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

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.

Effects of Currently Used Antifouling Booster Biocides on Green Fluorescent Proteins in Anemonia Viridis

Some of the antifouling booster biocides affects the marine ecosystem negatively. The booster biocides which are resistant to degradation are accumulated in the sediment of the oceans. One of the sedentary organisms in the Mediterranean Sea is Anemonia viridis. The aim of this study is to show the toxicities of common biocides such as irgarol, seanine-211, zinc omadine, and acticide on the fluorescence by GFPs of A.viridis. The decreases in the fluorescence intensities of the GFP were measured within different booster biocide concentrations. The results show that fluorescent intensities of GFP proteins decreased more than 50 percent when they are exposed to different concentrations of irgarol, zinc omadine, acticide. In conclusion, ecosystem health should be prioritized when new antifouling paint compositions are proposed. From the results, it seems that A.viridis can be considered as a vulnerable organism and also it is sensitive to booster biocides within self-polishing antifouling paint formulations.

Hull Roughness and its Effects on Planing Boat Performance

The effects of hull roughness on loss of speed at constant power are investigated. Vessel lifetime roughness profiles are postulated based on construction, coatings and maintenance. These are utilized to determine loss of speed and change in running attitude for planing boats. The formulations are directly applicable to any planing boat for which a lifetime roughness profile is constructed as presented. The approach to developing the speed/power predictions and the roughness profile is provided. This approach can be utilized to analyze the effects of roughness due to hull material utilized and quality of construction, roughness from paints and coatings and their method of application as well as damage to the coating during maintenance, deterioration of the hull structure material, as well as biofouling influenced by the type of antifouling paint or coating and method of application. It provides a means for investigating different magnitudes and scenarios of these causes of roughness rather than providing only example results.

The Presence of Marine Filamentous Fungi on a Copper-Based Antifouling Paint

Marine biofouling is undesirable growth on submerged substances, which causes a major problem for maritime industries. Antifouling paints containing toxic compounds such as copper are used to prevent marine biofouling. However, bacteria and diatoms are usually found in biofilms developed on such paints. In this study, plastic panels painted with a copper-based self-polishing antifouling paint were exposed to biofouling for 6 months in the Marina Bandar Rowdha, Sea of Oman. Clean panels were used as a control substratum. Marine filamentous fungi from protected and unprotected substrate were isolated on a potato dextrose agar. Pure isolates were identified using sequences of the ITS region of rDNA. Six fungal isolates (Alternaria sp., Aspergillus niger, A. terreus, A. tubingensis, Cladosporium halotolerans, and C. omanense) were obtained from the antifouling paint. Four isolates (Aspergillus pseudodeflectus, C. omanense, and Parengyodontium album) were isolated from clean panels and nylon ropes. This is the first evidence of the presence of marine fungi on antifouling paints. In comparison with isolates from the unprotected substrate, fungi from the antifouling paint were highly resistant to copper, which suggests that filamentous fungi can grow on marine antifouling paints.

Biocides in Antifouling Paint Formulations Currently Registered For Use

Antifouling paints incorporate biocides in their composition seeking to avoid or minimize the settlement and growing of undesirable fouling organisms. Therefore, biocides are released into the aquatic environments also affecting several non-target organisms and, thus, compromising ecosystems. Despite global efforts to investigate the environment occurrence and toxicity of biocides currently used in antifouling paints, the specific active ingredients that have been used in commercial products are poorly known. Thus, the present study assessed the frequencies of occurrence and relative concentrations of biocides in antifouling paint formulations registered for marketing worldwide. The main data were obtained from databases of governmental agencies, business associations and safety data sheets from paint manufacturers around the world. Results pointed out for 25 active ingredients currently used as biocides, where up to six biocides have been simultaneously used in the examined formulations. Cuprous oxide, copper pyrithione, zinc pyrithione, zineb, DCOIT and cuprous thiocyanate were the most frequently ones, with mean relative concentrations of 35.9±12.8 %, 2.9±1.6 %, 4.0±5.3 %, 5.4±2.0 %, 1.9±1.9 % and 18.1±8.0 % (w/w) of respective biocide present in the antifouling paint formulations. Surprisingly, antifouling paints containing TBT as active ingredient are still being registered for commercialization nowadays. These results can be applied as a proxy of biocides that are possibly being used by antifouling systems and, consequently, released into the aquatic environment, which can help to prioritize the active ingredients that should be addressed in future studies.