The pharmaceutical use of permethrin: Sources and behavior during municipal sewage treatment

This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ 2010 Springer Science+Business Media, LLC.Permethrin entered use in the 1970s as an insecticide in a wide range of applications, including agriculture, horticultural, and forestry, and has since been restricted. In the 21st century, the presence of permethrin in the aquatic environment has been attributed to its use as a human and veterinary pharmaceutical, in particular as a pedeculicide, in addition to other uses, such as a moth-proofing agent. However, as a consequence of its toxicity to fish, sources of permethrin and its fate and behavior during wastewater treatment are topics of concern. This study has established that high overall removal of permethrin (approximately 90%) was achieved during wastewater treatment and that this was strongly dependent on the extent of biological degradation in secondary treatment, with more limited subsequent removal in tertiary treatment processes. Sources of permethrin in the catchment matched well with measured values in crude sewage and indicated that domestic use accounted for more than half of the load to the treatment works. However, removal may not be consistent enough to achieve the environmental quality standards now being derived in many countries even where tertiary treatment processes are applied.United Utilities PL

Removal processes for tributyltin during municipal wastewater treatment

This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ 2013 Springer.The fate and behaviour of tributyltin (TBT) at two wastewater treatment works was examined. Both sites had two inlet streams, and each utilised high rate biological filters (biofilters) on one the streams, before treatment of the combined flows on trickling filters, with one having additional tertiary processes, installed to remove ammonia and solids. The study was designed to determine if these processes enhanced the removal of TBT. Degradation of TBT was observed in one of the biofilters, possibly as a result of temperature and hydraulic loading. At the treatment works with tertiary processes, the mass flux showed the overall removal of TBT was 68 %, predominantly due to removal with solids in the primary settlement processes. However, overall removal of 95 % was observed in the conventional trickling filter works with 94 % of this due to biodegradation in the trickling filter. The two works both removed TBT, but at different treatment stages and by different processes. Differences in the form (solubility) of TBT in the influent may have attributed to this, although further understanding of factors controlling degradation would allow for a more complete assessment of the potential of biological processes to remove hazardous compounds from wastewaters.United Utilities PL

The fate of steroid estrogens: Partitioning during wastewater treatment and onto river sediments

This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ 2010 Springer Science+Business Media B.V.The partitioning of steroid estrogens in wastewater treatment and receiving waters is likely to influence their discharge to, and persistence in, the environment. This study investigated the partitioning behaviour of steroid estrogens in both laboratory and field studies. Partitioning onto activated sludge from laboratory-scale Husmann units was rapid with equilibrium achieved after 1 h. Sorption isotherms and Kd values decreased in the order 17α-ethinyl estradiol > 17α-estradiol > estrone > estriol without a sorption limit being achieved (1/n >1). Samples from a wastewater treatment works indicated no accumulation of steroid estrogens in solids from primary or secondary biological treatment, however, a range of steroid estrogens were identified in sediment samples from the River Thames. This would indicate that partitioning in the environment may play a role in the long-term fate of estrogens, with an indication that they will be recalcitrant in anaerobic conditions.EPSR

Household Disposal of Pharmaceuticals as a Pathway for Aquatic Contamination in the United Kingdom

Pharmaceuticals are produced and used in increasingly large volumes every year. With this growth comes concern about the fate and effects of these compounds in the environment. The discovery of pharmaceuticals in the aquatic environment has stimulated research in the last decade. A wide range of pharmaceuticals has been found in fresh and marine waters, and it has recently been shown that even in small quantities, some of these compounds have the potential to cause harm to aquatic life. The primary pathway into the environment is the use and disposal of medicines; although much of the research in the area currently focuses on the removal of pharmaceuticals during sewage treatment processes, disposal via household waste might be a significant pathway requiring further research. To investigate the household disposal of unused and expired pharmaceuticals as a source of pharmaceutical compounds in the environment, we carried out a survey and interviewed members of 400 households, predominantly from southeastern England. We used the information on when and how they disposed of unfinished pharmaceuticals to construct a conceptual model to assess the pathways of human pharmaceuticals into the environment. The model demonstrated that disposal of unused pharmaceuticals, either by household waste or via the sink or toilet, may be a prominent route that requires greater attention

Risk-based prioritization of pharmaceuticals in the natural environment in Iraq

Numerous studies have demonstrated the occurrence of pharmaceuticals in the natural environment, raising concerns about their impact on non-target organisms or human health. One region where little is known about the exposure and effects of pharmaceuticals in the environment is Iraq. Due to the high number of pharmaceuticals used by the public health sector in Iraq (hospitals and care centres) and distributed over the counter, there is a need for a systematic approach for identifying substances that should be monitored in the environment in Iraq and assessed in terms of environmental risk. In this study, a risk-based prioritization approach was applied to 99 of the most dispensed pharmaceuticals in three Iraqi cities, Baghdad, Mosul and Basrah. Initially, information on the amounts of pharmaceuticals used in Iraq was obtained. The top used medicines were found to be paracetamol, amoxicillin and metformin with total annual consumption exceeding 1000 tonnes per year. Predicted environmental concentrations (PECs) and predicted no-effect concentrations (PNECs), derived from ecotoxicological end-points and effects related to the therapeutic mode of action, were then used to rank the pharmaceuticals in terms of risks to different environmental compartments. Active pharmaceutical ingredients used as antibiotics, antidepressants and analgesics were identified as the highest priority in surface water, sediment and the terrestrial environment. Antibiotics were also prioritized according to their susceptibility to kill or inhibit the growth of bacteria or to accelerate the evolution and dissemination of antibiotic-resistant genes in water. Future work will focus on understanding the occurrence, fate and effects of some of highly prioritized substances in the environment

Estrogens Can Disrupt Amphibian Mating Behavior

The main component of classical contraceptives, 17α-ethinylestradiol (EE2), has high estrogenic activity even at environmentally relevant concentrations. Although estrogenic endocrine disrupting compounds are assumed to contribute to the worldwide decline of amphibian populations by adverse effects on sexual differentiation, evidence for EE2 affecting amphibian mating behaviour is lacking. In this study, we demonstrate that EE2 exposure at five different concentrations (0.296 ng/L, 2.96 ng/L, 29.64 ng/L, 2.96 µg/L and 296.4 µg/L) can disrupt the mating behavior of adult male Xenopus laevis. EE2 exposure at all concentrations lowered male sexual arousal, indicated by decreased proportions of advertisement calls and increased proportions of the call type rasping, which characterizes a sexually unaroused state of a male. Additionally, EE2 at all tested concentrations affected temporal and spectral parameters of the advertisement calls, respectively. The classical and highly sensitive biomarker vitellogenin, on the other hand, was only induced at concentrations equal or higher than 2.96 µg/L. If kept under control conditions after a 96 h EE2 exposure (2.96 µg/L), alterations of male advertisement calls vanish gradually within 6 weeks and result in a lower sexual attractiveness of EE2 exposed males toward females as demonstrated by female choice experiments. These findings indicate that exposure to environmentally relevant EE2 concentrations can directly disrupt male mate calling behavior of X. laevis and can indirectly affect the mating behavior of females. The results suggest the possibility that EE2 exposure could reduce the reproductive success of EE2 exposed animals and these effects might contribute to the global problem of amphibian decline

PDE4 inhibition enhances hippocampal synaptic plasticity in vivo and rescues MK801-induced impairment of long-term potentiation and object recognition memory in an animal model of psychosis

Inhibition of phosphodiesterase type 4 (PDE4) by rolipram (4-(3-(cyclopentyloxy)-4-methoxyphenyl)-pyrrolidin-2-one) has been the focus of many behavioral and molecular studies in the recent years. Rolipram exhibits memory-enhancing effects in rodents. In vitro studies have shown that long-term potentiation (LTP), which may comprise a cellular substrate for learning, is also enhanced by rolipram. However, effects have not been assessed in vivo. Rolipram has antipsychotic properties. Psychosis affects cognition and in animal models of psychosis LTP is impaired. In this study, we investigated if PDE4 inhibition improves LTP in healthy animals in vivo and if PDE4 inhibition rescues impaired LTP and prevents object recognition memory deficits in an animal model of psychosis. Recordings were made from the hippocampus of adult, freely behaving Wistar rats. Thirty minutes after treatment with rolipram or vehicle, a tetanus was applied to the medial perforant path to elicit short-term potentiation (STP) in the dentate gyrus. At this time-point, radioimmunoassay revealed that rolipram significantly elevated cyclic adenosine monophosphate levels in the dorsal hippocampus, in line with reports by others that rolipram mediates decreased PDE4 activity. In healthy animals, both intracerebroventricular and subcutaneous treatment with rolipram facilitated STP into LTP, suggesting that PDE4 inhibition may have a permissive role in plasticity mechanisms that are relevant for learning and memory. One week after a single systemic treatment with the irreversible N-methyl--aspartate antagonist, MK801, LTP and object recognition memory were significantly impaired, but could be rescued by PDE4 inhibition. These data suggest that the relief of cognitive disturbances in psychosis models by rolipram may be mediated in part by a rescue of hippocampal LTP

Impact of anti-inflammatories, beta-blockers and antibiotics on leaf litter breakdown in freshwaters

Pharmaceuticals are now recognised as important pollutants in freshwater systems but a shortcoming of effects studies is that they have focused on structural endpoints and impacts on ecosystem functioning are poorly understood. The decomposition of organic matter is an important functional process in aquatic systems and it is known that this can be impacted by the presence of pollutants. Previous studies on leaf litter breakdown have only considered the effects of antibiotics and not other groups of drugs though. The current study investigated the effects of anti-inflammatories, a beta-blocker and an antibiotic on microbially mediated breakdown of leaf litter in the laboratory, colonisation of leaf packs by benthic macroinvertebrates when placed in a stream and shredding of leaf litter by these organisms. Furthermore, the effects of single compounds relative to their mixture were assessed. It was found that exposure of leaf litter to the study compounds did not influence its breakdown by microbes in the laboratory or macroinvertebrates in a stream. Exposure of leaf litter to pharmaceuticals also had no effect on its colonisation by macroinvertebrates in this study. Many unknowns remain, however, and further studies of the effects of pharmaceuticals on structural and functional endpoints are needed to aid aquatic conservation