The effects of environmental antidepressants on macroinvertebrates: a mini review

Pharmaceuticals and personal care products constitute one of the most common groups of contaminants in surface waters, and little is known about their impact on aquatic wildlife. The antidepressant fluoxetine is among more prevalent categories of pharmaceuticals detected in the aquatic environment. Typical surface water concentrations are in a wide range that can lead to alterations in life of aquatic macroinvertebrates. Because the mode of fluoxetine action is thought to be by modulation of the neurotransmitter serotonin, macroinvertebrates that possess relevant transporters and receptors sensitive are potentially affected by this pharmaceutical. Available information of how this emerging contaminant may affect macroinvertebrate communities is limited. This review describes the influence of pharmaceuticals on aquatic fauna in general and reports the environmental concentrations of some widely used antidepressants. Additionally, we highlighted the effects of fluoxetine as an antidepressant of concern, because of its abundance and potential for toxicity to aquatic macroinvertebrates.     

Preliminary risk assessment database and risk ranking of pharmaceuticals in the environment

There is increasing concern about pharmaceuticals entering surface waters and the impacts these compounds may have on aquatic organisms. Many contaminants, including pharmaceuticals, are not completely removed by wastewater treatment. Discharge of effluent into surface waters results in chronic low-concentration exposure of aquatic organisms to these compounds, with unknown impacts. Exposure of virulent bacteria in wastewater to antibiotic residues may also induce resistance, which could threaten human health. The purpose of this study was to provide information on pharmaceutical threats to the environment. A preliminary risk assessment database for common pharmaceuticals was created and put into a web-accessible database named "Pharmaceuticals in the Environment, Information for Assessing Risk" (PEIAR) to help others evaluate potential risks of pharmaceutical contaminants in the environment. Information from PEIAR was used to prioritize compounds that may threaten the environment, with a focus on marine and estuarine environments. The pharmaceuticals were ranked using five different combinations of physical-chemical and toxicological data, which emphasized different risks. The results of the ranking methods differed in the compounds identified as high risk; however, drugs from the central nervous system, cardiovascular, and anti-infective classes were heavily represented within the top 100 drugs in all rankings. Anti-infectives may pose the greatest overall risk based upon our results using a combination of factors that measure environmental transport, fate, and aquatic toxicity. The dataset is also useful for highlighting information that is still needed to assuredly assess risk.     

Impacts of emerging organic contaminants on freshwater resources: review of recent occurrences, sources, fate and effects

Rapid urbanization and frequent disposal of wastewater to surface water cause widespread contamination of freshwater supplies with emerging contaminants, such as pharmaceuticals, insecticides, surfactants, endocrine disruptors, including hormones. Although these organic contaminants may be present at trace levels, their adverse effects on aquatic life, animals and even humans are a growing concern. Numerous studies have been published on the occurrence and fate of emerging organic contaminants in different parts of the world, spanning a wide range of sources and aquatic environments including freshwater catchments, effluent wastewater streams, lakes, rivers, reservoirs, estuaries and marine waters. This paper reviews recent studies on the occurrence and fate of frequently detected pharmaceuticals and hormones and identifies areas that merit further research.     

Identification and chemical characterization of specific organic constituents of petrochemical effluents

Based on extensive GC/MS screening analyses, the molecular diversity of petrochemical effluents discharged to a river in North Rhine-Westphalia was characterised. Within a wide spectrum of organic wastewater constituents, specific compounds that might act as source indicators have been determined. This differentiation was based on (i) the individual molecular structures, (ii) the quantitative appearance of organic compounds in treated effluents and (iii) the information on their general occurrence in the technosphere and hydrosphere. Principally, site-specific indicators have been distinguished from candidates to act as general petrochemical indicators. Further on, monitoring the environmental behaviour of target organic contaminants in an aquatic system shortly after their release into the river allowed a first evaluation of the impact of the petrogenic emission in terms of the quantity and spatial distribution.The identification of petrogenic contaminants was not restricted to constituents of the effluents only, but comprised the compounds circulating in the wastewater systems within a petrochemical plant. A number of environmentally relevant and structurally specific substances that are normally eliminated by wastewater treatment facilities were identified. Insufficient wastewater treatment, careless waste handling or accidents at industrial complexes are potential sources for a single release of the pollutants.This study demonstrates the relevance of source specific organic indicators to be an important tool for comprehensive assessment of the potential impact of petrochemical activities to the contamination of an aquatic environment.     

Cholinesterase activities in the scallop Pecten jacobaeus: characterization and effects of exposure to aquatic contaminants

Nearshore marine environments of industrialized countries are increasingly threatened by anthropogenic pollution. It is therefore a priority task to investigate the sensitivity of new ecotoxicological warning signals of the occurrence and effects of aquatic pollutants. The main aims of the present study were: 1) to characterize the biochemical properties of ChEs in tissues of the bivalve Pecten jacobaeus, using different specific substrates and selective inhibitors; 2) to measure sensitivity of ChE activities to in vitro exposure to the OPs azamethiphos and DFP and to the heavy metals cadmium and zinc. Our final aim was to carry out a preliminary evaluation of the suitability of ChEs measurement in tissues of the scallop for monitoring marine environmental quality and neurotoxic compounds contamination in the Mediterranean Sea. Responses to specific inhibitors have suggested that ChEs in adductor muscle share many characteristics with vertebrate acetylcholinesterase. Dose-dependent inhibition of ChE was observed in response to in vitro exposure to environmental contaminants such as cadmium and azamethiphos. Sensitivity to zinc and DFP was lower. ChEs in P. jacobaeus might therefore have potential as a sensitive biomarker for monitoring marine pollution. Results of the present study will be useful to focus further experiment of exposure to pollutants under in vivo conditions. CAPSULE: Cholinesterase activities in scallop Pecten jacobaeus were observed to be sensitive to contaminants in vitro and may therefore have potential as biomarkers for monitoring water pollution.     

Occurrence, fate and removal of synthetic oral contraceptives (SOCs) in the natural environment: a review

Synthetic oral contraceptives (SOCs) are a group of compounds with progestagenic and/or androgenic activities, with some also possessing estrogenic activities. Recent research has documented that some of these emerging contaminants have adverse effects on aquatic organisms at very low concentrations. To facilitate the evaluation of their latent risks, published works on their occurrence and fate in the environment are reviewed. Androgenic/progestagenic relative potencies or relative binding affinity of these SOCs as well as their physicochemical properties and toxicity are summarized. Appropriate analytical methods are outlined for various environmental sample types, including methods of sample preparation and limit of detection/quantification (LOD/LOQ). Finally results on their occurrence and fate in wastewater treatment plants (WWTPs) and other environments are critically examined.     

Aquatic contamination and ecological risk. An attempt to a conceptual framework

The aim of this paper has been to introduce a conceptual model concerning the causal relationships determining the “road between dose and response” of toxic substances in aquatic environments. The paper is focused on metals and utilizes mercury as a type element. The approach puts special emphasis on the environmental factors regulating the potential effects of contaminants and stresses the importance of sedimentology in ecotoxicology. The approach discusses concepts like ecological effect, dose and sensitivity. A potential ecological risk index to be used in practical environmental control programs must also be based upon tested and comparatively inexpensive standard methods. Such an index should account for “biological contact area”, “biological contact time” and “additive effects”. A fundamental concept in this approach is the residual term, which describes the fact that it is impossible in ecological contexts to reach a complete understanding.     

Indirect effects of contaminants in aquatic ecosystems

Contaminants such as petroleum hydrocarbons, heavy metals and pesticides can cause direct toxic effects when released into aquatic environments. Sensitive species may be impaired by sublethal effects or decimated by lethality, and this ecological alteration may initiate a trophic cascade or a release from competition that secondarily leads to responses in tolerant species. Contaminants may exert direct effects on keystone facilitator and foundation species, and contaminant-induced changes in nutrient and oxygen dynamics may alter ecosystem function. Thus, populations and communities in nature may be directly and/or indirectly affected by exposure to pollutants. While the direct effects of toxicants usually reduce organism abundance, indirect effects may lead to increased or decreased abundance. Here we review 150 papers that reference indirect toxicant effects in aquatic environments. Studies of accidental contaminant release, chronic contamination and experimental manipulations have identified indirect contaminant effects in pelagic and benthic communities caused by many types of pollutants. Contaminant-induced changes in behavior, competition and predation/grazing rate can alter species abundances or community composition, and enhance, mask or spuriously indicate direct contaminant effects. Trophic cascades were found in 60% of the manipulative studies and, most commonly, primary producers increased in abundance when grazers were selectively eliminated by contaminants. Competitive release may also be common, but is difficult to distinguish from trophic cascades because few experiments are designed to isolate the mechanism(s) causing indirect effects. Indirect contaminant effects may have profound implications in environments with strong trophic cascades such as the freshwater pelagic. In spite of their undesirable environmental influence, contaminants can be useful manipulative tools for the study of trophic and competitive interactions in natural communities.     

Screening risk assessment tools for assessing the environmental impact in an abandoned pyritic mine in Spain

This paper describes a new methodology for assessing site-specific environmental impact of contaminants. The proposed method integrates traditional risk assessment approaches with real and variable environmental characteristics at a local scale. Environmental impact on selected receptors was classified for each environmental compartment into 5 categories derived from the whole (chronic and acute) risk assessment using 8 risk levels. Risk levels were established according to three hazard quotients (HQs) which represented the ratio of exposure to acute and chronic toxicity values. This tool allowed integrating in only one impact category all the elements involved in the standard risk assessment.The methodology was applied to an abandoned metal mine in Spain, where high levels of As, Cd, Zn and Cu were detected. Risk affecting potential receptors such as aquatic and soil organisms and terrestrial vertebrates were assessed. Whole results showed that impact to the ecosystem is likely high and further investigation or remedial actions are necessary. Some proposals to refine the risk assessment for a more realistic diagnostic are included.     

Integrated modelling of eutrophication and organic contaminant fate & effects in aquatic ecosystems. A review

Eutrophication and contamination with micropollutants have been major problems in water quality management. Both problems have been subjected to extensive research and modelling but traditionally are treated separately. Traditional simulation models for aquatic systems can be categorised as eutrophication models, contaminant fate models, food web models and food chain bioaccumulation models. Because they are single issue models, many interactions and feedbacks between the food web, nutrient and toxicant cycles are missed. Linking these models is essential to evaluate the fate and risks of contaminants in systems with changing nutrient loading, to assess the natural attenuation of contaminants or to understand the selfpurifying capacity of ecosystems. Combination of the single issue models requires inclusion of 'interaction processes' to account for the coupling between the (sub-) model types, such as organic carbon cycling. toxicity, transport and accumulation of organic contaminants in the food chain, and bottom up versus top down control of primary production and nutrient cycling. This review first provides a brief overview of traditional approaches in modelling eutrophication, contaminant fate, food web dynamics and food chain bioaccumulation. Second, five existing integrated eutrophication, fate and/or effects models are reviewed. Third, the gaps and limitations in modelling the four types of interaction processes are discussed. It is concluded that these models are invaluable tools to focus attention to feedback mechanisms that are often overlooked, to identify dominating processes in ecosystems, to formulate counterintuitive hypotheses on ecosystem functioning, or to assess short term risks of acutely toxic stressors. However, the potential of integrated models for long term simulations of contaminant exposure. food chain bioaccumulation and effects to higher trophic levels remains limited, mainly because of principal limitations in food web modelling. In contrast, the potential of integrated models for long term simulations of contaminant fate is better because the environmental distribution of contaminants is mainly determined by the major abiotic compartments and by biotic compartments at the base of the food chain.     

Fate of oil dispersants in aquatic environment

Chemical oil dispersants have been used throughout most of the world to combat oil spills. However, their fate in aquatic environment remains uncertain. This study was conducted to investigate the persistence of five oil dispersants in the aquatic environment. The results indicate that petroleum utilizing bacteria possess high potential for the biodegradation of oil dispersants. The order of biodegradability for the five oil dispersants was as follows: Magnus 101 > BP1100X>BP1100>Linco No. 4>Corexit 8666. From the results of this study and a review of the literature data, it can be concluded that treatment of oil spills with chemical dispersants is unlikely to cause any build-up of organic contaminants in the aquatic environment.     

Dissolved and bioavailable contaminants in the Seine river basin

Diffusive Gradient in Thin Films (DGT) and Semi-Permeable Membrane Devices (SPMDs) were deployed in the Seine river basin in order to assess labile metals and truly dissolved Polycyclic Aromatic Hydrocarbons. We show that the tools are reliable in aquatic environments to assess the speciation of dissolved contaminants and hence provide a good insight into the potential bioavailability of contaminants. The deployment of the DGT and SPMDs in contrasting environments in the Seine river basin allowed distinction to be made of availability of contaminants between headwater streams and much more impacted river reaches and an assessment of bioavailability. At the stations under urban influence, the impact of dissolved organic matter on both copper and PAHs bioavailability is less pronounced than at upstream stations, where humic substances dominate.     

Pollution of air,soil, freshwater and the sea

The main pollution problems of air, water and land are outlined. Although examples of intensive pollution ("hot‐spots") are probably less common than in the 19th century, current pollution is more widespread and the number of pollutants much greater. This makes the recognition of pollution more difficult and emphasizes the need for studies on the chronic effects of low concentrations of contaminants on individuals, populations, and communities. A study is also needed of synergistic effects resulting from the co‐action of contaminants which individually may be below threshold toxicity levels. Studies are also needed on the range of natural tolerance to a given toxin possessed by individuals and single species populations and on the environmental‐experimental aspects of selection pressures. The need for field experiments and a predictive model approach is stressed. The use of organisms as indicators and integrators of environmental pollutant burdens provides a quick and effective comparative method of mapping geographical and secular changes in contaminants.     

Zebrafish larvae as a model for the evaluation of inorganic arsenic and tributyltin bioconcentration

The European REACH legislation establishes the need to study the toxicity, persistence and bioaccumulation of those chemicals with an exceeding production of 100 tons and/or chemicals considered PBTs substances (Persistence, Bioaccumulation and Toxicity). Currently, the OECD technical guideline 305 is the most used protocol to determine bioconcentration factors of contaminants in aquatic environments. However, this procedure implies high cost and amount of adult fishes. Zebrafish (Danio Rerio) has been selected since this animal model has several advantageous features over other vertebrates, mainly fast embryonic development and easy growth. The analytical methodology here developed has been applied to calculate the bioconcentration factors (BCFs) of two contaminants: inorganic arsenic and tributyltin (measured as arsenic and tin). The method is based on the use of an ultrasonic probe assisted extraction for accelerating the sample treatment followed by detection using graphite furnace atomic absorption spectrometry with Zeeman correction (ZGFAAS). Results obtained for the BCFs values are in good agreement with previously reported data on freshwater aquatic organisms. In the case of arsenic, after exposing larvae to concentrations of 5 and 50 μg L⁻¹, very low BCFs were observed (between 2.2 and 9.5); while for tributyltin, the BCFs observed were within the range 840-1280 after exposure to concentrations of 0.2 and 2.0 μg L⁻¹, respectively. This study shows the use of zebrafish larvae together with the proposed analytical approach as a promising alternative to the OECD 305 test to evaluate the BCFs of classical and emergent contaminants.     

Comparison of contaminants from different trophic levels and ecosystems

The present paper provides an overview of the priority contaminants and media from the Greenland part of the Arctic Monitoring and Assessment Program. Levels and accumulation patterns of heavy metals, POPs and a radionuclide (137Cs) are compared from the terrestrial, freshwater and marine ecosystems. Of the nine compounds presented, seven (Cd, Hg, Se, sigma PCB, sigma DDT, sigma HCH, HCB) increased in concentration towards higher trophic levels. For these contaminants the concentrations in soil and aquatic sediment were in the same order of magnitude, whereas the concentrations in marine biota were higher than found in the freshwater and terrestrial ecosystems probably due to the presence of longer food chains. Pb and 137Cs showed the reverse pattern compared with the other compounds. The concentrations in soil and aquatic sediments decreased in the order terrestrial, freshwater and marine ecosystems, which was reflected in the biota as well. Reindeer had similar or lower levels of Pb and 137Cs than lichens. Levels of Pb and 137Cs in marine biota did not show the same clear increase towards higher trophic as found for the other analysed compounds. Greenland Inuit contains considerably less mercury but higher levels of sigma PCB, sigma DDT and HCB than other Arctic marine top consumers.     

Managing airport stormwater containing deicers: challenges and opportunities

Stormwater runoff at airports is a significant and costly issue, especially for the stormwater laden with deicing contaminants of high Biochemical Oxygen Demand (BOD) and aquatic toxicity. To reduce the loading of deicing constituents in stormwater and to manage the increasing pressure of tightening regulations, identifying fate and transport and evaluating environmental risks of deicing stormwater are of critical importance. In this review, the regulatory development of airport deicing stormwater management was first discussed, along with the milestone Airport Cooperative Research Program (ACRP) Report 14 publication. The deicer usage and fugitive losses can be reduced and the amount of deicer collected can be increased by having a better understanding of the fate and transport of deicing constituents in stormwater. As such, an overview and evaluation of the constituents of concern in deicers were provided to support the assessment of environmental impacts and mitigation recommendations. The state of knowledge of airport deicing stormwater management was then reviewed, which needs to be synthesized into a national guidance document. A guidebook and a decision tool for airports were proposed to adopt specific practical stormwater management strategies while balancing their priorities in environmental, economic, and social values against operational constraints. These challenges pose great opportunities to improve the current practices of airport deicing stormwater management.     

闽江福州段水环境容量合理利用探讨

在福州市水环境容量核算的基础上,对闽江福州段水环境容量利用中存在的问题进行分析和探讨,提出水环境容量合理利用的建议对策。     

Environmental stress and recovery: the geochemical record of human disturbance in New Bedford Harbor and Apponagansett Bay,Massachusetts (USA)

Sediments record the history of contamination to estuaries. Analysis of the concentrations of toxic organic compounds, contaminant and crustal metals, organic carbon content and isotopic composition in sediment cores from two estuarine systems in Buzzards Bay allowed reconstruction of human impacts over 350 years. Vertical distributions of the contaminants correlate with changes in the nature of watershed/estuarine activities. All contaminants were highly enriched (tens to hundreds times background) in modern New Bedford Harbor sediments. Enrichment began around the turn of the 20th century for all but PCBs, which were first synthesized in the 1930s. An increase in organic carbon content and a shift of carbon isotopes toward a more terrestrial signature illustrates increasing anthropogenic impact in New Bedford as population grew along with the industrial base. Institution of environmental protection measures in the late 20th century was reflected in decreased, although still substantially elevated, concentrations of contaminants. A lack of industrial development in Apponagansett Bay resulted in much lower concentrations of the same indicators, although specific contaminants related to the early whaling industry increased significantly above background as early as the late 18th century. The similarity of indicators in older portions of cores from NBH and unimpacted Apponagansett Bay demonstrates that cores can be used to establish reference conditions as successfully as using separate sites judged a priori to represent the reference state. The historical reconstruction approach provides the basis for establishing relationships between environmental stressors and factors that drive the stressors, as well as a framework for the assessment of ecological response(s) to environmental stressors over a range of time and/or exposure scales.     

Selenium accumulation in aquatic biota downstream of a uranium mining and milling operation

Uranium mining and milling operations have the potential to release trace elements such as arsenic, molybdenum, nickel, selenium and uranium and ions (e.g., sulfate, ammonium) into the receiving aquatic ecosystem. The major implication of elevated environmental selenium is its propensity to accumulate in the aquatic food chain, potentially impairing fish reproduction. The objective of this study was to investigate the accumulation of selenium in the major compartments of aquatic ecosystems (lakes) upstream and downstream of a uranium mine in northern Saskatchewan, Canada. Selenium concentrations in aquatic biota were elevated in the exposure lake although water and sediment concentrations were low (0.43 μg/L and 0.54 μg/g dry weight, respectively). Biomagnification of selenium resulted in approximately 1.5 to 6 fold increase in the selenium concentration between plankton, invertebrates and fish. However, no biomagnification was observed between forage and predatory fish. Although some aquatic biota (e.g., forage fish) exceeded the lower limit of the proposed 3 to 11 μg/g (dry weight) dietary toxicity threshold for fish, no adverse effects of selenium could be identified in this aquatic system. Continued environmental monitoring is recommended to avoid potential selenium impacts.