Health risk of swimming pool disinfection by-products: a regulatory perspective.

While disinfection of swimming pools is indispensable for microbiological safety, it may lead to the formation of disinfection by-products. Most studies agree that inhalation exposure is the predominant pathway of the associated health risks, but assumptions are based on concentrations measured in water and evaporation models. Pool water and air were sampled in 19 swimming pools. Trihalomethanes were detected in all sites; chloroform being the most abundant species. Concentrations ranged between 12.8-71.2 µg/L and 11.1-102.2 µg/m3 in pool water and air, respectively. The individual lifetime carcinogenic risk associated with chloroform in swimming pools exceeded 10-6 in all age groups for recreational swimmers and 10-5 for elite swimmers and staff, even if the pool complied with the national standards. Inhalation exposure was estimated and found to be the most relevant, however, different mass transfer models from water measurements significantly under- or overestimated the health burden compared to direct calculation from the concentration in air. The observed health risks call for defining regulatory values and monitoring requirement of indoor air quality in swimming pools.

Pathogenic and phylogenetic features of 2 multiresistant Pseudomonas aeruginosa strains originated from remediated sites.

OBJECTIVES: To evaluate the possible occupational hazard of environmental strains of opportunistic Pseudomonas aeruginosa on hydrocarbon contaminated sites during remediation, 2 multidrug-resistant isolates originating from environmental (soil and groundwater) samples were examined. MATERIAL AND METHODS: Antibiotic resistance profiles of the examined 2 strains were determined by Etest® against 20 different agents. Virulence investigations included the hemolytic activity test, the detection of virulence-related gene sequences such as exoA, exoU, exoS, exoY, exoT and the determination of intraperitoneal LD50 (the lethal dose, 50%) values in a mouse model. The hydrocarbon-degrading ability was evaluated in a gravimetric experiment, in vitro. The phylogenetic relationship of the isolates was investigated with a multilocus sequence typing scheme. RESULTS: Multidrug resistant environmental strains of P. aeruginosa are strongly related to isolates that have proven effects on the infection of patients who suffer from cystic fibrosis, have a notable hemolytic activity, carry important virulence markers (exoS or exoU, respectively) and retain their hydrocarbon degradation ability (87.4% and 62.8% hydrocarbon degradation rate, respectively). CONCLUSIONS: Pseudomonas aeruginosa presumably raise considerable concerns for human health in the environment, already well known among nosocomial isolates, and the application of environmental strains of this species for environmental purposes is questionable.

Potential toxic effects of iron oxide nanoparticles in in vivo and in vitro experiments.

The aim of this study was to determine the potential toxic effects of iron(II,III)oxide nanoparticles (IONPs). In in vivo experiments, the toxic effects of IONPs were monitored in adult male Wistar rats by morphological methods after a single intratracheal instillation. For the control group 1 ml of physiological saline per animal was given, and the treatment group received the same volume of a suspension containing 1 and 5 mg kg⁻¹ body weight IONPs. Lungs and internal organs underwent histopathological examination after 1, 3, 7, 14 and 30 days. The mutagenic effect of these nanoparticles was evaluated by the bacterial reverse mutation assay on Salmonella typhimurium TA98, TA100, TA1535 and TA1537 strains, and on Escherichia coli WP2uvrA strain, in the presence and absence of the mammalian metabolic activation system S9. The in vitro cytotoxic effect of IONPs was also examined in Vero cells after short-term (4 h) and long-term (24 h) exposure. There were no pathological changes in examined internal organs, except a very weak pulmonary fibrosis developing by the end of the first month in the treated rats. While in vitro MTT assay showed a moderate cytotoxic effect, IONPs proved to be devoid of mutagenic effect in the bacterial systems tested. The results may be a useful extension of our knowledge on the safety of magnetite nanoparticles in view of their possible medical applications, such as in hyperthermia and magnetic resonance imaging.

Environmental health aspects of drinking water-borne outbreak due to karst flooding: case study.

Climate change may increase the incidence of waterborne diseases due to extreme rainfall events, and consequent microbiological contamination of the water source and supply. As a result of the complexity of the pathways from the surface to the consumer, it is difficult to detect an association between rainfall and human disease. The water supply of a Hungarian city, Miskolc (174,000 inhabitant), is mainly based on karstic water, a vulnerable underground water body. A large amount of precipitation fell on the catchment area of the karstic water source, causing an unusually strong karstic water flow and flooding, and subsequent microbiological contamination. The presence of several potential sources of contamination in the protective zone of the karstic water source should be emphasized. The water supplier was unprepared to treat the risk of waterborne outbreak caused by an extreme weather event. Public health intervention and hygienic measures were taken in line with epidemiological actions, focusing on the protection of consumers by providing safe drinking water. The contamination was identified, and measures were taken for risk reduction and prevention. This case study underlines the increasing importance of preparedness for extreme water events in order to protect the karstic water sources and to avoid waterborne outbreaks.

Paediatric environmental health in Hungary.

A review is given on the state of activities regarding environmental health in Hungary, with special respect to present and future health of children.