Aquatic Ecotoxicology

Advancing Tools for Dealing with Emerging Risks

Claude Amiard-Triquet, Jean-Claude Amiard, Catherine Mouneyrac, Claude Amiard-Triquet, Jean-Claude Amiard, Catherine Mouneyrac

• Publisher: Academic Press
• Year: 2015
• ISBN:
  9780128011768
• Topic: Biological Sciences
• Subtopic: Marine Biology
• Index: Biological Sciences

Aquatic Ecotoxicology: Advancing Tools for Dealing with Emerging Risks presents a thorough look at recent advances in aquatic ecotoxicology and their application in assessing the risk of well-known and emerging environmental contaminants.

This essential reference, brought together by leading experts in the field, guides users through existing and novel approaches to environmental risk assessment, then presenting recent advances in the field of ecotoxicology, including omics-based technologies, biomarkers, and reference species.

The book then demonstrates how these advances can be used to design and perform assays to discover the toxicological endpoints of emerging risks within the aquatic environment, such as nanomaterials, personal care products, PFOS and chemical mixtures. The text is an invaluable reference for any scientist who studies the effects of contaminants on organisms that live within aquatic environments.

• Provides the latest perspectives on emerging toxic risks to aquatic environments, such as nanomaterials, pharmaceuticals, chemical mixtures, and perfluorooctane sulfonate (PFOS)
• Offers practical guidance on recent advances to help in choosing the most appropriate toxicological assay
• Presents case studies and information on a variety of reference species to help put the ecotoxicological theory into practical risk assess

Chapter 1

Introduction

Claude Amiard-Triquet

Abstract

The aquatic environment appears as the final destination for most of anthropogenic contaminants released from industry, agriculture, urbanization, transport, tourism, and everyday life. On the other hand, inland, coastal, and marine waters provide many services important for human well-being. The conservation of ecosystems and human health is based on a sound assessment of the risks associated with the presence of contaminants in the aquatic environment. The aim of this book is to use cross-analyses of procedures, biological models, and contaminants to design ecotoxicological tools suitable for better environmental assessments, particularly in the case of emerging contaminants and emerging concern with legacy pollutants.

Keywords

Aquatic environment; Bioaccumulation; Bioassays; Bioindicators; Biomarkers; Ecotoxicological tools; Emerging contaminants; Emerging risks; Exposure; Risk assessment

Chapter Outline

1.1 Ecotoxicological Tools Currently Used for Risk Assessment in Aquatic Media 2

1.2 How Can We Improve Risk Assessment? 3

1.3 The Choice of Biological Models for Bioassays, Biomarkers, and Chemical Monitoring 10

1.4 Emerging Concern with Legacy Pollutants and Emerging Contaminants 13

References 18

Many different classes of contaminants enter the environment as a consequence of human activities, including industry, agriculture, urbanization, transport, tourism, and everyday life. Initially, air pollutants are atmospheric contaminants and solid wastes are terrestrial contaminants, whereas liquid effluents are aquatic contaminants. Processes involved in the fate of contaminants in each compartment—air, soil, water—lead to many intercompartment exchanges, governed by advection (e.g., deposition, run-off, erosion), diffusion (e.g., gas absorption, volatilization), and degradation, both biotic and abiotic (Figures 2.2 and 2.3, this book), and by large-scale transport from atmospheric and marine currents. The aquatic environment appears as the final destination for most of anthropogenic contaminants, and aquatic sediments, either deposited or in suspension, as the major sink for their storage with only few exceptions (e.g., perfluorooctanoic acid [PFOA], Post et al., 2012; water-soluble pesticides such as alachlor, atrazine, and diuron).

It is generally admitted that about 100,000 molecules are introduced in aquatic media intentionally (e.g., pesticides, antifouling paints) and more often unintentionally as incompletely treated sewages or because of accidents. In most cases, several classes of contaminants are present concomitantly, thus being able to act in addition, synergy, or antagonism (Chapter 18).

The Millennium Ecosystem Assessment (MEA, 2005) highlights how ecosystem services are important as determinants and constituents of human well-being. Inland, coastal, and marine waters are important contributors of core services (nutrient cycling, primary production). They are also part contributors in providing services (water, food, biochemicals, genetic resources) and cultural services (such as recreation and ecotourism, aesthetic and educational benefits). As emphasized by Maltby (2013), applying approaches based on the ecosystem service concept to the protection, restoration, and management of ecosystems requires the development of new understanding, tools, and frameworks.

Legislation has been adopted on a worldwide scale to improve the status of aquatic ecosystems (e.g., United States’ Clean Water Act, 1972; European Community Water Framework Directive, ECWFD, 2000). Environmental management aiming at the improvement of chemical and ecological quality in aquatic media must be based on robust risk assessments. Retrospective risk assessments are performed when sites have potentially been impacted in the past. When they show a degradation of environmental quality, the restoration of degraded habitats and ecosystems must be addressed. Prospective, or predictive, risk assessments aim at assessing the future risks of anthropogenic pressure such as climate change or releases of new chemicals into the environment. Strategies to limit the risks of both new and existing chemicals include the federal Toxic Substances Control Act (1976) in the United States, and a new chemical policy, Registration, Evaluation, and Authorization of CHemicals in Europe (2006).

1.1. Ecotoxicological Tools Currently Used for Risk Assessment in Aquatic Media

Conventional risk assessment (Chapter 2) in different environments aims at establishing a comparison between the degree of exposure expected or measured in the field and the effects induced by a contaminant or a class of contaminants. It is mainly based on the determination of predicted environmental concentrations (PECs) and predicted no effect concentrations (PNECs). The procedure has been described in the Technical Guidance Document on Risk Assessment in support of European Commission regulations (TGD, 2003). PECs and PNECS are then used in a risk quotient approach: very simplistically, if the PEC/PNEC ratio is lower than 1, the substance is not considered to be of concern; if the PEC/PNEC ratio is higher than 1, further testing must be carried out to improve the determination of PEC or PNEC with subsequent revision of PEC/PNEC ratio, or risk reduction measures must be envisaged (TGD, 2003).

Environmental quality standards ([EQS] concentration in water, sediment, or biota that must not be exceeded) are a major tool to protect the aquatic environment and human health (Chapter 3). An overshoot of EQS at a given site triggers management actions (e.g., research for contamination sources, reduction of contaminant discharges). EQS for sediment and biota are needed to ensure protection against indirect effects and secondary poisoning. To date, no EQSs are available for sediments under the ECWFD (2000), partly because the total dose of a pollutant in sediment has a low ecotoxicological significance and the bioavailable fraction must be determined using specific methods (Chapter 3). In addition, different sediment quality guidelines are commonly used by official organisms in the US (National Oceanic and Atmospheric Administration) (Long et al., 1995; MacDonald et al., 1996), Canada (http://ceqg-rcqe.ccme.ca/), Australia (McCready et al., 2006), etc. An overshoot of these guidelines at a given site triggers additional investigations on the impacts and their extent.

Environmental monitoring is then indispensable to assess if environmental concentrations meet standards/guidelines (Chapter 3). An excellent example is provided by the Coordinated Environmental Monitoring Program undertaken under the OSPAR Commission that aims at protecting and conserving the Northeast Atlantic and its resources. Guidelines for monitoring of hazardous substances in sediment and biota are available at http://www.ospar.org/content/content.asp?menu=00900301400135_000000_000000. OSPAR monitoring guidance is regularly reviewed in collaboration with the International Council for the Exploration of the Sea and, where necessary, updated to take account of new developments such as the inclusion of new monitoring parameters.

However, chemical measurements of contaminants in environmental matrices pose a number of problems in many monitoring programs:

1. Analytical efforts focus on chemicals that are perceived to be relatively easy to analyze (heavy metals, DDT and its metabolites, γHCH, αHCH, some congeners of polychlorobiphenyls [PCBs], some individual polycyclic aromatic hydrocarbons [PAHs], etc.);

2. Complex mixtures present in multipolluted environments include many classes of compounds that are not yet accessible to analysis or are extremely expensive to analyze, particularly emerging contaminants (nanomaterials) or known contaminants of emerging concern (pharmaceuticals, personal care products) and their metabolites;

3. As previously mentioned for sediments, the total dose of a pollutant in any compartment of the environment (water, sediment, biota) has a low ecotoxicological significance since their physicochemical forms govern their bioaccessibility and biological effects.

1.2. How Can We Improve Risk Assessment?

To improve exposure assessment, it is indispensable to take into account the physicochemical characteristics of different classes of contaminants (Chapter 4). In the case of metals, a number of chemical speciation models allows a good characterization of the metal chemical species in a solution containing inorganic ligands and well-characterized organic ligands, particularly natural organic matter that is one of the most dominating processes in freshwater and salinity (chlorinity) in seawater (Paquin et al., 2002; VanBriesen et al., 2010). Different procedures have been described to take into account bioavailability concepts in the risk assessment process or environmental quality criteria setting. The Free Ion Activity Model (FIAM) has been designed to take into account the central role of the activity of the free metal ion as a regulator of interactions (both uptake and toxicity) between metals and aquatic organisms (Campbell, 1995). As the FIAM, the Biological Ligand Model is a chemical equilibrium-based model but at the center of this model is the site of action of toxicity in the organism that corresponds to the biotic ligand. The Biological Ligand Model can be used to predict the degree of metal binding at this site of action, and this level of accumulation is in turn related to a toxicological response (Paquin et al., 2002).

Passive samplers are devices that rely on diffusion and sorption to accumulate analytes in the sampler (Mills et al., 2010). Among these techniques, diffusive equilibration in thin films and diffusive gradients in thin films allow a better understanding of the speciation of metals in the environment, differentiating between free-, inorganic-, and organic-bound metal species and organometallic compounds. Other passive samplers can be used for different classes of organic chemicals, also providing a partial determin...