Trihalomethanes in chlorine and bromine disinfected swimming pools: Air-water distributions and human exposure

This first study of trihalomethanes (THMs) in swimming pools using bromine agents for water disinfection under real conditions shows that the mixtures of these compounds are largely dominated by bromoform in a similar process as chloroform becomes the dominant THM in pools disinfected with chlorine agents. Bromoform largely predominates in air and water of the pool installations whose concentration changes are linearly correlated. However, the air concentrations of bromoform account for about 6–11% of the expected concentrations according to theoretical partitioning defined by the Henry law. Bromoform in exhaled air of swimmers is correlated with the air concentrations of this disinfectant by-product in the pool building. Comparison of the THM exhaled air concentrations between swimmers and volunteers bathing in the water without swimming or standing in the building outside the water suggest that physical activity enhance exposure to these disinfectant by-products. They also indicate that in swimming pools, besides inhalation, dermal absorption is a relevant route for the incorporation of THMs, particularly those with lower degree of bromination.     

Baseline blood trihalomethanes,semen parameters and serum total testosterone: A cross-sectional study in China

Toxicological studies showed that trihalomethanes (THMs), the most abundant classes of disinfection by-products (DBPs) in drinking water, impaired male reproductive health, but epidemiological evidence is limited and inconsistent. This study aimed to examine the associations of baseline blood THMs with semen parameters and serum total testosterone in a Chinese population. We recruited 401 men seeking semen examination from the Reproductive Center of Tongji Hospital in Wuhan, China between April 2011 and May 2012. Baseline blood concentrations of THMs, including chloroform (TCM), bromodichloromethane (BDCM), dibromochloromethane (DBCM), and bromoform (TBM) were measured using SPME-GC/ECD method. Semen quality and serum total testosterone were analyzed. Multivariable linear regressions were used to assess the associations of baseline blood THM concentrations with semen parameters and serum total testosterone levels. We found that baseline blood THM concentrations were not associated with decrements in sperm motility, sperm straight-line and curvilinear velocity. However, moderate levels of BDCM (β = − 0.13 million; 95% CI: − 0.22, − 0.03) and DBCM (β = − 4.74%; 95% CI: − 8.07, − 1.42) were associated with decreased sperm count and declined sperm linearity compared with low levels, respectively. Suggestive dose–response relationships were also observed between elevated blood TCM or ∑ THMs (sum of TCM, BDCM, DBCM and TBM) concentration and decreased sperm concentration (both p for trend = 0.07), and between elevated blood DBCM concentration and decreased serum total testosterone (p for trend = 0.07). Our results indicate that elevated THM exposure may lead to decreased sperm concentration and serum total testosterone. However, the effects of THM exposure on male reproductive health still warrant further studies in humans.     

Characteristics of PM10, PM2.5, CO2 and CO monitored in interiors and platforms of subway train in Seoul, Korea

This study was performed to investigate the concentration of PM₁₀ and PM_2.5 inside trains and platforms on subway lines 1, 2, 4 and 5 in Seoul, KOREA. PM₁₀, PM_2.5, carbon dioxide (CO₂) and carbon monoxide (CO) were monitored using real-time monitoring instruments in the afternoons (between 13:00 and 16:00). The concentrations of PM₁₀ and PM_2.5 inside trains were significantly higher than those measured on platforms and in ambient air reported by the Korea Ministry of Environment (Korea MOE). This study found that PM₁₀ levels inside subway lines 1, 2 and 4 exceeded the Korea indoor air quality (Korea IAQ) standard of 150 μg/m³. The average percentage that exceeded the PM₁₀ standard was 83.3% on line 1, 37.9% on line 2 and 63.1% on line 4, respectively. PM_2.5 concentration ranged from 77.7 μg/m³ to 158.2 μg/m³, which were found to be much higher than the ambient air PM_2.5 standard promulgated by United States Environmental Protection Agency (US-EPA) (24 h arithmetic mean: 65 μg/m³). The reason for interior PM₁₀ and PM_2.5 being higher than those on platforms is due to subway trains in Korea not having mechanical ventilation systems to supply fresh air inside the train. This assumption was supported by the CO₂ concentration results monitored in tube of subway that ranged from 1153 ppm to 3377 ppm. The percentage of PM_2.5 in PM₁₀ was 86.2% on platforms, 81.7% inside trains, 80.2% underground and 90.2% at ground track. These results indicated that fine particles (PM_2.5) accounted for most of PM₁₀ and polluted subway air. GLM statistical analysis indicated that two factors related to monitoring locations (underground and ground or inside trains and on platforms) significantly influence PM₁₀ (p < 0.001, R² = 0.230) and PM_2.5 concentrations (p < 0.001, R² = 0.172). Correlation analysis indicated that PM₁₀, PM_2.5, CO₂ and CO were significantly correlated at p < 0.01 although correlation coefficients were different. The highest coefficient was 0.884 for the relationship between PM₁₀ and PM_2.5.     

Sorption of trihalomethanes in foods

Trihalomethanes (THMs, namely, CHCl₃, CHCl₂Br, CHClBr₂ and CHBr₃) are disinfection by-products that are present in drinking water. These toxic chemicals are also present in meat, dairy products, vegetables, baked goods, beverages and other foods, although information regarding their concentrations and origin is very limited. This study investigates sorption of THMs occurring during rinsing and cooking of foods and the significance of food as an exposure source.Initial estimates of THM uptake were measured in experiments representing rinsing with tap water at 25 C using nine types of food, and for cooking in tap water at 90 C for fourteen other foods. A subset of foods was then selected for further study over a range of THM concentrations (23.7–118.7 μg/l), temperatures (25 C and 90 C), food concentrations (0.2–1.4, food weight: water weight), and contact times (5–240 min). Data were analyzed using regression and exponential models, and diffusion models were used to help explain the trends of THM uptake.Among vegetables, sorbed THM concentrations at 25 C were 213 to 774 ng/g for CHCl₃, 53 to 609 ng/g for CHCl₂Br, and 150–845 ng/g for CHClBr₂. Meats at 90 C tended to have higher concentrations, e.g., 870–2634 ng/g for CHCl₃. Sorbed concentrations increased with contact time and THM concentration, and decreased with food concentration in rinsing tests (using spinach, iceberg-head lettuce and cauliflower) and cooking tests (using tomato, potato, beef and miso–tofu soup). For most foods, THM uptake was diffusion limited and several hours were needed to approach steady-state levels. Swelling, hydrolysis and other physical and chemical changes in the food can significantly affect sorption. Screening level estimates for CHCl₃ exposures, based on experimental results and typical food consumption patterns, show that uptake via foods can dominate that due to direct tap water consumption, suggesting the importance of sorption and the need for further evaluation of THM intake due to foods.     

Concentrations and determinants of outdoor, indoor and personal nitrogen dioxide in pregnant women from two Spanish birth cohorts

Determinants of outdoor, indoor and personal concentrations of nitrogen dioxide (NO₂) were assessed in a subset of pregnant women of the Spanish INMA (Environment and Childhood) Study. Home indoor and outdoor NO₂ concentrations were measured during 48 h with passive samplers for 50 and 58 women from the INMA cohorts of Valencia and Sabadell, respectively. Women from Sabadell also carried personal NO₂ samplers during the same period. Data on time–activity patterns, socio-economic characteristics, and environmental exposures were obtained through questionnaires. Multiple linear regression models were developed to predict NO₂ levels.In Valencia, median outdoor NO₂ levels (42 µg/m³) were higher than median indoor levels (36 µg/m³). In Sabadell, personal NO₂ showed the highest median levels (40 µg/m³), followed by indoor (32 µg/m³) and outdoor (29 µg/m³) levels. Personal exposure to NO₂ correlated best with the indoor NO₂ levels. Temporal and traffic-related variables were significant predictors for outdoor NO₂ levels. Thirty-two percent of the indoor NO₂ variability in the two cohorts was explained by outdoor NO₂ levels and the use of the gas appliances. The model for personal exposure accounted for 59% of the variance in NO₂ levels in Sabadell with four predictor variables (outdoor and indoor NO₂ levels, time spent in outdoor environments and time exposed to a gas cooker). No significant association was found between personal or indoor NO₂ levels and exposure to environmental tobacco smoke (ETS) at home.Personal NO₂ levels were found to be strongly influenced by indoor NO₂ concentrations. The study supports the use of time–activity patterns along with indoor measurements to predict personal exposure to traffic-related air pollution.     

A quantitative integrated assessment of pollution prevention achieved by Integrated Pollution Prevention Control licensing

This paper presents an innovative, quantitative assessment of pollution avoidance attributable to environmental regulation enforced through integrated licensing, using Ireland's pharmaceutical-manufacturing sector as a case study. Emissions data reported by pharmaceutical installations were aggregated into a pollution trend using an Environmental Emissions Index (EEI) based on Lifecycle Assessment methodologies. Complete sectoral emissions data from 2001 to 2007 were extrapolated back to 1995, based on available data. Production volume data were used to derive a sectoral production index, and determine ‘no-improvement’ emission trends, whilst questionnaire responses from 20 industry representatives were used to quantify the contribution of integrated licensing to emission avoidance relative to these trends. Between 2001 and 2007, there was a 40% absolute reduction in direct pollution from 27 core installations, and 45% pollution avoidance relative to hypothetical ‘no-improvement’ pollution. It was estimated that environmental regulation avoided 20% of ‘no-improvement’ pollution, in addition to 25% avoidance under business-as-usual. For specific emissions, avoidance ranged from 14% and 30 kt a^− 1 for CO₂ to 88% and 598 t a^− 1 for SO_x. Between 1995 and 2007, there was a 59% absolute reduction in direct pollution, and 76% pollution avoidance. Pollution avoidance was dominated by reductions in emissions of VOCs, SO_x and NO_x to air, and emissions of heavy metals to water. Pollution avoidance of 35% was attributed to integrated licensing, ranging from between 8% and 2.9 t a^− 1 for phosphorus emissions to water to 49% and 3143 t a^− 1 for SO_x emissions to air. Environmental regulation enforced through integrated licensing has been the major driver of substantial pollution avoidance achieved by Ireland's pharmaceutical sector — through emission limit values associated with Best Available Techniques, emissions monitoring and reporting requirements, and performance targets specified in environmental management plans. This compliant sector offers a positive, but not necessarily typical, case study of IPPC effectiveness.     

Effects of cadmium on forearm bone density after reduction of exposure for 10 years in a Chinese population

The main focus of this study was to evaluate long term effects of cadmium on forearm bone mineral density after stopping ingestion of cadmium-polluted rice for 10 years in a Chinese population. A total of 532 persons (338 women and 194 men), living in control, moderately and heavily polluted areas, were included in this study. The residents living in the polluted area ceased ingesting cadmium-polluted rice in 1996. All participants were require to answer a questionnaire and the bone mineral density (BMD) was measured by dual energy X-ray absorptiometry (DXA) at the proximal radius and ulna. Samples of urine and blood were collected for determination of cadmium in urine (UCd) and blood (BCd).The BMD of subjects living in the heavily polluted area was significantly lower than that of those living in control area in both men and women (p < 0.01). For the people living in the moderately polluted area, only the women's BMD was greatly lower compared to that in the control area (p < 0.05). The BMD declined with the increasing BCd and UCd in both sexes, especially in the highest level (BCd > 5 µg/L, UCd > 10 µg/g crea) groups (p < 0.01). It was found that there were significant differences in the prevalence of osteoporosis among the different areas (χ² = 13.046, p = 0.0003) and different UCd groups (χ² = 4.511, p = 0.0337) in women, but not in men (χ² = 0.962, p = 0.3268; χ² = 1.906, p = 0.1675). But a significant difference exists in the prevalence of osteoporosis among different BCd groups in both genders (χ² = 9.304, p = 0.00229, in women; χ² = 4603, p = 0.0319, in men). This study suggested that cadmium could play a long-term role on bone and more attention should be paid to cadmium effects on bone metabolism after reduction of exposure.     

Evaluation of DNA damage in the root cells of Allium cepa seeds growing in soil of high background radiation areas of Ramsar – Iran

Plants are unique in their ability to serve as in situ monitors for environmental genotoxins. We have used the alkaline comet assay for detecting induced DNA damage in Allium cepa to estimate the impact of high levels of natural radiation in the soils of inhabited zones of Ramsar. The average specific activity of natural radionuclides measured in the soil samples for ²²⁶Ra was 12,766 Bq kg⁻¹ whereas in the control soils was in the range of 34–60 Bq kg⁻¹. A positive strong significant correlation of the DNA damage in nuclei of the root cells of A. cepa seeds germinated in the soil of high background radiation areas with ²²⁶Ra specific activity of the soil samples was observed. The results showed high genotoxicity of radioactively contaminated soils. Also the linear increase in the DNA damage indicates that activation of repair enzymes is not triggered by exposure to radiation in HBRA.     

Organochlorine and heavy metals in newborns: Results from the Flemish Environment and Health Survey (FLEHS 2002–2006)

To collect regional information on internal levels of pollutants in humans in Flanders, 1196 mother–child pairs were systematically recruited in 2002–2003 via 25 maternities across Flanders. Cd, Pb, PCB congeners 118, 170, 138, 153 and 180, p,p′-DDE — a key metabolite of DDT- and hexachlorobenzene (HCB) were measured in cord blood or plasma. Cd was detected in 64% of the samples (geometric mean 0.21 µg/L cord blood). p,p′-DDE (110 ng/g plasma lipids) and Pb (14.7 µg/L blood), were measurable in nearly all samples. The individual PCB congeners could be detected in 40 to 81% of the newborns (138 + 153 + 180 = 64.4 ng/g plasma lipids). HCB (18.9 ng/g plasma lipids) and dioxin-like compounds measured by DR-CALUX® (23 pg CALUX-TEQ/g lipids) were above detection limit in more than 75% of the samples. Age and smoking habits of the mothers, did not influence the cord blood Pb and Cd levels. The organochlorines increased 4 to 9% per year of the mother's age (partial R² = 0.05 to 0.22). Mothers had 2.6% less PCBs in cord blood (partial R² = 0.02) for each unit increase in pre-pregnancy BMI. Season of delivery, breastfeeding previous children or consumption of local dairy products, were minor determinants. Up to 20% of the variability in organochlorine concentrations was explained by residence area. It was concluded that the place of birth in Flanders is an important determinant of the load of pollutants measured at the start of life. This underlines the validity of human biomonitoring on (relatively) small geographical scale.     

Risk assessment of PCDD/Fs levels in human tissues related to major food items based on chemical analyses and micro-EROD assay

Nine groups of food items (freshwater fish, marine fish, pork, chicken, chicken eggs, leafy, non-leafy vegetables, rice and flour) and three types of human samples (human milk, maternal serum and cord serum) were collected for the analysis of PCDD/Fs. Results of chemical analysis revealed PCDD/Fs concentrations (pg g^− 1 fat) in the following ascending order: pork (0.289 pg g^− 1 fat), grass carp (Ctenopharyngodon idellus) (freshwater fish) (0.407), golden thread (Nemipterus virgatus) (marine fish) (0.511), chicken (0.529), mandarin fish (Siniperca kneri) (marine fish) (0.535), chicken egg (0.552), and snubnose pompano (Trachinotus blochii) (marine fish) (1.219). The results of micro-EROD assay showed relatively higher PCDD/Fs levels in fish (2.65 pg g^− 1 fat) when compared with pork (0.47), eggs (0.33), chicken (0.13), flour (0.07), vegetables (0.05 pg g^− 1 wet wt) and rice (0.05). The estimated average daily intake of PCDD/Fs of 3.51 pg EROD-TEQ/kg bw/day was within the range of WHO Tolerable Daily Intake (1–4 pg WHO-TEQ/kg bw/day) and was higher than the Provisional Tolerable Daily Intake (PMTL) (70 pg for dioxins and dioxin-like PCBs) recommended by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) [Joint FAO/WHO Expert Committee on Food Additives (JECFA), Summary and conclusions of the fifty-seventh meeting, JECFA, 2001.]. Nevertheless, the current findings were significantly lower than the TDI (14 pg WHO-TEQ/kg/bw/day) recommended by the Scientific Committee on Food of the Europe Commission [European Scientific Committee on Food (EU SCF), Opinions on the SCF on the risk assessment of dioxins and dioxin-like PCBs in food, 2000.]. However, it should be noted that micro-EROD assay overestimates the PCDD/Fs levels by 2 to 7 folds which may also amplify the PCDD/Fs levels accordingly. Although the levels of PCDD/Fs obtained from micro-EROD assay were much higher than those obtained by chemical analysis by 2 to 7 folds, it provides a cost-effective and rapid screening of dioxin levels in food and human samples.     

Assessment of environmental tobacco smoke and respirable suspended particle exposures for nonsmokers in Hong Kong using personal monitoring

One hundred and ninety-four randomly selected nonsmoking subjects collected air samples in their breathing zone by wearing personal monitors for 24 h. The study was centered in Hong Kong, and comprised housewives in one group, primarily for assessing exposures in the home, and office workers in a second group to assess the contribution of the workplace to overall exposure. Samples collected were analysed for respirable suspended particles (RSP), nicotine, 3-ethenylpyridine, and environmental tobacco smoke (ETS) particles using ultraviolet absorbance (UVPM), fluorescence (FPM), and solanesol measurements (SolPM). Saliva cotinine analyses were also undertaken to confirm the nonsmoking status of the subjects and to investigate their correlation with ETS exposure measurements. Approximately 6% of the subjects in Hong Kong misclassified their nonsmoking status. Median time-weighted average (TWA) RSP concentrations varied from 43 to 54 μg m⁻³ with no significant differences detected between any of the groups investigated. Office workers who lived and worked with smokers were exposed to 2.6 μg m⁻³ ETS particles (SolPM) and 0.44 μg m⁻³ nicotine, based on median TWA concentrations. Median concentrations of ETS particles and nicotine were below the limits of quantification for housewives living with smokers and were not significantly different from those for housewives living with nonsmokers. It would therefore be unreliable in Hong Kong to use a smoking spouse as a marker for assessing health risks related to ETS exposure. The office workers in this study were significantly more exposed to ETS than housewives from either smoking or nonsmoking homes, and the workplace was estimated to contribute over 33% of the annual exposure to ETS particles and nicotine. Exposure estimates suggest that the most highly exposed office workers in this study receive between 11 and 50 cigarette equivalents per year, based upon upper decile levels for ETS particles and nicotine, respectively.     

Contribution of (222)Rn-bearing water to indoor radon and indoor air quality assessment in hot spring hotels of Guangdong, China

This study investigates the contribution of radon (²²²Rn)-bearing water to indoor ²²²Rn in thermal baths. The ²²²Rn concentrations in air were monitored in the bathroom and the bedroom. Particulate matter (PM, both PM₁₀ and PM_2.5) and carbon dioxide (CO₂) were also monitored with portable analyzers. The bathrooms were supplied with hot spring water containing 66-260 kBq m⁻³ of ²²²Rn. The results show that the spray of hot spring water from the bath spouts is the dominant mechanism by which ²²²Rn is released into the air of the bathroom, and then it diffuses into the bedroom. Average ²²²Rn level was 110-410% higher in the bedrooms and 510-1200% higher in the bathrooms compared to the corresponding average levels when there was no use of hot spring water. The indoor ²²²Rn levels were influenced by the ²²²Rn concentrations in the hot spring water and the bathing times. The average ²²²Rn transfer coefficients from water to air were 6.2 × 10⁻⁴-4.1 × 10⁻³. The 24-h average levels of CO₂ and PM₁₀ in the hotel rooms were 89% and 22% higher than the present Indoor Air Quality (IAQ) standard of China. The main particle pollutant in the hotel rooms was PM_2.5. Radon and PM₁₀ levels in some hotel rooms were at much higher concentrations than guideline levels, and thus the potential health risks to tourists and especially to the hotel workers should be of great concern, and measures should be taken to lower inhalation exposure to these air pollutants.     

Personal monitoring for nitrogen dioxide exposure: Methodological considerations for a community study

Personal exposure to nitrogen dioxide (NO₂) and time spent in various locations were measured for 66 family members from 19 homes in the Portage, WI area during March 1981. Passive diffusion NO₂ monitors were placed outdoors, in the kitchen, and in one bedroom on each floor of the homes, and were worn by family members. Individuals from gas-cooking homes had significantly higher average NO₂ exposures than those from homes using electricity for cooking (mean difference 19.37 μg/m³). Personal exposures were more closely related to bedroom levels than to kitchen or outdoor concentrations for both cooking fuel groups. Several preliminary models are presented which relate average personal NO₂ exposure to indoor and ambient levels, and also to the proportion of time spent in different locations. These models are capable of explaining nearly 90% of the variation about the mean in personal exposure.     

Multi-pathway risk assessment of trihalomethanes exposure in Istanbul drinking water supplies

The lifetime cancer risk and the hazard index of trihalomethanes (THMs) through oral ingestion, dermal absorption, and inhalation exposure from tap water of 15 districts in Istanbul are estimated. The most dominant THM compounds are chloroform, bromodichloromethane (BDCM), and dibromochloromethane (DBCM) in Istanbul tap water. The results indicate that within three different pathways, Istanbul residents had a higher cancer risk through oral ingestion than through the other two pathways. The lifetime cancer risks of oral ingestion for total THMs was highest in Esenyurt district, while the lowest lifetime cancer risk for total THMs was in Basaksehir district. The lifetime cancer risks of chloroform, BDCM, and DBCM from tap water of all 15 districts were higher than 10(-6), the negligible risk level defined by the USEPA. Among the 15 districts, people living in Esenyurt have the highest risk of cancer due to the THM exposure through the multi-pathways, mainly because of the exposure to BDCM and DBCM. The total cancer risk analysis concluded that each year approximately 5 of the 8 million Istanbul residents could get cancer from the daily intake of tap water.     

Disinfection by-products exposure and intra-uterine growth restriction: Do genetic polymorphisms of CYP2E1or deletion of GSTM1 or GSTT1 modify the association?

BackgroundExposure to disinfection by-products (DBPs) during pregnancy was associated with reduced foetal growth. Genetic susceptibility might play a role, especially for genes encoding for the Cytochrome P450 (CYP2E1) and Glutathione S-Transferase (GST) enzymes, involved in metabolism and activation of DBPs. Few epidemiological studies evaluated these gene-environment interactions and their results were never replicated.ObjectiveThis study aims to examine interactions between trihalomethanes (THM) or haloacetic acids (HAA) exposure and genetic polymorphisms on small for gestational age (SGA) neonates by investigating single nucleotide polymorphisms (SNPs) in CYP2E1 gene and GSTM1 and GSTT1 deletions in mothers-children pairs.MethodsA population-based case-control study of 1549 mothers and 1455 children was conducted on SGA and THM/HAA exposure. DNA was extracted from blood or saliva cells. Targeted SNPs and deletions were genotyped. Statistical interaction between SNPs/deletions and THMs or HAAs in utero exposure with regard to SGA occurrence was evaluated by unconditional logistic regression with control of potential confounders.ResultsPreviously reported positive modification of the effect of THM uterine exposure by mothers or newborns CYP2E1 rs3813867 C allele or GSTM1 deletion was not replicated. However interactions with CYP2E1 rs117618383 and rs2515641 were observed but were not statistically significant after correction for multiple testing.ConclusionsPrevious positive interactions between THMs exposure and CYP2E1 and GSTM1 were not replicated but interactions with other CYP2E1 polymorphisms are reported.     

Farmworker children's residential non-dietary exposure estimates from micro-level activity time series

Farmworkers' children may have increased pesticide exposure through dermal absorption and non-dietary ingestion, routes that are difficult to measure and model. The Cumulative Aggregate Simulation of Exposure (CASE) model, integrates the complexity of human behavior and variability of exposure processes by combining micro-level activity time series (MLATS) and mechanistic exposure equations. CASE was used to estimate residential non-dietary organophosphate pesticide exposure (i.e., inhalation, dermal, and non-dietary ingestion) to California farmworker children and evaluate the micro-activity approach. MLATS collected from children and distributions developed from pesticide measurements in farmworkers' residences served as inputs. While estimated diazinon exposure was greater for inhalation, chlorpyrifos exposure was greater for the other routes. Greater variability existed between children (σ_B² = 0.22–0.39) than within each child's simulations (σ_W² = 0.01–0.02) for dermal and non-dietary ingestion. Dermal exposure simulations were not significantly different than measured values from dosimeters worn by the children. Non-dietary ingestion exposure estimates were comparable to duplicate diet measurements, indicating this route may contribute substantially to aggregate exposure. The results suggest the importance of the micro-activity approach for estimating non-dietary exposure. Other methods may underestimate exposure via these routes. Model simulations can be used to identify at-risk children and target intervention strategies.     

Personal exposure to HBCDs and its degradation products via ingestion of indoor dust

Personal exposures via ingestion of indoor dust to α-, β-, and γ-hexabromocyclododecanes (HBCDs) and the degradation products (pentabromocyclododecenes (PBCDs) and tetrabromocyclododecadienes (TBCDs)) were estimated for 21 UK adults. Under an average dust ingestion scenario, personal exposures ranged from 4.5 to 1851 ng ΣHBCDs day^? 1; while the range under a high dust ingestion scenario was 11 to 4630 ng ΣHBCDs day^? 1. On average, personal exposure to ΣHBCDs via dust ingestion in this study was 35% α-, 11% β-, and 54% γ-HBCD. However, while exposure to β-HBCD (4–18% of ΣHBCDs) was relatively consistent with the proportion of this diastereomer in the HBCD commercial formulation; exposures to α- and γ-isomers (11–58% and 29–82% of ΣHBCDs respectively) showed substantial variation from the commercial formulation pattern. Personal exposures to ΣTBCDs (median = 0.2 ng day^? 1 under an average dust ingestion scenario) and ΣPBCDs (1.4 ng day^? 1) were significantly lower (p < 0.05) than for ΣHBCDs (48 ng day^? 1). Despite this, the exposure of one participant to ΣPBCDs exceeded the exposure to ΣHBCDs received by 85% of the other participants. On average, house dust provided the major contribution to personal exposure via dust ingestion to all target compounds due to the large time fraction spent in houses. In contrast, although participants spent less time in cars than in offices, car dust makes a higher average contribution (17%) to ΣHBCDs exposure than office dust (13%).     

Personal monitoring of air pollution exposures

In industrial hygiene and health physics the goal has been to protect the health of the individual. Therefore monitoring the exposure people actually receive has been the principal concern. In regulating public exposures to air pollution, the focus has been much different. Recently, use of personal monitors and alternative means of estimating actual exposures has expanded rapidly. The role of personal monitors in epidemiology, exposure studies, and in supplementing the existing fixed station monitoring network for establishing trends and for regulatory purposes is discussed. The implications for air quality standards in recent findings of personal and indoor exposures is considered. New developments that are needed, and those that are not needed, are outlined.     

Plutonium isotopes in surface air of Prague in 1986–2006

Monitoring of ^239,240Pu in surface air of Prague started in 1986 in connection with the Chernobyl accident. Measurable activities of 10–28 μBq m⁻³ were found from 29 April 1986 to 5 May 1986. In the most of the monitoring periods of 1987–1996, activities of ^239,240Pu in air were not measurable. Positive values for ^239,240Pu and ²³⁸Pu in air could be obtained after installation of an aerosol sampler with higher flow-rate in 1997. Activity concentrations of ^239,240Pu and ²³⁸Pu in Prague air in the most of quarters of 1997–2006 were in the range 0.53–5.06 and <0.16–1.10 nBq m⁻³, respectively. Seasonal fluctuations can be found in content of ^239,240Pu in air. Activity ratios of ²³⁸Pu/^239,240Pu in air are higher than those in top soil, so it can be supposed that ²³⁸Pu is coming to air of Prague also from other sources than resuspension of fallout from atmospheric nuclear tests.     

Effects of radionuclide and rainfall characteristics on field loss parameters of grass

The decrease of foliar activity in vegetation after its initial contamination by foliar deposition is termed “field loss” (Chamberlain, 1970). This work investigated further laboratory data concerning field loss of ¹³⁴Cs, ¹³⁷Cs, ⁸⁵Sr, ¹³³Ba and ^123mTe deposited on grassland (Madoz-Escande et al., 2005). Treatments consisted in rainfall scenarios cumulating 14 mm per week, combining two levels of intensity (8 or 30 mm/h) and two levels of frequency/precocity (late once or early twice-a-week). The time course of field loss was monitored in the edible tissues which were sampled by mowing between the rainfalls. Data were analyzed with an offset exponential loss model which is applicable to chronic contamination and is consistent with approaches adopted in radiological assessment models. Its parameters were estimated by the maximum-likelihood method, and their accuracy was determined by nonparametric boostrap. Radionuclide and rainfall conditions significantly affected the estimated rate (λ₁) and extent (A₁) of field loss. Field loss rate (λ₁) and nonentrainable fraction (1 − A₁) varied by a factor 1.5–3. Cesium was very mobile but persistent. On the contrary Tellerium was found less labile, but eventually was almost completely eliminated. Strontium and Barium had intermediate behaviors. Field loss was more efficient for moderate late once-a-week rainfalls (8 mm/h). Higher rainfall intensity reduced more the radionuclides losses than higher rainfall frequency/precocity. This paper reports statistically relevant effects that should be considered for more realistic assessments.