Monitoring behavioural responses to metals inGammarus pulex (L.) (Crustacea) with impedance conversion

Improving the assessment of polluted sites using an integrated bio-physico-chemical monitoring framework

Soil - water pollution resulting from anthropogenic activities is a growing concern internationally. Effective monitoring techniques play a crucial role in the detection, prevention, and remediation of polluted sites. Current pollution monitoring practices in many geographical locations are primarily based on physico-chemical assessments which do not always reflect the potential toxicity of contaminant 'cocktails' and harmful chemicals not screened for routinely. Biomonitoring provides a range of sensitive techniques to characterise the eco-toxicological effects of chemical contamination. The bioavailability of contaminants, in addition to their effects on organisms at the molecular, cellular, individual, and community level allows the characterisation of the overall health status of polluted sites and ecosystems. Quantifying bioaccumulation, changes to community structure, faunal morphology, behavioural, and biochemical responses are standard procedures employed in biomonitoring studies in many High-Income Countries (HICs). This review highlights the need to integrate biomonitoring tools alongside physico-chemical monitoring techniques by using 'effect-based' tools to provide more holistic information on the ecological impairment of soil-water systems. This paper considers the wider implementation of biomonitoring methods in Low to Middle Income Countries (LMICs) and their significance in pollution investigations and proposes an integrated monitoring framework that can identify toxicity drivers by utilising 'effect-based' and 'risk-based' monitoring approaches.

Advances in real-time monitoring of water quality using automated analysis of animal behaviour

Monitoring of freshwater quality and its potential sudden contamination is integral to human health, sustainable economic development and prediction of pollutant impact on aquatic ecosystems. Although there have been significant advances in technologies for automated sampling and continuous analysis of water physicochemical parameters, the current capabilities for real-time warning against rapidly developing unknown mixtures of chemical hazards are still limited. Conventional chemical analysis systems are not suitable for assessing unknown mixtures of chemicals as well as additive and/or synergetic effects on biological systems. From the perspective of neurotoxicology the acute exposures to chemical agents that affect nervous system and can enter the freshwater supplies accidentally or as a result of deliberate action, can only be reliably assessed using appropriate functional biological models. In this regard real-time biological early warning systems (BEWS), that can continuously monitor behavioural and/or physiological parameters of suitable aquatic bioindicator species, have been historically proposed to fill the gap and supplement conventional water quality test strategies. Alterations in sub-lethal neuro-behavioural traits have been proven as very sensitive and physiologically relevant endpoints that can provide highly integrative water quality sensing capabilities. Although BEWS are commonly regarded as non-specific and lacking both quantitative and qualitative detection capabilities, their advantages, if properly designed and implemented, lie in continuous sensing and early-warning information about sudden alteration in water quality parameters. In this work we review the future prospects of real-time biological early warning systems as well as recent developments that are anchored in historical successes and practical deployment examples. We concentrate on technologies utilizing analysis of behavioural and physiological endpoints of animal bioindicators and highlight the existing challenges, barriers to future development and demonstrate how recent advances in inexpensive electronics and multidisciplinary bioengineering can help revitalize the BEWS field.

The effects of wastewater effluent on multiple behaviours in the amphipod, Gammarus pulex

The prevalence of pharmaceuticals and personal care products (PPCPs) in lotic habitats is increasing, with the main source of these contaminants being effluent from waste water treatment works (WwTW). There is still much uncertainty about the impacts of these PPCPs at environmentally relevant concentrations and their potential effects on aquatic ecology. Behaviour is a sensitive endpoint which can help evaluate possible population level effects from changes in physiology. This paper evaluates the effects of WwTW effluent on a range of behaviours in the freshwater invertebrate, Gammarus pulex. Effluent taken from the outflow of two WwTW in southern England was used in the study. Behavioural analyses, namely feeding rate, phototaxis, activity, velocity and precopula pairing, were measured in G. pulex following a period of one and three weeks after exposure to a 50% or 100% effluent and a control. Mortality remained very low throughout the 3 week experiment (0-10%, n = 20) and no significant changes in moulting frequency were observed (p > 0.05). No significant effects on feeding or velocity or phototaxis following 3 weeks of effluent exposures were observed (p > 0.05). However, significant reductions were observed in the overall activity over 3 weeks across which appeared to be exacerbated by exposure to effluents. Interestingly, males exposed for 3 weeks to WwTW effluent re-paired with unexposed females significantly faster (4-6x) than control animals. This result was consistent between the effluents taken from the two WwTW. The implications of these behavioural changes are currently unknown but highlight the need for a varied set of tools to study the behavioural changes in wildlife.

The Impact of Metal-Rich Sediments Derived from Mining on Freshwater Stream Life

Metal-rich sediments have the potential to impair life in freshwater streams and rivers and, thereby, to inhibit recovery of ecological conditions after any remediation of mine water discharges. Sediments remain metal-rich over long time periods and have long-term potential ecotoxicological interactions with local biota, unless the sediments themselves are physically removed or replaced by less metal-rich sediment. Laboratory-derived environmental quality standards are difficult to apply to the field situation, as many complicating factors exist in the real world. Therefore, there is a strong case to consider other, field-relevant, measures of toxic effects as alternatives to laboratory-derived standards and to seek better biological tools to detect, diagnose and ideally predict community-level ecotoxicological impairment. Hence, this review concentrated on field measures of toxic effects of metal-rich sediment in freshwater streams, with less emphasis on laboratory-based toxicity testing approaches. To this end, this review provides an overview of the impact of metal-rich sediments on freshwater stream life, focusing on biological impacts linked to metal contamination.

Behavioural effects on marine amphipods exposed to silver ions and silver nanoparticles

Behavioural responses to contaminants are an important endpoint in ecotoxicology because they link effects at biochemical or cellular levels to impacts on individual fitness. Due to the increasing use of silver in nanomaterials, studies of its effects on the behaviour of aquatic organisms are important to assess the risks of silver nanoparticles (AgNP) released into the environment. The aim of this work was to evaluate the behavioural effects of silver on the marine amphipod Echinogammarus marinus after exposure to AgNO₃ via water and AgCl or AgNP via food. Swimming activity of the amphipods was tracked during 6 min alternating dark and light conditions. Animals swam slower and responded less to light at higher concentrations of silver in the water. No differences were found in the behaviour of animals exposed via feeding up to 28 days, hence, longer exposure times may be required for the observation of effects. This is the first work to appraise behaviour effects of silver ions and AgNP on marine amphipods. Although the protocol has been successfully developed for this purpose, specimens appeared to habituate to test conditions during the experiments. Therefore, the need for further understanding of baseline behaviours in these model organisms is discussed.

Shedding light on the effects of hydraulic fracturing flowback and produced water on phototactic behavior in Daphnia magna

The effluent produced during hydraulic fracturing (i.e. flowback and produced water; FPW), is a complex hyper-saline solution that is known to negatively impact the survival and the fitness of the water flea Daphnia magna, but to date effects on behavior are unstudied. In the current study, the effects of FPW on phototactic behavior of D. magna were examined. Exposure of naïve animals to FPW resulted in a dose-dependent increase in the speed of appearance of daphnids in the illuminated zone of the test apparatus (i.e. a faster positive phototaxis response). A similar dose-dependent response was observed in a test solution where the salt content of FPW was recreated in the absence of other components, suggesting that the effect was largely driven by salinity. The effect of FPW was significant when the raw FPW sample was diluted to 20% of its initial strength, while the effect of salt-matched solution was significant at a 10% dilution. A distinct effect was observed following FPW pre-exposure. After a 24 h pre-exposure to 1.5% FPW, Daphnia displayed a significantly inhibited positive phototaxis response when examined in control water, relative to control animals that were not pre-exposed to FPW. This effect was not observed in salinity pre-exposed animals, however these daphnids displayed a significantly reduced phototactic response when tested in saline waters, indicating a loss of the positive phototaxis seen in naïve organisms. These data indicate that FPW can induce perturbations in the behavior of aquatic invertebrates, an effect that may influence processes such as feeding and predation rates.

Species-specific behaviours in amphipods highlight the need for understanding baseline behaviours in ecotoxicology

Behavioural studies in ecotoxicology are increasing with techniques and endpoints used in pharmacology being translated to other vertebrate and invertebrate species. Despite this, data on the baseline behaviours of model organisms, and inter-species variability in behaviour are currently under-studied. This study assessed a range of behaviours associated with anxiety including swimming speed, phototaxis and thigmotaxis in a marine and freshwater amphipod (Echinogammarus marinus and Gammarus pulex). Differences in sensitivity to these assays were observed between species with E. marinus showing a greater sensitivity to the phototaxis assay than G. pulex, while in thigmotaxis assays G. pulex appeared better suited than E. marinus for measuring differences in the use of central zones. Significant inter-species differences were also observed in swimming patterns when breaking the data into ten second time bins but not when data was broken into two-minute time bins. The results of this study provide evidence of phototactic and thigmotactic behaviours in two model crustacean species with potential for use in behavioural ecotoxicology. Inter-species variability in sensitivity to behavioural assays highlights the importance of systematic assessment of baseline responses for all model species used in behavioural studies. Careful analysis of data is also required when performing behavioural studies so as not to lose sensitivity in your data.

Influence of temperature on toxicity of single pharmaceuticals and mixtures, in the crustacean A. desmarestii

Lethal and sublethal responses of the shrimp Atyaephyra desmarestii exposed to three pharmaceutical compounds, Diclofenac (DF), Ibuprofen (IB) and Carbamazepine (CBZ), individually and in mixtures, were evaluated under two temperature scenarios. LC50 (96h) values were obtained individually at 20° and 25°C. At 25°C, mortality in binary and ternary mixtures is higher than at 20°C. The toxicity of the mixtures was predicted on the basis of individual mortality data using two toxicity models: Concentration addition (CA) and Independent action (IA). Our results showed that neither CA nor IA unequivocally predicted the observed toxicity of binary and ternary mixtures. For sublethal toxicity, selected endpoints were: ingestion rate, osmoregulatory capacity and respiration rate. Regarding osmoregulatory capacity, no significant differences were found. The highest ingestion rates were recorded in organisms exposed at 25°C, irrespective of the compound, after 30 and 60min of exposure. At 20°C, there was a significant decrease in respiration rate (Dunnett́s test p<0.05) under conditions of severe anoxia (1mg O2L(-1)) in organisms exposed to 13.3μgL(-1) of DF. At 25°C a significantly lower respiration rate with respect to the control (Dunnett́s test p<0.05) was found in organisms exposed to 13.8μgL(-1) of CBZ under conditions of moderate hypoxia and well-oxygenated water (3 and 5mg O2L(-1), respectively). The respiratory independence of organisms exposed to the higher temperature (25°C) also decreased. This study shows that CBZ and DF individually, even at relatively low concentrations, may produce respiratory deficiencies in the freshwater shrimp, Atyaephyra desmarestii under certain temperature and water oxygenation conditions, thus reducing its ability to function.

Sublethal toxicity of untreated and treated stormwater Zn concentrations on the foraging behaviour of Paratya australiensis (Decapoda: Atyidae)

Aquatic organisms use chemical cues to perform key ecological behaviours such as locating food. Anthropogenic pollutants have the potential to disrupt these behaviours by down-regulating chemoreception. Urban stormwater runoff is a major source of metal pollution, particularly Zn, and is a leading contributor to the degradation of receiving waters. Consequently, significant remedial efforts have focused on using constructed stormwater wetlands to reduce pollutant loads. However, no studies have examined the efficacy of water quality improvements on ecologically relevant behaviours in aquatic biota. We conducted controlled laboratory experiments to test whether untreated (100 and 400 µg L(-1)) and treated (40 µg L(-1)) stormwater Zn concentrations observed in constructed wetlands interfere with the foraging behaviour of the glass shrimp (Paratya australiensis). The ability of shrimp to perceive, approach and search for a chemoattractant source was used to assess foraging behaviour. Abnormal foraging behaviour was observed in shrimp exposed to Zn at untreated stormwater concentrations. The strongest change relative to the control was observed for perception, which decreased by more than 80 and 60 % in the 400 µg Zn L(-1) and 100 µg Zn L(-1) groups, respectively. The behaviour of shrimp exposed to Zn concentrations measured in treated stormwater did not differ from the controls. The results suggest that the reduction of stormwater Zn concentrations via wetland treatment can prevent abnormal contamination-induced behaviours in shrimp, leading to improved aquatic ecosystem health. This study also highlights the subtle, but biologically significant impacts arising from sublethal exposures of Zn, and emphasise the utility of behavioural toxicology. The behavioural test used here is a simple and effective approach that could be incorporated into studies assessing the efficacy of stormwater treatment.

Exposure to cerium dioxide nanoparticles differently affect swimming performance and survival in two daphnid species

The CeO₂ NPs are increasingly used in industry but the environmental release of these NPs and their subsequent behavior and biological effects are currently unclear. This study evaluates for the first time the effects of CeO₂ NPs on the survival and the swimming performance of two cladoceran species, Daphnia similis and Daphnia pulex after 1, 10 and 100 mg.L⁻¹ CeO₂ exposures for 48 h. Acute toxicity bioassays were performed to determine EC₅₀ of exposed daphnids. Video-recorded swimming behavior of both daphnids was used to measure swimming speeds after various exposures to aggregated CeO₂ NPs. The acute ecotoxicity showed that D. similis is 350 times more sensitive to CeO₂ NPs than D. pulex, showing 48-h EC₅₀ of 0.26 mg.L⁻¹ and 91.79 mg.L⁻¹, respectively. Both species interacted with CeO₂ NPs (adsorption), but much more strongly in the case of D. similis. Swimming velocities (SV) were differently and significantly affected by CeO₂ NPs for both species. A 48-h exposure to 1 mg.L⁻¹ induced a decrease of 30% and 40% of the SV in D. pulex and D. similis, respectively. However at higher concentrations, the SV of D. similis was more impacted (60% off for 10 mg.L⁻¹ and 100 mg.L⁻¹) than the one of D. pulex. These interspecific toxic effects of CeO₂ NPs are explained by morphological variations such as the presence of reliefs on the cuticle and a longer distal spine in D. similis acting as traps for the CeO₂ aggregates. In addition, D. similis has a mean SV double that of D. pulex and thus initially collides with twice more NPs aggregates. The ecotoxicological consequences on the behavior and physiology of a CeO₂ NPs exposure in daphnids are discussed.

Effects of sublethal cadmium exposure on antipredator behavioural and antitoxic responses in the invasive amphipod Dikerogammarus villosus

Amphipods are recognised as an important component of freshwater ecosystems and are frequently used as an ecotoxicological test species. Despite this double interest, there is still a lack of information concerning toxic impacts on ecologically relevant behaviours. The present study investigated the influence of cadmium (Cd), a non-essential heavy metal, on both antipredator behaviours and antitoxic responses in the invasive amphipod Dikerogammarus villosus under laboratory conditions. Amphipod behaviour (i.e. refuge use, aggregation with conspecifics, exploration and mobility) was recorded following a 4-min test-exposure to 500 µg Cd/L with or without a 24-h Cd pre-exposure and in the presence or absence of a high perceived risk of predation (i.e. water scented by fish predators and injured conspecifics). Following behavioural tests, malondialdehyde (MDA) levels, a biomarker for toxic effect, and energy reserves (i.e. lipid and glycogen contents) were assessed. Cd exposures induced (1) cell damage reflected by high MDA levels, (2) erratic behaviour quantified by decreasing refuge use and exploration, and increasing mobility, and (3) a depletion in energy reserves. No significant differences were observed between 4-min test-exposed and 24-h pre-exposed individuals. Gammarids exposed to Cd had a disturbed perception of the alarm stimuli, reflected by increased time spent outside of refuges and higher mobility compared to gammarids exposed to unpolluted water. Our results suggest that Cd exposure rapidly disrupts the normal behavioural responses of gammarids to alarm substances and alters predator-avoidance strategies, which could have potential impacts on aquatic communities.

Ecotoxicological effects of activated carbon amendments on macroinvertebrates in nonpolluted and polluted sediments

Amendment of contaminated sediment with activated carbon (AC) is a remediation technique that has demonstrated its ability to reduce aqueous concentrations of hydrophobic organic compounds. The application of AC, however, requires information on possible ecological effects, especially effects on benthic species. Here, we provide data on the effects of AC addition on locomotion, ventilation, sediment avoidance, mortality, and growth of two benthic species, Gammarus pulex and Asellus aquaticus , in clean versus polycyclic aromatic hydrocarbon (PAH) contaminated sediment. Exposure to PAH was quantified using 76 μm polyoxymethylene passive samplers. In clean sediment, AC amendment caused no behavioral effects on both species after 3-5 days exposure, no effect on the survival of A. aquaticus , moderate effect on the survival of G. pulex (LC(50) = 3.1% AC), and no effects on growth. In contrast, no survivors were detected in PAH contaminated sediment without AC. Addition of 1% AC, however, resulted in a substantial reduction of water exposure concentration and increased survival of G. pulex and A. aquaticus by 30 and 100% in 8 days and 5 and 50% after 28 days exposure, respectively. We conclude that AC addition leads to substantial improvement of habitat quality in contaminated sediments and outweighs ecological side effects.

Effect of gender on physiological and behavioural responses of Gammarus roeseli (Crustacea Amphipoda) to salinity and temperature

The importance of potentially interacting factors in organisms responses to a stress are often ignored or underestimated in ecotoxicology. In laboratory experiments we investigated how gender, temperature and age influence the behaviour and the physiology of the freshwater amphipod Gammarus roeseli under salinity stress. Our results revealed a significant higher sensitivity of females in survival, ventilation and ionoregulation whereas no inter-age differences were reported. Water temperature also exerted a significant effect in survival and ventilation of G. roeseli. Some of those factors appeared to interact significantly. This study provides evidence that gender can affect organisms responses to a stressor and consequently has to be considered while assessing a stress impact. We discussed the potential relationships between biological and behavioural responses.

Can behavioural responses of Lumbriculus variegatus (Oligochaeta) assess sediment toxicity? A case study with sediments exposed to acid mine drainage

The São Domingos mine (Portugal) is, potentially, a good site for ecotoxicological studies, due to a pH and metal gradient of acid mine drainage. In this study, the toxicity of several mine sediments was evaluated using the aquatic oligochaete Lumbriculus variegatus as a test organism. Our hypothesis was that exposure to contaminated sediments would cause behavioural early warning responses in L. variegatus. Five sites, with pH ranging from 2.5 to 6.5, and with associated metals, were investigated. The results showed poor sediment quality in most of the collected sediments and Fe, S and As were the dominant elements in the samples. High mortalities were observed, ranging from 32.6 to 100%, indicating severe contamination. The collected sediments did not support good L. variegatus growth and significantly changed its behaviour. Early warning responses consisted of decreased locomotion and decreased peristaltic movements. A behaviour inhibition will affect the ecosystem balance by limiting the organisms' ability to avoid capture, which leads to a higher risk of predation.

Contrasting sensitivities to toxicants of the freshwater amphipods Gammarus pulex and G. fossarum

Amphipods are an important component of freshwater ecosystems. They are very often used in ecotoxicology, particularly the freshwater amphipod Gammarus pulex. However, there is scarce information on the sensitivity to toxicants of other species within the genus Gammarus. The present study aims to: (1) to compare sensitivities to ivermectin and cadmium between two species of freshwater amphipods (G. pulex and G. fossarum); (2) to compare sensitivities to these toxicants between juveniles and adults within each species; and (3) to assess whether the sensitivity to toxicants of these co-generic species is related with the wideness of their natural distribution area. Eight independent short-term bioassays (96 h) were conducted to assess sensitivity for ivermectin and cadmium for juvenile and adult life stages for each species. The LC50 (mortality) and EC50 (mortality plus immobility) were calculated to 48 and 96 h of continuous exposure. Our results showed that G. pulex was less tolerant to ivermectin than G. fossarum, the reverse being true for cadmium. In general, juveniles of both species were less tolerant to cadmium than adults. In the case of ivermectin, only for G. fossarum EC50 values were different between life stages. These results suggest that the risk assessment of toxicants to freshwater amphipods should include bioassays with the most sensitive species and life stage.

Gammarus spp. in aquatic ecotoxicology and water quality assessment: toward integrated multilevel tests

The amphipod genus Gammarus is widespread and is structurally and functionally important in epigean freshwaters of the Northern Hemisphere. Its presence is crucial, because macroinvertebrate feeding is a major rate-limiting step in the processing of stream detrius. In addition, Gammarus interacts with multiple trophic levels bu functioning as prey, predator, herbivore, detritivore, and shredder. Such a broad span of ecosystem participation underlines the importance of Gammarus to pollutants and other disturbances may render it a valuable indicator for ecosystem health. This review summarizes the vast number of studies conducted with Gammarus spp. for evaluating aquatic ecotoxicology endpoints and examines the suitability of this native invertabrate species for the assessment of stream ecosystem health in the Northern Hemisphere. Numerous papers have been published on how pollutants affect gammarind behavior (i.e., mating, predator avoidance), reproduction, development, feeding activity, population structure, as well as the consequences of pollution on host-parasite, predator-prey, or native-invasive species interactions. Some biochemical and molecular biomarkers have already been established, such as the measurement of vitellogenin-like proteins, metallothioneins, alkali-labile phosphates (in proteins), and lipogenic enzyme activities for assessing endocrine distribution and detoxification mechanisms.

Behavioural responses of indigenous benthic invertebrates (Echinogammarus meridionalis, Hydropsyche pellucidula and Choroterpes picteti) to a pulse of Acid Mine Drainage: a laboratorial study

The drainage of abandoned mines leads to several ecological problems, particularly the acidification of surface freshwater systems and heavy metal contamination. In order to study the possibility of using the behavioural early warning responses of Portuguese indigenous benthic invertebrates to detect an acute short-term pulse of Acid Mine Drainage (AMD), experiments with the Multispecies Freshwater Biomonitor MFB were performed and locomotion and ventilation were measured as endpoints. AMD was collected from the "São Domingos" mine (Southeast Portugal) and the following species were selected: Echinogammarus meridionalis (Pinkster, 1973), Hydropsyche pellucidula (Curtis, 1834) and Choroterpes picteti (Eaton, 1870). For simulating the pulsed exposure, AMD was added to river water where invertebrates were collected and pH was lowered until reaching 3.5. The effects of H+ and heavy metals were discriminated using HCl positive controls. In addition to behaviour, mortality was registered. E. meridionalis was the most sensitive species in terms of mortality and behavioural endpoints, followed by C. picteti and H. pellucidula. E. meridionalis early warning responses consisted of increased locomotion with subsequent increase in ventilation, whereas for C. picteti only an increase in locomotion was observed. H. pellucidula showed no early warning responses. This work demonstrates the suitableness of using benthic invertebrates' behavioural early warning responses for detecting spikes of pollutants like AMD.

Importance of exposure route for behavioural responses in Lumbriculus variegatus Müller (Oligochaeta: Lumbriculida) in short-term exposures to Pb

GOAL, SCOPE AND BACKGROUND

Lumbriculus variegatus Miller (Oligochaeta), a common freshwater sediment-dweller, has frequently been used in toxicokinetic studies, although has been less used in ecotoxicity tests.

METHODS

For the first time the Multispecies Freshwater Biomonitor (MFB) was applied in a short-term whole-sediment toxicity test. The MFB automatically and quantitatively recorded the spontaneous locomotory behaviour of Lumbriculus variegatus in exposures with two compartments, water and sediment. The study questioned, whether the animals altered their locomotion depending on the compartment which was spiked with lead (Pb).

RESULTS AND DISCUSSION

As in the exposures to Pb-contaminated water/clean sediment, the animals exposed to Pb-contaminated sediment/clean water showed higher activities in intermediate Pb-concentrations. This indicates, that spontaneous locomotory activity is affected by Pb-concentrations at sublethal levels regardless of whether the Pb-concentration is found in the water or in the sediment, because these animals use both environmental compartments simultaneously. However, within the same Pb-levels, the animals showed higher locomotory activity in contaminated water compared with contaminated sediment. This indicates a possible tendency to withdraw from ('avoidance') contaminated water into the clean sediment compartment, whereas there was no withdrawal from contaminated sediment into clean water. The latter might be explained by the fact that withdrawal from sediment to water might increase the risk of predation and drift in nature, whereas retracting to sediment might provide shelter,

CONCLUSIONS

The study showed that spontaneous locomotory responses of L. variegatus to Pb depend on whether the water or sediment is contaminated. The study also concluded that the Multispecies Freshwater Biomonitor can be applied effectively in sediment toxicity testing.

RECOMMENDATIONS AND PERSPECTIVES

More emphasis should be given to the interactions of water/sediment in sediment ecotoxicity tests to better simulate field conditions and increase ecological realism in risk assessment, especially as quantitative recording methods exisit.

Biomonitoring with Gammarus pulex at the Meuse (NL), Aller (GER) and Rhine (F) rivers with the online Multispecies Freshwater Biomonitor®

Biological early warning systems represent a set of tools that may be able to respond to certain chemical monitoring requirements of recent European legislation, the Water Framework Directive (WFD2000/60/EC), that aims to improve and protect water quality across Europe. In situ biomonitoring was performed along the rivers Meuse (NL), Aller (GER) and Rhine (F) within the frame of the European Union-funded Project SWIFT-WFD. Gammarus pulex was used as a test organism during the evaluation of the Multispecies Freshwater Biomonitor(R) (MFB), an online biomonitor to quantitatively record different behaviour patterns of animals. At the river Meuse G. pulex reacted to pulse exposure of either a mixture of trace metals or of several organic xenobiotics, by showing up to 20% decreased locomotory activity (already at the 1st pulse) and increased mortality (at 2nd or 3rd pulse only). G. pulex deployed within the MFB system were observed to survive well at the monitoring station on the Aller (100%) and monitoring did not result in the measurement of chemical irregularities. In contrast, deployment at the monitoring station on the Rhine river demonstrated that the test organism was able to detect chemical irregularities by up to 20% decreased locomotory activity in the animals. The MFB proved to be an alert system for water quality monitoring at sensitive sites and sites with accidental pollution.

Use of the multispecies freshwater biomonitor to assess behavioral changes of Corophium volutator (Pallas, 1766) (Crustacea, Amphipoda) in response to toxicant exposure in sediment

Automated sediment toxicity testing and biomonitoring has grown rapidly. This study tested the suitability of the marine amphipod Corophium volutator (Pallas, 1766) for sediment biomonitoring using the Multispecies Freshwater Biomonitor (MFB). Two experiments were undertaken to (1) characterize individual behaviors of C. volutator using the MFB and (2) examine behavioral changes in response to sediment spiked with the pesticide Bioban. Four behaviors were visually identified (walking, swimming, grooming and falling) and characterized in the MFB as different patterns of locomotor activity (0-2 Hz range). Ventilation was not visually observed but was detected by the MFB (2-8 Hz). No clear diel activity patterns were detected. The MFB detected an overall increase in C. volutator locomotor activity after Bioban addition to the sediments (56, 100, 121 mg kg(-1)). C. volutator was more active (both locomotion and ventilation) in the water column than the spiked sediment. C. volutator appears a sensitive and appropriate species for behavioral sediment toxicity assessment and biomonitoring.

Behavioural responses of Gammarus pulex (Crustacea, Amphipoda) to low concentrations of pharmaceuticals

The continuous discharge of pharmaceuticals and personal care products into the environment results in a chronic exposure of aquatic organisms to these substances and their metabolites. As concentrations in surface waters are in the ng/L range, and sometimes in the low microg/L range, they are not likely to result in lethal toxicity. However, prolonged exposure to low concentrations of anthropogenic chemicals may lead to sublethal effects, including changes in behaviour. The aim of this study was to assess the effect of three pharmaceuticals, the antidepressant fluoxetine, the analgesic ibuprofen and the anti-epileptic carbamazepine, and one cationic surfactant, cetyltrimethylammonium bromide (CTAB), on the activity of the benthic invertebrate Gammarus pulex (Crustacea: Amphipoda: Gammaridae). We used the multispecies freshwater biomonitor to assess changes in activity of G. pulex in a quantitative manner. Exposure to low concentrations (10-100ng/L) of fluoxetine and ibuprofen resulted in a significant decrease in activity, whereas the activity of G. pulex at higher concentrations (1microg/L-1mg/L) was similar to the control. Response to carbamazepine showed a similar pattern, however, differences were not significant. The tested surfactant CTAB evoked a decrease in activity at increasing concentration. These behavioural effect concentrations were 10(4) to 10(7) times lower than previously reported LOECs and in the range of environmentally occurring concentrations. The potential consequences of this decreased activity for G. pulex population growth and benthic community structure and the exposure to mixtures of pharmaceuticals deserves further attention.

Behavioral changes and acute toxicity to the freshwater shrimp Atyaephyra desmaresti Millet (Decapoda: Natantia) from exposure to acid mine drainage

Short-term 48 h laboratory bioassays with water from an acid mine drainage (AMD: pH 3.3, 4.4, 5.0, 5.5, 6.4, control) and water from an arsenic containing reservoir were performed with the freshwater shrimp Atyaephyra desmaresti Millet, validated in situ and compared to acidified control water (ACID). Behaviour, mortality and time to death were monitored with the Multispecies Freshwater Biomonitor (MFB). The shrimps had equal 24 h-LC50s at pH 4 in AMD and ACID. However, after 48 h AMD proved more toxic (48 h-LC50 at pH 5.2) than ACID (48 h-LC50 at pH 4.5). Stress behaviour in AMD consisted at pH < or = 6.4 of a pH-dependent decrease in activity, with disappearance of circadian rhythmicity, and at pH 4.4 a clear increase of ventilation. At pH 5.5 bioaccumulation of metals was higher and locomotion lower than at pH 5.0. In ACID, only at pH < or = 4.4 locomotion became abated and arythmic. Locomotion in the field was equal or higher compared to the laboratory, whereas the ventilation was higher in the laboratory. A. desmaresti is a valuable species to be used in short term behavioural bioassays of AMD in Europe.

Behaviour of the three-spined stickleback, Gasterosteous aculeatus (Gasterosteidae, Teleostei) in the multispecies freshwater biomonitor: a validation of automated recordings at three levels of ammonia pollution

The validity of using an automated online biomonitoring system, the multispecies freshwater biomonitor (MFB), in recording the physiological and behavioural activities of the three-spined stickleback Gasterosteous aculeatus, is assessed. The direct impact of the alternating electrical current generated by the impedance converter on fish activity was measured using a repeated measures design, machine on/machine off. Twelve subjects were used in each of three experimental groups: (1). standard hard water environment (control), (2). 0.1mM NH(4)Cl and (3). 10mM NH(4)Cl. Impedance generated waves were compared to corresponding manually recorded behavioural observations in an attempt to calibrate the MFB, assigning particular behaviours to a particular frequency and amplitude range. Data analysis suggests that the MFB current did not affect fish behaviour at any of the three contamination levels studied. Furthermore, analysis of the frequency with which behavioural activity changed (activity phases classified as inactive or active) showed that MFB behavioural data was not significantly different from that recorded manually. This suggested that the MFB recorded the behaviours that were concurrently observed. The feasibility of using the MFB as an effective behavioural early warning system in an aquacultural environment and as a scientific tool for toxicity testing is discussed.

Behavioural response of the cladoceran Daphnia magna STRAUS to sublethal Copper stress--validation by image analysis

In this study changes in the locomotory behaviour of the freshwater cladoceran Daphnia magna STRAUS were used as sublethal indicators of toxic copper (Cu) stress. The behavioural responses were determined by a real time image analysis, using a video camera and a Pentium-PC equipped with a standard low cost frame grabber. For a sequence of 50 images per group, where 10 daphnids were moving simultaneously, the trajectories have been reconstructed in binary image sequences. As biological endpoints, we defined the average swimming velocity and the average duration of swimming activity and inactivity. The behavioural responses of the daphnids were analysed under normal conditions (without Cu stress) and after application of sublethal Cu stress of following concentrations (in microg l(-1) (ppb)): C1=1, C2=5, C3=10, C4=20, C5=30. The test organisms were exposed to the Cu concentration for 24 h under static conditions. Already after 9 h of Cu-exposure a significant (*P<0.05) decrease of the average swimming velocity could be observed at the group of the highest Cu concentration (30 ppb). After 13 h of Cu-contamination the swimming velocity was significantly (*P<0.05) reduced at group of 20 ppb Cu-treatment and after 14 h a significant (*P<0.05) decrease of the average swimming velocity could be measured at the group of 10 ppb Cu-treatment. No significant decrease of the swimming velocity could be observed in the 1 and 5 ppb Cu-treatment.

The effect of copper on osmoregulation in the freshwater amphipod Gammarus pulex

The influence of copper on osmoregulation in the freshwater amphipod Gammarus pulex was determined from the analysis of water permeability, haemolymph sodium concentration, sodium influx and gill Na(+)/K(+) ATPase and Mg(2+) ATPase activity. Exposure to nominal copper concentrations of 100 microg l(-1) or greater caused a significant reduction in both haemolymph sodium concentration and sodium influx within 4 h. Measurements of water permeability, expressed as the half-time of exchange of body water (t(1/2)), excluded structural gill damage as the cause of this fall in haemolymph sodium. Copper at 10 microg l(-1) or above in the assay solution significantly reduced gill Na(+)/K(+) ATPase activity. In contrast gill Mg(2+) ATPase activity was markedly less affected by copper. These differences in enzyme sensitivity were considered with respect to the potential mechanisms of copper toxicity.

Elucidating the routes of exposure for organic chemicals in the earthworm, Eisenia andrei (Oligochaeta)

Earthworms take up organic compounds through their skin as well as from their food, but the quantitative contribution of each route is unclear. In this contribution, we experimentally validate an accumulation model containing a separate compartment for the gut. Uptake from the gut is modeled as passive diffusion from the dissolved phase in the gut contents. For the experiments, we exposed Eisenia andrei in artificial soil spiked with tetrachlorobenzene, hexachlorobenzene, and PCB 153. Apart from the standard accumulation and elimination experiments, we ligatured the worm (using tissue adhesive) to prevent feeding. Model fits were good, thus supporting the validity of the model. The contribution of the gut route increased with increasing hydrophobicity of the chemical, and for PCB 153 the gut route clearly dominated. Despite the importance of the gut route, the final steady-state body residues did not exceed equilibrium partitioning predictions by more than 25%. Rate constants for exchange across the skin and the gut wall could be separately identified. The rate constant across the skin decreases with K(ow) but was generally higher than data derived from water-only exposure. The relationship with hydrophobicity was less clear for the rate constant across the gut wall.

Short-term responses of Oryzias latipes (Pisces: Adrianichthyidae) and Macrobrachium nipponense (Crustacea: Palaemonidae) to municipal and pharmaceutical waste water in Beijing, China: survival, behaviour, biochemical biomarkers

Whole effluent toxicity was assessed for the fish Oryzias latipes and the prawn Macrobrachium nipponense for 18 h in a dilution series (0-66%) of the inflow and effluent of a municipal waste water treatment plant as well as waste water from a teramycin producing pharmaceutical industry, before, during and after a pilot laboratory purification process. The waste waters caused acute toxicity as measured by inhibition of light emission in the luminiscent bacterium Vibrio qingaiensis sp. nov. (Q67). EROD and aryl hydrocarbon hydroxylase activity in in vitro carp liver-cells showed a dose-dependent toxic response to the municipal waste water. Behavioural responses and time-to-death of fish and prawn, recorded online with the "Multispecies Freshwater Biomonitor" proved to be concentration- and time-dependent sensitive toxicity indicators in both types of waste water. Behaviour changed stepwise from normal activity to (increased or decreased) activity to more time spent on ventilation and finally to increased morbidity at higher concentration and time of exposure. The municipal waste water treatment plant managed to reduce toxicity to bacteria (Q67), prawn and fish. The pharmaceutical waste water treatment process still has to be improved, in order to reduce toxicity for fish and prawn.

Biomimetic extraction of PAHs and PCBs from soil with octadecyl-modified silica disks to predict their availability to earthworms

We developed a model to predict the availability of PAHs and PCBs to earthworms (Lumbricus terrestris L.) in soils. We related the uptake of PAHs and PCBs by earthworms to the extraction with octadecyl-modified silica disks (C18 disks). Eleven soils (data set A) were used to develop the model, and 14 additional soils (data set B) were used to validate it independently. The biota-to-soil accumulation factors (BSAFs) of higher molecular weight PAHs (> or =202 g mol(-1)) and PCBs were higher than the corresponding Cl8 disk-soil partition coefficients (Kdisk) in the soils of data set A. This suggested that PAHs and PCBs were not only partitioned between soil and earthworms but also selectively ingested or metabolized. Nevertheless, we could predict the BSAFs of individual PAHs and PCBs for data set A by regression equations of log BSAF on log Kdisk (r=0.47-0.87). To predict the BSAFs of all PAHs and PCBs, respectively, we derived a model for each compound class that uses Kdisk and K(ow) values. Both the compound and the compound-class specific model were suitable to predict the BSAFs of PAHs and PCBs in data set B within a factor of 10-15.

Behavioural early warning responses to polluted water : Performance ofGammarus pulex L. (Crustacea) andHydropsyche angustipennis (Curtis) (Insecta) to a complex industrial effluent

Behavioural early warning responses to polluted surface water from an industrial effluent have been measured in two freshwater macroinvertebrate species using the four electrode impedance conversion technique. Specimens ofGammarus pulex (L.) andHydropsycho angustipennis (Curtis) were caught from reference streams and exposed to water from above and below the factory and to reference water for about 1 h with different kinds of behaviour being registered on-line every 10 min, such as time spent on locomotion, number of "high swimming peaks", number of activity phases, cleaning, time spent on ventilation, ventilation frequency and netspinning. Additionally, G.pulex was exposedin situ above and 100 m, 500 m and 1000 m below the factory for 24 h.G.pulex reacted to water pollution within 1 h with less time spent on locomotion, fewer "high swimming peaks" and lower number of activity phases (p < 0.01). The same results were found after thein situ exposure (p < 0.05) and the pollution gradient mirrored survival and behavioural performance of the organisms.H. angustipennis reacted to water pollution within 1 h with decreased time spent on ventilation (p < 0.001), no change in locomotion and netspinning during daytime. During the night, exposure to water pollution resulted in increased locomotion (p < 0.0001).Simultaneous multispecies on-line biomonitoring of industrial effluents is recommended for reliable risk assessment.