Observed and predicted combination effects of the antifouling agents irgarol 1051, TBT and Sea-Nine TM 211 on the structural and functional properties of marine microalgal communities

• Risks of mixtures of pollutants in ecosystems cannot be assessed when chemicals are treated as acting alone. This issue is increasingly recognised, but valid and useful tools for considering mixtures are needed. However the concepts Concentration Addition (CA) and Independent Action (IA) has been shown to have potential for predicting mixture toxicities. With the aim to evaluate CA and IA under ecologically realistic conditions the antifouling agents irgarol 1051, Sea-NineTM211 and TBT were tested singly and in an equieffective mixture on marine periphyton communities in a semistatic SWIFT test. Periphyton was established on 1.5 cm2 glass discs submerged in the Gullmar fjord, Sweden and then incubated for 96 h under constant light and temperature in a medium of GF/F filtered seawater with added phosphate, nitrate and toxicant(s). Effects were then quantified by comparing analysed pigment and species composition between treatments and controls using Bray-Curtis dissimilarity index. The observed mixture effect on species composition was in perfect agreement with CA, while IA was accurate for lower observed effects but overestimated the toxicity at higher. Using pigments for predictions was found to be sensitive as this reflected lower observed effects on species composition. IA and CA are beleived to apply for mixtures of toxicants with dissimilar and similar biochemical mechanisms of action respectively and as irgarol, TBT and Sea-Nine are dissimilarly acting the most accurate prediction should be IA. However biochemical modes of action may become less relevant for predictions in an ecological context where a mode of action could be defined more by impacts on specific species and trophic levels. Results indicates that risks of mixtures should be considered and are predictable.

Ämnesord

NATURVETENSKAP  -- Biologi -- Ekologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Ecology (hsv//eng)

NATURVETENSKAP  -- Geovetenskap och miljövetenskap -- Miljövetenskap (hsv//swe)

NATURAL SCIENCES  -- Earth and Related Environmental Sciences -- Environmental Sciences (hsv//eng)

Publikations- och innehållstyp

ref (ämneskategori)

kon (ämneskategori)