Susana M. Moreira

A short‐term sublethal in situ toxicity assay with hediste diversicolor (polychaeta) for estuarine sediments based on postexposure feeding

This study evaluated a short-term sublethal endpoint for in situ toxicity assays for estuarine sediments, based on postexposure feeding of the polychaete Hediste (Nereis) diversicolor Müller. A method for precisely quantifying postexposure feeding rates of H. diversicolor was established under laboratory conditions using Artemia franciscana Kellog nauplii. The sensitivity of the postexposure feeding response to copper was investigated by comparing postexposure feeding rates to growth and lethality. The 48-h and 96-h median lethal concentration (LC50) of copper were 241 and 125 microg/L, respectively, whereas the 48-h median inhibitory concentration (IC50) for postexposure feeding and the 20-d IC50 for growth were 52 and 25 microg/L of copper, respectively. The influence of different exposure conditions (substrate, temperature, salinity, food availability, and light) on H. diversicolor postexposure feeding was assessed; temperature and salinity were found to influence significantly postexposure feeding. The effectiveness of the proposed in situ assay was investigated by deploying it at two reference and six contaminated Portuguese estuaries. A 48-h exposure period was followed by a 1-h postexposure feeding period. High organism recoveries (89-100%) were obtained. Postexposure feeding was depressed significantly (17-90%) at all contaminated sites relatively to reference sites. The proposed in situ assay with H. diversicolor was shown to be a potential useful tool for estuarine sediment toxicity testing.

Hazardous and Noxious Substances (HNS) in the marine environment: Prioritizing HNS that pose major risk in a European context

Increases in the maritime transportation of Hazardous and Noxious Substances (HNS), alongside the need for an effective response to HNS spills have led environmental managers and the scientific community to focus attention on HNS spill preparedness and responsiveness. In the context of the ARCOPOL project, a weight-of-evidence approach was developed aimed at prioritizing HNS that pose major environmental risks to European waters. This approach takes into consideration the occurrence probability of HNS spills in European Atlantic waters and the severity of exposure associated with their physico-chemical properties and toxicity to marine organisms. Additionally, a screening analysis of the toxicological information available for the prioritization of HNS was performed. Here we discuss the need for a prioritization methodology to select HNS that are likely to cause severe marine environmental effects as an essential step towards the establishment of a more effective preparedness and response to HNS incidents.

Short-term sublethal (sediment and aquatic roots of floating macrophytes) assays with a tropical chironomid based on postexposure feeding and biomarkers

This study proposes assays with a freshwater chironomid, Chironomus xanthus, distributed over South America, based on subindividual (acetylcholinesterase activity) and individual (survival and postexposure feeding) level endpoints. Sediment and aquatic-rooted floating macrophyte assays were developed, due to the importance of both substrates for toxicant exposure in subtropical/tropical environments. Assays were evaluated under realistic exposure scenarios by simulating a runoff over an agricultural field dosed with deltamethrin. In situ assays were performed within microcosms to discriminate the effects of deltamethrin from those of additional potential stress factors (organism handling and caging, microcosms, use of aquatic roots, and runoff per se). A laboratory sediment assay based on feeding was conducted with samples from the microcosms. In all assays, both sublethal endpoints were responsive to deltamethrin and more sensitive than survival. Survival and feeding were more sensitive in situ than in the laboratory. In the in situ sediment assays, both sublethal endpoints were within a similar range of sensitivity; they were significantly inhibited as of the lowest Decis dose, from approximately 20 to 70%. In situ feeding was more sensitive in the sediment than in the macrophyte assay, where it was inhibited significantly only at the two highest Decis doses (up to approximately 60%). Larval performance was not influenced significantly by any of the other potential stress factors.

Ecotoxicological tools for the tropics: sublethal assays with fish to evaluate edge-of-field pesticide runoff toxicity.

This study proposes short-term sublethal assays for the tropics using the fish Poecilia reticulata. Assays were evaluated under realistic exposure scenarios by simulating a runoff over an agricultural area sprayed with deltamethrin (Decis). In situ assays were performed inside microcosms set up to simulate runoff water entrance in lentic systems. Laboratory assays were conducted with water samples from the microcosms. In both assays the biochemical parameters were similarly responsive to Decis, with a significant inhibition of acetylcholinesterase (30-46%) and induction of lactate dehydrogenase (33-67%) and glutathione S-transferases (48-176%) activities, observed as of the lowest Decis dose. Postexposure feeding was more sensitive in the laboratory assay than in situ. Among the additional potential stressors, only acetylcholinesterase was significantly influenced by the runoff per se. The proposed methodologies were well adapted for assays with P. reticulata, as organisms were easily deployed and retrieved and enzymatic activities and postexposure feeding were sensitive endpoints.

Review on hazardous and noxious substances (HNS) involved in marine spill incidents—An online database

In this review, we have collected information on the behavior, fate, weathering, and impact of hazardous and noxious substances (HNS) accidentally spilled at sea on the marine biota. The information was compiled on a datasheet and converted into a database that can be accessed by the general public (www.ciimar.up.pt/hns). Systematization of data is important to assist stakeholders involved in HNS spill preparedness and response, facilitating the incorporation of lessons from past incidents in the decision process. The database contains 184 entries of HNS spilled in 119 incidents in marine waters around the world. Data were analyzed in terms of HNS physical behavior in water according to SEBC (Standard European Behavior Classification) codes. The most common products involved in accidental spills in the marine environment were identified and major lessons highlighted. From the analysis, it was determined that most HNS spills were poorly documented and information was mistreated. In most cases, no monitoring programs were implemented following the incident. This conduct has occurred in 24 out of 119 incidents analyzed and has consequently limited the information on fate, behavior, and weathering of HNS spilled that could have been recovered. Major gaps were identified, and priorities and recommendations were drawn as a step toward improving preparedness and response to HNS spills.

Review of oil and HNS accidental spills in Europe: identifying major environmental monitoring gaps and drawing priorities.

The European Atlantic area has been the scene of a number of extensive shipping incidents with immediate and potential long-term impacts to marine ecosystems. The occurrence of accidental spills at sea requires an effective response that must include a well executed monitoring programme to assess the environmental contamination and damage of the affected marine habitats. Despite a number of conventions and protocols developed by international and national authorities that focused on the preparedness and response to oil and HNS spills, much remains to be done, particularly in relation to the effectiveness of the environmental monitoring programmes implemented after oil and HNS spills. Hence, the present study reviews the status of the environmental monitoring programmes established following the major spill incidents over the last years in European waters, aiming at identifying the key monitoring gaps and drawing priorities for an effective environmental monitoring of accidental spills.

An in situ assay with the microalga Phaeodactylum tricornutum for sediment‐overlying water toxicity evaluations in estuaries

Given the urgent need for ecologically relevant toxicity tools specific to estuarine systems, the main goal of the present study was to develop and evaluate the potential of an in situ algal assay for estuarine sediment-overlying water toxicity evaluations using the microalga Phaeodactylum tricornutum immobilized in alginate beads. With its simple and cost-effective design, the assay apparatus, coupled with the use of microalgae immobilized in alginate beads, allowed rapid and easy deployment as well as retrieval of assay chambers. The effectiveness of the proposed in situ assay was investigated by deploying it at two reference and six contaminated Portuguese estuaries. By deploying open chambers both with and without an artificial nutrient source and closed chambers with an artificial seawater medium, it was possible to discriminate toxic effects from those caused by differences in temperature, light, and nutrient conditions across sites. A reduction in algal growth was found at contaminated sites relative to reference sites. The strontium alginate beads used for microalgae immobilization were found to be appropriate to perform in situ assays, showing no signs of disruption or dissolution after up to 8 d of exposure in estuarine sediment-overlying waters. The proposed in situ assay was shown to be a useful tool for estuarine sediment-overlying water toxicity testing to provide relevant data concerning primary production to estuarine ecological risk assessment studies.

Simulation of a Hazardous and Noxious Substances (HNS) spill in the marine environment: lethal and sublethal effects of acrylonitrile to the European seabass.

Despite the extensive maritime transportation of Hazardous and Noxious Substances (HNS), there is a current lack of knowledge on the effects posed by HNS spills on the marine biota. Among the HNS identified as priority, acrylonitrile was selected to conduct ecotoxicological assays. We assessed the acute and subletal effects of acrylonitrile in seabass, followed by a recovery phase to simulate the conditions of a spill incident. The work aimed at testing a broad range of biological responses induced by acrylonitrile. Sublethal exposure to the highest two doses increased the fish mortality rate (8.3% and 25% mortality in 0.75 and 2 mg L(-1) acrylonitrile concentrations), whereas no mortality were observed in control and 0.15 mg L(-1) treatments. Additionally, important alterations at sub-individual level were observed. Acrylonitrile significantly induced the activities of Catalase- CAT and Glutathione S-Transferase - GST; and the levels of DNA damage were significantly increased. Conversely, Superoxide Dismutase- SOD - activity was found to be significantly inhibited and no effects were found on Lipid Peroxidation- LPO and ethoxyresorufin O-deethylase - EROD - activity. Following a 7d recovery period, the levels of CAT, GST and EROD fell to levels at or below those in the control. In the 2 mg L(-1) group, SOD remained at the levels found during exposure phase. This study has gathered essential information on the acute and subletal toxicity of acrylonitrile to seabass. It also demonstrated that 7d recovery allowed a return of most endpoints to background levels. These data will be useful to assist relevant bodies in preparedness and response to HNS spills.

Freshwater-saltwater interface and estuarine sediment in situ assays based on post-exposure feeding of chironomids and polychaetes

An integrated approach for ecological and ecotoxicological sediment assessments along the freshwater saltwater interface (FSI) and estuarine areas in general was developed, through the adaptation of recently proposed methods for the midge larvaChironomus riparius (an in situ assay based on post-exposure feeding for sediment toxicity assessments in freshwater systems) and the development of new techniques for the polychaeteHediste (Nereis) diversicolor (an in situ post-exposure feeding assay). Based on the previously proposed methods, improvements were made to the feeding quantification ofC. riparius fourth instar larvae. A method to quantify the post-exposure feeding ofH. diversicolor was developed and optimized under laboratory conditions using newly hatchedArtemia franciscana nauplii as a food source. Assay chambers and procedures fromC. riparius assays were easily adapted forH. diversicolor in situ exposures. Sediment assays using this integrated approach were successfully performed at an uncontaminated river-estuarine system. They consisted of a 48-h exposure followed by a 1-h post-exposure feeding for chironomids and a 2-h post-exposure feeding for polychaetes. Good recovery rates were obtained after the 48-h field exposure. Fluctuations in various physicochemical variables at the FSI, due to the tidal regime, did not significantly influenceC. riparius larval post-exposure feeding rates, suggesting that uncontaminated freshwater sites located upstream of FSI areas can be used as reference sites forC. riparius in situ evaluations in estuaries. Adapted assay chambers and procedures were suitable forH. diversicolor in situ exposures.

Management of contaminated marine marketable resources after oil and HNS spills in Europe

Different risk evaluation approaches have been used to face oil and hazardous and noxious substances (HNS) spills all over the world. To minimize health risks and mitigate economic losses due to a long term ban on the sale of sea products after a spill, it is essential to preemptively set risk evaluation criteria and standard methodologies based on previous experience and appropriate scientifically sound criteria. Standard methodologies are analyzed and proposed in order to improve the definition of criteria for reintegrating previously contaminated marine marketable resources into the commercialization chain in Europe. The criteria used in former spills for the closing of and lifting of bans on fisheries and harvesting are analyzed. European legislation was identified regarding food sampling, food chemical analysis and maximum levels of contaminants allowed in seafood, which ought to be incorporated in the standard methodologies for the evaluation of the decision criteria defined for oil and HNS spills in Europe. A decision flowchart is proposed that opens the current decision criteria to new material that may be incorporated in the decision process. Decision criteria are discussed and compared among countries and incidents. An a priori definition of risk criteria and an elaboration of action plans are proposed to speed up actions that will lead to prompt final decisions. These decisions, based on the best available scientific data and conducing to lift or ban economic activity, will tend to be better understood and respected by citizens.