Home Assessment of Indoor Microbiome (HAIM) in Relation to Lower Respiratory Tract Infections among Under-Five Children in Ibadan, Nigeria: The Study Protocol.

The association between household air pollution and lower respiratory tract infections (LRTI) among children under five years of age has been well documented; however, the extent to which the microbiome within the indoor environment contributes to this association is uncertain. The home assessment of indoor microbiome (HAIM) study seeks to assess the abundance of indoor microbiota (IM) in the homes of under-five children (U-5Cs) with and without LRTI. HAIM is a hospital- and community-based study involving 200 cases and 200 controls recruited from three children's hospitals in Ibadan, Nigeria. Cases will be hospital-based patients with LRTI confirmed by a pediatrician, while controls will be community-based participants, matched to cases on the basis of sex, geographical location, and age (±3 months) without LRTI. The abundance of IM in houses of cases and controls will be investigated using active and passive air sampling techniques and analyzed by qualitative detection of bacterial 16SrRNA gene (V3-V4), fungal ITS1 region, and viral RNA sequencing. HAIM is expected to elucidate the relationship between exposure to IM and incidence of LRTI among U-5Cs and ultimately provide evidence base for strategic interventions to curtail the burgeoning burden of LRTI on the subcontinent.

Multiple Sources of the Outbreak of Legionnaires' Disease in Genesee County, Michigan, in 2014 and 2015.

BACKGROUND: A community-wide outbreak of Legionnaires' disease (LD) occurred in Genesee County, Michigan, in 2014 and 2015. Previous reports about the outbreak are conflicting and have associated the outbreak with a change of water source in the city of Flint and, alternatively, to a Flint hospital. OBJECTIVE: The objective of this investigation was to independently identify relevant sources of Legionella pneumophila that likely resulted in the outbreak. METHODS: An independent, retrospective investigation of the outbreak was conducted, making use of public health, health care, and environmental data and whole-genome multilocus sequence typing (wgMLST) of clinical and environmental isolates. RESULTS: Strong evidence was found for a hospital-associated outbreak in both 2014 and 2015: a) 49% of cases had prior exposure to Flint hospital A, significantly higher than expected from Medicare admissions; b) hospital plumbing contained high levels of L. pneumophila; c) Legionella control measures in hospital plumbing aligned with subsidence of hospital A-associated cases; and d) wgMLST showed Legionella isolates from cases exposed to hospital A and from hospital plumbing to be highly similar. Multivariate analysis showed an increased risk of LD in 2014 for people residing in a home that received Flint water or was located in proximity to several Flint cooling towers. DISCUSSION: This is the first LD outbreak in the United States with evidence for three sources (in 2014): a) exposure to hospital A, b) receiving Flint water at home, and c) residential proximity to cooling towers; however, for 2015, evidence points to hospital A only. Each source could be associated with only a proportion of cases. A focus on a single source may have delayed recognition and remediation of other significant sources of L. pneumophila. https://doi.org/10.1289/EHP5663.

Quantitative and qualitative analysis of antimicrobial usage at farm and flock level on 181 broiler farms in nine European countries.

OBJECTIVES: To control the emerging threat of antimicrobial resistance, international policy appeals for appropriate monitoring of antimicrobial usage (AMU) at supranational, species and farm level. The aim of this study was to quantify AMU in broilers at farm and flock level in nine European countries. METHODS: Antimicrobial treatment data of one flock and purchased antimicrobials over one year were collected at 181 European broiler farms. Afterwards AMU was quantified using treatment incidence (TI) per 100 days based on Defined Daily Dose (DDDvet), Defined Course Dose (DCDvet) or Used Daily Dose (UDDvet) values. Total AMU at flock level was obtained by summing the TIDDDvet of all treatments in the sampled flock (TIDDDvetFl*). RESULTS: The median TIDDDvetFl* was 9.0 (95% CI 5.5-10.8), meaning that broilers were treated with antimicrobials during 9% of their rearing period. TIDDDvetFl* varied considerably within and between countries. However, in every country at least one untreated flock was present. Average TIDDDvetFl* at country level ranged from 3.3 to 36.7. Polymyxins, extended-spectrum aminopenicillins and fluoroquinolones were the most used antimicrobials, accounting for 26%, 26% and 18% of total AMU, respectively. Twenty-six percent of the farms started a treatment on day 1 of production, and 49% of overall AMU was administered within the first week. CONCLUSIONS: Results show that rearing broilers without AMU is feasible. However, a huge variation in AMU in terms of amount, moment of administration and antimicrobial classes was observed. This shows that there is still ground to be covered when it comes to AMU on broiler farms.

Contact dermatitis is an unrecognized problem in the construction industry: Comparison of four different assessment methods.

BACKGROUND: A high contact dermatitis symptoms prevalence has been observed in Dutch construction workers. METHODS: Contact dermatitis was diagnosed by an expert panel using questionnaire data and photographs of 751 subjects' hands. A subset was evaluated by two occupational physicians. Their diagnoses were compared to those of the expert panel. In addition, two self-reported questionnaire-based assessment methods were compared to the expert panel evaluation. Associations between contact dermatitis and determinants were assessed using log-binomial regression analysis. RESULTS: Contact dermatitis prevalence was high: 61.4% (expert panel's diagnosis) and 32.9% (self-reported). Agreement between occupational physicians and the expert panel was low but increased after training. Washing hands with solvents and performing job-related tasks at home were related to contact dermatitis. CONCLUSIONS: Contact dermatitis prevalence among construction workers is high. Recognition of contact dermatitis by occupational physicians is poor but can be improved by training. Awareness of skin disorders should be raised.

Mobility assessment of a rural population in the Netherlands using GPS measurements.

BACKGROUND: The home address is a common spatial proxy for exposure assessment in epidemiological studies but mobility may introduce exposure misclassification. Mobility can be assessed using self-reports or objectively measured using GPS logging but self-reports may not assess the same information as measured mobility. We aimed to assess mobility patterns of a rural population in the Netherlands using GPS measurements and self-reports and to compare GPS measured to self-reported data, and to evaluate correlates of differences in mobility patterns. METHOD: In total 870 participants filled in a questionnaire regarding their transport modes and carried a GPS-logger for 7 consecutive days. Transport modes were assigned to GPS-tracks based on speed patterns. Correlates of measured mobility data were evaluated using multiple linear regression. We calculated walking, biking and motorised transport durations based on GPS and self-reported data and compared outcomes. We used Cohen's kappa analyses to compare categorised self-reported and GPS measured data for time spent outdoors. RESULTS: Self-reported time spent walking and biking was strongly overestimated when compared to GPS measurements. Participants estimated their time spent in motorised transport accurately. Several variables were associated with differences in mobility patterns, we found for instance that obese people (BMI > 30 kg/m2) spent less time in non-motorised transport (GMR 0.69-0.74) and people with COPD tended to travel longer distances from home in motorised transport (GMR 1.42-1.51). CONCLUSIONS: If time spent walking outdoors and biking is relevant for the exposure to environmental factors, then relying on the home address as a proxy for exposure location may introduce misclassification. In addition, this misclassification is potentially differential, and specific groups of people will show stronger misclassification of exposure than others. Performing GPS measurements and identifying explanatory factors of mobility patterns may assist in regression calibration of self-reports in other studies.

Quantitative assessment of antimicrobial resistance in livestock during the course of a nationwide antimicrobial use reduction in the Netherlands.

OBJECTIVES: To quantify associations between antimicrobial use and acquired resistance in indicator Escherichia coli over a period of time which involved sector-wide antimicrobial use reductions in broilers and pigs (years 2004-14), veal calves (2007-14) and dairy cattle (2005-14). Prevalence estimates of resistance were predicted for a hypothetical further decrease in antimicrobial use. METHODS: Data reported annually for the resistance surveillance programme in the Netherlands were retrieved. Two multivariate random-effects logistic models per animal sector were used to relate total and class-specific antimicrobial use (as defined daily dosages per animal per year, DDDA/Y) with the probability of E. coli resistance to a panel of 10 antimicrobial agents. RESULTS: Positive dose-response relationships (ORs) were obtained from all models. Specific resistance phenotypes were more often associated with total antimicrobial use than with class-specific use. The most robust associations were found in pigs and veal calves. Resistance to historically widely used antimicrobials (e.g. penicillins, tetracyclines) was, in relative terms, less influenced by drug use changes over time than resistance to newer or less prescribed antimicrobials (e.g. third-/fourth-generation cephalosporins, fluoroquinolones). In pigs and veal calves, prevalence estimates for the most common resistance phenotypes were projected to decline ∼5%-25% during 2014-16 if total antimicrobial use reduction reached 80%; projections for poultry and dairy cows were more modest. CONCLUSIONS: Epidemiological evidence indicated that drug use history and co-selection of resistance are key elements for perpetuation of resistance. Data suggest that recent Dutch policies aimed at reducing total use of antimicrobials have decreased E. coli resistance in the pig and veal calf production sectors while the impact on the dairy cattle and poultry sectors is less clear.

Hazard quotient profiles used as a risk assessment tool for PFOS and PFOA serum levels in three distinctive European populations.

Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) blood levels are commonly used as biomarkers of human environmental exposure to these compounds. Many biomonitoring studies indicate 100% detection for PFOS and PFOA thus justifying a concern of possible risk for the most exposed individuals. This study addresses the predictive value of hazard quotients (HQs) calculated on the basis of serum PFOS and PFOA in male and female populations of reproductive age in Greenland, Poland and Ukraine. Overall, 2026 results of PFOS and PFOA serum concentrations (589 males, 1437 females) were obtained from the INUENDO database. HQs were calculated from the actual biomonitoring results and literature-based animal data linking toxicological outcomes and critical PFOS/PFOA serum levels. HQs for serum PFOS were calculated based on Points of Departure (PoD) at 13µgmL(-1) (cynomolgus monkeys, 183days, changes in THS and T3) and for PFOA at 7.1µgmL(-1) serum (male rats, 90days, hepatocellular necrosis, increased liver weight). Uncertainty factors were applied to reflect interspecies differences and human variability. Serum HQs were expressed as a ratio relative to the point of departure for each PFOS and PFOA. Only in the three cases of males in Greenland were there serum PFOS levels showing HQ values exceeding 1, so indicating that such serum levels may be of concern. The mean serum concentration of PFOS was significantly higher in male than in female populations. Despite significant differences between HQ profiles for PFOS and PFOA in donors from Greenland, Poland and Ukraine, the concentrations of these perfluoroalkylated compounds do not indicate a cause for concern, except for the three aforementioned cases from Greenland. This study demonstrates that the HQ approach can help to interpret human biomonitoring data and thus serve as a valuable tool in further risk assessment priority settings and may also be used as a basis for taking decisions in risk management.

Phthalates, perfluoroalkyl acids, metals and organochlorines and reproductive function: a multipollutant assessment in Greenlandic, Polish and Ukrainian men.

OBJECTIVES: Numerous environmental contaminants have been linked to adverse reproductive health outcomes. However, the complex correlation structure of exposures and multiple testing issues limit the interpretation of existing evidence. Our objective was to identify, from a large set of contaminant exposures, exposure profiles associated with biomarkers of male reproductive function. METHODS: In this cross-sectional study (n=602), male partners of pregnant women were enrolled between 2002 and 2004 during antenatal care visits in Greenland, Poland and Ukraine. Fifteen contaminants were detected in more than 70% of blood samples, including metabolites of di(2-ethylhexyl) and diisononyl phthalates (DEHP, DiNP), perfluoroalkyl acids, metals and organochlorines. Twenty-two reproductive biomarkers were assessed, including serum levels of reproductive hormones, markers of semen quality, sperm chromatin integrity, epididymal and accessory sex gland function, and Y:X chromosome ratio. We evaluated multipollutant models with sparse partial least squares (sPLS) regression, a simultaneous dimension reduction and variable selection approach which accommodates joint modelling of correlated exposures. RESULTS: Of the over 300 exposure-outcome associations tested in sPLS models, we detected 10 associations encompassing 8 outcomes. Several associations were notably consistent in direction across the three study populations: positive associations between mercury and inhibin B, and between cadmium and testosterone; and inverse associations between DiNP metabolites and testosterone, between polychlorinated biphenyl-153 and progressive sperm motility, and between a DEHP metabolite and neutral α-glucosidase, a marker of epididymal function. CONCLUSIONS: This global assessment of a mixture of environmental contaminants provides further indications that some organochlorines and phthalates adversely affect some parameters of male reproductive health.

Quartz and respirable dust in the Dutch construction industry: a baseline exposure assessment as part of a multidimensional intervention approach.

Quartz exposure can cause several respiratory health effects. Although quartz exposure has been described in several observational workplace studies, well-designed intervention studies that investigate the effect of control strategies are lacking. This article describes a baseline exposure study that is part of a multidimensional intervention program aiming to reduce quartz exposure among construction workers. In this study, personal respirable dust and quartz exposure was assessed among 116 construction workers (bricklayers, carpenters, concrete drillers, demolishers, and tuck pointers). Possible determinants of exposure, like job, tasks, and work practices, use of control measures, and organizational and psychosocial factors, were explored using exposure models for respirable dust and quartz separately. Stratified analyses by job title were performed to evaluate the effect of control measures on exposure and to explore the association between control measures and psychosocial factors. Overall, 62% of all measurements exceeded the Dutch occupational exposure limit for quartz and 11% for respirable dust. Concrete drillers and tuck pointers had the highest exposures for quartz and respirable dust (0.20 and 3.43mg m(-3), respectively). Significant predictors of elevated quartz exposure were abrasive tasks and type of material worked on. Surprisingly, in a univariate model, an increased knowledge level was associated with an increase in exposure. Although control measures were used infrequently, if used they resulted in approximately 40% reduction in quartz exposure among concrete drillers and tuck pointers. Only among concrete drillers, the use of control measures was associated with a higher score for social influence (factor 1.6); knowledge showed an inverse association with use of control measures for concrete drillers, demolishers, and tuck pointers. In conclusion, the detailed information on determinants of exposure, use of control measures, and constraints to use these control measures can be used for the determination and systematic prioritization of intervention measures used to design and implement our intervention strategy. This study underlines the need for multidisciplinary workplace exposure control strategies although larger study populations are necessary to determine a possible causal association between organizational and psychosocial factors and psychosocial factors and control measures.

Leukemia from dermal exposure to cyclophosphamide among nurses in The Netherlands: quantitative assessment of the risk.

Several studies showed that oncology nurses are exposed to antineoplastic drugs via the skin during daily activities. Several antineoplastic drugs (including cyclophosphamide) have been classified as carcinogenic to humans. This study aims to assess the leukemia risk of occupational exposure to cyclophosphamide. Average task frequencies from the population of oncology nurses in the Netherlands and task-based dermal exposure intensities were used to calculate oncology nurses' dermal exposure levels. A dermal absorption model in combination with a physiologically based pharmacokinetic model was used to assess the delivered dose of cyclophosphamide and its active metabolites in the bone marrow. This delivered dose was subsequently related to pharmacodynamic and epidemiological information from a longitudinal study with cyclophosphamide-treated patients to estimate the excess lifetime leukemia risk at age 80 for Dutch oncology nurses after 40 years of exposure to cyclophosphamide. The excess lifetime leukemia risk at age 80 of an exposed oncology nurse after 40 years of dermal exposure to cyclophosphamide was estimated to be 1.04 per million oncology nurses. This risk could potentially increase to a maximum of 154 per million if a nurse performs all cyclophosphamide-related tasks with the maximum frequency (as observed in this population) and is exposed to maximum exposure intensities for each task without using protective gloves for 40 years. This study indicates that the risk of an oncology nurse in a Dutch hospital with an average dermal exposure to cyclophosphamide is well below the maximum tolerable risk of one extra death from cancer per 250 deaths after 40 years of occupational exposure, and that this level is not exceeded in a worst-case scenario.

Potential public health consequences of exposure assessment for Staphylococcus aureus: commentary on the paper by Masclaux et al.

The study of Masclaux et al., in this issue of the Annals of Occupational Hygiene, describes measurement of Staphylococcus bacteria in pig farms using classical viable measurement techniques and molecular techniques. Molecular techniques find application in hygiene field studies more often and create new opportunities. Common dust sampling approaches can be used in combination with molecular techniques and high numbers of samples can be processed creating opportunities for hygiene control and for exposure assessment in the context of epidemiological surveys. Hygienists should be aware of the advantages and disadvantages of the use of these techniques. Aspects of microbial sampling are briefly reviewed.

Quality of evidence must guide risk assessment of asbestos.

In 2011, we reported on the sensitivity of lung cancer potency estimates for asbestos to the quality of the exposure assessment component of underlying evidence. Both this meta-analysis and a separate reassessment of standards published by the Health Council of the Netherlands (Gezondheidsraad) have been commented on by Berman and Case. A criticism is that we used a truncated data set. We incrementally excluded poorer-quality studies to evaluate trends in meta-analyzed lung cancer potency estimates (meta-K (L) values). This was one of three analysis approaches we presented. The other two used the full set of studies: a meta-analysis stratified by covariates and dichotomized by poorer and better exposure assessment aspects; and a meta-regression modeling both asbestos fiber type and these covariates. They also state that our results are not robust to removal of one study. We disagree with this claim and present additional sensitivity analyses underpinning our earlier conclusion that inclusion of studies with higher-quality asbestos-exposure assessment yield higher meta-estimates of the lung cancer risk per unit of exposure. We reiterate that potency differences for predominantly chrysotile- versus amphibole-asbestos-exposed cohorts are difficult to ascertain when meta-analyses are restricted to studies with fewer exposure assessment limitations. We strongly argue that the existence of any uncertainty related to potency issues should not hamper the development of appropriate evidence-based guidelines and stringent policies in order to protect the public from hazardous environmental and occupational exposures.

What are the benefits of medical screening and surveillance?

Pre-employment examination is considered to be an important practice and is commonly performed in several countries within the European Union. The benefits of medical surveillance programmes are not generally accepted and their structure is often inconsistent. The aim of this review was to evaluate, on the basis of the available literature, the usefulness of medical screening and surveillance. MEDLINE was searched from its inception up to March 2010. Retrieved literature was evaluated in a peer-review process and relevant data was collected following a systematic extraction schema. Pre-placement screening identifies subjects who are at an increased risk for developing work-related allergic disease, but pre-employment screening is too low to be used as exclusion criteria. Medical surveillance programmes can identify workers who have, or who are developing, work-related asthma. These programmes can also be used to avoid worsening of symptoms by implementing preventive measures. A combination of different tools within the surveillance programme, adjusted for the risk of the individual worker, improves the predictive value. Medical surveillance programmes provide medical as well as socioeconomic benefits. However, pre-employment screening cannot be used to exclude workers. They may act as a starting point for surveillance strategies. A stratified approach can increase the effectiveness and reduce the costs for such programmes.

The management of work-related asthma guidelines: a broader perspective.

The aim of the European Respiratory Society work-related asthma guidelines is to present the management and prevention options of work-related asthma and their effectiveness. Work-related asthma accounts for 5-25% of all adult asthma cases and is responsible for a significant socioeconomic burden. Several hundred occupational agents, mainly allergens but also irritants and substances with unknown pathological mechanisms, have been identified as causing work-related asthma. The essential message of these guidelines is that the management of work-related asthma can be considerably optimised based on the present knowledge of causes, risk factors, pathomechanisms, and realistic and effective interventions. To reach this goal we urgently require greatly intensified primary preventive measures and improved case management. There is now a substantial body of evidence supporting the implementation of comprehensive medical surveillance programmes for workers at risk. Those workers who fail surveillance programmes need to be referred to a clinician who can confirm or exclude an occupational cause. Once work-related asthma is confirmed, a revised risk assessment in the workplace is needed to prevent further cases. These new guidelines confirm and extend already existing statements and recommendations. We hope that these guidelines will initiate the much-needed research that is required to fill the gaps in our knowledge and to initiate substantial improvements in preventative measures.

Bioaerosol exposure assessment in the workplace: the past, present and recent advances.

Louis Pasteur described the first measurements of airborne microorganisms in 1861. A century later, the inhalation of spores from thermophilic microorganisms was shown to induce attacks of farmers' lung in patients with this disease, while endotoxins originating from Gram-negative bacteria were identified as causal agents for byssinosis in cotton workers. Further epidemiological and toxicological studies have demonstrated inflammatory, respiratory, and pathogenic effects following exposure to bioaerosols. Exposure assessment is often confounded by the diversity of bioaerosol agents in the environment. Microorganisms represent a highly diverse group that may vary in toxicity. Fungi and bacteria are mainly quantified as broad groups using a variety of viable and nonviable assessment methods. Endotoxins and ß(1 → 3)-glucans are mainly measured by their activity in the Limulus amebocyte lysate assay, enzymes by immuno-chemical methods and mycotoxins by liquid chromatography-mass spectrometry. Few health-based occupational exposure limits (OELs) are available for risk assessment. For endotoxins, a health-based OEL of 90 endotoxin units m(-3) has been proposed in the Netherlands. A criteria document for fungal spores recently proposed a lowest observed effect level of 100,000 spores m(-3) for non-pathogenic and non-mycotoxin producing species based on inflammatory respiratory effects. Recent developments in bioaerosol assessment were presented at the Organic Dust Tromsø Symposium including molecular biological methods for infectious agents and organisms that are difficult to cultivate; studies of submicronic and hyphal fragments from fungi; the effect of biodiversity of microorganisms in asthma studies; and new/improved measurement methods for fungal antigens, enzymes and allergens. Although exposure assessment of bioaerosol agents is complex and limited by the availability of methods and criteria, the field is rapidly evolving.

Cost-benefit analysis in occupational health: a comparison of intervention scenarios for occupational asthma and rhinitis among bakery workers.

OBJECTIVES: Use of cost-benefit analysis in occupational health increases insight into the intervention strategy that maximises the cost-benefit ratio. This study presents a methodological framework identifying the most important elements of a cost-benefit analysis for occupational health settings. One of the main aims of the methodology is to evaluate cost-benefit ratios for different stakeholders (employers, employees and society). The developed methodology was applied to two intervention strategies focused on reducing respiratory diseases. METHODS: A cost-benefit framework was developed and used to set up a calculation spreadsheet containing the inputs and algorithms required to calculate the costs and benefits for all cost elements. Inputs from a large variety of sources were used to calculate total costs, total benefits, net costs and the benefit-to-costs ratio for both intervention scenarios. RESULTS: Implementation of a covenant intervention program resulted in a net benefit of €16 848 546 over 20 years for a population of 10 000 workers. Implementation was cost-effective for all stakeholders. For a health surveillance scenario, total benefits resulting from a decreased disease burden were estimated to be €44 659 352. The costs of the interventions could not be calculated. CONCLUSION: This study provides important insights for developing effective intervention strategies in the field of occupational medicine. Use of a model based approach enables investigation of those parameters most likely to impact on the effectiveness and costs of interventions for work related diseases. Our case study highlights the importance of considering different perspectives (of employers, society and employees) in assessing and sharing the costs and benefits of interventions.

A meta-analysis of asbestos and lung cancer: is better quality exposure assessment associated with steeper slopes of the exposure-response relationships?

BACKGROUND: Asbestos is a well-recognized cause of lung cancer, but there is considerable between-study heterogeneity in the slope of the exposure-response relationship. OBJECTIVE: We considered the role of quality of the exposure assessment to potentially explain heterogeneity in exposure-response slope estimates. DATA SOURCES: We searched PubMed MEDLINE (1950-2009) for studies with quantitative estimates of cumulative asbestos exposure and lung cancer mortality and identified 19 original epidemiological studies. One was a population-based case-control study, and the others were industry-based cohort studies. DATA EXTRACTION: Cumulative exposure categories and corresponding risks were abstracted. Exposure-response slopes [KL (lung cancer potency factor of asbestos)] were calculated using linear relative risk regression models. DATA SYNTHESIS: We assessed the quality of five exposure assessment aspects of each study and conducted random effects univariate and multivariate meta-regressions. Heterogeneity in exposure-response relationships was greater than expected by chance (I2 = 64%). Stratification by exposure assessment characteristics revealed that studies with well-documented exposure assessment, larger contrast in exposure, greater coverage of the exposure history by exposure measurement data, and more complete job histories had higher meta-KL values than did studies without these characteristics. The latter two covariates were most strongly associated with the KL value. Meta-KL values increased when we incrementally restricted analyses to higher-quality studies. CONCLUSIONS: This meta-analysis indicates that studies with higher-quality asbestos exposure assessment yield higher meta-estimates of the lung cancer risk per unit of exposure. Potency differences for predominantly chrysotile versus amphibole asbestos-exposed cohorts become difficult to ascertain when meta-analyses are restricted to studies with fewer exposure assessment limitations.

What's in the pool? A comprehensive identification of disinfection by-products and assessment of mutagenicity of chlorinated and brominated swimming pool water.

BACKGROUND: Swimming pool disinfectants and disinfection by-products (DBPs) have been linked to human health effects, including asthma and bladder cancer, but no studies have provided a comprehensive identification of DBPs in the water and related that to mutagenicity. OBJECTIVES: We performed a comprehensive identification of DBPs and disinfectant species in waters from public swimming pools in Barcelona, Catalonia, Spain, that disinfect with either chlorine or bromine and we determined the mutagenicity of the waters to compare with the analytical results. METHODS: We used gas chromatography/mass spectrometry (GC/MS) to measure trihalomethanes in water, GC with electron capture detection for air, low- and high-resolution GC/MS to comprehensively identify DBPs, photometry to measure disinfectant species (free chlorine, monochloroamine, dichloramine, and trichloramine) in the waters, and an ion chromatography method to measure trichloramine in air. We assessed mutagenicity with the Salmonella mutagenicity assay. RESULTS: We identified > 100 DBPs, including many nitrogen-containing DBPs that were likely formed from nitrogen-containing precursors from human inputs, such as urine, sweat, and skin cells. Many DBPs were new and have not been reported previously in either swimming pool or drinking waters. Bromoform levels were greater in brominated than in chlorinated pool waters, but we also identified many brominated DBPs in the chlorinated waters. The pool waters were mutagenic at levels similar to that of drinking water (approximately 1,200 revertants/L-equivalents in strain TA100-S9 mix). CONCLUSIONS: This study identified many new DBPs not identified previously in swimming pool or drinking water and found that swimming pool waters are as mutagenic as typical drinking waters.

Exposure assessment for a nested case-control study of lung cancer among European asphalt workers.

OBJECTIVE: Development of a method for retrospective assessment of exposure to bitumen fume, bitumen condensate, organic vapour, polycyclic aromatic hydrocarbons, and co-exposures to known or suspected lung carcinogens for a nested case-control study of lung cancer mortality among European asphalt workers. METHODS: Company questionnaires and structured questionnaires used in interviews and industry-specific job-exposure matrices (JEMs) were elaborated and applied. Three sources of information were eventually used for exposure assessment and assignment: (i) data obtained in cohort phase, (ii) data from living subjects, next-of-kin, and fellow-workers questionnaires, and (iii) JEMs for bitumen exposure by inhalation and via skin and co-exposures to known or suspected lung carcinogens within and outside cohort companies. Inhalation and dermal exposure estimates for bitumen were adjusted for time trends, time spent in a job, and other determinants of exposure (e.g. oil gravel paving). Clothing patterns, personal protective devices, and personal hygiene were taken into consideration while estimating dermal exposure. RESULTS: Occupational exposures could be assessed for 433 cases and 1253 controls for relevant time periods. Only 43% of work histories were spent inside original asphalt and construction companies. A total of 95.8% of job periods in cohort companies could be coded at a more detailed level. Imputation of work time and 'hygienic behaviour' multipliers was needed for <10% of work history years. Overall, downward trends in exposure were present and differences existed between countries and companies. As expected, correlations were strongest (r > 0.7) among bitumen-related agents, while correlations between coal tar, bitumen-related agents, and established lung carcinogens were weaker (r < 0.4). CONCLUSIONS: A systematic and detailed approach was developed to estimate inhalation and dermal exposure for a nested case-control study among asphalt workers.

beta-(1,3)-Glucan exposure assessment by passive airborne dust sampling and new sensitive immunoassays.

Associations between house dust-associated beta-(1,3)-glucan exposure and airway inflammatory reactions have been reported, while such exposures in early childhood have been suggested to protect against asthma and wheezing. Most epidemiological studies have used reservoir dust samples and an inhibition enzyme immunoassay (EIA) for beta-(1,3)-glucan exposure assessment. The objective of this study was to develop inexpensive but highly sensitive enzyme immunoassays to measure airborne beta-(1,3)-glucans in low-exposure environments, like homes. Specificities of available anti-beta-(1,3)-glucan antibodies were defined by direct and inhibition experiments. Three suitable antibody combinations were selected for sandwich EIAs. beta-(1,3)-Glucans in passive airborne dust collected with an electrostatic dust fall collector (EDC) and floor dust from seven homes were measured with the three EIAs. Floor dust samples were additionally analyzed in the inhibition EIA. The sandwich EIAs were sensitive enough for airborne glucan measurement and showed different specificities for commercial glucans, while the beta-(1,3)-glucan levels in house dust samples correlated strongly. The feasibility of measuring glucans in airborne dust with the recently introduced EDC method was further investigated by selecting the most suitable of the three EIAs to measure and compare beta-(1,3)-glucan levels in the EDC and in floor and actively collected airborne dust samples of the previously performed EDC validation study. The EDC beta-(1,3)-glucan levels correlated moderately with beta-(1,3)-glucans in actively collected airborne dust and floor dust samples, while the glucan levels in the airborne dust and floor dust samples did not correlate. The combination of the newly developed beta-(1,3)-glucan sandwich EIA with EDC sampling now allows assessment in large-scale population studies of exposure to airborne beta-(1,3)-glucans in homes or other low-exposure environments.