Search Results (8)

Environmental concerns regarding the ecotoxicological effects of antifouling biocides have led to the development of products targeting biofilm-forming bacteria. However, the potential for sublethal biocide exposure to promote bacterial adaptation and increase the risk of resistance development poses a potential threat to marine ecosystems and human health, yet it remains insufficiently understood. Although this study focuses on conventional antifouling biocides, the findings are intended to inform the future development and evaluation of both conventional and environmentally friendly antifouling technologies by highlighting the importance of assessing resistance induction at sublethal concentrations. In this study, the effects of three representative antifouling biocides on marine bacterial growth and bacterial adhesion were investigated. Sea-Nine 211 (DCOIT), copper sulphate (CuSO₄), and tributyltin oxide (TBTO; included as a historical reference compound due to its environmental persistence) were tested at four concentrations (0.01, 0.1, 1.0, and 10 µg/mL) against six marine biofilm-forming bacteria: Vibrio proteolyticus, V. aestuarianus, V. harveyi, V. natriegens, Shewanella putrefaciens and Pseudoalteromonas elyakovii. The results showed that Sea-Nine 211 exhibited a strong antibacterial effect at 10 µg/mL against all tested species except V. harveyi, whereas at the lowest concentration it promoted bacterial adhesion in V. proteolyticus. In contrast, TBTO and CuSO₄ showed limited antibacterial activity and increased microbial adhesion at the three lowest concentrations tested. These findings demonstrate that antifouling biocides can induce distinct responses depending on the concentration, ranging from growth inhibition to enhanced bacterial adhesion. Given that reducing biocide release has been proposed as a strategy to mitigate environmental impacts, our results highlight two potential challenges: (i) reduced antifouling efficacy at sublethal concentrations and (ii) an increased risk of bacterial adaptation associated with enhanced adhesion. To support future monitoring and resistance risk assessment, we propose a conceptual Resistance Risk Index (RRI) framework that could contribute to the sustainable management of antifouling agents while accounting for local environmental conditions. Full article

A simple analytical method was developed and evaluated for the determination of two antifouling biocides using an ionic liquid-dispersive liquid–liquid micro-extraction (IL-DLLME) and a high-performance liquid chromatography–electrospray ionization mass spectrometry (LC-ESI-MS) analysis. Irgarol 1051 and Sea-Nine 211 were extracted from deionized water, lake water, and seawater using IL 1-hexyl-3-methylimidazolium hexafluorophosphate ([HMIm][PF6]) and ethyl acetate as the extraction solvent and the dispersion solvent. Several factors were considered, including the type and volume of extraction and dispersive solvent, IL amount, sample pH, salt effect, and cooling temperature. The developed method resulted in a recovery range of 78.7–90.3%, with a relative standard deviation (RSD, n = 3) less than 7.5%. The analytes were enriched greater than 40-fold, and the limits of detection (LOD) for two antifouling biocides were 0.01–0.1 μg L⁻¹. The method was effectively applied for the analysis of real samples of freshwater as well as samples of seawater. Full article

Copepods, the dominant member of zooplankton and major grazers of phytoplankton in the pelagic ecosystem, are at risk from exposure to antifouling biocides. To evaluate the developmental toxicity of antifouling biocides (Diuron, Irgarol 1051, Sea-nine 211) and wastewater (from high-pressure water blasting (WHPB) and its MeOH extract (WHPB-MeOH)) in the copepod Paracalanus parvus sl, we investigated the chemical concentration, egg-hatching rate, and nauplius mortality. WHPB samples were obtained through hull-cleaning activities involving WHPB in a dry dock. Among the biocides, Sea-nine 211 had the strongest effects on hatching rates and nauplius mortality, which was followed by Diuron and Irgarol 1051. In the WHPB and WHPB-MeOH samples, there was no significant difference between the experimental groups in terms of the egg-hatching rate; however, WHPB was found to be more toxic in terms of nauplius mortality, suggesting that metals in WHPB may also adversely affect nauplius survival in P. parvus sl. A comparison of the LC₅₀ results of Sea-nine 211 and WHPB revealed that WHPB had a negative effect on nauplius mortality even at a 100-fold lower concentration. Therefore, if chemical contaminants generated during in-water cleaning activity are discharged continuously into the ports without being properly collected through a post-treatment system, they are expected to negatively impact the population of copepods near the port. Although verification is needed through additional experiments, our results could be used for a baseline study concerning the toxicity of antifouling biocides on marine copepod species. Full article

To evaluate the effects of antifouling paints and biocides on larval settlement and metamorphosis, newly hatched swimming larvae of the compound ascidian Botryllus schlosseri, a dominant species of soft-fouling in coastal communities, were exposed to (i) substrata coated with seven antifouling paints on the market containing different biocidal mixtures and types of matrices and (ii) sea water containing various concentrations of eight biocidal constituents. All antifouling paints showed high performance, causing 100% mortality and metamorphic inhibition, with ≥75% not-settled dead larvae. All antifouling biocides prevented the settlement of larvae. The most severe larval malformations, i.e., (i) the formation of a bubble encasing the cephalenteron and (ii) the inhibition of tail resorption, were observed after exposure to metal and organometal compounds, including tributyltin (TBT) at 1 μM (325.5 µg L⁻¹), zinc pyrithione (ZnP) at 1 μM (317.7 µg L⁻¹), and CuCl at 0.1 μM (98.99 µg L⁻¹), and to antimicrobials and fungicides, including Sea-Nine 211 at 1 μM (282.2 µg L⁻¹) and Chlorothalonil at 1 μM (265.9 µg L⁻¹). The herbicides seemed to be less active. Irgarol 1051 was not lethal at any of the concentrations tested. Diuron at 250 μM (58.2 mg L⁻¹) and 2,3,5,6-tetrachloro-4-(methylsulphonyl)pyridine (TCMS pyridine) at 50 μM (14.8 mg L⁻¹) completely inhibited larval metamorphosis. These results may have important implications for the practical use of different antifouling components, highlighting the importance of their testing for negative impacts on native benthic species. Full article

Antifouling compounds are widely used in paints applied on ship hulls to prevent attachment of fouling organisms. However, a certain amount of these chemicals could leach from the painted surface, enter seawater, and pose deleterious effects on various marine biotas. The present study aimed to determine the concentration of organotin (OT) compounds and booster biocides in sediments collected from the seagrass area of Sungai Pulai estuary, Malaysia. The sediment samples were collected from three points on the seagrass bed, brought back to the laboratory, extracted using standard extraction procedure, and the analytes were analysed using gas chromatography-mass spectrometry (GC-MS) method. The results showed that tributyltin (TBT) concentrations in sediments were within the range of 8.1 ± 0.4 to 10.6 ± 0.5 µg/kg, whereas the values of triphenyltin (TPT) were between 17.1 ± 0.9 and 19.4 ± 1.0 µg/kg. The range of concentration of booster biocides, namely diuron, dichlofluanid chlorothalonil, Irgarol 1051, M1, and Sea-Nine 211, were from <0.1 to 22.9 ± 1.1, 48.7 ± 2.4 to 800 ± 40, <0.1 to 6.2 ± 0.3, <0.1 to 1.4 ± 0.1, 44 ± 2.2 to 877 ± 44, and 9.1 ± 0.5 to 170 ± 8.5 µg/kg, respectively. The concentration of organotin was much lower than the previous study conducted in southern Johor. Meanwhile, the increased concentration of booster biocides proves the use of these compounds as antifouling paints in shipping systems nowadays. Full article

Accumulation of Ot alternative antifoulants in sediment is the focus of this research. Much research had been done on surface sediment, but in this report, the accumulation in the sediment core was studied. The Ot alternative antifoulants, Diuron, Sea-Nine211, and Irgarol 1051, and the latter’s degradation product, M1, were investigated in five samples from the northern part of Hiroshima Bay. Ot compounds (tributyltin (TBT) and triphenyltin (TPT)) were also investigated for comparison. In addition, metal (Pb, Cu, Zn, Fe and Mn) levels and chronology were measured to better understand what happens after accumulation on the sea floor. It was discovered that Ot alternative antifoulant accumulation characteristics in sediment were like Ot compounds, with the concentration in the sediment core being much higher than surface sediment. The concentration in sediment seems to have been affected by the regulation of Ot compounds in 1990, due to the concentration of Ot alternative antifoulants and Ot compounds at the survey point in front of the dock, showing an increase from almost the same layer after the regulation. Full article

Biocides are chemical substances that can deter or kill the microorganisms responsible for biofouling. The rapid expansion of the aquaculture industry is having a significant impact on the marine ecosystems. As the industry expands, it requires the use of more drugs, disinfectants and antifoulant compounds (biocides) to eliminate the microorganisms in the aquaculture facilities. The use of biocides in the aquatic environment, however, has proved to be harmful as it has toxic effects on the marine environment. Organic booster biocides were recently introduced as alternatives to the organotin compounds found in antifouling products after restrictions were imposed on the use of tributyltin (TBT). The replacement products are generally based on copper metal oxides and organic biocides. The biocides that are most commonly used in antifouling paints include chlorothalonil, dichlofluanid, DCOIT (4,5-dichloro-2-n-octyl-4-isothiazolin-3-one, Sea-nine 211^®), Diuron, Irgarol 1051, TCMS pyridine (2,3,3,6-tetrachloro-4-methylsulfonyl pyridine), zinc pyrithione and Zineb. There are two types of risks associated with the use of biocides in aquaculture: (i) predators and humans may ingest the fish and shellfish that have accumulated in these contaminants and (ii) the development of antibiotic resistance in bacteria. This paper provides an overview of the effects of antifouling (AF) biocides on aquatic organisms. It also provides some insights into the effects and risks of these compounds on non-target organisms. Full article

Polysaccharides are an important source of organic carbon in the marine environment and degradation of the insoluble and globally abundant cellulose is a major component of the marine carbon cycle. Although a number of species of cultured bacteria are known to degrade crystalline cellulose, little is known of the polysaccharide hydrolases expressed by cellulose-degrading microbial communities, particularly in the marine environment. Next generation 454 Pyrosequencing was applied to analyze the microbial community that colonizes and degrades insoluble polysaccharides in situ in the Irish Sea. The bioinformatics tool MG-RAST was used to examine the randomly sampled data for taxonomic markers and functional genes, and showed that the community was dominated by members of the Gammaproteobacteria and Bacteroidetes. Furthermore, the identification of 211 gene sequences matched to a custom-made database comprising the members of nine glycoside hydrolase families revealed an extensive repertoire of functional genes predicted to be involved in cellulose utilization. This demonstrates that the use of an in situ cellulose baiting method yielded a marine microbial metagenome considerably enriched in functional genes involved in polysaccharide degradation. The research reported here is the first designed to specifically address the bacterial communities that colonize and degrade cellulose in the marine environment and to evaluate the glycoside hydrolase (cellulase and chitinase) gene repertoire of that community, in the absence of the biases associated with PCR-based molecular techniques. Full article