Concentrations and Risk Assessment of Metals, Antifouling Paint Particles and Microplastics in Coastal Sediment of a Marina in Simon’s Town, South Africa

Abstract

Maintenance of maritime vessels includes the removal of paint from hulls that ultimately ends up the aquatic environment. Coastal maritime vessel maintenance is a source of metals, antifouling paint particles (APPs) and microplastics (MPs) that ends up in the coastal environment. Simon’s Town is a small urban town in False Bay, Cape Town, South Africa, where maritime activities take place (there is a naval harbour, marina and boat maintenance facility). The aim of this study was to measure metals, APPs and MPs in Simon’s Town, to assess the impact of maritime activities and a storm water pipe in a protected marina. Sediment samples were collected from 6 sites during winter 2018. Sediment and extracted APPs were analysed for metal content and MPs characterised based on type (visual and polymer), colour and size. Metal and MP fragment concentrations were highest at the slipway of a boatyard / maintenance facility, decreasing with increased distance from the slipway. MP filaments were highest close to the storm water outfall pipe. Our results suggest that boating maintenance facilities are potential sources metals and MP APP fragments, with storm water pipes potential sources of MP filaments. Various indices applied to assessed the potential impacts of metals and MPs, suggests that these contaminants have the potential to severely adversely impact the intertidal ecosystem investigated.