Yves Levi

Estimation of illicit drugs consumption by wastewater analysis in Paris area (France)

Illicit drugs consumption is actually an important public health concern that needs to be well defined to be managed. A new method, expressed as sewage epidemiology has been proposed by Daughton and developed by Zuccato. This method involves estimating the consumption from the measurement of drug residues in sewage. Several studies have been carried out, leading to an assessment of drugs consumption in some European countries. This work, carried out in Paris area (France) brings new data to this assessment and allows a comparison of cocaine and MDMA consumptions with European estimations. Four wastewater treatment plants (WWTPs) have been retained for the study, taking into account biological treatment, volume capacity, geographic location and social environment. Cocaine and its major metabolite benzoylecgonine (BZE), amphetamine, 3,4-methylenedioxymethamphetamine (MDMA) and buprenorphine were measured in raw water and WWTP effluent using HPLC-MS/MS after SPE extraction. Amphetamine was rarely detected. Cocaine and BZE were quantified at levels from 5 to 282 ng L(-1) and 15 to 849 ng L(-1), respectively. MDMA and buprenorphine concentrations remained under 20 ng L(-1). Cocaine consumption was estimated from cocaine or BZE concentrations measured in raw water and the results showed significant difference in drug taking during week or weekend. The estimated doses observed in this study are lower than those reported for others countries, especially Spain and Italy. MDMA consumption was estimated at lower levels than cocaine.

An ATP-based method for monitoring the microbiological drinking water quality in a distribution network

The titration of adenosine triphosphate (ATP) by bioluminescence permits rapid evaluation of the quantity of viable micro-organisms present in a water sample. During two sampling campaigns, Société Anonyme de Gestion des Eaux de Paris (SAGEP) tested a new extraction and titration system of bacterial ATP in the Paris drinking water distribution network. As far as the entire set of results of analyses of water in the network is concerned there is a linear relationship between log [ATP] and log(HPC-R2A/ml). Furthermore, as regards the drinking water originating from treatment of surface waters, some of the results obtained indicate a slight change as regards the Paris network in the microbiological quality. This is certainly linked to the distance travelled from the production location as well as to a reservoir effect observed on a site. Conversely, no change is apparent with regard to waters of underground origin. Lastly, despite changes in temperature and chlorine residual, no significant influence has been observed, essentially because of the very low density of culturable bacteria.

In vitro assessment of thyroid and estrogenic endocrine disruptors in wastewater treatment plants, rivers and drinking water supplies in the greater Paris area (France).

The presence of estrogenomimetic compounds in the environment, and particularly in water resources, is well known. In contrast, little data is available about the disruption of the thyroid system, even though thyroid hormones are strongly involved in regulating metabolism, growth and development. The aim of this study was to carry out a parallel evaluation of the disruptions of thyroid and estrogenic hormone receptor transcriptional activities, induced by water samples from two wastewater treatment plants (WWTPs), in the river Seine, and from four drinking treatment plants located in the Paris area. Two in vitro bioassays were used for the evaluation of thyroid (PC-DR-LUC) and estrogenic (MELN) disruption. Our observations of thyroidal activity show that a disruption potential was only present in the WWTPs influents, whereas estrogenicity was systematically detected in both influents and effluents. The great majority of endocrine activity was removed during the biological process. In the river Seine, only estrogenicity was detected, and no activity was observed in drinking water supplies. Fractionation of the influents revealed that most of the thyroidal effect was associated with compounds with low polarity, and could be partly attributable to 4-nonylphenol.

Chlorine demand of biofilms in water distribution systems

Abstract Fixed biomass (biofilms) chlorine demand, produced from 3 test waters, is studied by the means of two methods: directly on colonized plastic beads and indirectly on biomass extracted after sonication. The first method results show that a steady state of biomass formation can be reached after an incubation period depending on test water quality. At steady state biofilms chlorine demand increases linearly with BDOC of water and increases according to the ratio surface/volume. The second method results show that extracted biomass chlorine demand is related with protein concentration and heterotrophic plate counts level in the extracts.

A colorimetric and fluorometric microplate assay for the detection of microcystin-LR in drinking water without preconcentration

Protein phosphatase inhibition assays currently used for the detection of cyanobacterial peptide hepatotoxins in drinking water require an enrichment step using C18 cartridges to achieve lower the detection limit. This paper describes a colorimetric and fluorometric protein phosphatase inhibition method for the direct detection of microcystin-LR (MCYST-LR) in drinking water without complex clean-up steps and preconcentration procedures. In this assay three different substrates, p-nitrophenyl phosphate (p-NPP) and two fluorogenic compounds, 4-methylumbelliferyl phosphate (MUP) and 6,8-difluoro-4-methylumbelliferyl phosphate DiFMUP), were tested. The detection limits of the assay are 0.25 and 0.1 microg/l using colorimetric and fluorometric methods, respectively. These levels are well below the provisional guideline value for MCYST-LR of 1 microg/l of drinking water. The detection limit of the fluorometric method is comparable to that of the classical ELISA test. Although both the latter tests allow the detection of MCYST-LR in drinking water directly without pretreatment, the protein phosphatase inhibition assay remain less expensive and therefore more attractive for use in the routine assessment of drinking water contamination by microcystins.

Dynamic modelling of bacterial growth in drinking water networks

Abstract Numerous biological and physicochemical reactions take place in drinking water distribution systems, and give rise to phenomena whereby the organoleptic or bacteriological characteristics of the distributed water are modified. Drinking water may contain residual biodegradable dissolved organic compounds which provide a primary source for the formation of a trophic chain inside the pipes. Bacterial biomasses develop mainly on the internal surface of the pipes, where they are relatively well protected from the action of chlorination agents. The detachment of these biomasses is responsible for most of the bacterial proliferation observed in water samples taken in distribution systems, and also contributes to the installation of undesirable metazoea such as Asellus aquaticus . Combatting these biological developments calls for the application of preventive and remedial treatments, and these can be studied more closely by the use of modelling. This article proposes a model for the study of the behaviour of bacterial biomasses in distribution networks, taking into account the various major parameters which govern their structure, such as the ratio of biodegradable dissolved organic carbon (BDOC), temperature, residual chlorine, pH and the hydraulic conditions of each pipe. The model makes use of the data supplied by the Piccolo hydraulic modelling software, which can provide predictive mapping of the situation of each section of the network. What is more, by taking into account the physicochemical and biological variations in the water at the intake to the network, this dynamic model forecasts the evolution of the variables depending on residence time but also on time, thus enabling better visualisation of a disruption in the system in real time. We discuss the influence of the expression of the detachment of fixed bacteria on solutions of the system of differential equations. Use of the model reveals threshold values of temperature and BDOC which can enable a natural limitation of bacterial biomasses in the network without the use of chlorine.

Free chlorine consumption induced by cast iron corrosion in drinking water distribution systems

Among the various causes of chlorine consumption in drinking water distribution networks, corrosion has not been so far seriously considered. This work focused on the corrosion study of cast iron, as a representative material of those networks, by both electrochemical methods (steady-state curves, corrosion potential and electrochemical impedance data) and classical photograph observations in the absence and in the presence of chlorine. From impedance results and photographs, a scheme of the different corrosion products layers, that is based on the de Levies theory, is proposed. By fitting this physical model to experimental impedance diagrams, the anodic charge transfer resistance can be extracted and thus a reliable value of the corrosion rate can be given. The general conclusion is that free chlorine is not electrochemically consumed at the metal surface though it is more easily reducible than oxygen. Therefore, the corrosion of cast iron pipes induces only a chemical decay of chlorine corresponding to its reaction with ferrous ions released by iron dissolution and the total consumption rate is exactly obtained from the corrosion current density.

Seasonal variation of microcystin concentrations in the Saint-Caprais reservoir (France) and their removal in a small full-scale treatment plant

At the Saint-Caprais reservoir (France), a mono-specific bloom of Aphanizomenon flos-aquae occurs every year in the autumn months. Levels of microcystin-LR (MCYST-LR) in this reservoir were evaluated by protein phosphatase type 2A (PP2A) inhibition test as MCYST-LR equivalents in both raw and drinking water. Analysis by HPLC of the crude extract of the mono-specific bloom of A. flos-aquae revealed the presence of MCYST-LR with a low concentration of 270.3 +/- 20.4 ng/g wet weight. MCYST-LR equivalent concentrations in raw water were correlated with the cyanobacteria biomass and they varied between 14 and 74 ng/l. The removal of A. flos-aquae and microcystins were evaluated in a small full-scale plant associated with the Saint-Caprais reservoir. Total elimination of cyanobacterial cells and the low concentration of hepatotoxins was achieved through the combined action of pre-ozonation at 0.07 mg/l and adsorption on powdered activated carbon at 20 mg/l. However, pre-chlorination at 0.42 mg/l followed by 20 mg/l of powdered activated carbon removed only 45% of hepatotoxins.

Fractionation of dissolved organic matter from surface waters using macroporous resins

Abstract To obtain fractions enriched with biodegradable dissolved organic carbon (BDOC) or with organic compounds responsible for the chlorine demand (CID) and for trihalomethane formation potential (THMFP), Seine river water samples were percolated on various macroporous resins (anionic, cationic and non-ionic) and compared with granulated activated carbon (GAC). In addition, measurement of UV absorbance at 254 nm and the fluorescence index (λexcitation 320 nm) had allowed to follow up the retention of dissolved organic matter by the different adsorbants. In contrast to cationic and non-ionic resins, anionic resins confirm their excellent retention capacity of organic compounds responsible for UV 254 absorbance and fluorescence index. The relative values of BDOC/DOC ratio (mg-C/mg-C) are slightly increased in the effluents of anionic resins, indicating that they retain a little preferentially the refractory fraction instead of the biodegradable fraction. There is no significant difference between the ratio of CID/DOC (mg-Cl2/mg-C) in influent and effluent of anionic resins. Cationic resin has a low capacity for retention of DOC, but they seem to retain significantly the organic compounds responsible for CID. The capability of anionic resins to retain THMFP is similar to that of GAC.

Modeling of hospital wastewater pollution by pharmaceuticals: first results of Mediflux study carried out in three French hospitals

A study has been carried out in three French hospitals in order to assess and model the pharmaceutical load in hospital wastewater and its impact in WWTP. This study, called Mediflux, consisted of three successive steps: first, an original prioritization procedure developed in our laboratory enabled us to select a list of relevant molecules from different Anatomical Therapeutic Chemical (ATC) classes containing pharmaceuticals for specific hospital use such as anesthetics or antineoplastic agents and pharmaceuticals dispensed in the community. Then, analytical quantification procedures were developed and validated according to 2002/657/EC European directive. Sampling campaigns were performed in three different hospitals, two located in the Paris area and one in a medium-sized city 150 km from Paris. Sampling was also carried out in wastewater treatment plants. At the same time, in order to model the pharmaceutical loads from hospitals, predicted concentrations were calculated as a first approach assuming it would be a single-box model, i.e. hospitals have no effect on drug loads and only human metabolism is taken into account to evaluate the fraction of drugs eliminated in hospital effluent. In the last step, the comparison of measured and calculated concentrations showed a satisfactory correlation for some pharmaceuticals, mainly those with short elimination half-lifes and weak human metabolism. For others, it appeared that modeling should take into account various factors such as out patient use, pharmacokinetic data and molecule stability in wastewater.