Indoor swimming pool environments and self-reported irritative and respiratory symptoms among lifeguards.

A web survey was conducted among 870 lifeguards (current and former) to assess the relationship between exposure to indoor swimming pool environments and respiratory health. Associations between respiratory symptoms and asthma with varying lengths of occupational exposure were assessed by multiple logistic regression. Lifeguards exposed more than 500 hours in the previous 12 months experienced more cough (adjustedOR = 2.54, IC95 % = 1.51-4.25), throat (aOR = 2.47, IC95 % = 1.44-4.24) and eye irritation (aOR = 4.34, IC95 % = 2.52-7.50) during this period than non-exposed lifeguards. Upper and lower respiratory symptoms while on duty were related to duration of lifetime exposure (> 500 days vs. ≤ 50 days: Upper aOR = 5.84, IC95 % = 3.60-9.50; Lower aOR = 2.53, IC95 % = 1.58-4.06). Physician-diagnosed asthma was high among lifeguards (23 %). Highly exposed asthmatic lifeguards (> 500 hours) over the previous 12 months had a significantly higher risk (aOR = 3.74, IC95 % = 1.39-10.02) of suffering from asthma attack(s) than non-exposed asthmatic subjects. Exposure to indoor swimming pool environments is related to respiratory symptoms among lifeguards.

Investigation of Air Quality Problems in an Indoor Swimming Pool: A Case Study.

INTRODUCTION: Trichloramine (NCl3) is the contaminant suspected the most to cause irritative respiratory symptoms among swimmers and swimming pool workers. Following complaints by employees working in an indoor swimming pool, this study set out to identify the determinants of NCl3 air concentrations in that particular swimming pool. METHODS: To document NCl3 air levels, air samples (n = 26) were collected once or twice a day for 3 h, at least 3 days per week, between October and December 2011. Water samples were taken three times during air sampling to verify free chlorine, chloramines, alkalinity, conductivity, pH, water temperature, and turbidity. Water changes were also recorded, along with the number of bathers. Ventilation (outdoor air flow) was modified to verify the influence of this important variable. Data were evaluated by analysis of variance. RESULTS: Mean NCl3 air concentration was 0.38 mg m(-3). The best model explaining variations of NCl3 air levels (r2 = 0.83) included sampling period (P = 0.002, NCl3 was higher in the evening versus the morning), water changes (P = 0.02, NCl3 was lower with water changes between 60 and 90 min day(-1) versus <60 min day(-1)), and ventilation (P = 0.0002, NCl3 was lower with ≥2 air changes per hour (ACH) versus <1 ACH). DISCUSSION AND CONCLUSION: Although based on only 26 air samples, our results indicate that ventilation is an important determinant of NCl3 air concentration in swimming pool air. There is limited information available on the air quality of indoor swimming pools and the relationship with ventilation. Efforts are needed to document the situation and to develop state-of-the-art facilities for ventilation of indoor swimming pools.

Contamination of public whirlpool spas: factors associated with the presence of Legionella spp., Pseudomonas aeruginosa and Escherichia coli.

This work explores the factors associated with contamination of public spas by Legionella spp., Pseudomonas aeruginosa and Escherichia coli. Physicochemical and microbiological parameters were measured in water samples from 95 spas inQuébec, Canada. Spa maintenance was documented by a questionnaire. Legionella spp. were detected in 23% of spas, P. aeruginosa in 41% and E. coli in 2%. Bacteria were found in concerning concentrations (Legionella spp. ≥ 500 CFU/l, P. aeruginosa ≥ 51 CFU/100 ml or E. coli ≥ 1 CFU/100 ml) in 26% ofspas. Observed physicochemical parameters frequently differed from recommended guidelines. The following factors decreased the prevalence of concerning microbial contamination: a free chlorine concentration ≥ 2 mg/l or total bromine ≥ 3 mg/l (p = 0.001), an oxidation-reduction potential (ORP) > 650 mV (p = 0.001), emptying and cleaning the spa at least monthly (p = 0.019) and a turbidity ≤ 1 NTU (p = 0.013). Proper regulations and training of spa operators are critical for better maintenance of these increasingly popular facilities.

Waterborne outbreaks: a public health concern for rural municipalities with unchlorinated drinking water distribution systems.

OBJECTIVES: The objective of this study is to describe an important waterborne outbreak of gastrointestinal illness observed in a rural municipality of Quebec. METHODS: A population-based retrospective cohort study was conducted to identify risk factors associated with acute gastroenteritis. Indirect surveillance data were used to estimate the extent and the resolution of the epidemic. RESULTS: The cohort consisted of 140 randomly selected individuals of whom 22 met the illness case definition (15.7% attack rate). The epidemic curve was similar to the evolution of antidiarrheal products sold by the only pharmacy in town and calls made to the Health Info Line. Bivariate analysis led to identifying five risk factors of gastrointestinal illness: consumption of municipal water, contact with someone with acute gastroenteritis (within and outside of the household), contact with a child in daycare, and being less than 35 years of age. Drinking municipal water had the highest risk ratio (RR = 24.31; 95% CI = 1.50-393.4). Drinking water from a private artesian well was a protective factor (RR = 0.28; 95% CI = 0.09-0.90). CONCLUSION: This study highlighted that managing the risks associated with the consumption of untreated drinking water remains an important public health challenge, particularly in small rural municipalities vulnerable to climate variability.

Public Health Consequences of Lead in Drinking Water.

PURPOSE OF REVIEW: Lead can enter drinking water from lead service lines and lead-containing plumbing, particularly in the presence of corrosive water. We review the current evidence on the role of drinking water as a source of lead exposure and its potential impacts on health, with an emphasis on children. Drinking water guidelines and mitigation strategies are also presented. RECENT FINDINGS: The impact of lead on neurodevelopmental effects in children even at low levels of exposure is well established. Population and toxicokinetic modeling studies have found a clear relationship between water lead levels and blood lead levels in children at low levels of lead in drinking water. Various mitigation strategies can lower lead levels in water. The importance of drinking water as a contributor to total lead exposure depends on water lead levels and the amount consumed, as well as the relative contribution of other sources. Efforts should be made to reduce lead exposure for all sources, including drinking water, considering that no threshold level of exposure exists for the neurodevelopmental effects of lead in children.

Deriving A Drinking Water Guideline for A Non-Carcinogenic Contaminant: The Case of Manganese.

Manganese is a natural contaminant of water sources. It is an essential oligo-element, which may exert toxicity at high doses, particularly via inhalation. Its toxicity by the oral route is less known, but epidemiological and experimental studies tend to support its neurodevelopmental toxicity in infants and children. This paper describes the method used by a middle-size public health institution to derive a Drinking Water Guideline (DWG) for manganese. After reviewing the work done by major public health institutions, authors confirmed the use of experimental data to derive a point-of-departure (POD) of 25 mg of manganese/kg/day, based on neurodevelopmental effects on pup rats. Then, a total uncertainty factor of 450 was applied to calculate a Toxicological Reference Value (TRV) of 55 µg/kg/day. The final DWG proposed for manganese is 60 µg/L and is based on a relative source contribution (RSC) of water of 20% and an infant drinking scenario of 182 mL/kg of body weight (BW) of water (95th percentile of the ingestion rate distribution for 0⁻6 months). Despite its limitations, e.g., starting with the work done by other agencies, such an approach demonstrates in a transparent way the rationale and challenging choices made by regulators when deriving a DWG.

Microbiological guideline values for recreational bathing in Canada: Time for change?

Recreational bathing is an activity practiced by thousands of Canadians every year. While its health benefits are numerous, bathing in polluted water can also be a source of health problems. These problems are generally nonspecific and are difficult to detect through usual health monitoring systems. Most involve ear and eye ailments, febrile respiratory illness and, particularly, gastroenteritis. In 1992, Health Canada recommended microbiological guideline values for recreational water quality. The values are based on the presence of fecal indicator bacteria, namely, enterococci for marine water, and Escherichia coli or fecal coliforms for fresh water. In marine water, the guideline value is set at 35 enterococci/100 mL, while in fresh water, the standard is 200 E coli/100 mL or 200 fecal coliforms/100 mL when experience demonstrates that over 90% of the fecal coliforms are E coli. Notwithstanding certain variances, many Canadian provinces apply these guidelines. However, in Ontario, the guideline is 100 E coli/100 mL. Over the past several years, many epidemiological studies, including randomized clinical trials, have examined the relationship between bathing in polluted water and ensuing health problems. On review of this literature, the Canadian guideline values for marine water seems appropriate, but scientific evidence argues toward lowering the Canadian guideline values for fresh water to 100 E coli/100 mL, in line with the standard currently in effect in Ontario.

The impact of drinking water, indoor dust and paint on blood lead levels of children aged 1-5 years in Montréal (Québec, Canada).

Lead is neurotoxic at very low dose and there is a need to better characterize the impact of domestic sources of lead on the biological exposure of young children. A cross-sectional survey evaluated the contribution of drinking water, house dust and paint to blood lead levels (BLLs) of young children living in old boroughs of Montréal (Canada). Three hundred and six children aged 1 to 5 years and currently drinking tap water participated in the study. For each participant, residential lead was measured in kitchen tap water, floor dust, windowsill dust and house paint and a venous blood sample was analyzed. Multivariate logistic regression was used to evaluate the association between elevated BLL in the children (≥ 75th percentile) and indoor lead contamination by means of odds ratios (OR) using 95% confidence intervals (CI). There was an association between BLL ≥75th percentile (1.78 µg/dL) and water lead when the mean water concentration was >3.3 µg/L: adjusted OR=4.7 (95% CI: 2.1-10.2). Windowsill dust loading >14.1 µg/ft(2) was also associated with BLL ≥1.78 µg/dL: adjusted OR=3.2 (95% CI: 1.3-7.8). Despite relatively low BLLs, tap water and house dust lead contribute to an increase of BLLs in exposed young children.

Prospective study of acute health effects in relation to exposure to cyanobacteria.

We conducted a study to investigate the relationship between exposure to cyanobacteria and microcystins and the incidence of symptoms in humans living in close proximity to lakes affected by cyanobacteria. The design was a prospective study of residents living around three lakes (Canada), one of which has a water treatment plant supplying potable water to local residents. Participants had to keep a daily journal of symptoms and record contact (full or limited) with the water body. Samples were collected to document cyanobacteria and microcystin concentrations. Symptoms potentially associated with cyanobacteria (gastrointestinal: 2 indices (GI1: diarrhea or abdominal pain or nausea or vomiting; GI2: diarrhea or vomiting or [nausea and fever] or [abdominal cramps and fever]); upper and lower respiratory tract; eye; ear; skin; muscle pain; headaches; mouth ulcers) were examined in relation with exposure to cyanobacteria and microcystin by using Poisson regression. Only gastrointestinal symptoms were associated with recreational contact. Globally, there was a significant increase in adjusted relative risk (RR) with higher cyanobacterial cell counts for GI2 (<20,000 cells/mL: RR=1.52, 95% CI=0.65-3.51; 20,000-100,000 cells/mL: RR=2.71, 95% CI=1.02-7.16; >100,000 cells/mL: RR=3.28, 95% CI=1.69-6.37, p-trend=0.001). In participants who received their drinking water supply from a plant whose source was contaminated by cyanobacteria, an increase in muscle pain (RR=5.16; 95% CI=2.93-9.07) and gastrointestinal (GI1: RR=3.87; 95% CI=1.62-9.21; GI2: RR=2.84; 95% CI=0.82-9.79), skin (RR=2.65; 95% CI=1.09-6.44) and ear symptoms (RR=6.10; 95% CI=2.48-15.03) was observed. The population should be made aware of the risks of gastrointestinal symptoms associated with contact (full or limited) with cyanobacteria. A risk management plan is needed for water treatment plants that draw their water from a source contaminated with cyanobacteria.

Housing characteristics and indoor concentrations of nitrogen dioxide and formaldehyde in Quebec City, Canada.

Concentrations of nitrogen dioxide and formaldehyde were determined in a study of 96 homes in Quebec City, Canada, between January and April 2005. In addition, relative humidity, temperature, and air change rates were measured in homes, and housing characteristics were documented through a questionnaire to occupants. Half of the homes had ventilation rates below 7.5 L/s person. Nitrogen dioxide (NO2) and formaldehyde concentrations ranged from 3.3 to 29.1 microg/m3 (geometric mean 8.3 microg/m3) and from 9.6 to 90.0 microg/m3 (geometric mean of 29.5 microg/m3), respectively. The housing characteristics documented in the study explained approximately half of the variance of NO2 and formaldehyde. NO2 concentrations in homes were positively correlated with air change rates (indicating a significant contribution of outdoor sources to indoor levels) and were significantly elevated in homes equipped with gas stoves and, to a lesser extent, in homes with gas heating systems. Formaldehyde concentrations were negatively correlated with air change rates and were significantly elevated in homes heated by electrical systems, in those with new wooden or melamine furniture purchased in the previous 12 months, and in those where painting or varnishing had been done in the sampled room in the previous 12 months. Results did not indicate any significant contribution of indoor combustion sources, including wood-burning appliances, to indoor levels of formaldehyde. These results suggest that formaldehyde concentrations in Quebec City homes are caused primarily by off-gassing, and that increasing air change rates in homes could reduce exposure to this compound. More generally, our findings confirm the influence of housing characteristics on indoor concentrations of NO2 and formaldehyde.

Exposure to carbon monoxide during indoor karting.

Karting is a recreational activity of increasing popularity and it is often practiced indoors leading to build up of toxic gases in ambient air. This study was realised to verify the level of exposure to carbon monoxide (CO) in ten male racers (Age: 15 to 49 years old) during a 45-min race. The alveolar concentration of CO (alvCO) for each participant was measured before and after the race. The ambient CO level was determined continuously from the start to the end of the race with two detectors. Mean ambient air CO concentration was 41 ppm and the average increase of alvCO for the ten subjects was 16.2 ppm corresponding to about 3% COHb. Based on these results and on the Coburn model, a reference limit of 25 ppm was suggested for a 1 h exposure during indoor karting. At the request of the public health authorities, some modifications were made to the karts, to the CO monitoring surveillance system and to the ventilation system of the building. CO concentrations were monitored thereafter. The guideline of 25 ppm for 60 min was always respected.

Estimating the mercury exposure dose in a population of migratory bird hunters in the St. Lawrence River region, Québec, Canada.

St. Lawrence River hunters (Québec, Canada) are exposed to the pollutants, especially mercury, that contaminate birds and fish. However, the health risks of this have remained unclear because of a lack of information about the hunters' duck, geese, and sportfish consumption habits. A nutritional survey was set up to characterize waterfowl and sportfish consumption in St. Lawrence River duck hunters and to estimate their daily exposure to mercury. During the winter of 2000, 512 hunters selected from the Canadian Wildlife Service database completed a self-administered questionnaire. Daily exposure to contaminants was measured using data from the Canadian Wildlife Service (waterfowl) and available data on St. Lawrence River sportfish. The annual average consumption was 7.5 meals of ducks and geese and 8.7 meals of sportfish. The daily exposure to mercury related to waterfowl consumption was below the Canadian tolerable daily intake (TDI) of 0.47 microg/kg body wt/day for all participants. The daily mercury intake associated with fish consumption was greater than the TDI in 2 duck hunters. The daily exposure to mercury was higher than the TDI in 4 participants when both waterfowl and fish consumption were combined. Our results suggest that fish consumption (especially freshwater fish) represents the main source of exposure to pollutants in duck hunters.

Experimental validation of a statistical model for evaluating the past or future magnetic field exposures of a population living near power lines.

This study was designed to provide an experimental validation for a statistical model predicting past or future exposures to magnetic fields (MF) from power lines. The model estimates exposure, combining the distribution of ambient MF in the absence of power lines with the distribution of past or future MF produced by power lines. In the study, validation is carried out by comparing exposures predicted by the model with the actual measurements obtained from a large-scale epidemiological study. The comparison was made for a group of 220 women living near a 735 kV power line. Knowing that the individual arithmetic means of MF exposures follow a log-normal distribution, the Pearson correlation between the log-transformed measured means and the calculated ones was determined and found to be 0.77. Predicted values of MF exposures were slightly lower than measured values. The calculated geometric mean of the group was 0.33 microT, compared to 0.38 microT for the measured geometric mean. The present study shows good agreement between the measured MF exposure of an individual inside a house near a 735 kV line and the MF exposure calculated using a statistical model.