Novel antifouling agent zinc pyrithione: determination, acute toxicity, and bioaccumulation in marine mussels (Mytilus galloprovincialis)

Abstract

Antifouling biocide zinc pyrithione (ZnPT) and its biological fate have received little attention because this compound was assumed not to be persistent in marine ecosystems. An analytical procedure was developed that has proved to be efficient and very sensitive in extracting ZnPT and its main secondary products, Zn and ionized pyrithione (PT(-)), from both seawater and biological samples, namely in the gills and digestive gland of the bioindicator species Mytilus galloprovincialis. Short-term experiments were carried out to investigate ZnPT toxicity and bioaccumulation. The effects on survival and tissue bioaccumulation of ZnPT and its secondary products were studied on adult mussels from a natural population, collected in the harbor area of Porto Santo Stefano (Italy) and exposed to sublethal doses of the biocide for up to 7 d. Zinc pyrithione was shown to be persistent in the experimental seawater in the short term. A basal level of ZnPT and ionized PT(-) was detected in the mussels, indicating that ZnPT availability in the sampling site is already high enough to induce a detectable accumulation in individuals of the native population. Zinc pyrithione rapidly accumulated in the tissues of the exposed mussels, proportionately to both exposure concentration and time, identifying the gills and digestive gland as important targets in the biological pathway of the contaminants. Even though the 7-d median lethal concentration (LC50) = 8.27 µM established here appears high with respect to reported ZnPT environmental concentrations, the results indicate that this biocide could represent a threat for marine organisms in coastal environments and that further investigations on its biological effects at sublethal doses are needed.

Antimacrofouling Efficacy of Innovative Inorganic Nanomaterials Loaded with Booster Biocides

“…Avelelas et al [25], who evaluated the lethal effect of LDH, LDH-ZnPT and ZnPT on the sibling Atlantic species M. edulis, also demonstrated that LDH-ZnPT was much lethal (96 h-LC 50 = 0.123 mg/L) than the free biocide (96 h-LC 50 = 0.211 mg/L). The LC 50 values of free ZnPT obtained for the ATL mussels are also in full agreement with a past study testing this biocide on M. galloprovincialis (96 h-LC 50 = 4.8 mg/L; 48 h-LC 50 = 14.7 mg/L) [37].…”

“…In the yeast Sacharomyces cerevisiae the biocide was found to up-regulate genes related to ion transport and down-regulate genes related to the biosynthesis of cytochrome [40]. ZnPT has been shown to cause accumulation of zinc in the tissues of Mytilus galloprovincialis, being transported from the gills via the hemolymph to the digestive gland, which functions as the main center for metabolic regulation [37]. Sub-lethal concentrations of ZnPT also activate the antioxidant protective mechanism, including an increased activity of antioxidant enzymes [25,41].…”

Acute and chronic toxicities of zinc pyrithione alone and in combination with copper to the marine copepod Tigriopus japonicus

“…A field experiment reported a half-life of 209 min at a depth of 0.5 m for CuPT, and photodegradation was absent at 1 m or more below surface after 1-h exposure to penetrating sunlight (Grunnett and Dahllöf, 2005). Marcheselli et al (2010b) also found that half of the initial ZnPT quantity remained after 48-h light exposure (indirect sunlight plus laboratory fluorescent lamps). Notably, CuPT had been detected in marine sediment samples from Vietnam (range: <2-420 g/kg-dry wt.)…”

“…A total pyrithione concentration of 105 nM was detected in water samples collected from Mersey estuary, UK indicating the possible existence of pyrithiones like ZnPT and CuPT in marine water columns (Mackie et al, 2004). Marcheselli et al (2010b) reported a basal level of ZnPT and ionized pyrithione (PT − ) in the mussels Mytilus galloprovincialis inside a busy harbour of Italy, indicating that the level of ZnPT in the harbour is high enough to induce a detectable accumulation in native organisms, and the study also showed a rapid accumulation of ZnPT in the mussel in laboratory experiment, suggesting that ZnPT has potentials to accumulate in the trophic chain.…”

Immunotoxicity in ascidians: Antifouling compounds alternative to organotins—IV. The case of zinc pyrithione

“…However, it has recently been demonstrated that ZnP degrades less rapidly than expected. Great uncertainty now exists concerning the persistence of the biocide in the marine environment, especially where the influence of light is limited (Marcheselli et al, 2010). Where UV radiation is scarce, ZnP is adsorbed in sediments and becomes an only slightly available metal complex, but zinc represents a risk to the environment in a long-term scenario (Comber et al, 2002).…”