samples were analyzed for silver, iron, manganese, lead, nickel, magnesium, cadmium, zinc, sodium, potassium, pH, turbidity, dissolved oxygen, electrical conductivity, alkalinity, total hardness, chloride, nitrate and sulphate following standard methods of water analysis. Results obtained were compared with global background values and WHO guidelines for drinking water. The pH values ranged from 4.17 ± 0.26 to 6.07 ± 0.27 while the metal pollution indexes are between 0.01 and 0.11. Cadmium, manganese, iron and nitrate (mg/L) levels were found to be relatively high in most of the water samples. Results obtained were analyzed statistically. Health risk assessment for exposure to cancer and non-cancer indices was evaluated. Kempster and co-workers classification of drinking water quality was applied; nineteen of the twenty household water samples were found to fall short of the ideal water quality suitable for lifetime use.

EPHECT III: Health risk assessment of exposure to household consumer products

In the framework of the EU EPHECT project (Emissions, Exposure Patterns and Health Effects of Consumer Products in the EU), irritative and respiratory effects were assessed in relation to acute (30-min) and long-term (24-h) inhalation exposure to key and emerging indoor air pollutants emitted during household use of selected consumer products. A detailed Health Risk Assessment (HRA) was performed for five selected pollutants of respiratory health relevance, namely acrolein, formaldehyde, naphthalene, d-limonene and α-pinene. For each pollutant, the Critical Exposure Limit (CEL) was compared to indoor air concentrations and exposure estimates for the use of 15 selected consumer products by two population groups (housekeepers and retired people) in the four geographical regions of Europe (North, West, South, East), which were derived previously based on microenvironmental modelling. For the present HRA, health-based CELs were derived for certain compounds in case indoor air quality guidelines were not available by the World Health Organization for end-points relevant to the current study. For each pollutant, the highest indoor air concentrations in each microenvironment and exposure estimates across home microenvironments during the day were lower than the corresponding acute and long-term CELs. However, considerable contributions, especially to acute exposures, were obtained in some cases, such as formaldehyde emissions resulting from single product use of a floor cleaning agent (82% CEL), a candle (10% CEL) and an electric air freshener (17% CEL). Regarding multiple product use, the case of 30-min formaldehyde exposure reaching 34% CEL when eight product classes were used across home microenvironments, i.e. all-purpose/kitchen/floor cleaning agents, furniture/floor polish, combustible/electric air fresheners, and perfume, needs to be highlighted. Such estimated values should be evaluated with caution, as these may be attributed to the exposure scenarios specifically constructed for the present study, following a ‘most-representative worst-case scenario’ approach for exposure and health risk assessment.

Distinct genotype-dependent differences in transcriptome responses in humans exposed to environmental carcinogens.

Considering genetic variability in population studies focusing on the health risk assessment of exposure to environmental carcinogens may provide improved insights in individual environmental cancer risks. Therefore, the current study aims to determine the impact of genetic polymorphisms on the relationship between exposure and gene expression, by identifying exposure-dependently coregulated genes and genetic pathways. Statistical analysis based on mixed models, was performed to relate gene expression data from 134 subjects to exposure measurements of multiple carcinogens, 28 polymorphisms, age, sex and biomarkers of cancer risk. We evaluated the combined exposure to cadmium, lead, polychlorinated biphenyls, p,p'-dichlorodiphenyldichloroethylene, hexachlorobenzene and 1-OH-pyrene, and the outcome was biologically interpreted by using ConsensusPathDB, thereby focusing on carcinogenesis-related pathways. We found generic and carcinogenesis-related pathways deregulated in both sexes, but males showed a stronger transcriptome response than females. We highlighted NOTCH1, CBR1, ITGB3, ITGA4, ADI1, HES1, NCOA2 and SMARCA2 in view of their direct link with cancer development. Two of these, NOTCH1 and ITGB3, are also known to respond to PCBs and cadmium chloride exposure in rodents and to lead in humans. Subjects carrying a high number of risk alleles appear more responsive to combined carcinogen exposure with respect to the induced expression of some of these cancer-related genes, which may be indicative of increased cancer risk as a consequence of environmental factors.

Indoor air pollution from gas cooking in five Taiwanese families

There is a high lung cancer prevalence in females in Taiwan with a relatively low number of smokers. Exposure to air pollution from cooking (APC) has been suspected as one of the major risk factors for lung cancer since cooking is one of the major sources of particulate matter (PM) and polycyclic aromatic hydrocarbons (PAHs) in household buildings. Many studies have demonstrated that occupational exposure (40 h per week) to APC in commercial kitchens and restaurants could cause a cancer risk higher than 10−6. However, currently the data of exposure to APC in household kitchens are relatively few in Taiwan. Therefore, we conducted a health risk assessment for exposure to APC in five household kitchens in northern Taiwan during 2010–2011.Twenty-four-hour monitoring of the particle concentration shows that particle number concentrations during non-cooking hours ranged from 1220 to 6200 particles/cm3 and increased to 1,400,000 particles/cm3 during cooking hours, and most of these particles are ultrafine ones. Some of the measurement results (PM10 > 80 μg/m3 at 3 kitchens) exceed the current indoor air quality standards of Taiwan. The gas-particle partitioning of PAHs in household APC indicates that most of the low molecular PAHs (2 and 3 rings) are in the gas phase, while the high molecular PAHs (more than 4 rings) are particle-bound. The particulate-phase PAHs contribute more than 95% of the benzo[a]pyrene equivalent concentration. The incremental lifetime cancer risk resulting from exposure to the household APC could be higher than the acceptable level of 10−6, and thus of health concerns.

Health risk assessment for exposure to benzene in petroleum refinery environments.

The health risk resulting from benzene exposure in petroleum refineries was calculated using data from the scientific literature from various countries throughout the world. The exposure data was collated into four scenarios from petroleum refinery environments and plotted as cumulative probability distributions (CPD) plots. Health risk was evaluated for each scenario using the Hazard Quotient (HQ) at 50% (CEXP50) and 95% (CEXP95) exposure levels. Benzene levels were estimated to pose a significant risk with HQ50 > 1 and HQ95 > 1 for workers exposed to benzene as base estimates for petroleum refinery workers (Scenario 1), petroleum refinery workers evaluated with personal samplers in Bulgarian refineries (Scenario 2B) and evaluated using air inside petroleum refineries in Bulgarian refineries (Scenario 3B). HQ50 < 1 were calculated for petroleum refinery workers with personal samplers in Italian refineries (Scenario 2A), air inside petroleum refineries (Scenario 3A) and air outside petroleum refineries (Scenario 4) in India and Taiwan indicating little possible adverse health effects. Also, HQ95 was < 1 for Scenario 4 however potential risk was evaluated for Scenarios 2A and 3A with HQ95 > 1. The excess Cancer risk (CR) for lifetime exposure to benzene for all the scenarios was evaluated using the Slope Factor and Overall Risk Probability (ORP) methods. The result suggests a potential cancer risk for exposure to benzene in all the scenarios. However, there is a higher cancer risk at 95% (CEXP95) for petroleum refinery workers (2B) with a CR of 48,000 per 106 and exposure to benzene in air inside petroleum refineries (3B) with a CR of 28,000 per 106.

Commentary on: de Ree H, et al. “Health risk assessment of exposure to tricresyl phosphates (TCPs) in aircraft: A commentary” [Neurotoxicology (2014), http://dx.doi.org/10.1016/j.neuro.2014.08.011

Environmental toxicants such as bisphenol-A (BPA) and polychlorinated biphenyls (PCBs) are prevalent in our water supply, soil, and many food products and can profoundly affect the central nervous system. Both BPA and PCBs can disrupt endocrine signaling, which is important for auditory development and function, but the effect of these toxicants on the auditory periphery is not understood. In this study we investigated the effect of PCB-95 and BPA on lateral line development, function, and regeneration in larval zebrafish. The lateral line is a system of mechanosensory hair cells on the exterior of the fish that are homologous to the hair cells located in the mammalian inner ear. We found that PCB-95 had no effect on lateral line development or hair cell survival. BPA also did not affect lateral line development, but instead had a significant effect on both hair cell survival and regeneration. BPA-induced hair cell loss is both dose- and time-dependent, with concentrations of 1 μM or higher killing lateral line hair cells during a 24 h exposure period. Pharmacologic manipulation experiments suggest that BPA kills hair cells via activation of oxidative stress pathways, similar to prior reports of BPA toxicity in other tissues. We also observed that hair cells killed with neomycin, a known ototoxin, failed to regenerate normally when BPA was present, suggesting that BPA in aquatic environments could impede innate regenerative responses in fishes. Collectively, these data demonstrate that BPA can have detrimental effects on sensory systems, both in aquatic life and perhaps in terrestrial organisms, including humans.

Toxicity Assessment in Artisanal Miners from Low-level Mercury Exposure in Bornuur and Jargalant Soums of Mongolia

The toxicity assessment study population is based in Bornuur and Jargalant soums of Tuv province in Mongolia, which are known for historic and current gold mining activity. The findings correlate with conclusions from a mercury exposure health risk assessment conducted by the WHO in 2008 and several subsequent epidemiological studies conducted at the Toxicology division of Mongolia's National Center for Public Health (NCPH). The outcomes of this investigation indicate that low-level mercury exposure caused symptomatic central nervous system toxicity associated with chronic exposure to mercury in Bornuur and Jargalant soums.

Health risk assessment of exposure to TriCresyl Phosphates (TCPs) in aircraft: A commentary

Possible exposure to TriCresyl Phosphates (TCPs) has led to concerns among airline crew members. One isomer, Tri-ortho-Cresyl Phosphate (ToCP) is known to be neurotoxic and exposure to ToCP via contaminated cabin air has been suggested to be associated with the alleged Aerotoxic syndrome. The symptoms associated with Aerotoxic syndrome are diverse, including headaches, loss of balance, numbness and neurobehavioral abnormalities such as emotional instability, depression and cognitive dysfunction. Other ortho-isomers are toxic as well, but the non-ortho isomers are regarded as less toxic.In a collaborative effort to increase insight into the possible association between exposure to TCPs via contaminated cabin air and Aerotoxic syndrome, we performed an exposure- and toxicological risk assessment. Measurements in KLM 737 aircraft have demonstrated the presence of non-ortho isomers in low concentrations, though ToCP and other ortho-isomers could not be detected. Based on this exposure assessment, we established a toxicological risk model that also takes into account human differences in bioactivation and detoxification to derive a hazard quotient. From this model it appears unlikely that the health effects and alleged Aerotoxic syndrome are due to exposure to ToCP. Alternative explanations for the reported symptoms are discussed, but evaluation of the current findings in light of the criteria for occupational disease leads to the conclusion that the Aerotoxic Syndrome cannot be regarded as such. Additional research is thus required to unravel the underlying causes for the reported health complaints.

Inhalation exposure to 1,2-dichloropropane: Distribution of blood and tissue concentrations of 1,2-dichloropropane in rats during and after exposure

The present investigation was undertaken to determine the distribution and accumulation of 1,2-dichloropropane (DCP) in the blood, lung, liver, kidney, and abdominal fat of rats during and after inhalation exposure. Male rats were exposed to 80 or 500 ppm (v/v) DCP vapor for 360 min and the concentrations of DCP in the blood and tissues during the inhalation exposure period and after the end of the exposure period were measured. DCP accumulation in the abdominal fat was much greater than that in the blood and other tissues. Eighteen hours after the end of inhalation exposure, DCP could still be detected in the abdominal fat in the 80-ppm group, and in the blood, liver, kidney, and abdominal fat in the 500-ppm group. Our results are valuable data pertaining to the pharmacokinetics of DCP and to human health risk assessment of exposure to DCP vapor by inhalation.

Use of in vitro data in developing a physiologically based pharmacokinetic model: Carbaryl as a case study

In vitro-derived information has been increasingly used to support and improve human health risk assessment for exposure to chemicals. Physiologically based pharmacokinetic (PBPK) modeling is a key component in the movement toward in vitro-based risk assessment, providing a tool to integrate diverse experimental data and mechanistic information to relate in vitro effective concentrations to equivalent human exposures. One of the challenges, however, in the use of PBPK models for this purpose has been the need for extensive chemical-specific parameters. With the remarkable advances in in vitro methodologies in recent years, in vitro-derived parameters can now be easily incorporated into PBPK models. In this study we demonstrate an in vitro data based parameterization approach to develop a physiologically based pharmacokinetic and pharmacodynamic (PBPK/PD) model, using carbaryl as a case study. In vitro experiments were performed to provide the chemical-specific pharmacokinetic (PK) and pharmacodynamic (PD) parameters for carbaryl in the PBPK model for this compound. Metabolic clearance and cholinesterase (ChE) interaction parameters for carbaryl were measured in rat and human tissues. These in vitro PK and PD data were extrapolated to parameters in the whole body PBPK model using biologically appropriate scaling. The PBPK model was then used to predict the kinetics and ChE inhibition dynamics of carbaryl in vivo. This case study with carbaryl provides a reasonably successful example of utilizing the in vitro to in vivo extrapolation (IVIVE) approach for PBPK model development. This approach can be applied to other carbamates with an anticholinesterase mode of action as well as to environmental chemicals in general with further refinement of the current shortcomings in the approach. It will contribute to minimizing the need for in vivo human data for PBPK model parameterization and evaluation in human risk assessments.