Toxicity of wastewater from health care facilities assessed by different bioassays.

OBJECTIVES: The purpose of this study was to determine toxicity of wastewater from hospitals in the Czech Republic using traditional and alternative toxicological methods. The pilot study comprised weekly dynamics of sewage ecotoxicity of treated wastewater from one hospital in two different seasons. A detailed investigation of wastewater ecotoxicity, genotoxicity and reprotoxicity followed in five different hospitals. METHODS: The seven following bioassays were used in this study: algal growth inhibition test (ISO 8692), Vibrio fischeri test (ISO 11348-2), Daphnia magna acute toxicity test (ISO 6341), Allium cepa assay, Ames test (OECD TG 471), Comet assay and YES/YAS assay. RESULTS: The wastewater ecotoxicity during one week showed no differences in separate working days, however, higher toxicity values were recorded in May compared to November. In the following study, samples from two of the five hospitals were classified as toxic, the others as non toxic. Genotoxicity has not been confirmed in any sample. In several cases, wastewater samples exhibited agonist activity to the estrogen and androgen receptors. CONCLUSION: The study demonstrated different levels of toxicity of treated hospital wastewater. Variable sensitivity of individual bioassays for tested wastewater samples was recognized. A more extensive study including proposal for improvement of hospital wastewater treatment within the Czech Republic can be recommended with the aim to decrease the discharge of toxic chemicals into the local sewage system and the environment.

Exposure to airborne fungi during sorting of recyclable plastics in waste treatment facilities.

BACKGROUND: In working environment of waste treatment facilities, employees are exposed to high concentrations of airborne microorganisms. Fungi constitute an essential part of them. This study aims at evaluating the diurnal variation in concentrations and species composition of the fungal contamination in 2 plastic waste sorting facilities in different seasons. MATERIAL AND METHODS: Air samples from the 2 sorting facilities were collected through the membrane filters method on 4 different types of cultivation media. Isolated fungi were classified to genera or species by using a light microscopy. RESULTS: Overall, the highest concentrations of airborne fungi were recorded in summer (9.1×103-9.0×105 colony-forming units (CFU)/m3), while the lowest ones in winter (2.7×103-2.9×105 CFU/m3). The concentration increased from the beginning of the work shift and reached a plateau after 6-7 h of the sorting. The most frequently isolated airborne fungi were those of the genera Penicillium and Aspergillus. The turnover of fungal species between seasons was relatively high as well as changes in the number of detected species, but potentially toxigenic and allergenic fungi were detected in both facilities during all seasons. CONCLUSIONS: Generally, high concentrations of airborne fungi were detected in the working environment of plastic waste sorting facilities, which raises the question of health risk taken by the employees. Based on our results, the use of protective equipment by employees is recommended and preventive measures should be introduced into the working environment of waste sorting facilities to reduce health risk for employees. Med Pr 2017;68(1):1-9.

Methods of sampling airborne fungi in working environments of waste treatment facilities.

OBJECTIVES: The objective of the present study was to evaluate and compare the efficiency of a filter based sampling method and a high volume sampling method for sampling airborne culturable fungi present in waste sorting facilities. MATERIAL AND METHODS: Membrane filters method was compared with surface air system method. The selected sampling methods were modified and tested in 2 plastic waste sorting facilities. RESULTS: The total number of colony-forming units (CFU)/m3 of airborne fungi was dependent on the type of sampling device, on the time of sampling, which was carried out every hour from the beginning of the work shift, and on the type of cultivation medium (p < 0.001). Detected concentrations of airborne fungi ranged 2×102-1.7×106 CFU/m3 when using the membrane filters (MF) method, and 3×102-6.4×104 CFU/m3 when using the surface air system (SAS) method. CONCLUSIONS: Both methods showed comparable sensitivity to the fluctuations of the concentrations of airborne fungi during the work shifts. The SAS method is adequate for a fast indicative determination of concentration of airborne fungi. The MF method is suitable for thorough assessment of working environment contamination by airborne fungi. Therefore we recommend the MF method for the implementation of a uniform standard methodology of airborne fungi sampling in working environments of waste treatment facilities.

Occurrence of perchloroethylene in surface water and fish in a river ecosystem affected by groundwater contamination.

Long-term monitoring of the content of perchloroethylene (PCE) in a river ecosystem affected by groundwater contamination was performed at a site in the Czech Republic. The quality of surface water was monitored quarterly between 1994 and 2013, and fish were collected from the affected ecosystem to analyse the content of PCE in their tissue in 1998, 2011 and 2012. Concentrations of PCE (9-140 µg/kg) in the tissue of fish collected from the contaminated part of the river were elevated compared to the part of the river unaffected by the contamination (ND to 5 µg/kg PCE). The quality of surface water has improved as a result of groundwater remediation during the evaluated period. Before the remedial action, PCE concentrations ranged from 30 to 95 µg/L (1994-1997). Following commencement of remedial activities in September 1997, a decrease in the content of PCE in the surface water to 7.3 µg/L (1998) and further to 1 µg/L (2011) and 1.1 µg/L (2012) led to a progressive decrease in the average concentration of PCE in the fish muscle tissue from 79 µg/kg (1998) to 24 (2011) and 30 µg/kg (2012), respectively. It was determined that the bioconcentration of PCE does not have a linear dependence because the decrease in contamination in the fish muscle tissue is not directly proportional to the decrease in contamination in the river water. The observed average bioconcentration factors were 24 and 28 for the lower concentrations of PCE and 11 for the higher concentrations of PCE in the river. In terms of age, length and weight of the collected fish, weight had the greatest significance for bioconcentration, followed by the length, with age being evaluated as a less significant factor.

Bioindicators of wastewater ecotoxicity.

Wastewater, especially containing hospital effluents, exhibits high chemical complexity and specificity since it includes various chemicals, biocides, pharmaceuticals, surfactants, radionuclides, disinfectants and pathogens. Biological tests provide true evidence of the wastewater quality and unlike chemical analytical tests show comprehensive pollution effects on the environment and human health. Normalized conventional bioassays are not sensitive enough for ecotoxicological evaluation of wastewater and there is a great need for the development of suitable sensitive bioassays in order to characterize properly the residual toxicity of treated effluents. Provisions of binding EU legislation regarding protection of animals used for scientific purposes and legislation dealing with test methods for identification and classification of health hazard of chemicals, pharmaceuticals, biocides, medical devices and consumer products such as cosmetics for environmental ecosystems and for man require to employ alternative toxicological methods respecting the 3Rs concept with priority given to methods in vitro. The Fish Embryo Test (FET) is identified as a relevant, reliable and efficient alternative test method in vitro for determination of acute toxicity for fish. Using the FET, additional toxicological endpoints may be investigated to assess organ specific bioaccumulation, genotoxicity and mutagenicity, developmental toxicity, teratogenicity, various forms of neurotoxicity or endocrine disruptivity. The addition of multiparametric sensitive endpoints makes the FET a true alternative in vitro assay and a powerful tool in toxicology.

Genotoxicity of wastewater from health care facilities.

Health care facilities use for therapeutic purposes, diagnostics, research, and disinfection a high number of chemical compounds, such as pharmaceuticals (e.g. antibiotics, cytostatics, antidepressants), disinfectants, surfactants, metals, radioactive elements, bleach preparations, etc. Hospitals consume significant amounts of water (in the range of 400 to 1200 liters/day/bed) corresponding to the amount of wastewater discharge. Some of these chemicals are not eliminated in wastewater treatment plants and are the source of pollution for surface and groundwater supplies. Hospital wastewater represents chemical and biological risks for public and environmental health as many of these compounds might be genotoxic and are suspected to contribute to the increased incidence of cancer observed during the last decades. The changes of the genetic information can have a lethal effect, but more often cause tumor processes or mutations in embryonic development causing serious defects. A review of the available literature on the mutagenicity/genotoxicity of medical facilities wastewater is presented in this article.

The mercury burden of the Czech population: An integrated approach.

In this paper an integrated approach in assessment of the population exposure from various sources of total mercury (THg) oral intake in the Czech Republic is presented. The information on total mercury levels in diet, drinking water, surface urban soil and body fluids and tissues stem from the Czech national Environmental Health Monitoring System (EHMS) operated since 1994. The THg concentration was determined by the special atomic absorption spectrophotometer AMA 254. The data on THg content in food from the sales network were collected in 12 cities. The estimated average dietary intake representing more than 95% of weight of usual diet composition ranged 1-2% of the JECFA/FAO WHO provisional tolerable weekly intake (PTWI) value for total mercury (5 microg/kg b.w./week). Data on drinking water quality stem from the nationwide monitoring database. The content of THg in drinking water is generally low; only 0.2% of the Czech population supplied with drinking water from the distribution networks (total of 92% of the population) has a mercury intake from drinking water higher than 1% PTWI and not exceeding 5% PTWI. The estimation of potential mercury intake by unintentional consumption of soil in small children was based on THg content in surface soil of a total of 324 nursery schools in 24 cities and towns. Median value was 0.16 mg/kg. Human biomonitoring was performed in 9 Czech cities. In 2007, the mercury median values in blood of adults (N=412) were 0.85 and 0.89 microg/l in males and in females, respectively; urine median value in adults was 1.10 microg/g creatinine. In 2008, the blood median value in children (N=324) amounted to 0.35 microg/l; urine median value is 0.16 microg/g creatinine. In children's hair the median THg value was 0.18 microg/g. The correlation between fish consumption and blood THg levels was observed in both adults and children. Also the biomonitoring outputs did not reveal a substantial burden of the population.

Crop-specific human exposure assessment for polycyclic aromatic hydrocarbons in Czech soils.

Polycyclic aromatic hydrocarbons (PAH) are pollutants frequently found in soils, particularly in urban areas. From polluted soils, the PAH can be taken up into crops and the consumption of these crops can result in a human health risk. We estimated the bioconcentration factors (BCF) in the edible plant tissues for PAH using crop-specific models for leafy vegetables, root vegetables, potatoes and tree fruits. The estimates were compared with results from the empirical regression of Travis and Arms (T&A) for above-ground vegetation. The comparison shows that the use of crop-specific models resulted in lower BCF values of pollutant concentrations in fruits, potatoes and leafy vegetables, particularly for the heavier PAH (M>220 g mol(-1)). However, the crop-specific models yielded higher BCF values for root vegetables (carrot) and leafy vegetables if the attached soil particles (1%) were considered. Consequently, the average daily intake of benzo(a)pyrene (BaP) by an adult Czech through fruits and vegetables was estimated with the crop-specific models to be 190 ng BaP per person, and 460 ng BaP per person with the T&A regression, for a soil concentration of 1 mg BaP kg(-1) soil (wet wt.). A virtually safe oral dose of BaP, as a marker of the carcinogenic PAH, was suggested by a European expert commission to be below 4.2 to 35 ng per person and day. Using these figures, an acceptable soil concentration of BaP was estimated for the purpose of crop production to be below 0.02 or 0.18 mg kg(-1) (wet wt.) with the crop-specific models, and below 0.01 or 0.08 mg kg(-1) (wet wt.) with T&A. The results demonstrate clearly the advantage of the crop-specific exposure assessment: it can be adapted to different food baskets and allows more effective risk assessment and management of soil pollution.