Prioritisation of organic contaminants in a river basin using chemical analyses and bioassays

Region-specific contaminant prioritisation is an important prerequisite for sustainable and cost-effective monitoring due to the high number of different contaminants that may be present. Surface water and sediment samples from the Sava River, Croatia, were collected at four locations covering a 150-km-long river section characterised by well-defined pollution gradients. Analysis of contaminant profiles along the pollution gradients was performed by combining toxicity screening using a battery of small-scale or in vitro bioassays, which covered different modes of action, with detailed chemical characterisation based on gas chromatography/mass spectrometry (GC/MS) and liquid chromatography/quadrupole time-of-flight mass spectrometry (LC-QTOF-MS). A large number of contaminants, belonging to different toxicant classes, were identified in both analysed matrices. Analyses of water samples showed that contaminants having polar character occurred in the highest concentrations, while in sediments, contributions from both non-polar and amphiphilic contaminants should be taken into account. Estimated contributions of individual contaminant classes to the overall toxicity indicated that, besides the classical pollutants, a number of emerging contaminants, including surfactants, pharmaceuticals, personal care products and plasticizers, should be taken into consideration in future monitoring activities. This work demonstrates the importance of the integrated chemical and bioanalytical approach for a systematic region-specific pollutant prioritisation. Finally, the results presented in this study confirm that hazard assessment in complex environmental matrices should be directed towards identification of key pollutants, rather than focusing on a priori selected contaminants alone.

Evaluation of uncertainties associated with the determination of community drug use through the measurement of sewage drug biomarkers

The aim of this study was to integrally address the uncertainty associated with all the steps used to estimate community drug consumption through the chemical analysis of sewage biomarkers of illicit drugs. Uncertainty has been evaluated for sampling, chemical analysis, stability of drug biomarkers in sewage, back-calculation of drug use (specific case of cocaine), and estimation of population size in a catchment using data collected from a recent Europe-wide investigation and from the available literature. The quality of sampling protocols and analytical measurements has been evaluated by analyzing standardized questionnaires collected from 19 sewage treatments plants (STPs) and the results of an interlaboratory study (ILS), respectively. Extensive reviews of the available literature have been used to evaluate stability of drug biomarkers in sewage and the uncertainty related to back-calculation of cocaine use. Different methods for estimating population size in a catchment have been compared and the variability among the collected data was very high (7-55%). A reasonable strategy to reduce uncertainty was therefore to choose the most reliable estimation case by case. In the other cases, the highest uncertainties are related to the analysis of sewage drug biomarkers (uncertainty as relative standard deviation; RSD: 6-26% from ILS) and to the back-calculation of cocaine use (uncertainty; RSD: 26%). Uncertainty can be kept below 10% in the remaining steps, if specific requirements outlined in this work are considered. For each step, a best practice protocol has been suggested and discussed to reduce and keep to a minimum the uncertainty of the entire procedure and to improve the reliability of the estimates of drug use.

Effects of salinity on the toxicity of ionic silver and Ag-PVP nanoparticles to Tisbe battagliai and Ceramium tenuicorne

The toxic effects of polyvinylpyrrolidone (PVP) coated silver nanoparticles (Ag-NP(PVP)) and ionic Ag, to Tisbe battagliai (Tb) and Ceramium tenuicorne (Ct) were investigated and the usefulness of standardised marine guidelines for ENP risk assessment were assessed. The toxicity of Ag-NP(PVP) [CtEC(50)=26.6μg/L, TbEC(50)=7.9μg/L] and Ag(+) [CtEC(50)=2312.2μg/L, Tb EC(50)=90.9μg/L] to both test species differed, with the silver ENPs being more toxic. In contrast to Ag(+) the toxicity of Ag-NP(PVP) increased significantly with increasing salinity, however, after thorough characterisation it was not possible to correlate the behaviour of the particles with an increase in toxicity and salinity. The results suggest that the observed toxicity is being elicited by the free ionic silver complexing in solution and also from an unknown potential particle related effect.

Post-incident monitoring to evaluate environmental damage from shipping incidents: chemical and biological assessments

Oil and chemical spills in the marine environment are an issue of growing concern. Oil exploration and exploitation is moving from the continental shelf to deeper waters, and to northern latitudes where the risk of an oil spill is potentially greater and may affect pristine ecosystems. Moreover, a growing number of chemical products are transported by sea and maritime incidents of hazardous and noxious substances (HNS) are expected to increase. Consequently, it seems timely to review all of the experience gained from past spills to be able to cope with appropriate response and mitigation strategies to combat future incidents. Accordingly, this overview is focused on the dissemination of the most successful approaches to both detect and assess accidental releases using chemical as well as biological approaches for spills of either oil or HNS in the marine environment. Aerial surveillance, sampling techniques for water, suspended particles, sediments and biota are reviewed. Early warning bioassays and biomarkers to assess spills are also presented. Finally, research needs and gaps in knowledge are discussed.

Comparing illicit drug use in 19 European cities through sewage analysis

The analysis of sewage for urinary biomarkers of illicit drugs is a promising and complementary approach for estimating the use of these substances in the general population. For the first time, this approach was simultaneously applied in 19 European cities, making it possible to directly compare illicit drug loads in Europe over a 1-week period. An inter-laboratory comparison study was performed to evaluate the analytical performance of the participating laboratories. Raw 24-hour composite sewage samples were collected from 19 European cities during a single week in March 2011 and analyzed for the urinary biomarkers of cocaine, amphetamine, ecstasy, methamphetamine and cannabis using in-house optimized and validated analytical methods. The load of each substance used in each city was back-calculated from the measured concentrations. The data show distinct temporal and spatial patterns in drug use across Europe. Cocaine use was higher in Western and Central Europe and lower in Northern and Eastern Europe. The extrapolated total daily use of cocaine in Europe during the study period was equivalent to 356 kg/day. High per capita ecstasy loads were observed in Dutch cities, as well as in Antwerp and London. In general, cocaine and ecstasy loads were significantly elevated during the weekend compared to weekdays. Per-capita loads of methamphetamine were highest in Helsinki and Turku, Oslo and Budweis, while the per capita loads of cannabis were similar throughout Europe. This study shows that a standardized analysis for illicit drug urinary biomarkers in sewage can be applied to estimate and compare the use of these substances at local and international scales. This approach has the potential to deliver important information on drug markets (supply indicator).

[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.

The binding of phenanthrene to engineered silver and gold nanoparticles

The steadily rising production and use of engineered nanoparticles (ENP) leads to their entry into the aquatic environment. In addition to the various adverse effects that have been seen for different organisms, ENP are suspected to influence the transport, bioavailability and toxic properties of a range of environmental contaminants that may adsorb to their surface. In this study, the binding properties of the polycyclic aromatic hydrocarbon phenanthrene to stabilized silver and gold ENP were investigated using a novel mass balance based single-equilibrium approach. Only citrate coated gold ENP (AuNP(CIT)) were found to bind phenanthrene. No binding was observed for polyvinylpyrolidone coated silver ENP (AgNP(PVP)) nor citrate coated silver ENP (AgNP(CIT)) suggesting that the properties of the core material have a major influence on binding reactions. A binding coefficient K(b) was defined as the ratio between the concentration of phenanthrene associated to the AuNP(CIT) and that freely dissolved in the exposure medium. Temperature was not seen to significantly influence K(b) within an environmentally relevant range (4-25 °C). The presence of methanol significantly reduced or prevented the formation of the AuNP(CIT)-phenathrene complex. Results suggest that the binding is a low energy physio-sorption, likely associated to a partial displacement or specific arrangement of the citrate capping on the gold core.

Estimation of cocaine consumption in the community: a critical comparison of the results from three complimentary techniques

OBJECTIVES

A range of approaches are now available to estimate the level of drug use in the community so it is desirable to critically compare results from the differing techniques. This paper presents a comparison of the results from three methods for estimating the level of cocaine use in the general population.

DESIGN

The comparison applies to; a set of regional-scale sample survey questionnaires, a representative sample survey on drug use among drivers and an analysis of the quantity of cocaine-related metabolites in sewage.

SETTING

14 438 participants provided data for the set of regional-scale sample survey questionnaires; 2341 drivers provided oral-fluid samples and untreated sewage from 570 000 people was analysed for biomarkers of cocaine use. All data were collected in Oslo, Norway.

RESULTS

0.70 (0.36-1.03) % of drivers tested positive for cocaine use which suggest a prevalence that is higher than the 0.22 (0.13-0.30) % (per day) figure derived from regional-scale survey questionnaires, but the degree to which cocaine consumption in the driver population follows the general population is an unanswered question. Despite the comparatively low-prevalence figure the survey questionnaires did provide estimates of the volume of consumption that are comparable with the amount of cocaine-related metabolites in sewage. Per-user consumption estimates are however highlighted as a significant source of uncertainty as little or no data on the quantities consumed by individuals are available, and much of the existing data are contradictory.

CONCLUSIONS

The comparison carried out in the present study can provide an excellent means of checking the quality and accuracy of the three measurement techniques because they each approach the problem from a different viewpoint. Together the three complimentary techniques provide a well-balanced assessment of the drug-use situation in a given community and identify areas where more research is needed.

The current status of community drug testing via the analysis of drugs and drug metabolites in sewage

Over the past few years the analysis of drug residues in sewage has been promoted as a means of estimating the level of drug use in communities. Measured drug residue concentrations in the sewage are used to determine the load (total mass) of the drug being used by the entire community. Knowledge of the size or population of the community then allows for the calculation of drug-use relative to population (typically drug-mass/day/1000 inhabitants) which facilitates comparisons between differing communities or populations. Studies have been performed in many European countries, including Norway, as well as in the US and Australia. The approach has successfully estimated the use of cocaine, amphetamine, methamphetamine, MDMA, cannabis, nicotine and alcohol. The analysis of biomarkers of drug use in sewage has great potential to support and complement existing techniques for estimating levels of drug use, and as such has been identified as a promising development by the European Monitoring Centre for Drugs and Drug Addiction (EMCDDA; www.emcdda.europa.eu/wastewater-analysis). The approach is not without its challenges, and ongoing collaboration across Europe aims at agreeing upon best-practice and harmonising the methods being used. In Norway development is being performed through the NFR RUSMIDDEL funded DrugMon (www.niva.no/drugmon) project that has led to the development of many new techniques, significantly improved our understanding of the uncertainties associated with the approach and allowed the coordination of Europe wide collaboration which has included all important intercalibration exercises. Application of the technique can provide evidence-based and real-time estimates of collective drug use with the resulting data used to improve the much needed estimates of drug use and dependency.

Quantitative assessment of time dependent drug-use trends by the analysis of drugs and related metabolites in raw sewage

BACKGROUND

Accurate and timely information on the scale and dynamics of drug consumption is important for assessing the needs of law enforcement and public health services in a community.

AIMS

This paper presents a detailed examination of a comprehensive sewage-sampling campaign for the purposes of increasing an understanding of the dynamics of drug-flows in sewage streams, and developing new methodology by which this technique can support traditional drug-use surveys.

METHODS

A total of 104 sewage samples were collected from a treatment plant servicing approximately 500000 people and analysed for levels of methamphetamine, cocaine and cocaine metabolites. Careful examination of the kinetics of drug-flow profiles was then performed in order to identify trends or patterns of use within the community.

RESULTS

Results were validated against identical measurements of pharmaceutical reference compounds. Consumption profiles for cocaine and methamphetamine were found to differ in terms of frequency and timing of use. The majority of cocaine consumption occurs during the evening hours and 45% of consumption of this drug occurs in weekend periods. The flow of methamphetamine in the sewage system appears more evenly spread throughout the week.

CONCLUSIONS

This result is consistent with both an extended excretion half-life and a pattern of use that is more evenly balanced across all days of the week. Comprehensive investigation in to the scale and kinetics of drug flow in a sewage stream can therefore provide valuable information, not only in terms of the volume of drug consumed, but also in terms of identifying differing usage-patterns over daily and weekly time-scales.

In situ calibration of a passive sampling device for selected illicit drugs and their metabolites in wastewater, and subsequent year-long assessment of community drug usage

Polar organic chemical integrative samplers (POCIS) were calibrated in situ for selected illicit drugs and their metabolites at a sewage treatment works. Eleven out of 13 target compounds were detected and eight of those exhibited linear uptake kinetics with sampling rates between 0.035 and 0.150 L d(-1). Subsequently POCIS were deployed for 2 week periods over the course of a whole year, in order to examine trends in drug usage. Amphetamine and methamphetamine showed several similar peaks in concentration during the course of the year as did cocaine and two of its metabolites. Low levels of ecstasy were observed, with a prominent peak in May and a steady increase toward the end of the year. The antihistamine Cetirizine showed a clear increase in use during the summer months as expected and back calculation of the yearly dosage from POCIS accumulations yielded very similar results to that registered in the Norwegian prescription database. Estimations of cocaine usage using the parent compound averaged between 0.31 and 2.8 g d(-1) per 1000 inhabitants. POCIS is a cost-effective technique for the long-term monitoring of drug usage of a defined population and may overcome the difficulties of representative sampling associated with autosampling equipment.

Analysis and interpretation of specific ethanol metabolites, ethyl sulfate, and ethyl glucuronide in sewage effluent for the quantitative measurement of regional alcohol consumption

BACKGROUND

The quantitative measurement of urinary metabolites in sewage streams and the subsequent estimation of consumption rates of the parent compounds have previously been demonstrated for pharmaceuticals and narcotics. Ethyl sulfate and ethyl glucuronide are excreted in urine following the ingestion of alcohol, and are useful biomarkers for the identification of acute alcohol consumption. This study reports a novel ion-exchange-mediated chromatographic method for the quantitative measurement of ethyl sulfate and ethyl glucuronide in sewage effluent, and presents a novel calculation method for the purposes of relating the resulting sewage concentrations with rates of alcohol consumption in the region.

METHODS

A total of 100 sewage samples covering a 25-day period were collected from a treatment plant servicing approximately 500,000 people, and analyzed for levels of ethyl sulfate and ethyl glucuronide. The resulting data were then used to estimate combined alcohol consumption rates for the region, and the results were compared with alcohol related sales statistics for the same region.

RESULTS

Ethyl glucuronide was found to be unstable in sewage effluent. Ethyl sulfate was stable and measurable in all samples at concentrations ranging from 16 to 246 nM. The highest concentrations of the alcohol biomarker were observed during weekend periods. Sixty one percent of the total mass of ethyl sulfate in sewage effluent corresponds to alcohol consumption on Friday and Saturday. Sales statistics for alcohol show that consumption in the region is approximately 6,750 kg/d. The quantity of ethyl sulfate passing through the sewage system is consistent with consumption of 4,900 to 7,800 kg/d.

CONCLUSIONS

  Sewage epidemiology assessments of ethyl sulfate can provide accurate estimates of community alcohol consumption, and detailed examination of the kinetics of this biomarker in sewage streams can also identify time-dependent trends in alcohol consumption patterns.

Assessment of toxicological profiles of the municipal wastewater effluents using chemical analyses and bioassays

The hazardous chemical contamination of untreated wastewater and secondary effluent from the wastewater treatment plant (WWTP) of the city of Zagreb, Croatia was comprehensively characterized using large-volume solid-phase extraction (SPE) and silica gel fractionation, followed by a detailed analysis of the resulting extracts by a combination of chemical and bioassay methods. Over 100 individual contaminants or closely related-contaminant groups were identified by high-resolution gas chromatography/mass spectrometry (GC/MS) and liquid chromatography/quadrupole time-of-flight mass spectrometry (LC-QTOF). Ecotoxicity profiling of the investigated samples, including cytotoxicity, chronic toxicity and EROD activity; inhibition of the multixenobiotic resistance (MXR), genotoxicity and estrogenic potential, revealed the most significant contribution of toxic compounds to be present in polar fractions. Wastewater treatment using conventional activated sludge process reduced the initial toxicity of raw wastewater to various extents, ranging from 28% for algal toxicity to 73.2% for an estrogenic activity. The most efficient toxicity removal was observed for the polar compounds.

Uptake and effects of manufactured silver nanoparticles in rainbow trout (Oncorhynchus mykiss) gill cells

Nanoparticles are already widely used in technology, medicine and consumer products, but there are limited data on their effects on the aquatic environment. In this study the uptake and effect of citrate (AgNP(CIT)) and polyvinylpyrrolidone (AgNP(PVP)) coated manufactured silver nanoparticles, as well as AgNO(3) (Ag(+)) were tested using primary gill cells of rainbow trout (Oncorhynchus mykiss). Prior to use, the nanoparticles were characterized for size, surface charge and aggregation behavior. Gill cells were cultured either as monolayers on solid support, or as multilayers on a permeable support cell culturing system, enabling transport studies. The uptake of silver nanoparticles and Ag(+) after exposure to 10 mg L(-1) was determined with microscopical methods and inductively coupled plasma mass spectrometry (ICP-MS). Cytotoxicity, in terms of membrane integrity, as well as oxidative stress (depletion of reduced glutathione) was tested at silver concentrations ranging from 0.1 mg L(-1) to 10 mg L(-1). Results show that AgNP(CIT) nanoparticles are readily taken up into gill cell monolayers while uptake was less for AgNP(PVP). In contrast, it appears that the slightly smaller AgNP(PVP) were transported through cultured multilayers to a higher extent, with transport rates generally being in the ng cm(-2) range for 48 h exposures. Transport rates for all exposures were dependent on the epithelial tightness. Moderate cytotoxic effects were seen for all silver treatments. Levels of reduced glutathione were elevated in contrast to control groups, pointing on a possible overcompensation reaction. Taken together silver nanoparticles were taken up into cells and did cause silver transport over cultured epithelial layers with uptake and transport rates being different for the two nanoparticle species. All silver treatments had measurable effects on cell viability.

Effects-directed analysis of sediments from polluted marine sites in Norway

The environmental status of two polluted marine sites in Norway was investigated by a combination of target chemical analysis and effect-directed analysis (EDA). The two selected sites, the Grenland area and Oslo harbor, in addition to two reference sites, were classified according to the Norwegian environmental classification system based upon results of the target chemical analyses. The polluted sites were characterized by high levels of metals, polycyclic aromatic hydrocarbons (PAH), and polychlorinated biphenyls (PCB). High levels of organotin compounds were also detected in Oslo harbor. The aryl hydrocarbon receptor (AhR) agonist activity in extracts of sediments from marine sites close to Oslo, Oslo harbor, and Grenland were investigated using the CALUX (chemical-activated luciferase expression) assay, which showed elevated levels of activity. As expected from the history of dioxin release into the Grenland area, the results were highest in this area. The presence of estrogen receptor (ER) and androgen receptor (AR) antagonists was also detected in the sediment extracts. Following fractionation of the sediment extracts, EDA was used to tentatively identify the AhR agonists. The compounds responsible for AhR agonist activity in samples from Oslo harbor were isolated in fraction 13, and to a lesser extent in fractions 9-11. In Grenland, the main activity was found in the more polar fractions, namely fractions 14-18. The AhR agonists identified in Oslo harbor were mainly PAH, while in the Grenland area the compounds identified were mainly nitrogen/oxygen-containing polyaromatic compounds (N/O-PAC).

Effects of dispersed aggregates of carbon and titanium dioxide engineered nanoparticles on rainbow trout hepatocytes

The purpose of this study was to investigate the cytotoxicity and oxidative stress responses of selected engineered carbon and titanium dioxide (TiO2) nanomaterials to rainbow trout (Oncorhynchus mykiss) primary hepatocytes. The engineered nanomaterials tested were C(60) fullerenes, multiwall nanotubes (MWNT), single-wall nanotubes (SWNT) (functionalized and nonfunctionalized), and TiO2 of 5 and 200 nm in size. Characterization of these materials showed that they were typically present in solution as agglomerates. The engineered nanoparticle agglomerates were cytotoxic at nominal concentrations of >3 mg/L, and certain MWNT and SWNT produced significant intracellular reactive oxygen species (ROS) production as well as cytotoxicity. Analyses of the MWNT responsible for ROS production and cytotoxicity for selected transition metals demonstrated the presence of residual cobalt (Co), which was not present in the nonreactive/non-bioactive MWNT. Cobalt alone was not able to induce the observed effects in hepatocyte cells; however, coexposure with MWNT resulted in an increase in cytotoxicity. Data suggest that trace metals often associated with commercial nanotubes are responsible for the observed biological effects. In addition, other mechanisms, such as the proposed facilitated transport (e.g., Trojan horse) type mechanism of uptake, may provoke an increased response compared to aqueous exposures of trace metals in the absence of carbon nanoparticles.

Diurnal variations in the occurrence and the fate of hormones and antibiotics in activated sludge wastewater treatment in Oslo, Norway

We present an assessment of the dynamics in the influent concentration of hormones (estrone, estriol) and antibiotics (trimethoprim, sulfamethoxazole, tetracycline, ciprofloxacin) in the liquid phase including the efficiency of biological municipal wastewater treatment. The concentration of estradiol, 17-alpha-ethinylestradiol, doxycycline, oxytetracycline, demeclocycline, chlortetracycline, cefuroxime, cyclophosphamide, and ifosfamide were below the limit of detection in all of the sewage samples collected within this study. Two different types of diurnal variation pattern were identified in the influent mass loads of selected antibiotics and hormones that effectively correlate with daily drug administration patterns and with the expected maximum human hormone release, respectively. The occurrence of natural hormones and antimicrobials, administered every 12 hours, shows a daily trend of decreasing contaminant mass load, having the maximum values in the morning hours. The occurrence of antibiotics, typically administered every 8 hours, indicates a daily peak value in samples collected under the highest hydraulic loading. The efficiency of biological removal of both hormones and antibiotics is shown to be limited. Compared to the values obtained in the influent samples, increased concentrations are observed in the biologically treated effluent for trimethoprim, sulfamethoxazole and ciprofloxacin, mainly as a result of deconjugation processes. Ciprofloxacin is shown as the predominant antimicrobial compound in the effluent, and it is present at quantities approximately 10 fold greater than the total mass of the other of the compounds due to poor removal efficiency and alternating solid-liquid partitioning behaviour. Our results suggest that, to increase the micro-pollutant removal and the chemical dosing efficiency in enhanced tertiary treatment, significant benefits can be derived from the optimisation of reactor design and the development of control schemes that accounts for diurnal secondary effluent micro-pollutant and hydraulic loading patterns.

Effects of silver and gold nanoparticles on rainbow trout (Oncorhynchus mykiss) hepatocytes

The use of nanomaterials is rapidly increasing, while little is known about their possible ecotoxicological effects. This work investigates the toxic effects of silver (Ag) and gold (Au) nanoparticles on rainbow trout hepatocytes. In addition to toxicity assessment the particles were characterized by transmission electron microscopy (TEM) and nanoparticle tracking analysis (NTA). Hepatocyte primary cultures were exposed to Au and Ag nanoparticles, with and without dissolved organic carbon (DOC), as well as HAuCl(4) and AgNO(3) as ionic solutions at concentrations up to 17.4mg/L and 19mg/L, respectively. Ag and Au particles were within the small nanometer size range when dispersed in pure water. In media with higher ionic strength and DOC, particles tended to agglomerate. Cytotoxicity assessments showed that Ag nanoparticles caused a significant reduction in membrane integrity and cellular metabolic activity in a concentration-dependent manner. Au nanoparticles caused a threefold elevation of ROS levels, but no cytotoxicity occurred at concentrations tested. The addition of DOC did not alter the particles potency of cytotoxicity or ROS induction capacity. The current study shows that Ag and Au nanoparticles have adverse effects on rainbow trout hepatocytes at low mg/L concentrations.

Impacts of competitive inhibition, parent compound formation and partitioning behavior on the removal of antibiotics in municipal wastewater treatment

We present a process model that predicts the removal of the antibiotic micropollutants, sulfamethoxazole (SMX), tetracycline (TCY), and ciprofloxacin (CIP), in an activated sludge treatment system. A novel method was developed to solve the inverse problem of inferring process rate, sorption, and correction factor parameter values from batch experimental results obtained under aerobic and anoxic conditions. Instead of spiking the batch reactors with reference substances, measurements were made using the xenobiotic organic micropollutant content of preclarified municipal sewage. Parent compound formation and removal were observed, and the model developed using the simulation software West showed limited efficiency to describe the selected micropollutants profiles, when growth substrate removal occurs. The model structure was optimized by accounting for competitive inhibition by readily biodegradable substrates on the cometabolic micropollutant biotransformation processes. Our results suggest that, under anoxic conditions, hydrophobicity-independent mechanisms can significantly impact solid-liquid partitioning that our model takes into account by using the sorption coefficient as a lumped parameter. Forward dynamic simulations were carried out to evaluate the developed model and to confirm it for SMX using data obtained in a full-scale treatment plant. Evaluation of measured and simulation results suggest that, robust model prediction can be achieved by approximating the influent load of chemicals biodegrading via a given parent compound, e.g., human conjugates, as an antibiotic mass that is proportional to the parent compound load.

The environmental fate and effects of antifouling paint biocides

Antifouling (AF) biocides are the active ingredients in AF paints that prevent the settlement, adhesion and growth of organisms to a painted surface. A wide range of chemicals are used as AF biocides, which have very different physico-chemical properties and therefore differing environmental fates, behaviour and effects. Copper has been used as an antifoulant for centuries and extensive research has been performed to understand how copper speciation influences bioavailability and toxicity. For biocides that have been widely used over a number of decades, for example Irgarol 1051 and diuron, there are a large amount of environmental data in the public domain, including for their respective metabolites, that allows their environmental safety and potential risk to the environment to be assessed. For other biocides such as dichlofluanid, DCOIT (SeaNine 211) and zinc/copper pyrithione, there is a good understanding of their fate and effects. However, few monitoring studies have been performed and not so much is known about the fate and effects of their metabolites. There are also new or candidate biocides such as triphenylborane pyridine, Econea, capsaicin and medetomidine for which there is very little information in the public domain. This review provides an overview of the environmental fate and occurrence data that are in the public domain for AF biocides and provides some insight into the effects of these compounds on non-target organisms.

Monitoring the freely dissolved concentrations of polycyclic aromatic hydrocarbons (PAH) and alkylphenols (AP) around a Norwegian oil platform by holistic passive sampling

In order to assess the environmental impact of aquatic discharges from the offshore oil industry, polar organic chemical integrative samplers (POCIS) and semipermeable membrane devices (SPMDs) were deployed around an oil platform and at reference locations in the North Sea. Exposure to polycyclic aromatic hydrocarbons (PAH) and alkylated phenols (AP) was determined from passive sampler accumulations using an empirical uptake model, the dissipation of performance reference compounds and adjusted laboratory derived sampling rates. Exposure was relatively similar within 1-2 km of the discharge point, with levels dominated by short chained C1-C3 AP isomers (19-51 ngL(-1)) and alkylated naphthalenes, phenanthrenes and dibenzothiophenes (NPD, 29-45 ngL(-1)). Exposure stations showed significant differences to reference sites for NPD, but not always for more hydrophobic PAH. These concentrations are several orders of magnitude lower than those reported to give both acute and sub-lethal effects, although their long term consequences are unknown.

Effect-directed identification of naphthenic acids as important in vitro xeno-estrogens and anti-androgens in North sea offshore produced water discharges

Produced water from offshore oil production platforms represents the largest direct discharge of effluent into the offshore environment. Produced water effluents contain a complex mixture of substances which are known to bind to the estrogen receptor (ER) and antagonize the androgen receptor (AR). Short-chain petrogenic alkylphenols have been identified as responsible for around 35% of the ER agonist activity measured in vitro while the compounds responsible for antagonizing the androgen receptor are unknown. For the first time we report that petrogenic naphthenic acids are weak ER agonists that account for much of the 65% of the "unknown" ER agonist potency in North Sea produced waters while also disrupting the binding of AR agonists to the AR ligand receptor. We also report other known petrogenic components such as polycyclic aromatic hydrocarbons (PAHs) and alkylphenols as environmental AR antagonists. Our investigation shows that these petrogenic components are responsible for the majority of the ER and AR receptor mediated activity in produced waters. This hypothesis is supported by data from an effects-directed analysis of produced water using normal-phase high-performance liquid chromatography (HPLC) fractionation in combination with the yeast estrogen and androgen assays as well as androgen receptor binding assays of commercially available mixtures of naphthenic acids.

Small but different effect of fouling on the uptake rates of semipermeable membrane devices and polar organic chemical integrative samplers

Semipermeable membrane devices (SPMD) and polar organic chemical integrative samplers (POCIS) were exposed to a cocktail of organic chemicals using a flow-through system. Samplers were removed and analyzed every 7 d over a four-week period in order to determine sampling rates (Rs) for individual compounds. Prior to laboratory exposure, half of the samplers were allowed to foul naturally for six weeks, in order to examine differences in uptake due to fouling. The amount of fouling ranged from 0.2 to 2.8 g dry weight/dm2 for POCIS and 0.1 to 1.4 g dry weight/dm2 for SPMDs, and the pattern of accumulation was also different between them. The Rs values were determined by fitting curves to time course uptake data and also by using performance reference compounds (PRCs) for SPMDs. Sampling rates ranged from 2.7 to 14.2 L/d for SPMDs and 0.01 to 0.27 L/d for POCIS. Fouled SPMDs showed a reduction in Rs (<20%) for all but one compound, and there was a similar reduction in the release of PRCs. However, PRC-predicted R, values were overall somewhat higher than those from fitted curves. Uptake of alkylated phenols in POCIS was generally higher (up to 55%) in fouled samplers. The reason for this is not known, but is possibly due to some reduction in interactions with the membrane in fouled samplers. There was no overall pattern in the relationship of sampling rate differences with log Kow or over time for either sampler. Release of compounds from POCIS after a drop in exposure water concentrations provides some encouragement for the application of a PRC approach to polar passive samplers.

Determination of pharmaceutical compounds in hospital effluents and their contribution to wastewater treatment works

A method was developed for the simultaneous determination of almost 40 pharmaceuticals; including antidepressants, non-steroidal anti-inflammatories, analgesics, hypolipidemics, alpha- and beta-blockers, an anti cancer drug, anti-fungal agents, an opiate, an antibiotic, an anti-coagulant, a diuretic, an anti-anginal and an anti-diabetic compound. This was used to assess the contribution of pharmaceuticals originating from hospital effluents to one of Oslo city's wastewater treatment works. Some pharmaceuticals were found to contribute to more of the wastewater loading than others. 11% of the propranolol entering the wastewater treatment works stems from hospital effluent, approximately 2% of the atenolol, carbemazepine, metaprolol and atorvastatin, and for several other compounds the contribution is less than 1%. This assessment shows that point sources discharges from hospitals typically make a small contribution to the overall pharmaceutical load when compared to municipal areas, however this varies from substance to substance and is not the case when a drug's use is primarily hospital based.

Identification of nonregulated pollutants in North Sea-produced water discharges

Produced water collected from oil and gas platforms on the United Kingdom Continental Shelf was characterized for nonregulated pollutants through an effects-directed analysis procedure. Produced water samples were characterized for the presence of aryl hydrocarbon receptor (AhR) and estrogen receptor (ER) agonists using the dioxin-responsive, chemical-activated luciferase gene expression assay (DR-CALUX) and yeast estrogen screen (YES) bioassays. The AhR and ER agonists were then isolated by normal-phase, high-performance liquid chromatography and identified using gas chromatography coupled to mass spectrometry in a number of formats. The identified compounds were cross-referenced with those compounds routinely analyzed and regarded by the Oslo and Paris (OSPAR) Commission for the North East Atlantic as priority hazardous substances. The occurrence in produced water of a number of nonregulated compounds with demonstrable potential environmental effects is presented, to our knowledge for the first time. These include persistent organic contaminants, such as hexachlorobenzene, decachlorobiphenyl, and octachlorodibenzofuran.

Masking effect of anti-androgens on androgenic activity in European river sediment unveiled by effect-directed analysis

This study shows that the androgen receptor agonistic potency is clearly concealed by the effects of androgen receptor antagonists in a total sediment extract, demonstrating that toxicity screening of total extracts is not enough to evaluate the full in vitro endocrine disrupting potential of a complex chemical mixture, as encountered in the environment. The anti-androgenic compounds were masking the activity of androgenic compounds in the extract with relatively high anti-androgenic potency, equivalent to 200 nmol flutamide equivalents/g dry weight. A two-step serial liquid chromatography fractionation of the extract successfully separated anti-androgenic compounds from androgenic compounds, resulting in a total androgenic potency of 3,820 pmol dihydrotestosterone equivalents/g dry weight. The fractionation simplified the chemical identification analysis of the original complex sample matrix. Seventeen chemical structures were tentatively identified. Polyaromatic hydrocarbons, a technical mixture of nonylphenol and dibutyl phthalate were identified to contribute to the anti-androgenic potency observed in the river sediment sample. With the GC/MS screening method applied here, no compounds with AR agonistic disrupting potencies could be identified. Seventy-one unidentified peaks, which represent potentially new endocrine disrupters, have been added to a database for future investigation.

Ecotoxicity of the degradation products of triphenylborane pyridine (TPBP) antifouling agent

Triphenylborane pyridine (TPBP) is an alternative to organotin antifouling compounds. This work aimed to identify the unknown Peak #1, and to evaluate the ecotoxicity of TPBP and its degradation products. Peak #1 was produced from TPBP dissolved in acetonitrile under UV-A photolysis using a high-pressure mercury lamp. The Peak #1 fraction was purified using two-step column chromatography from a TPBP-acetonitrile solution. The major compound of the fraction was identified as being biphenyl from the 1H NMR and 13C NMR spectra. The ecotoxicity of four degradation products (diphenylborane hydroxide, phenylborane dihydroxide, phenol, and biphenyl) and TPBP towards two marine planktons were assessed. The 48 h LC(50) values of the crustacean, Artemia salina, were 0.13 mg L(-1) for TPBP, 14 mg L(-1) for biphenyl, 17 mg L(-1) for phenol, and > 50 mg L(-1) for the other degradation products. The 72 h EC(50) values of the diatom, Skeletonema costatum, were 0.0022 mg L(-1) for TPBP, 1.2 mg L(-1) for biphenyl, and > 2 mg L(-1) for the other degradation products. Thus, the ecotoxicity of biphenyl and the other degradation products were not high compared to the parent compound, TPBP.

Environmental assessment of Norwegian priority pharmaceuticals based on the EMEA guideline

An environmental risk assessment of eleven pharmaceuticals according to the guideline recommended by the European Medicines Evaluation Agency (EMEA) was performed. Cefuroxime, ciprofloxacin, cyclophosphamide, diclofenac, ethinylestradiol, ibuprofen, metoprolol, paracetamol, sulfamethoxazole, tetracycline and trimethoprim were selected for assessment by the Norwegian Pollution Control Authority. Predicted environmental concentrations (PECs) were calculated according to both the EMEA guideline and a conventional model for comparison and ranged from 0.0002 to 45 microg/L. Available acute and chronic toxicity data were collected from the literature, although no data were available for cyclophosphamide. Toxicity tests showed cyclophosphamide to have relatively low acute toxicity with an EC50 for Pseudokirchneriella subcapitata >100 mg/L and a Daphnia magna reproduction NOEC of 56 mg/L. These and the literature data were used to derive predicted no effect concentrations (PNEC). Risk quotients (PEC/PNEC) were then calculated for all 11 pharmaceutical compounds. Risk quotients greater than 1 were obtained for ciprofloxacin, diclofenac, ethinylestradiol, sulfamethoxazole and tetracycline according to the EMEA guideline. Measured environmental concentrations (MECs) confirmed that the release of ciprofloxacin from wastewater treatment works may potentially be of environmental concern in Norway.

Dissolved organic carbon reduces the toxicity of copper to germlings of the macroalgae, Fucus vesiculosus

This study investigates the effects of waterborne copper exposure on germling growth in chemically defined seawater. Germlings of the macroalgae, Fucus vesiculosus were exposed to a range of copper and dissolved organic carbon (DOC as humic acid) concentrations over 14 days. Germling growth was found to be a sensitive indicator of copper exposure with total copper (TCu) and labile copper (LCu) EC(50) values of approximately 40 and 20 microg/L, respectively, in the absence of added DOC. The addition of DOC into the exposure media provided germlings with protection against copper toxicity, with an increased TCu EC(50) value of 117.3 microg/L at a corrected DOC (cDOC from humic acid only) concentration of 2.03 mg/L. The LCu EC(50) was not affected by a cDOC concentration of 1.65 mg/L or less, suggesting that the LCu concentration not the TCu concentration was responsible for inhibiting germling growth. However, at a cDOC concentration of approximately 2mg/L an increase in the LCu EC(50) suggests that the LCu concentration may play a role in the overall toxicity to the germlings. This is contrary to current understanding of aquatic copper toxicity and possible explanations for this are discussed.

Chronic toxicity of the Sava River (SE Europe) sediments and river water to the algae Pseudokirchneriella subcapitata

The Sava River, the largest and most commercially valuable water body in the riparian countries, receives inputs of organic and inorganic compounds from a variety of domestic and industrial activities that may affect the health of human beings and wildlife. In this work, the chronic toxicity of sediment, sediment porewater and surface water from the Sava River and connecting tributaries to the freshwater algae Pseudokirchneriella subcapitata was assessed to characterise the potential impact on aquatic organisms. Samples of different environmental matrices were either tested directly (porewater) or subjected to pre-concentration (sediments and surface water) prior to testing in a 72 h growth inhibition assay using P. subcapitata. The results show that a combination of pre-concentration and bioassay testing was able to characterise the toxic potential and to identify several compartment-specific "hot spots" along the Sava River. Based on the resulting data, a crude risk assessment identified that some of the locations may represent a risk to algae. Additional testing using multiple species and exposure phases is required to conduct a thorough risk assessment, however.

Effects of dissolved organic carbon on the toxicity of copper to the developing embryos of the Pacific oyster (Crassostrea gigas)

The effects of humic acid (HA) on copper speciation and its subsequent toxicity to the sensitive early life stages of the Pacific oyster (Crassostrea gigas) are presented. Differential pulse anodic stripping voltammetry with a hanging mercury drop electrode was used to measure the copper species as labile copper (LCu; free ion and inorganic copper complexes) and total copper (TCu) with respect to increasing HA concentration. The TCu and LCu 50% effect concentrations (EC50s) in the absence of HA were 20.77 microg/L (95% confidence interval [CI], 24.02-19.97 microg/L) and 8.05 microg/L (95% CI, 9.6-5.92 microg/L) respectively. A corrected dissolved organic carbon (DOC) concentration (HA only) of 1.02 mg/L was required to significantly increase the TCu EC50 to approximately 41.09 microg/L (95% CI, 44.27-37.52 microg/L; p < 0.05), almost doubling that recorded when DOC (as HA) was absent from the test media. In contrast, the LCu EC50 was unaffected by changes in DOC concentration and was stable throughout the corrected DOC concentration range. The absence of change in the LCu EC50, despite increased HA concentration, suggests that the LCu fraction, not TCu, was responsible for the observed toxicity to the oyster embryo. This corresponds with the current understanding of copper toxicity and supports the free-ion activity model for copper toxicity.

The effect of resuspending sediment contaminated with antifouling paint particles containing Irgarol 1051 on the marine macrophyte Ulva intestinalis

The effect of resuspending sediment contaminated with Irgarol 1051 based antifouling paint particles on the green macroalga Ulva intestinalis was examined. U. intestinalis was also exposed to sediment spiked with Irgarol 1051. The macroalga were exposed over 21 days to the resuspension of sediments containing 61.2 mg kg(-1) of antifouling paint particles containing Irgarol 1051 that provided aqueous Irgarol 1051 concentrations of approximately 0.3 microg l(-1), Irgarol 1051 and appropriate controls. The growth response was compared with that for 'clean' sediment. Resuspension of sediment was associated with reduced growth when compared to seawater alone. Resuspension of sediment spiked with Irgarol 1051 was associated with a greater reduction in growth, with growth being significantly reduced when sediment containing antifouling paint particles was resuspended. The data suggest that the prolonged disturbance of sediments containing antifouling paint particles in marinas represents a potential and as yet unquantified hazard to photosynthetic organisms.

Estrogen receptor (ER) agonists and androgen receptor (AR) antagonists in effluents from Norwegian North Sea oil production platforms

The in vitro estrogen receptor (ER) agonist and androgen receptor (AR) antagonist potencies of offshore produced water effluents collected from the Norwegian Sector were determined using recombinant yeast estrogen and androgen screens. Solid phase extraction (SPE) concentrates of the effluents showed E2 agonist activities similar to those previously reported for the United Kingdom (UK) Continental Shelf (<0.1-4 ng E2 L(-1)). No activity was detected in the filtered oil droplets suggesting that produced water ER activity is primarily associated with the dissolved phase. Targeted analysis for methyl- to nonyl-substituted alkylphenol isomers show the occurrence of known ER agonists in the analysed samples. For the first time, AR antagonists were detected in both the dissolved and oil associated phase at concentrations of between 20 and 8000 microg of flutamide equivalents L(-1). The identity of the AR antagonists is unknown, however this represents a significant input into the marine environment of unknown compounds that exert a known biological effect. It is recommended that further analysis using techniques such as bioassay-directed analysis is performed to identify the compounds/groups of compounds that are responsible in order to improve the assessment of the risk posed by produced water discharges to the marine environment.

Effects-directed analysis of organic toxicants in wastewater effluent from Zagreb, Croatia

The organic toxicants present in the effluent of the main sewer of the city of Zagreb, Croatia were isolated and identified through the use of effects-directed characterisation techniques. At the time of investigation, the wastewater effluent received no treatment and was comprised of a mixture of effluent from domestic and industrial sources. The organic load of the wastewater was isolated by solid phase extraction and toxicity profiles obtained using reverse-phase HPLC. All procedures were evaluated through the analysis of a series of reference compounds of widely differing polarity. Toxicity profiles for EROD activity (CYP1A induction), vitellogenin induction (estrogenic activity), cytotoxicity (membrane stability and metabolic inhibition) were obtained using a rainbow trout (Oncorhynchus mykiss) primary hepatocyte bioassay. The suite of bioassays showed biological responses after exposure to the raw extracts for all the endpoints tested. However, a combination of mixture toxicity and cytotoxicity in the complex raw extract had some masking effect on the sub-lethal responses of vitellogenin and EROD induction. Bioassay testing of the fine fractions obtained by HPLC produced a range of endpoint-specific toxicity profiles for each sample. A number of compounds were identified by the use of GC-MS and LC-MS/MS as responsible for the observed effects. The steroid estrogens 17 beta-estradiol and estriol were identified by LC-MS/MS as estrogen receptor agonists in two of the estrogenic fractions. In addition, GC-MS analysis identified different alkylphenols, benzophenone and methylparaben which also contributed to the estrogenic activity of the sample. Polycyclic aromatic hydrocarbons (PAHs), alkyl substituted PAHs, nitro-polycyclic aromatic compounds (nitro-PACs), carbazoles and alkyl substituted carbazoles and other known CYP1A inducers were identified by GC-MS analysis as responsible for some of the observed EROD activity. Some active compounds remain unidentified.

Using environmental analytical data to estimate levels of community consumption of illicit drugs and abused pharmaceuticals

A solid phase extraction (SPE) method has been developed and applied in conjunction with a previously reported liquid chromatography tandem mass spectrometry (LC-MS-MS) procedure for the determination of illicit drugs and abused pharmaceuticals in treated wastewater and surface water samples at the ng L(-1) level. A full method validation was also performed and determined levels of analytical sensitivity were found to lie in the 1-10 ng L(-1) range using river water as a test sample matrix and a sample size of 500 mL. The developed procedure was successfully applied for the determination of the chosen analytes in wastewater treatment plants in Dublin, Ireland and rapidly expanding commuter towns in the surrounding counties. Cocaine was detected in 70% of the collected samples in the range of 25-489 ng L(-1), its primary metabolite, benzoylecognine (BZE) was also detected in the range of 22-290 ng L(-1). Other substances detected included morphine, Tempazepam and the primary metabolite of methadone.

Bioanalytical characterisation of estrogen and arylhydrocarbon receptor agonists in transplanted blue mussels (Mytilus edulis): proof of concept

The characterisation of estrogen (ER) and arylhydrocarbon (AhR) receptor agonists was performed in extracts of the tissues of transplanted blue mussels (Mytilus edulis). The yeast estrogen screen (YES) was used to detect the presence of ER agonists, whilst the DR-CALUX assay was used to detect AhR agonists. The concentration of ER agonists in mussel tissue from the Tees estuary, Brancaster and River Crouch (UK) were below the limits of detection for the YES assay (0.87 pg E2 g(-1)). AhR agonists were measured at concentrations of between 1 and 950 pg TCDD g(-1) in mussel tissue. A bioassay-directed fractionation of the sample extracts, followed by advanced broad spectrum gas chromatography-mass spectrometry analysis was then used in an attempt to identify the AhR agonists present. This showed that a complex mixture of AhR agonists occurs in the samples and that further work will be required in order to isolate and identify the individual compounds responsible.

Improved method for the determination of zinc pyrithione in environmental water samples incorporating on-line extraction and preconcentration coupled with liquid chromatography atmospheric pressure chemical ionisation mass spectrometry

A method has been developed for the determination of zinc pyrithione (ZnPT) in environmental water samples using monolithic reversed-phase silica columns for rapid on-line large volume solid phase extraction in tandem with on-line matrix removal using sacrificial strong anion exchange (SAX) columns. This is coupled with reversed-phase liquid chromatography with atmospheric pressure chemical ionisation mass spectrometric detection. Limits of detection in spiked river water samples, using a 200 mL preconcentration volume, were determined as 18 ng L(-1), with a limit of quantitation of 62 ng L(-1). The percentage recovery from spiked river water was found to be 72+/-9 (n=3 extractions), whilst overall method precision, following 10 repeat complete analyses was found to be 27% RSD at 1 microg L(-1). Linearity was determined over the concentration range of 0.25-10 microg L(-1) and the calculated regression coefficient was R(2)=0.9802. The method was used to investigate the environmental fate of zinc pyrithione in waters and its partition coefficient between sediment and water phases.

Assessment of the risk posed by the antifouling booster biocides Irgarol 1051 and diuron to freshwater macrophytes

Antifouling paints are used to reduce the attachment of living organisms to the submerged surfaces of ships, boats and aquatic structures, usually by the release of a biocide. Two 'booster' biocides in common use are the triazine herbicide Irgarol 1051 (N-2-methylthio-4-tert-butylamino-6-cyclopropylamino-s-triazine), and diuron (1-(3,4-dichlorophenyl)-3,3-dimethylurea), which are designed to inhibit algal photosynthesis. Previous research has been directed at the effects of these compounds in marine and estuarine environments. In 2001 we sampled the main rivers and shallow freshwater lakes (Broads) of East Anglia UK for Irgarol 1051, its metabolite GS26575 (2-methylamino-4-tert-butylamino-6-amino-s-triazine) and diuron in order to establish the baseline environmental concentrations of these compounds in freshwater systems of eastern UK and to investigate their possible effects on aquatic plants. Irgarol 1051, GS26575 and diuron were found in water samples collected from 21 locations. The highest concentrations were found in the Norfolk and Suffolk Broads in May. The rivers Great Ouse, Wissey, Bure and Yare also contained all three compounds, as did the Great Ouse Cut-off Channel. The toxicity of these biocides to three macrophyte species (Apium nodiflorum, Chara vulgaris, and Myriophyllum spicatum) was investigated. Deleterious effects on relative growth rate, the maximum quantum efficiency (Fv/Fm) of photosystem II and, for Apium, root mass production were found. C. vulgaris was generally most sensitive; growth, especially of roots, was strongly affected in A. nodiflorum; growth rate of M. spicatum was sensitive to diuron. No observed effect concentrations (NOEC) were interpolated using standard toxicological analysis. These were compared with measured environmental concentrations (MEC) to determine the ranges of risk quotients (MEC/NOEC). Both Irgarol 1051 and diuron represented significant risks to A. nodiflorum and C. vulgaris in this area.

The occurrence of selected pharmaceuticals in wastewater effluent and surface waters of the lower Tyne catchment

This paper presents the results of a survey of the wastewater effluent and surface waters of the lower river Tyne, UK. Samples were analysed by reversed-phase high-performance liquid chromatography-electrospray tandem mass spectrometry following solid phase extraction, for the presence of 13 pharmaceuticals selected from the priority lists of the UK Environment Agency and the Oslo and Paris Commission (OSPAR). The pharmaceutical compounds measured were acetyl-sulfamethoxazole, clofibric acid, clotrimazole, dextropropoxyphene, diclofenac, erythromycin, ibuprofen, mefenamic acid, paracetamol, propranolol, sulfamethoxazole, tamoxifen and trimethoprim. Of the wastewater treatment works (WTW) samples (n=9) analysed, all compounds except sulfamethoxazole and acetyl-sulfamethoxazole were detected at concentrations ranging from 11 to 69,570 ng l(-1) (in raw effluent). In the surface water samples (n=18), clotrimazole, dextropropoxyphene, erythromycin, ibuprofen, propranolol, tamoxifen and trimethoprim were detected at concentrations ranging from 4 to 2370 ng l(-1). Results of this study show that various pharmaceutical compounds are effectively reduced during their passage through a tertiary wastewater treatment works, whilst others are sufficiently persistent to occur in estuarine systems.

The stable aryl hydrocarbon receptor agonist potency of United Kingdom Continental Shelf (UKCS) offshore produced water effluents

The in vitro aryl hydrocarbon receptor (AhR) agonist potency of offshore produced water effluents, collected from the United Kingdom Continental Shelf, was determined using the dioxin responsive (DR)-chemically activated luciferase expression (CALUX) assay. Octadecylsilane (C18) solid phase extraction (SPE) extracts of produced water were exposed to DR-CALUX cells for 24h in order to investigate the contribution in potency from compounds that are stable to metabolism by the CALUX cells during exposure. The stable AhR agonist potency determined over 24h was highly variable and ranged from 1 to 430 ng TCDD TEQ(CALUX)l(-1). These data reflect the highly variable composition of produced water discharges from different production fields. It is recommended that further work be performed to characterise the full range of stable dioxin like AhR agonists present in offshore produced water discharges using techniques such as bioassay-directed analysis.

Investigating the environmental transport of human pharmaceuticals to streams in the United Kingdom

The occurrence of 12 selected pharmaceutical compounds and pharmaceutical compound metabolites in sewage treatment works (STW) effluents and surface waters was investigated. The substances selected for the monitoring programme were identified by a risk ranking procedure to identify those substances with the greatest potential to pose a risk to the aquatic environment. STW final effluent and surface water samples were collected from Corby, Great Billing, East Hyde, Harpenden and Ryemeads STWs. Ten of the 12 pharmaceutical compounds were detected in the STW effluent samples: propranolol (100%, median = 76 ng/l), diclofenac (86%, median = 424 ng/l), ibuprofen (84%, median = 3086 ng/l), mefenamic acid (81%, median = 133 ng/l), dextropropoxyphene (74%, median = 195 ng/l), trimethoprim (65%, 70 ng/l), erythromycin (44%, < 10 ng/l), acetyl-sulfamethoxazole (33%, median =< 50 ng/l), sulfamethoxazole (9%, median =< 50 ng/l), tamoxifen (4%, median =< 10 ng/l). In the corresponding receiving streams, fewer compounds and lower concentrations were found: propranolol (87%, median = 29 ng/l), ibuprofen (69%, median = 826 ng/l), mefenamic acid (60%, median = 62 ng/l), dextropropoxyphene (53%, median = 58 ng/l), diclofenac (47%, median =< 20 ng/l), erythromycin (38%, median =< 10 ng/l), trimethoprim (38%, median =< 10 ng/l), acetyl sulfamethoxazole (38%, median =< 50 ng/l). Four human pharmaceutical compounds were detected in samples upstream of the STWs sampled: ibuprofen (57%, median = 181 ng/l), trimethoprim (36%, median < 10 ng/l), erythromycin (17%, median =< 10 ng/l), propranolol (14%, median =< 10 ng/l), suggesting that longer range stream transport of some compounds is possible. The particular STW that was sampled and the month that it was sampled significantly influenced the measured concentrations of several, but not all, substances. There was no significant relationship between usage data and the overall frequency with which different substances were detected. There was however, some evidence to suggest that usage data are positively associated with concentrations of pharmaceuticals in effluent and, particularly, with concentrations measured in surface waters below STWs. These results suggest that most sewage treatment works in England and Wales are likely to be routinely discharging small quantities of pharmaceuticals into UK rivers. None of the pharmaceuticals were found at concentrations that were high enough to cause acute toxic impacts to aquatic organisms. However, insufficient data were available to be able to comment on whether the concentrations measured have the potential to result in more subtle long-term effects on aquatic organisms (e.g. effects on growth, ability to reproduce).