Potential disruptive effects of copper-based antifouling paints on the biodiversity of coastal macrofouling communities.

Francesca Cima,Roberta Varello

doi:10.1007/s11356-021-17940-2

Francesca Cima, Roberta Varello

Open Access

https://doi.org/10.1007/s11356-021-17940-2

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Abstract

The expanded use of copper(I)-based antifouling paints (AF) has increased copper leaching into coastal environments, requiring attention and legislative restrictions for potential long-term effects on benthic populations. The ecological succession of macrofouling communities was analysed on wooden and stainless steel panels coated with four copper(I)-based AF (Paints A-D) immersed for 10months in the Lagoon of Venice. With the exception of Paint B, which contained only copper(I) compounds and was based on hard-matrix technology, the other paints were based on self-polishing matrices and various booster biocides. The booster content was a mix of TBT compounds for Paint A, dichlofluanid for Paint C, Irgarol 1051, and chlorothalonil for Paint D. The macrofouling communities appeared dissimilar to those on the reference uncoated panels as regard the species richness, the coverage areas, and the biocoenosis structure. Generally, green algae, bryozoans, and barnacles were the most tolerant taxa and a negative species selection occurred for sponges, serpulids, and ascidians. Paints A and D showed the highest performance, and Paint D also prevented molluscs on wood panels. Paints B and C rapidly decreased their efficiency, the first probably due to the insoluble matrix with the highest biocidal leaching rate, and the second due to the presence of a booster with low toxicity. Paint B also inhibited red algae and molluscs, but Paint C did not reveal significant differences in types of species settlements with reference panels.

Highlights

Large amounts of antifouling paints are employed worldwide on vessels and permanently submerged structures to preserve them and reduce the associated economic costs
This study monitored the ecological succession of macrofouling communities on wooden and stainless steel panels immersed for 10 months in the southern basin of the Lagoon of Venice
Communities that are similar in terms of their species composition have been clustered together and represented through a dendrogram. On both the wooden and steel panels coated with antifouling paints, delays in the appearance of primary biofilms were observed, so these panels lacked the settlement of any kind of macrofouling organism until June or July

Summary

Introduction

Large amounts of antifouling paints are employed worldwide on vessels and permanently submerged structures to preserve them and reduce the associated economic costs. The severe damage caused to coastal ecosystems by the leaching of the biocidal substances contained in these paints has been well known since the 1980s for organotin compounds (Champ and Seligman, 1996). Both paint efficacy and its potential for negative effects on the environment are related to content and release rate of the biocides. Self-polishing paints are based on acrylic polymers, with which seawater reacts causing hydrolysis or ion exchange on the surface layer of the coating, allowing the biocide to be released into the water. Organotin copolymer paints, based on tributyltin methacrylate, were the first selfpolishing antifouling coatings, in which the copolymer acted as both the paint matrix and biocide (Swain, 1999)

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