The relative sensitivity of macrophyte and algal species to herbicides and fungicides: An analysis using species sensitivity distributions
Giddings, J. ; Arts, G.H.P. ; Hommen, U. - \ 2013
Integrated Environmental Assessment and Management 9 (2013)2. - ISSN 1551-3793 - p. 308 - 318.
Lemna spp. are the standard test species representing aquatic macrophytes in the current risk assessment schemes for herbicides and plant growth regulators in the European Union and North America. At a Society of Environmental Toxicology and Chemistry (SETAC) 2008 workshop on Aquatic Macrophyte Risk Assessment for Pesticides (AMRAP), a Species Sensitivity Distribution (SSD) working group was formed to address uncertainties about the sensitivity of Lemna spp. relative to other aquatic macrophyte species. For 11 herbicides and 3 fungicides for which relevant and reliable data were found for at least 6 macrophyte species, SSDs were fitted using lognormal regression. The positions of L. gibba (the most commonly tested Lemna species) and Myriophyllum spicatum (for which standardized test methods are under development) in each SSD were determined where data were available. The sensitivity of standard algal test species required for pesticide registration in the United States under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) relative to the macrophytes in each SSD was also examined (algae were not included in the SSD). L. gibba was among the most sensitive macrophyte species for approximately 50% of the chemicals examined. M. spicatum was among the most sensitive macrophytes for approximately 25% of the chemicals. In most cases, the lowest FIFRA algal species endpoint was lower than the most sensitive macrophyte endpoint. Although no single species consistently represented the most sensitive aquatic plant species, for 12 of 14 chemicals L. gibba and the FIFRA algae included an endpoint near or below the 5th percentile of the macrophyte SSD. For the other compounds, M. spicatum was the most sensitive species of all aquatic plants considered.
The Relative Sensitivity of Macrophyte and Algal Species to Herbicides and Fungicides: An Analysis Using Species Sensitivity Distributions
Giddings, J. ; Loutseti, S. ; Arts, G.H.P. ; Davies, J. ; Dobbs, M. ; Hanson, M. ; Hommen, U. - \ 2011
|Aquatic macrophyte risk Assessment: current status anbd future challenges
Arts, G.H.P. ; Davies, J. ; Dollinger, M. ; Giddings, J. ; Hanson, M. ; Knauer, K. ; Hommen, U. ; Loutseti, S. - \ 2011
In: Innovative approaches for the management of environmental risks from plant protection products, Montpellier, France, 26 - 28 October, 2011. - Montpellier, France : Euraqua-PEER - p. 10 - 10.
Aquatic macrophytes fulfill critical functions in ecosystems, contributing to structure and function. Aside from the floating, non-sediment rooting duckweed species (Lemna spp.), other aquatic macrophytes are not routinely considered in standard risk assessments for chemicals in Europe yet. In the pesticide regulation (1107/2009/EC) Lemna spp. are the Tier 1 test species. However, they differ from rooted and submerged macrophytes, most markedly in their short generation time and free-floating growth form. The concern, that risk assessments based on endpoints derived from tests with Lemna may not be protective for other macrophyte species, was a driving reason for the workshop “Aquatic Macrophyte Risk Assessment for Pesticides” (AMRAP) in 2008. The participants concluded that the risk assessment based on data obtained from Lemna studies may not be sufficiently protective in certain cases. Additional triggers for further testing were defined including the specific mode of action of pesticides and the possible exposure of macrophytes via sediment. Therefore, an additional Tier 1 test with a rooted dicotyledonous macrophyte, Myriophyllum spp., was proposed. Test protocols for Myriophyllum sp. are currently being ring-tested in order to become a standardized OECD test. If concern over the safety of a pesticide is still present after Tier 1 testing and risk evaluation, higher-tier assessments may be performed through e.g. the generation of further macrophyte species data for use in species sensitivity distributions (SSDs), or by conducting multi-species tests or microcosm and mesocosm studies. Species Sensitivity Distribution analyses on 14 compounds performed by a working group with Aquatic Macrophyte Ecoxicology Group (or AMEG, which emerged out of the AMRAP workshop) found that effects on L. gibba and the four algal species required for US pesticide registration are in most cases protective for rooted and submerged macrophyte species. Exceptions can generally be predicted based on the mode of action of the chemical. In European pesticide regulation (1107/2009/EC) Myriophyllum spp. and Glyceria maxima have recently been proposed as additional test species. Other regulatory frameworks include the Water Framework Directive (WFD) which aims to achieve a ‘good’ ecological and chemical status for all surface waters in the EU. Attainment of this status requires that chemical concentrations meet Environmental Quality Standards based on ecotoxicological data. The integration of climate change and how it can modify our understanding of ecosystems and effects in the field for risk evaluation poses additional challenges for aquatic macrophyte risk assessment. For example, modeling tools are needed to predict the effects of changing water temperature on plant growth and development and changing hydrological regimens might change exposure. While the potential effects and manner in which climate change might be manifest in freshwater ecosystems are still being discussed and quantified, the integration of these aspects into risk assessments is missing. Working on these concepts and translating patterns into robust aquatic macrophyte risk assessments is one of the challenging topics for future research.