Newsletter No 2 June 2010

Professorial lecture: Improving water quality and ecosystem health assessment

Professor dr. Dick Vethaak 

In May 2009, I was appointed Extraordinary Professor of Ecotoxicology of Delta and Coastal Waters at the Institute for Environmental Studies, VU University Amsterdam, sponsored by the research institute Deltares. The creation of this chair will strengthen cooperation between VU University Amsterdam and Deltares, and will also improve the knowledge position of the Netherlands in this field. I gave my inaugural lecture on 1 April 2010, highlighting the importance and usefulness of field research and describing innovative research strategies and measurement methods for evaluating the water quality and ecosystem health in delta and coastal waters. I also considered emerging contaminant threats and presented my future research plans. Here is a summary of the lecture.

cb_june10The discipline of ecotoxicology is undergoing big changes. In the coming years, increasing emphasis will be placed on combined risk assessment, an integrated ecosystem approach for the water system and the relationship with ecosystem services. In effect, this means a broadening of the ecotoxicology discipline through closer cooperation with other disciplines such as ecology, hydrodynamics, model making, medical biology and environmental economics. But there is also much to be done within ecotoxicology itself. For example, little is known as yet concerning the degree to which chemical substances can change the genetic composition of populations, or concerning the indirect effects of chemical substances at low concentrations on the functioning of ecosystems.

Why the special focus on the ecotoxicology of delta and coastal waters? Delta and coastal regions are very valuable – and also very vulnerable – ecosystems. It is estimated that the economic worth of goods and services supplied by delta and coastal ecosystems accounts for a total of 77 % of global ecosystem services. But delta and coastal ecosystems are exposed to increasing threats through problems such as chemical pollution, nutrient enrichment, the introduction of exotic species and climate-driven changes in sea levels. Both human welfare and the ecological services of deltas and coastal regions are closely related to the health of ecosystems. It is therefore crucially important to keep those ecosystems healthy.

cb_june10bThere are signs that the chemical quality of the surface water along the coast and in the estuaries has improved in recent years. Examples of this are the decreasing problems of imposex in snails caused by the toxic substance TBT (tributyltin), and the decrease in liver cancer in flatfish caused by carcinogenic PAHs (Polycyclic Aromatic Hydrocarbons). But is the environment getting cleaner? In the 60s and 70s, concentrations of some chemical substances (metals, pesticides, DDT, PCBs) in the environment were very high. Now, instead of standard research into clearly observable effects of simple substances, the focus is on new problem substances and the subtle effects of complex mixtures of substances. The question is: how do you measure this, and what are good indicators?

In monitoring programmes, bioeffect measurements (biomarkers and bioassays) are only sparsely included. The ‘toolbox’ is not adequate to cover the many chemical substances, and so it is important that the toolbox consists of a cohesive package of bioeffect measurements, which can provide an adequate safety network in respect of substances. In recent years, bioeffect measurements have increasingly been combined with chemical measurements. Such an integrated approach provides improved scope for interpretation and understanding of research or monitoring results. In addition, it is economical.

A system for monitoring and assessing the effects of environment contaminants, in which series of chemical measurements and bioeffect measurements are combined, is currently being developed by the international marine organizations ICES and OSPAR. This broad monitoring and assessment strategy consists of various indicators with associated assessment criteria that each cover a different component of the ecosystem. The approach covers three ecosystem components, namely water, sediment and organisms (biota), the latter aimed at fish, mussels and snails (Figure 1). The intention is to arrive at an aggregated indicator in order to be able to estimate the total chemical anthropogenic pressure on delta and coastal systems. While this is clearly a simplification of the marine ecosystem, it is based on the methods that are currently available. In the future, this set of methods can be extended. To be able to estimate whether an ecosystem is healthy or unhealthy, besides chemical and ecotoxicological indicators, more comprehensive ecological indicators are necessary to be able to assess on the effects of disturbances of the vitality and productivity of the ecosystem.

Another research focus is ecotoxicology in food chains.  In this context, three PhD projects are currently underway. The first concerns a study into the transfer, bioaccumulation and potential risks of known and ‘new’ persistent substances, such as brominated flame retardants (e.g. PBDEs, HBCDs) and perfluorinated compounds (e.g. PFOS) to top predators, such as the common tern and seals. Two other PhD projects, at the VU Institute for Environmental Studies and the University of Amsterdam Institute for Biodiversity and Ecosystem Dynamics (with funding from Deltares), are studying the (combined) effects of anthropogenic contaminants and natural algal toxins on primary producers (algae) in Dutch coastal waters and the potential effect of this on higher levels in the food chain.

In addition to brominated flame retardants and perfluorinated compounds, other problem substances are arising. In particular, this concerns veterinary drugs, nanoparticles and microplastics. The risks presented by all these substances to ecosystems are unclear, and we wish to carry out specific research into these in the coming years.

A challenging subject of research in the short term is the development of an integrated vision of the concept of ‘ecosystem health’, looking from a broad ecotoxicological perspective. In the longer term I wish to expand the research to the relationship between the health of the ecosystem and the health of humans and eventually to the translation into ecosystem services. The human toxicological and environmental economics expertise of the Institute for Environmental Studies provide good starting points for this.

Finally, another research task focuses on the creation of a battery of fast and cheap toxicity assays with cell lines and standard organisms for an initial evaluation of the water and sediment quality. The Institute for Environmental Studies has unique expertise in this area, and through cooperation with the Deltares laboratory, this ‘toxicological profiling tool’ can become adapted to assess groundwater quality and for use in the event of disasters (e.g. oil spill). In the coming years, we wish to expand the test battery with suitable new assays and end points (including immunotoxicity, neurotoxicity and omics technologies).

This research is scientifically exciting and socially-relevant. Both within Europe and in other countries (which have only recently approached the subject of environmental pollution) the practical application of this knowledge and technologies is of crucial importance. In Europe, for example, EU legislation requires a new approach to integrated monitoring of the coastal ecosystem and more knowledge on the potential effects of new problem substances. I hope during my tenure to be able to make a significant contribution to this.


Figure 1. The main components for a proposed integrated monitoring programme on effects of contaminants in marine ecosystems (from Thain et al., 2008, modified).


- Thain, John E., A. Dick Vethaak and Ketil Hylland (2008). Contaminants in marine ecosystems: developing an integrated indicator framework using biological effects techniques. Journal Mar. Sci. 65: 1508-1514.
- Hamers, T., Leonards, P.E.G., Legler, J., Vethaak, A.D.,Schipper, C.A. (2010). Toxicity Profiling: An Integrated Effect-Based Tool for Site-Specific Sediment Quality Assessment. Published Online: Apr 5 2010 10:17PM DOI: 10.1002/ieam.75
-Vethaak, A.D., Zo gezond als een vis, Deltares, 2010.

More information: website Deltares
Contact information: Professor dr. Dick Vethaak