Short-term effects of medetomidine on photosynthesis and protein synthesis in periphyton, epipsammon and plankton communities in relation to predicted environmental concentrations

Abstract

Medetomidine is a new antifouling substance, highly effective against barnacles. As part of a thorough ecotoxicological evaluation of medetomidine, its short-term effects on algal and bacterial communities were investigated and environmental concentrations were predicted with the MAMPEC model. Photosynthesis and bacterial protein synthesis for three marine communities, viz. periphyton, epipsammon and plankton were used as effect indicators, and compared with the predicted environmental concentrations (PECs). The plankton community showed a significant decrease in photosynthetic activity of 16% at 2 mg l⁻¹ of medetomidine, which was the only significant effect observed. PECs were estimated for a harbor, shipping lane and marina environment using three different model scenarios (MAMPEC default, Baltic and OECD scenarios). The highest PEC of 57 ng l⁻¹, generated for a marina with the Baltic scenario, was at least 10,000-fold lower than the concentration that significantly decreased photosynthetic activity. It is concluded that medetomidine does not cause any acute toxic effects on bacterial protein synthesis and only small acute effects on photosynthesis at high concentrations in marine microbial communities. It is also concluded that the hazard from medetomidine on these processes is low since the effect levels are much lower than the highest PEC.

The use of a Corophium volutator chronic sediment study to support the risk assessment of medetomidine for marine environments

“…This supports the evidence for medetomidine having a high surface affinity and a preference for adsorption [7]. A degradation half-life of 110 d for medetomidine has been used for calculating the PECs for this substance [19].…”

“…In another study, a significant decrease in photosynthetic activity of a plankton community was observed after exposure to 2 mg/L medetomidine . All these toxic effects are considered to be well above the highest predicted environmental water concentrations (PEC water ) for medetomidine of 57 ng/L (PEC derived for a Baltic marina scenario) . In addition to the relatively low toxicity of medetomidine, some of the observed behavioral effects of medetomidine to invertebrates have been shown to be reversible when the animals are removed to clean water .…”

“…These data are now supported by regulatory testing that found the median effective concentrations of medetomidine on the development of Pacific oyster (Crassostrea gigas) and sea urchin (Paracentrotus lividus) larvae to be 2.5 mg/L and 3.2 mg/L, respectively (unpublished data). In another study, a significant decrease in photosynthetic activity of a plankton community was observed after exposure to 2 mg/L medetomidine [19]. All these toxic effects are considered to be well above the highest predicted environmental water concentrations (PEC water ) for medetomidine of 57 ng/L (PEC derived for a Baltic marina scenario) [19].…”

Review: ecotoxicity of organic and organo-metallic antifouling co-biocides and implications for environmental hazard and risk assessments in aquatic ecosystems

“…For medetomidine, Wendt et al (2013) concluded that this antifoulant poses a low risk to the macroalgae Ulva lactuta because the maximum predicted environmental concentration (PEC) is low (0.057 µg l -1 , Ohlauson et al 2012). Conversely, the EC10 for egg production of the copepod A. tonsa was reported as 0.16 µg l -1 (Wendt et al 2016), suggesting that medetomidine might pose a risk to the marine environment, depending on the exposure conditions.…”

Substratum‐Associated Microbiota

“…Effectiveness and impact of a variety of antifouling agents were tested. Exposure of algae and bacteria to Medetomidine, a new antifouling substance useful against barnacles, did not result in acute toxic effects on bacterial protein synthesis and resulted in only small acute effects on photosynthesis activity of algae but only at concentrations that would be much higher than predicted environmental concentrations(Ohlauson et al, 2012). After two weeks of immersion, biofilms present on polystyrene, teflon and four antifouling paints were analyzed for the composition and abundance of marine bacterial and diatom assemblages(Briand et al, 2012).…”