Aquatic Toxicology and Ecology: New Concerns and New Techniques Highlighted in Portland
Peter S. Ross (Fisheries and Oceans Canada, Sidney BC, Canada)
Rain did not keep the scientists away from this year’s SETAC North America (SNA) Annual Meeting. Almost 700 presentations in 39 half-day sessions (more than300 talks and nearly 400 posters) were featured in the Aquatic Toxicology and Ecology track sessions. And if the rain encountered before or after conference hours were the subject of some conversation, it is worth noting that Portland’s 942 mm of rainfall per year sustains the great temperate rainforests of the U.S. Pacific Northwest. For SETAC, the rain highlights the interconnectedness between atmosphere and land, freshwater and marine, plant and animal, local and global. And while water and nutrient cycles support a rich variety of ecosystems in this coastal environment, they are also a conduit for many of the chemicals of concern to SETAC that escape during manufacture, transport, use and disposal.
The large number of high quality sessions in the Aquatic Toxicology and Ecology track rendered it impossible to take every opportunity to glean the latest frontiers in research. However, it is evident that the SETAC research family is prospering, and adapting to new developments and opportunities. Sessions on sediment/water quality topped the list for numbers of presentations, followed by metals in second place, and nanotoxicology, “-omics”, pharmaceuticals and personal care products (PPCPs), food web processes and Daphnia tied for third spot. A cursory comparison to publications produced since 2009 according to Cambridge Scientific Abstracts (CSA, Proquest, Ann Arbor MI, USA) indicates that of these keywords, metals, nanotoxicology and food web processes topped the list. The rapid emergence of nanotoxicology, PPCP, and “–omics”-related publications was also apparent, with more than 35% of total CSA citations in each of these areas arising from publications since 2009. This is noteworthy, as it indicates that SETAC is effectively responding to the shifting composition in the published literature and providing new opportunities to its membership.
Sediment and water quality issues were featured front and center at this year’s SNA meeting, reflecting the wide range of topics of interest in this area, and the very strong implications of scientific research and monitoring for management and regulatory application. As many presenters noted, however, considerable difficulties remain as to how to characterize and interpret the effects of complex mixtures of contaminants on biota, including the region’s sensitive salmonids. Since regulators, managers and risk assessors must be positioned to understand the real-world complexity of sediment and water quality as they strive to protect or remediate receiving environments, this subject area is bound to remain a priority for SETAC in the future.
Nanotechnology featured prominently at this year’s conference, perhaps no surprise given its rapid emergence as a concern in aquatic ecosystems. Many of the presentations this year focused on the development of analytical methods, and their application to test systems or species. The absence of standardized techniques to measure nanoparticles renders it exceedingly difficult to document their fate and effects in the environment. Advances have been constrained by the wide variety of nanoparticle structures and the diversity of nanoparticle forms in the aquatic environment, including parent compounds, colloids, aggregrates, and breakdown products. Given their wide use in cosmetics, coatings, paints, plastics, and as antimicrobials in clothing, a better understanding of major entry points into the aquatic environment is needed (e.g., wastewater treatment effluent). It is likely that SETAC’s annual meetings will continue to feature advances in the understanding of the fate, transport and effects of nanoparticles and their constituents including metals over the coming years.
Genomics, metabolomics, transcriptomics, and proteomics are increasingly “mainstream” at SETAC, as new “-omics” research methods have dramatically advanced our powers of inter- and intra-cellular observation. Miniaturization, automation and the ability to quantify thousands of genes, proteins or metabolites are providing considerable insight into animal physiology and the effects of contaminants on biota. Future SETAC meetings are bound to benefit from advances in systems biology and real world applications in the “–omics” world, as these largely discovery-based studies are increasingly understood in terms of animal health.
With new reports in the literature of feminization of fish downstream of wastewater treatment plants, advances in analytical methods and new insight into effects of PPCPs underscores SETAC’s important role in this field. The wide variety of PPCPs entering the receiving environment, their varying half-lives, and different mechanisms of action, offer a bewildering array of possible outcomes.
This year’s conference demonstrated that SETAC’s long-held interest in the fate and effects of metals is not waning. The sensitivity of salmonids to copper from urban runoff, the poorly understood speciation of mercury (Hg) in polar environments, the physiological interactions between Hg and selenium in aquatic wildlife, and the effects of cadmium on biota, were examined in some detail. Regulatory and management interest in this sector is high, as the burgeoning mining industry aims to better understand and mitigate its waste stream. In addition, the global Hg cycle was front and center at this year’s SETAC, as climate change raises new questions about the fate of this toxic metal in aquatic food webs, notably in the arctic. The target of an international Hg treaty by 2013 will only heighten interest in Hg at SETAC.
The aquatic food web is vulnerable to the accumulation and magnification of many persistent organic contaminants and some metals. SETAC has played an important role in research on food-web structure and the characterization of contaminant transport and fate in aquatic environments. Empirical and model-based studies continued this tradition at the Portland meeting by examining the interaction between chemicals and abiotic and biotic matrices in aquatic environments. Interesting presentations and discussions centered on the advantages and disadvantages of biomagnification factors (BMFs) and trophic magnification factors (TMFs). The heavy reliance of humankind (particularly aboriginal peoples) on aquatic foods as a major source of protein ensures that food webs will remain an important context for contaminant research and discussion at future SETAC meetings.
The recent Deepwater Horizon disaster in the Gulf of Mexico, lingering long-term concerns about the impacts of Exxon Valdez Oil Spill (EVOS) on wildlife, and mega-scale fossil fuel extraction from the Alberta oil sands, were highlighted at this year’s conference. The many thousands of hydrocarbons ensures ongoing challenges when conducting (or comparing) studies of source, transport, fate and effects. While continued debate regarding the long-term effects of hydrocarbons appears inevitable, there is little question that oil and gas exploration, transport, and consumption will continue in the future, and that more opportunities for timely research and dialogue will be needed to protect aquatic ecosystems from unwanted impacts.
Pyrethroid insecticides and other current use pesticides were prominently featured this year reflecting, in part, the heavily debated effects of some pesticides on amphibians, the poorly understood salmon disease syndromes in urban waterways, and the widespread use of new generation pesticides in domestic, agricultural and forestry applications. With persistent, fat-soluble contaminants in disfavor today, most current use pesticides tend to be more mobile (water-soluble) and less persistent in the environment. Although this reduces the likelihood of food web amplification, there are concerns about the fate and toxicity of breakdown products, and of adjuvant/carrier compounds.
Many other sessions highlighted topics of interest, including the use of Daphnia in toxicity testing, impacts of contaminants on macrophytes, contaminant research, monitoring and remediation in major water bodies such as the Great Lakes and Puget Sound, alternatives to animal testing in research, and balancing the control of invasive species while protecting endangered species.
Opportunities for multi-disciplinary sessions for future SETAC meetings may take advantage of some of the common themes that emerged in multiple sessions in this year’s Aquatic Toxicology and Ecology stream:
- The effects of complex mixtures on the health of biota;
- Climate-contaminant interactions and consequences for transport, fate and effects;
- Systems approaches to new “–omics” techniques and real-world applications;
- The health of aquatic ecosystems in urban and near-urban environments as related to non-point source pollution;
- Domestic waste streams and wastewater treatment plants;
- Oil and gas exploration and development;
- The validation, utility and application of food-web and multi-media transport models to guide, complement, or in some cases replace, empirical studies.
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