Occurrence of 95 pharmaceuticals and transformation products in urban groundwaters underlying the metropolis of Barcelona, Spain

The present paper presents the occurrence of 72 pharmaceuticals and 23 transformation products (TPs) in groundwaters (GWs) underlying the city of Barcelona, Spain. Thirty-one samples were collected under different districts, and at different depths. Aquifers with different geologic features and source of recharge were included, i.e., natural bank filtration, infiltration from wastewater and water supply pipes, rainfall recharge, etc. Antibiotics were the most frequently found compounds detected at levels reaching 1000 ng L(-1). Natural bank filtration from the river that receives large amounts of effluents from waste water treatment plants (WWTPs), turned out being the most influencing source of contamination, thus GW showed high range of compounds and concentrations as high as or even higher than in the river itself. In general, TPs were found at lower concentrations than the corresponding parent compounds, with some exceptions, such as 4OH propranolol and enalaprilat.

Occurrence and distribution of multi-class pharmaceuticals and their active metabolites and transformation products in the Ebro river basin (NE Spain)

The present work reports the occurrence of pharmaceuticals and their metabolites and transformation products (TPs) in the Ebro river basin (NE Spain). Twenty-four samples of water collected along the basin were analysed using a fully automated method based on on-line turbulent chromatography-liquid chromatography-tandem mass spectrometry (TFC-LC-MS/MS). In total, 17 metabolites, 7 of them with remaining pharmacologic activity, and 2 transformation products, along with 58 parent pharmaceuticals are analysed. Metabolites and TPs were found at concentrations of the same order of magnitude as their corresponding parent pharmaceuticals, with the exception of 10,11-epoxi-carbamazepine which was found at approximately 10 times higher concentration than its corresponding parent pharmaceutical carbamazepine. In general, levels of all target compounds were below 100 ng L(-1), with the exception of 14 compounds; among them the aforementioned 10,11-epoxicarbamazepine with a maximum concentration of more than 1600 ng L(-1). The analgesic propyphenazone, the psychiatric drug carbamazepine, the antibiotics clarithromycin and sulfadiazine, the cardiovascular drug propranolol, the antineoplastic tamoxifen and 1 pharmacologically active metabolite salicylic acid were found to be ubiquitous (detected in all samples). Smaller tributaries generally show higher concentrations than the main river Ebro, due to lower dilution of WWTP effluents discharged.

Atorvastatin up-regulate toxicologically relevant genes in rainbow trout gills

There are large and increasing discharges of statins into the aquatic environment. Statins are cholesterol-lowering pharmaceuticals, inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A reductase, an enzyme in the cholesterol synthesis pathway. Earlier studies have shown that statins will affect the expression of a range of genes in mammalian tissues and this group of pharmaceuticals has also been shown to affect membrane transporters. Changes in gene expression and ion transport in aquatic organisms may have dramatic consequences for the individual. The aim of the present study was to clarify whether waterborne exposure to a selected statin, atorvastatin, would affect gene expression in rainbow trout (Oncorhynchus mykiss) gill or liver or ion regulation in gills. Juvenile rainbow trout were exposed to two atorvastatin acid and atorvastatin lactone concentrations for 7 days (nominal concentrations 200 ng L(-1) and 10 μg L(-1)). The exposures caused up-regulated gene expression in gill, not liver, and only at the lowest concentration. Genes involved in membrane transport (pgp, mrp1), oxidative stress response (sod, mt), apoptosis (bax) and biotransformation (sult2b) were differentially expressed whereas the expression of genes involved in cholesterol biosynthesis (hmgr, fdps) or peroxisomal proliferation (ppar) were not affected. There were no significant changes in gill Na(+)/K(+) ATPase activity following exposure to atorvastatin. The pattern of differentially expressed genes in rainbow trout gills differ from responses previously observed in mammalian tissues following statin exposure.

[Pharmaceuticals as pollution]

The pharmaceuticals we humans use to treat illness and disease typically enter the aquatic environment via the sewer network and wastewater treatment works. Understanding the risks posed to the aquatic environment by these chemicals requires an understanding of the concentrations that exist in the environment and whether they are sufficiently high to have adverse effects on aquatic organisms. The main source of pharmaceuticals to wastewater treatment works is pharmaceuticals used by the general population. Only a small contribution is believed to come from hospitals. The predicted environmental concentrations of pharmaceuticals suggest that certain pharmaceuticals may pose a risk to the environment, but measurement of the actual concentrations present in effluents and recipient waters suggest that sophisticated wastewater treatment is effective for significantly reducing effluent concentrations, and that environmental concentrations of pharmaceuticals, in the Oslo Fjord, for example, are generally low. Humans also excrete the metabolites of the pharmaceuticals that they have used and these too may be released into the environment, sometimes in greater concentrations than the parent drug. The occurrence of most pharmaceuticals and their metabolites in the environment poses little acute environmental risk. However, the effects of long-term chronic exposure to these compounds are still poorly understood and the long-terms risks to the environment are still not clear. What is clear is that certain pharmaceuticals pose a greater environmental risk than others, and that where possible this knowledge should be used to inform users of more environmentally friendly alternatives.

An activated sludge modeling framework for xenobiotic trace chemicals (ASM-X): assessment of diclofenac and carbamazepine

Conventional models for predicting the fate of xenobiotic organic trace chemicals, identified, and calibrated using data obtained in batch experiments spiked with reference substances, can be limited in predicting xenobiotic removal in wastewater treatment plants (WWTPs). At stake is the level of model complexity required to adequately describe a general theory of xenobiotic removal in WWTPs. In this article, we assess the factors that influence the removal of diclofenac and carbamazepine in activated sludge, and evaluate the complexity required for the model to effectively predict their removal. The results are generalized to previously published cases. Batch experimental results, obtained under anoxic and aerobic conditions, were used to identify extensions to, and to estimate parameter values of the activated sludge modeling framework for Xenobiotic trace chemicals (ASM-X). Measurement and simulation results obtained in the batch experiments, spiked with the diclofenac and carbamazepine content of preclarified municipal wastewater shows comparably high biotransformation rates in the presence of growth substrates. Forward dynamic simulations were performed using full-scale data obtained from Bekkelaget WWTP (Oslo, Norway) to evaluate the model and to estimate the level of re-transformable xenobiotics present in the influent. The results obtained in this study demonstrate that xenobiotic loading conditions can significantly influence the removal capacity of WWTPs. We show that the trace chemical retransformation in upstream sewer pipes can introduce considerable error in assessing the removal efficiency of a WWTP, based only on parent compound concentration measurements. The combination of our data with those from the literature shows that solids retention time (SRT) can enhance the biotransformation of diclofenac, which was not the case for carbamazepine. Model approximation of the xenobiotic concentration, detected in the solid phase, suggest that between approximately 1% and 16% of the total solid carbamazepine and diclofenac concentrations, respectively, is due to sorption-the remainder being non-bioavailable and sequestered. We demonstrate the effectiveness of the model's predictive power over conventional tools in a statistical analysis, performed at four levels of structural complexity. To assess WWTP retrofitting needs to remove xenobiotic trace chemicals, we suggest using mechanistic models, e.g., ASM-X, in regional risk assessments. For preliminary evaluations, we present operating charts that can be used to estimate average xenobiotic removal rates in WWTPs as a function of SRT and the xenobiotics mass loads normalised to design treatment capacity.

Enzymatic and microbial transformation assays for the evaluation of the environmental fate of diclofenac and its metabolites

Diclofenac has been of environmental concern due to the potential harmful effects on non-target organisms at environmentally relevant concentrations. In this study, we evaluated the transformation kinetics of diclofenac and its two major metabolites in two laboratory-scale experiments: the transformation of diclofenac in the presence of rat liver S9 fraction with co-factors, and the transformation of diclofenac, 4'-hydroxy-diclofenac and diclofenac β-O-acyl glucuronide in the inoculum used for the OECD 301C ready-biodegradability test. 4'-Hydroxy-diclofenac was identified as the major phase I metabolite and diclofenac β-O-acyl glucuronide was identified as the major phase II metabolite in the S9 assay. Transformation of diclofenac in the microbial degradation test did not occur significantly for 28 d, whereas 4'-hydroxy-diclofenac degraded slowly, indicating that the biological removal of diclofenac is not likely to occur in conventional STPs unless sorptive removal is significant. However, diclofenac β-O-acyl glucuronide deconjugated to form equimolar diclofenac within 7 d, in the microbial degradation test. The mixture of diclofenac and its two metabolites, formed after incubating diclofenac in S9 medium for 2 h, was spiked in the inoculum to link both assays. The concentrations of diclofenac and its metabolites, measured over time, agreed well with predicted values, using rate parameters obtained from independent experiments. The results show that phase II metabolites generated in mammals may deconjugate easily in conventional STPs to form a parent compound and that these processes should be considered during the environmental monitoring and risk assessment of diclofenac.

Anticancer drugs in surface waters: what can we say about the occurrence and environmental significance of cytotoxic, cytostatic and endocrine therapy drugs?

This study considers the implications and research needs arising from anticancer (also referred to as antineoplastic) drugs being released into the aquatic environment, for the entire therapeutic classes used: cytotoxic, cytostatic and endocrine therapy drugs. A categorization approach, based on French consumption amounts, allowed to highlight parent molecules and several metabolites on which further occurrence and ecotoxicological studies should be conducted. Investigations of consumption trends at a national and a local scale show an increase in the use of anticancer drugs between 2004 and 2008, thus leading to increased levels released in the environment. It therefore appears necessary to continue surveying their presence in surface waters and in wastewater treatment plant (WWTP) effluents. Furthermore, due to the rise of anticancer home treatments, most of the prescribed molecules are now available in town pharmacies. Consequently, hospital effluents are no longer the main expected entry route of anticancer drugs into the aquatic environment. Concerning ecotoxicological risks, current knowledge remains insufficient to support a definitive conclusion. Risk posed by cytotoxic molecules is still not well documented and it is not possible to conclude on their long-term effects on non-target organisms. To date, ecotoxicological effects have been assessed using standardized or in vitro assays. Such tests however may not be suitable for anticancer drugs, and further work should focus on full-life cycle or even multigenerational tests. Environmental significance (i.e. occurrence and effects) of cytostatics (protein kinases inhibitors and monoclonal antibodies), if any, is not documented. Protein kinases inhibitors, in particular, deserve further investigation due to their universal mode of action. Finally, concerning endocrine therapy drugs, molecules such as antiestrogen Tamoxifen and its active metabolites, could be of concern. Overall, to accurately assess the ecotoxicological risk of anticancer drugs, we discuss the need to break away from tests on isolated molecules and to test effects of mixtures at the low ng.l(-1) range.

Species-dependent sensitivity to contaminants: an approach using primary hepatocyte cultures with three marine fish species

There is limited knowledge about the sensitivity of different fish species to environmental pollutants. Such information is pivotal in risk assessment and to understand why some species appear to be more tolerant to contaminants than others. The aim of the current study was to evaluate whether primary hepatocyte cultures of three marine fish species could be established in the field and whether their sensitivity to selected contaminants would differ. Primary hepatocyte cultures of three marine fish species (plaice, long rough dab, Atlantic cod) were established and exposed for 24 h to copper (20-2500 mg L⁻¹) and statins (1-200 mg L⁻¹). Endpoints were esterase activity, metabolic activity and reduced glutathione (GSH) content, all using fluorescent probes. Flatfish hepatocytes were more susceptible to copper and statin exposure than hepatocytes from cod. This study has shown that species-dependent differences in contaminant sensitivity can be investigated using primary hepatocyte cultures.