Relationship between environmental exposure to toluene,xylene and ethylbenzene and the expired breath concentrations for gasoline service workers

This study evaluated the relationship between the breath concentrations of, and personal exposure to, toluene, xylene and ethylbenzene of thirty workers from ten gasoline stations. Personal exposure air samples and workplace samples were collected simultaneously. Each subject provided a sample of exhaled breath after his or her personal exposure air was sampled. Twenty-five personal air, 17 workplace and 30 breath samples were collected in this study. Results indicated that breath concentrations of toluene and xylene were significantly correlated with personal monitoring concentrations. Furthermore, multiple regression analysis showed that exhaled toluene levels were highly influenced by personal toluene concentrations and the amount of personal gasoline sold (r2 = 0.762), while exhaled xylene levels depended on wind speed and personal xylene exposure concentrations (r2 = 0.665). Exhaled ethylbenzene levels were too low to present a relationship between concentrations and personal exposure levels. The exhaled toluene, xylene and ethylbenzene concentrations ranged from 4.3 to 41.8, 0.9 to 13.9, and 0.2 to 6.5 ppb, and the corresponding personal monitoring concentrations ranged from 60.3 to 572.3, 16.4 to 156.6, and 10.7 to 136.6, respectively. The average number of symptoms per person, according to neurotoxic questionnaire 16 (abbreviated as Q16) was 4.1 and six workers showed over six symptoms in Q16. This study suggests that exhaled toluene and xylene levels are suitable for use as biological exposure indices even at the ppb-level of exposure. Gasoline service workers are exposed to high levels of volatile organic compounds (VOCs) and the potential threats to their neurological systems deserve further investigation.     

Comparison of exhaled carbon monoxide levels among commuters and roadside vendors in an urban and a suburban population in Pakistan

Carbon monoxide (CO) is one of the six criteria air pollutants related to urbanization and has a wide range of health effects. The study measured and compared the exhaled CO levels among commuters and roadside vendors in potentially heavy and low traffic volume areas of Karachi, a megacity in Pakistan. Saddar town [areas of M. A. Jinnah Road (Tibet Center, Denso Hall) and Empress Market] was selected to represent an area of high traffic volume and the suburban town of Gadap (Gadap and Gulshan-e-Maymar) was selected to represent an area of no or low traffic volume. The study compared the CO exposure of commuters and roadside vendors in high and low traffic volume in Karachi. CO exposure was measured in expired air using the breath analyzer module of Bacharach Monoxor-II, USA. A total of 326 individuals (115 commuters and 211 stationary roadside vendors) from Saddar town (n?=?193) and Gadap town (n?=?133) were selected. In addition, CO levels in ambient air in the same areas, using portable CO analyzer (Bacharach, Monoxor-II, USA), were measured. The mean ambient CO level at Saddar town was 15.6 (SE ± 2.6) ppm compared to 3.3 (SE ± 0.3) ppm at Gadap town. The mean CO level in expired air was significantly higher among nonsmokers at Saddar town (12.8 ± 0.5 ppm) compared to the nonsmokers at Gadap town (7.8 ± 0.4 ppm). The mean CO level in expired air among smokers was twice that of nonsmokers (21.6 vs. 10.6 ppm). CO in expired air was greater among high traffic volume commuters and roadside stationary population in Karachi, Pakistan. The population in Karachi is exposed to high concentration of air pollutants. These pollutants need to be characterized for health effects and interventions needs to be developed.     

Carbon monoxide concentrations in outdoor wood-fired kitchens in Ouagadougou,Burkina Faso—implications for women’s and children’s health

A majority of households in developing countries rely on biomass fuel for cooking, typically burned in open fires or simple stoves. The incomplete combustion of these fuels causes adverse health effects such as respiratory diseases, especially among women and children. However, quantitative data on pollution levels and on associated diseases are limited. We examined cooking habits and self-reported health in 31 households with outdoor open wood fires in Ouagadougou, Burkina Faso, using structured interviews. In eight households, carbon monoxide (CO) was measured using passive sampling. In addition, meteorology and ambient CO concentrations were assessed. The average CO concentration during cooking was 4.3 ppm, with a maximum of 65.3 ppm and minimum of 0.3 ppm (1-min values). A clear daily pattern was observed, with relatively low concentrations during the day and high during the evening, occasionally exceeding the World Health Organization 1- and 8-h guidelines when the air stabilised. On average, CO concentrations were 43 % higher in kitchens located in closed yards than in those located in open yards, showing that fireplace location affected the levels. Eye irritation and coughing among women and children were reported by 30 % of the households. Based on previously reported relations between CO concentrations and fine particles (<2.5 μm), the exposure to biomass smoke appears to be high enough to pose a considerable health risk among women and children in households with outdoor open wood fires. The results suggest that burning should be limited between sunset and dawn and in areas with limited ventilation to reduce pollutions levels.     

Do the pollution related to high-traffic roads in urbanised areas pose a significant threat to the local population?

Many large neighbourhoods are located near heavy-traffic roads; therefore, it is necessary to control the levels of air pollution near road exposure. The primary air pollutants emitted by motor vehicles are CO, NO₂ and PM. Various investigations identify key health outcomes to be consistently associated with NO₂ and CO. The objective of this study was the measurement-based assessment for determining whether by high-traffic roads, such as motorways and express ways, and the concentrations of CO and NO₂ are within normal limits and do not pose threat to the local population. Average daily values (arithmetic values calculated for 1-h values within 24 h or less, depending on result availability) were measured for concentrations of NO₂ and CO by automatic stations belonging to the Voivodship Environmental Protection Inspectorate in Katowice, in areas with similar dominant source of pollutant emission. The measurements were made in three sites: near the motorway and expressway, where the average daily traffic intensity is 100983 and 35414 of vehicles relatively. No evidence was found of exceeding average daily values equal to the maximum allowable NO₂ concentration due to the protection of human health in the measurement area of the stations. No daily average values exceeding the admissible CO concentration (8-h moving average) were noted in the examined period. The results clearly show lack of hazards for general population health in terms of increased concentrations of CO and NO₂ compounds that are closely related to high intensity car traffic found on selected motorways and speedways located near the city centres.     

Determination of Heavy Metals in Water from Boreholes in Dumasi in the Wassa West District of Western Region of Republic of Ghana

Concentrations of heavy metals in the borehole at Dumasi in the Wassa West District of the Republic of Ghana have been measured in this study. The concentrations of the following metals in the ground water from Dumasi borehole are: Iron (Fe) – 7.52 ppm, Manganese (Mn) – 1.11 ppm, Arsenic (As) – 4.52 ppm, Chromium (Cr) – 0.026 ppm, Cobalt (Co) – 0.01 ppm, Zinc (Zn) – 0.007 ppm, Cadmium (Cd) – 0.002 ppm and Lead (Pb) – 0.005 ppm. The results of the study show that resident adults and children who use water from the boreholes are at serious risk from exposure to health hazards associated with exposure to the above metals in the boreholes in Dumasi. If the results of this study are applied to other mining communities, which lie on the Birimian and Tarkwaian rock system, then the residents are at serious risk from exposure to toxic metals from drinking water from the boreholes dug for them by mining companies operating in their communities.     

The health hazards of potentially toxic metals in the daily diets of adults and children from a mining and smelting region (Hezhang County) in southwestern China

Toxic metals accumulated in the human body are predominantly absorbed by the digestive tract in non-occupationally exposed populations. In the current study, we collected plowed soil samples, and investigated the varied food compositions in a mining and smelting area in southwestern China, to measure the concentrations of ten potentially toxic metals—As, Ba, Cd, Cr, Cu, Mn, Ni, Pb, Sr, and Zn. We collected information on the daily intakes of these metals to assess the health risks associated with their exposure among children and adults. The urine concentrations of the metals were also measured to obtain data on the amounts present in the body. The results showed that the hazard indexes (HIs) of As, Ba, Cd, Cr, Ni, Pb, and Sr were all larger than 1, for both adults and children; the Zn and Cu values were comparatively higher in children. The intake of staple foods of the region posed the greatest health risk, while drinking water only posed risks clearly associated with As exposure. The urine samples of local residents contained larger amounts of As, Cd, Cr, Cu, Mn, Ni, Pb, and Zn, confirming the hazards in the health risk assessment. Obvious differences in the urine metal concentrations between men and women were confirmed. In conclusion, higher concentrations of metals in the surface soil and rain water were the predominant cause of elevated exposure through home-grown crops and produce to accumulate in local residents’ bodies.     

Environmental and biological monitoring of methyl ethyl ketone (MEK)

This study was conducted to evaluate the usefulness of various biological parameters for monitoring of workers exposed to methyl ethyl ketone (MEK). Fifty male workers from a large magnetic videotape factory participated in this study. Personal air samples were collected using 3M organic vapor monitors and analysed for MEK by gas chromatography with flame ionisation detector (FID). 10 mL of urine; blood (1 mL) and exhaled air were also collected at the end of an 8-hour workshift. The headspace GC method was applied for measurement of urinary and blood MEK. MEK in expired air was analysed directly by using a GC/FID.The correlation coefficients (r) between environmental MEK and all other biological parameters measured show significant positive relationships. The r for environmental MEK and urine MEK was 0.84; for blood 0.73 and for breath 0.64. The correlation coefficients between blood and urine was 0.72; blood and breath was 0.88 and urine and breath 0.60. These findings suggest that measurements of unmetabolised MEK in blood, exhaled air and urine can be used for biological monitoring of MEK exposure. Nevertheless, laboratory methodological assessment is in favour of measuring urinary MEK as it is non-invasive and does not have to be analysed immediately after collection.     

Human exposure, health hazards, and environmental regulations

United States environmental regulations, intended to protect human health, generally fail to address major sources of pollutants that endanger human health. These sources are surprisingly close to us and within our control, such as consumer products and building materials that we use within our homes, workplaces, schools, and other indoor environments. Even though these indoor sources account for nearly 90% of our pollutant exposure, they are virtually unregulated by existing laws. Even pollutant levels found in typical homes, if found outdoors, would often violate federal environmental standards. This article examines the importance of human exposure as a way to understand and reduce effects of pollutants on human health. Results from exposure studies challenge traditional thinking about pollutant hazards, and reveal deficiencies in our patchwork of laws. And results from epidemiological studies, showing increases in exposure-related diseases, underscore the need for new protections. Because we cannot rely solely on regulations to protect us, and because health effects from exposures can develop insidiously, greater efforts are needed to reduce and prevent significant exposures before they occur. Recommendations include the development and use of safer alternatives to common products, public education on ways to reduce exposure, systematic monitoring of human exposure to pollutants, and a precautionary approach in decision-making.     

Exposure to rubber process dust and fume since 1970s in the United Kingdom; influence of origin of measurement data

The objective of this study was to compare measured concentrations of rubber process dust and rubber fume originating from different sources in the British rubber manufacturing industry. Almost 8000 exposure measurements were obtained from industry-based survey results collected by the British Rubber Manufacturers' Association (BRMA), and covering the years 1977 to 2002, and from a series of small surveys contained in the Health and Safety Executive's (HSE) National Exposure Database (HSE-NEDB) from 1980 to 2002. The analysis investigated temporal trends in the exposure concentrations and the underlying main factors responsible for these changes. Analyses were carried out using hierarchical linear mixed effects models. Average personal exposures to rubber process dust and rubber fumes were respectively a factor 2 and 4 higher for the HSE-NEDB data when compared to data originating from the industry (BRMA data). Personal exposure to rubber process dust decreased on average by 4.1% (95% CI 4.7-3.6) annually for the BRMA data and slightly less at 2.3% (95% CI 5.2-0.7%) per annum for the HSE-NEDB data. Personal exposure to rubber fume also showed a downward temporal trend of 2.9% (95% CI 3.6-2.3%) and 4.8% (95% CI 7.4-2.1%) annually for the BRMA and HSE-NEDB data, respectively. These trends differed considerably between departments. No major changes in the estimated temporal trends in exposure concentrations were observed after including the presence of local exhaust ventilation in the models for any department in the BRMA and HSE-NEDB datasets. Lack of information on the quality and status of the local exhaust ventilation is the most likely explanation for this. In conclusion, even though there were relatively similar downward time trends in both rubber process dust and fume concentrations in both datasets, the source of exposure data was an important determinant of average exposure concentrations present in the British rubber manufacturing industry. Lack of detailed auxiliary information on company size, reason for sampling, measurement strategy and other potentially important determinants of exposure prevented an explanation for the observed differences in exposure level.     

Occupational exposure to NDMA and NMor in the European rubber industry

Many nitrosamines are suspected of being human carcinogens, with the highest concentrations in the environment being measured in the rubber industry. Time trends of personal exposure to N-nitrosodimethylamine (NDMA) and to N-nitrosomorpholine (NMor) during the past two decades in the German rubber industry were analysed and compared with cross-sectional studies in the same period in the Netherlands, Poland, the UK and Sweden. In the majority of the surveyed departments exposures reduced over time, but considerable heterogeneity was present between departments and sectors. Significant reductions were primarily found in curing and post-treating departments and ranged from -3% year(-1) to -19% year(-1). In contrast, NDMA levels increased (+13% year(-1)) in maintenance and engineering in the tyres industry. Average NDMA-levels in general rubber goods (GRG) and NMor-levels in tyre production in Germany did not decrease significantly in the past two decades, whereas NDMA-levels in tyre production (-10% year(-1)) and NMor-levels in GRG (-7% year(-1)) declined significantly after the introduction of an exposure limit for total nitrosamines in Germany in 1988. Confidence intervals of average exposures in other studied countries largely overlap trends observed in Germany. Exposure to N-nitrosamines decreased on average two-to-five fold in the German rubber industry with comparable concentration levels in other European countries. Although average levels are well below the current limits exposure has not been eliminated, and incidental high exposures do still occur.     

Assessing the risk to firefighters from chemical vapors and gases during vehicle fire suppression

Despite the frequent occurrence of vehicle fires, very few studies investigating firefighters' potential inhalation exposures during vehicle fire suppression have been conducted. In this paper, we present an assessment of firefighters' health risk from vehicle fire suppression that accounts for the mixture of gases and vapors likely to be found in these fires. Summa canisters were used to collect emissions from the engine and cabin fires of a single vehicle and were analyzed for 75 volatile organic compounds (VOCs). Firefighters' breathing zone concentrations (BZCs) of aromatic hydrocarbons, aldehydes, isocyanates, and carbon monoxide were measured during the suppression of three vehicle fires. The Summa canister and BZC data were used to develop a simple model for predicting BZCs for the compounds that were not measured in the firefighters' breathing zones. Hazard quotients (HQs) were calculated by dividing the predicted and measured BZCs by the most conservative short-term exposure limits (STELs) or ceiling limits. Hazard indices (HIs) were determined by adding HQs for compounds grouped by the target organ for acute health effects. Any HIs above unity represented unacceptable risks. According to this mixture analysis, the estimated 95(th) percentile of the exposure distribution for the study population represents ≥ 9.2 times the acceptable level of risk to the respiratory tract and eyes. Furthermore, chemicals known or reasonably anticipated to be human carcinogens contributed to > 45% of these HIs. While STELs are not usually based on carcinogenicity, maintaining exposures below STELs may protect individuals from the biological stress that could result from short-term exposures to carcinogens over time. Although vehicle fires are suppressed quickly (<10 min), this assessment suggests that firefighters have the potential to be overexposed to acute toxins during vehicle fire suppression and should therefore wear self-contained breathing apparatus at all times during vehicle fire response.     

Urban daily life routines and human exposure to environmental discomfort

This study suggests a shift in focus from studying environmental discomfort in urban strategic stations, from which average results for the city or specific results for selected sites are deduced, and from measuring environmental conditions in fixed monitoring stations to a study in which we monitor, with mobile portable sensors, the exposure of people to environmental sources of discomfort while performing their daily life activities. Significant variations in sense of discomfort were measured in this study, and almost half of this variability was found to be explained while four independent environmental variables were considered: air quality (concentrations of CO), noise level, climatic variables (thermal load), and social loads. The study conducted in the city of Tel Aviv, which suffers from hot, humid summers and cool winters, and noise levels that reach the average levels of 85 dB, and relatively lower levels of exposure to the other potential stressors. These levels of combined exposures result in moderate levels of discomfort for young, healthy people once they experience the more stressing environments in the city. It is shown also that noise from other people is the most salient source of discomfort in Tel Aviv. Levels of discomfort accumulate during the working hours, either due to the impact of social loads or noise, but the subjects showed good coping abilities that enabled them to recover in late afternoons. It seems that thermal load does not have immediate impact, but rather cumulative ones, mainly during transitional seasons when subjects are less adaptive to extreme changes in weather.     

Effects of Traffic Management and Transport Mode on the Exposure of Schoolchildren to Carbon Monoxide

The exposure to CO of schoolchildren was assessed in the town of Northampton, UK, both by direct measurement and by GIS-based activity modelling. Personal measurement of CO showed that exposures when travelling by car were significantly greater than those when walking, although journey times by car were shorter. However, journey exposures had little effect on maximum 8h mean CO exposures. CO concentration fields in the study area were modelled from current traffic flows, and those expected under different traffic management scenarios. These fields were then used, in combination with children's home and school location, and their activity profiles, to simulate frequency distributions of exposure for different transport modes and traffic management scenarios. The results show a large variability in the effect of traffic management interventions, depending on the child's home and school location.     

Measurement of the proximity effect for indoor air pollutant sources in two homes

Personal exposure to air pollutants can be substantially higher in close proximity to an active source due to non-instantaneous mixing of emissions. The research presented in this paper quantifies this proximity effect for a non-buoyant source in 2 naturally ventilated homes in Northern California (CA), assessing its spatial and temporal variation and the influence of factors such as ventilation rate on its magnitude. To quantify how proximity to residential sources of indoor air pollutants affects human exposure, we performed 16 separate monitoring experiments in the living rooms of two detached single-family homes. CO (as a tracer gas) was released from a point source in the center of the room at a controlled emission rate for 5-12 h per experiment, while an array of 30-37 real-time monitors simultaneously measured CO concentrations with 15 s time resolution at radial distances ranging from 0.25-5 m under a range of ventilation conditions. Concentrations measured in close proximity (within 1 m) to the source were highly variable, with 5 min averages that typically varied by >100-fold. This variability was due to short-duration (<1 min) pollutant concentration peaks ("microplumes") that were frequently recorded in close proximity to the source. We decomposed the random microplume component from the total concentrations by subtracting predicted concentrations that assumed uniform, instantaneous mixing within the room and found that these microplumes can be modeled using a 3-parameter lognormal distribution. Average concentrations measured within 0.25 m of the source were 6-20 times as high as the predicted well-mixed concentrations.     

会泽某铅锌矿周边农田土壤重金属风险评价研究

采用现场采样与室内测试方法测定了会泽某铅锌矿周边农田土壤中Cd、As、Pb、Cr、Cu、Zn、Ni的含量,利用地积累指数法、潜在生态指数法对其土壤环境质量进行了评价,并应用US EPA推荐的健康风险评价法对重金属的健康风险进行了初步评价。结果表明,7种重金属均存在不同程度的富集或污染。多种重金属潜在生态风险指数属于中等及以上的风险状态,重金属潜在生态风险指数排序为CdPbAsCuNiZnCr。7种重金属在3种暴露途径下对儿童的非致癌健康风险均大于成人,但对成人、儿童均不存在显著的非致癌健康影响、非致癌健康总风险。As、Ni、Cr、Cd重金属的致癌风险值与4种元素总致癌风险值均未超出10-6~10-4的范围,尚不具备致癌风险。     

Non-Cancer Health Risk Assessment from Exposure to Cyanide by Resident Adults from the Mining Operations of Bogoso Gold Limited in Ghana

Cyanide is a very toxic chemical that is used to extract gold from its ores. Wastewaters from gold mining companies such as Bogoso Gold Limited (BGL) contain cyanide and other potentially toxic chemicals that have adverse effects on human beings and aquatic organisms. This study was conducted to evaluate the human health risk assessment from exposure to free cyanide via oral and dermal contact of surface/underground water by resident adults within the concession of Bogoso Gold Limited. The chronic non-cancer health risk from exposure to cyanide in River Bogo Upstream is 230 and 43 (by Central Tendency Exposure (CTE) parameters respectively). This means that approximately 230 and 43 resident adults are likely to suffer diseases related to cyanide intoxication via oral and dermal contact respectively. For chronic exposure to River Bogo Downstream by resident adults, the non-cancer health risks are: 0.031 and 0.57 via oral and dermal contact for CTE parameters respectively, which also means that, the non-cancer health risks associated with cyanide intoxication is negligible as the hazard index is less than 1.0 via oral and dermal contacts respectively. The results showed that health risk for acute exposure to cyanide by the resident adults is very high. Hence the residents attribute most of the unexplained deaths in the communities to accidental ingestion and dermal contact of cyanide water.     

Polycyclic aromatic hydrocarbons in soils from Urumqi, China: distribution, source contributions, and potential health risks

Concentrations of 16 priority polycyclic aromatic hydrocarbons (PAHs) were measured in 28 surface soils samples collected from Urumqi, northwest China, for examination of distributions, source contributions, and potential health effects. The results indicated that the sum of 16 PAHs concentration ranged from 331 to 15,799 μg?kg^?1 (dw) in soils, with a mean of 5,018?±?4,896 μg?kg^?1 (n?=?28). The sum of seven carPAHs concentration ranged from 4 to 1,879 μg?kg^?1 (dw; n?=?28). The highest ∑PAHs concentrations were found at roadsides and industrial sites, followed by those at parks, rural areas, and business/residential areas. Coal combustion, emission of diesel and gasoline from vehicles, and petroleum source were four sources of PAHs as determined by PMF analysis, which contributed 51.19, 19.02, 18.35, and 11.42 % to the PAH sources, respectively. Excellent coefficients of correlation between the measured and predicted PAHs concentrations suggested that the PMF model was very effective to estimate sources of PAHs in soils. Incremental lifetime cancer risk values at the 95th percentile due to human exposure to surface soils PAHs in Urumqi were 2.02?×?10^?6 for children and 2.72?×?10^?5 for adults. The results suggested that the current PAHs levels in soils from Urumqi were pervasive and moderately carcinogenic to children and adults.     

Mass, surface area and number metrics in diesel occupational exposure assessment

While diesel aerosol exposure assessment has traditionally been based on the mass concentration metric, recent studies have suggested that particle number and surface area concentrations may be more health-relevant. In this study, we evaluated the exposures of three occupational groups-bus drivers, parking garage attendants, and bus mechanics-using the mass concentration of elemental carbon (EC) as well as surface area and number concentrations. These occupational groups are exposed to mixtures of diesel and gasoline exhaust on a regular basis in various ratios. The three groups had significantly different exposures to workshift TWA EC with the highest levels observed in the bus garage mechanics and the lowest levels in the parking ramp booth attendants. In terms of surface area, parking ramp attendants had significantly greater exposures than bus garage mechanics, who in turn had significantly greater exposures than bus drivers. In terms of number concentrations, the exposures of garage mechanics exceeded those of ramp booth attendants by a factor of 5-6. Depending on the exposure metric chosen, the three occupational groups had quite different exposure rankings. This illustrates the importance of the choice of exposure metric in epidemiological studies. If these three occupational groups were part of an epidemiological study, depending on the metric used, they may or may not be part of the same similarly exposed group (SEG). The exposure rankings (e.g., low, medium, or high) of the three groups also changes with the metric used. If the incorrect metric is used, significant misclassification errors may occur.     

Study of personal exposure to airborne respirable particles and carbon monoxide

Simultaneous measurements of CO and respirable particles (RP) at outdoor network stations and of personal exposure in a sample of twelve volunteers were carried out during the winter and summer season of 1980/81 in order to evaluate how well personal exposure can be assessed from outdoor network station data.The results have shown that personal exposure of our subjects to both CO and RP is in best correlation with exposure at home where subjects spend in the average nearly 70% of their time. While personal exposure to CO can hardly be related to outdoor CO levels, personal exposure to RP is in fair agreement with simultaneously measured outdoor concentrations in winter (but not in summer). A large intercept on WAE axis of the WAE/RP relationship indicates that a considerable part of personal exposure to RP should be attributed to particles which are not of indoor origin. This part does not follow the seasonal and day-to-day changes in outdoor RP concentration and causes a negative, but highly significant correlation between WAE/RP ratio and RP.