Yves Perrodin

Groundwater contamination by microbiological and chemical substances released from hospital wastewater: Health risk assessment for drinking water consumers

Contamination of natural aquatic ecosystems by hospital wastewater is a major environmental and human health issue. Disinfectants, pharmaceuticals, radionuclides and solvents are widely used in hospitals for medical purposes and research. After application, some of these substances combine with hospital effluents and, in industrialised countries, reach the municipal sewer network. In certain developing countries, hospitals usually discharge their wastewater into septic tanks equipped with diffusion wells. The discharge of chemical compounds from hospital activities into the natural environment can lead to the pollution of water resources and risks for human health. The aim of this article is to present: (i) the steps of a procedure intended to evaluate risks to human health linked to hospital effluents discharged into a septic tank equipped with a diffusion well; and (ii) the results of its application on the effluents of a hospital in Port-au-Prince. The procedure is based on a scenario that describes the discharge of hospital effluents, via septic tanks, into a karstic formation where water resources are used for human consumption. COD, Chloroform, dichlomethane, dibromochloromethane, dichlorobromomethane and bromoform contents were measured. Furthermore, the presence of heavy metals (chrome, nickel and lead) and faecal coliforms were studied. Maximum concentrations were 700 NPP/100 ml for faecal coliforms and 112 mg/L for COD. A risk of infection of 10(-5) infection per year was calculated. Major chemical risks, particularly for children, relating to Pb(II), Cr(III), Cr(VI) and Ni(II) contained in the ground water were also characterised. Certain aspects of the scenario studied require improvement, especially those relating to the characterisation of drugs in groundwater and the detection of other microbiological indicators such as protozoa, enterococcus and viruses.

Daily physicochemical, microbiological and ecotoxicological fluctuations of a hospital effluent according to technical and care activities

The problem of hospital effluents falls into the framework of hazardous substances due to the specific substances used and discharged for the most part into urban drainage networks without prior treatment. This in-depth study has led to greater understanding of the effluents discharged by hospitals. The experimental program implemented consisted in carrying out parallel sampling of the effluents of one hospital: a 24 h-average sample and 5 periodic samples corresponding to fractions of times and hospital activities. The samples were characterized by physicochemical, microbiological and ecotoxicological analyses. The results highlight that the effluents contained very little bacterial flora and a moderate organic pollution. However, a numerous of specific pollutants were detected: AOX, glutaraldehyde, free chlorine, detergents, Freon 113 as well as alcohols, acetone, formaldehyde, acetaldehyde, ammonium, phenols and several metals. The battery of bioassays showed that the effluents had a high level of ecotoxicity partly linked to particles in suspension and, that pollution fluctuated greatly during the day in connection with hospital activities. Finally, the PNEC values compared to the concentrations of pollutants dosed in the effluents highlighted that their toxicity was mainly due to several major pollutants, in particular free chlorine. Some hypotheses require additional experiments to be carried out. They concern: reactions of fermentations likely to occur in the drainage network and to form secondary toxic compounds, retention of chlorine by particles and physicochemical characterization of suspended solids.

Identification and prioritization of bioaccumulable pharmaceutical substances discharged in hospital effluents.

The consumption of pharmaceuticals and their excretion in wastewater is a continuous source of pollution for aquatic ecosystems. In certain cases these compounds are found in the environment at concentrations high enough to cause disturbance in aquatic organisms. Aware of this problem hospitals are giving increasing attention to the nature of their effluents and their impact on the environment, by implementing more efficient effluent management policies. This concern is justified in view of the large volumes of toxic products consumed (detergents, disinfectants, pharmaceuticals, chemical reagents, radioactive elements, etc.). Moreover, these effluents usually do not undergo any specific treatment before being discharged into urban sewage networks. In this article, we present a method for selecting the pharmaceuticals discharged in hospital effluents that have the worst impact on the aquatic ecosystem, primarily based on their bioaccumulation potential. This study focused on the pharmaceuticals consumed at the Hospices Civils de Lyon (HCL), the second largest hospital structure in France (5200 hospital beds). Of the 960 substances consumed in HCL hospitals, a shortlist of 70 substances considered as being potentially bioaccumulable was established. The use of aggravating factors of risk has then led to the final selection of 14 priority compounds. They include 4 compounds consumed in large quantities in HCL hospitals, 6 endocrine disruptors and 4 potentially ecotoxic compounds. For all these compounds, it is now advisable to verify their bioaccumulation potential experimentally and confirm their presence in the environment. In addition, in order to monitor the risk relating to possible contamination of the food chain, it will be necessary to measure accumulated dose levels in species of different trophic levels. Lastly, chronic ecotoxicity tests will permit evaluating the danger and risk that some of these substances may represent for aquatic ecosystems.

Interactions between a polycyclic aromatic hydrocarbon mixture and the microbial communities in a natural freshwater sediment

The toxicity of a polycyclic aromatic hydrocarbon (PAH) mixture was assessed on the indigenous microbial communities of a natural freshwater sediment. The fate and effects of the PAH mixture (phenanthrene, fluoranthene and benzo(k)fluoranthene) were studied over 28 days. Bacterial communities were described by bacterial counts (total bacteria and viable bacteria), and by some hydrolytic enzyme activities (beta-glucosidase and leucine-aminopeptidase), PAH concentrations were measured in the overlying waters and in the sediments. No effect of PAH was detected at 30 mg/kg for all bacterial parameters. At 300 mg/kg, the quantity of total bacteria and the proportion of viable bacteria markedly decreased, compared to the control (0 mg PAH/kg). At 300 mg/kg, an increase of the beta-glucosidase activity and a decrease of the leucine-aminopeptidase activity were observed. For all treatments, the benzo(k)fluoranthene concentration in the sediment was stable over 28 days whereas, in the same time, only 3-6% of the initial concentrations of phenanthrene and fluoranthene remained. This study shows that (1) PAH induce perturbations of sediment microbial communities in terms of density and metabolism (but not always as an inhibition), (2) indigenous bacteria of sediments might be used for toxicity assessment of specific organic pollutants, (3) native microorganisms of sediment seem to have a high capacity for PAH degradation, depending on the physico-chemical properties and the bioavailability of the substance encountered.

Assessment of Sediment Ecotoxicity and Genotoxicity in Freshwater Laboratory Microcosms

One possible fate of dredged sediments is disposal in a submerged gravel pit, but this practice may be a source of contamination of the aquatic environment. In an attempt to assess the risks for the aquatic ecosystem, a microcosm test was conducted in the laboratory on three sediments of channel sections to be dredged. After a 3-day period of stabilization, pelagic organisms (microalgae, daphnids, duckweeds, pond snails) and benthic organisms (amphipods, chironomids) were introduced into microcosms. Survival and growth of organisms were monitored during 28 days. Genetic damage was measured weekly in pond snail hemocytes through the comet assay. The sediments contained high levels of metals (up to 740 mg copper/kg and 1220 mg zinc/kg), but were moderately contaminated by PAHs (total PAH content < 10 mg/kg) and PCBs (total PCB content < 0.6 mg/kg). Only moderate effects on the biota were observed, except for genetic damage on pond snail hemocytes which was significant in all microcosms. The absence of pronounced toxic effects on organisms was not expected since concentrations of some sediment toxicants were above threshold values reported in the literature, especially for metals in two sediments, and for PAHs in the three sediments. Speciation, influence of organic matter and presence of sulfides might explain the low toxicity observed. By contrast, assessment of DNA damage revealed to be more sensitive and enabled a ranking of sediments coherent with their toxic load. In the present work, the microcosm protocol previously set up with a formulated sediment appears to be fitted to natural sediments.

Ecological risk assessment of urban and industrial systems: a review.

Numerous ecological risk assessment methodologies have been developed over the last twenty years around the world for evaluating urban and industrial systems and installations, by both the organisations responsible for implementing regulations and the scientific community. Although these methodologies share the general principle underlying their use, they differ widely with respect to the approaches chosen and the resources employed to apply them. Also, they may even have different objectives: prior assessment as part of an impact study before building a new installation, or retrospective assessment, for example, in view to explaining the reasons for an impact recorded or for forecasting additional expected impacts. This article provides a synthesis of the different approaches used around the world for carrying out each of the major steps common to all ecological risk assessment methodologies. The advantages and limitations of these different options are discussed in order to provide elements for formulating any new methodology adapted to a given scenario. To conclude, perspectives for improving the tools required for these methodologies are proposed, and the research works to which priority should be given are identified.

Historical records, sources, and spatial trends of PCBs along the Rhône River (France)

Despite bans on PCB use since 1975 (open systems) and 1987 (closed systems), concentrations of PCBs in riverine fish in France continue to exceed regulatory levels. We present historical records of PCB concentrations in sediment cores from eight sites on the Rhône River, from Lake Geneva to the Mediterranean Sea. Maximum PCB concentrations (sum of seven indicator PCBs) increase downstream, from 11.50 μg/kg at the most upstream site to 417.1 μg/kg at the most downstream site. At some sites peak concentrations occur in sediment deposited as recently as the 2000s. Hierarchical clustering (five clusters) identified differences in PCB congener profiles within and between sites. Exponential models fit to decadal time windows indicate that rapid reductions in concentrations during about 1990-2000 have slowed, and that it might be decades before target concentrations in sediment that correspond to regulatory thresholds in fish will be reached at some sites.

Human health risk assessment of lead in drinking water: a case study from Port-au-Prince, Haiti

In Latin America and the Caribbean (LAC), human intoxication to lead is considered as an important public health issue. In Port-au-Prince, concentrations of lead ranging from 40 ?g/L to 90 ?g/L, greater than the threshold value (10 ?g/L) for drinking water, were measured in groundwater and drinking water. This study aims to assess human health risks generated by exposure to lead in the Port-au-Prince water supply. Two sampling campaigns were performed between April 2004 and December 2004 on different structures of the public water supply. A significant lead concentration of 250 ?g/L, greater than the threshold value, had been detected in a water tank. Risk of deterioration of the psychological development of children exposed to these waters was calculated. These results require monitoring in order to control the human health risk by lead in Port-au-Princes drinking water.

A posteriori assessment of ecotoxicological risks linked to building a hospital.

Hospital wastewater (HWW) contain a large number of chemical pollutants such as disinfectants, surfactants, and pharmaceutical residues. A part of these pollutants is not eliminated by traditional urban wastewater treatment plants (WWTP), leading to a risk for the aquatic ecosystems receiving these effluents. In order to assess this risk, we formulated a specific methodology based on the ecotoxicological characterisation of the hospital wastewater using a battery of three chronic bioassays (Pseudokirchneriella subcapitata, Heterocypris incongruens and Brachionus calyciflorus). We used it for the posteriori risk assessment of a hospital recently built in south-east France, and we studied the evolution of this risk during two years. We also used it to assess the decrease of the ecotoxicological risk after treatment of the effluent in a specific line of the local WWTP. Lastly, we compared these results with the risk assessment made before the building of the hospital in the context of a priori risk assessment. The results obtained showed an important evolution of the risk overtime, according to the hospital activities and the river flows, and a real decrease of the risk after treatment in the dedicated line. They also showed that the a priori assessment of ecotoxicological risks, made previously, was overstated, mainly because of the application of the precautionary principle.

Environmental behaviour of a construction made of a mixture of hydraulic binders and air pollution control residues from municipal solid waste incineration Part 1. Physico-chemical characterisation and modelling of the source term

Abstract The reuse of waste materials requires the development of assessment methods for the long-term release of pollutants (source term) from wastes (or materials containing wastes) in contact with water. These methods depend on the scenario conditions: characteristics of the materials (especially physical structure and composition), contact with water. The scenario studied here is a water storage reservoir for fire fighting. The reservoir construction is made of a mixture of hydraulic binders and air pollution control (APC) residues from a municipal solid waste incinerator (MSWI). The modelling of the source term is performed in 5 steps ranging from the physico-chemical characterisation of the material to the validation of the proposed model by means of field simulation devices. This article presents the first steps of the methodology: physico-chemical characterisation of the source term, identification of the main transfer mechanisms and laboratory scale modelling of the source term. During the physico-chemical characterisation, it has been shown that the solidified waste shows a high basic capacity and that a relative decrease in pH during leaching favours retention of the main pollutants. During the first leaching sequences, the dynamic leaching tests show that the release of pollutants such as cadmium, arsenic, zinc and lead is extremely low but that the release of alkaline species (sodium and potassium) and chloride is very high from the beginning, whereas the release of calcium remains very high even after 3600 h of leaching. Identification of the main transfer mechanisms concludes that the release of soluble pollutants is the combined result of diffusional transfer of pollutants in the solution and the physico-chemical specificity of the species. The modelling based on these features enables a good simulation of the release but reveals a deviation from the experimental results after 500 h for alkaline species and 1000 h for Ca and Cl leaching. However, this deviation only appears after release of the major part of these elements.