Toxicity and ecological risks of third-generation anti-fouling paints: Toxicity and effects of diclofluanid on marine organisms

Author(s)

Ana Carolina Feitosa Cruz

• Document type: Doctoral Thesis
• Press: São Vicente. 2019-02-13.
• Institution: Universidade Estadual Paulista (Unesp). Instituto de Biociências. São Vicente
• Defense date: 2019-01-14
• Advisor: Denis Moledo de Souza Abessa; Ítalo Braga de Castro

Abstract

Hundreds of compounds have been detected in different environmental compartments, which may be natural or anthropogenic origin. In many cases, little is known about these compounds, thus there is not regulations for them, leading them be considered effective contaminants and so are called emerging. Among these compounds can be cited the biocides of antifouling paints. They are used to protect and combat the formation and establishment of biofouling communities on surfaces exposed to seawater. They are applied in various structures, such as vessels, oil platforms, submarine pipelines, tanks for aquaculture, among others. Thus, these paints are used with the intention of preserving the structures, as well as maintaining navigability in the case of vessels. The compound of interest for this study is one of the biocides used in antifouling paints, dichlofluanid. Due to its physico-chemical characteristics, part of the dichlofluanid released in the water column tended to adsorb to the particulate material and then deposit in the sedimentary layers. In this way, this study aimed to evaluate the toxicity and subchronic effects of dichlofluanid exposures, after in water and sediment with marine species. In addition, sediment experiments also aimed to evaluate how different concentrations of organic matter in the sediments could influence on their responses. Embryos of the sea urchin Echinometra lucunter and ovigerous females of the copepod Nitocra sp for the ecotoxicological tests in water. The sediment tests were conducted with the copepod Nitocra sp. and with the amphipod Tiburonella viscana. For the exposure tests in water were used bivalves of the species Perna perna and for sediment with bilvalves of Anomalocardia flexuosa. Then, the neutral red retention technique was applied only to P. perna and DNA damage, LPO, GSH, GST, EROD, AChE and GPx for both species. For the sediments were also carried out the granulometric analyzes, calculation of the content of carbonates and organic matter. In ecotoxicological tests with aqueous solutions, the toxic levels were higher than the environmental concentrations. Embryos of E. lucunter presented higher percentages of abnormal larvae from the concentration of 1 μg/l, which was the lowest observed effect concentration (LOEC); the No Observed Effect Concentration (NOEC) was 0.1 μg/l. EC50-40h was 198.5 μg/l and EC10-40h was 0.3577 μg/l. In the Nitocra sp. Tests, LOEC was 100 μg/l and NOEC was 10 μg/l. EC10-7d was 0.0635 μg/l while EC50-7d was 583.83 μg/l. In the sediment tests, the concentrations tested were not toxic to the Nitocra sp and the copepod fecundities were similar when compared the two sediment types. For T. viscana, mortality rates increased by 40% at the concentration of 1000 ng/g and 30% at the concentration of 10000 ng/g. When comparing the two sediments, the greatest difference between mortalities was observed at 1000 ng/g, suggesting that there is an influence of organic matter on the toxicity of Diclofluanid. These investigations show that diclofluanid is toxic to marine invertebrates and that, in sediments, its toxicity can be influenced by the level of organic matter. For the subchronic exposures in water, it was possible to observe effect in the higher concentrations in the neutral red denoting loss of the lysosomal stability. For the biomarkers it was also possible to observe changes in the glands and digestive gills. For sediment it is possible to predict effect in both organs as well, and there is an increase in effects on sediments with higher organic matter contents. In the present study it was possible to verify that dichlofluanid was responsible for generating responses in all toxicity tests performed in water and only an acute effect on the sediment with high organic matter content. Biomarker data corroborate with toxicity tests. In water it is possible to observe an effect to the organisms in the highest concentrations tested and in sediment it is possible to observe an increase of effect in the organisms in the sediments rich in organic matter. (AU)

• FAPESP's process: 16/02029-4 - Toxicity and ecological risks of antifouling paints of third generation
• Grantee: Ana Carolina Feitosa Cruz
• Support Opportunities: Scholarships in Brazil - Doctorate