Potential of Nassarius nitidus for monitoring organotin pollution in the lagoon of Bizerta (northern Tunisia (original) (raw)
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Imposex and butyltin concentrations in snails from the lagoon of Bizerta (Northern Tunisia
Marine Biology Research, 2010
Imposex and butyltin concentrations were assessed in Hexaplex trunculus, Conus mediterraneus, Cyclope neritea and Nassarius mutabilis from Menzel Jemil, and H. trunculus and Stramonita haemastoma from the Bizerta channel. All females of the five species exhibited the characteristic development of male sex organs (penis and/or vas deferens). In Menzel Jemil, H. trunculus and C. mediterraneus exhibit similar imposex levels and were most affected (VDS reading 3-4). The development of a bud penis or a vas deferens sequence behind the right ocular tentacle was reported in Cyclope neritea and N. mutabilis (VDS 1). The concentration of tributyltin (TBT) was similar for the four species. The monobutyltin (MBT) was only detected in C. mediterraneus while the dibutyltin (DBT) was found in all gastropods at similar proportions as TBT. In the Bizerta channel, imposex levels were similar in both H. trunculus and S. haemastoma but imposex degree was higher in H. trunculus. This finding was confirmed by higher TBT concentration recorded in female of H. trunculus. These results suggested that H. trunculus is the more suitable bioindicator for monitoring TBT pollution.
Environmental Monitoring and Assessment, 2011
The imposex incidence and butyltin concentration i.e. tributyltin with its di- and mono-substituted metabolites were investigated in the muricid Bolinus brandaris sampled from two sites on the northern Tunisian coast (the Lagoon of Bizerta and the small Gulf of Tunis). Both populations had imposex, with stages of imposex development varying between VDS 1 and VDS 4.3. All imposex indices (imposex frequency (I %), female penis length, female vas deferens length, vas deferens sequence index, relative penis length index, and vas deferens length index) were significantly higher in snails from the Bizerta lagoon. Butyltins were detected in the whole tissues of both sexes from the two sites. TBT levels were higher in gastropods collected from the lagoon of Bizerta (12.65 ±1.48 ng Sn g − 1 dw in female and 15.21 ±1.13 ng Sn g − 1 dw in male) than in individuals from the Gulf of Tunis (10.71 ±1.26 ng Sn g − 1 dw in female and 11.65 ±1.63 ng Sn g − 1 dw in male), corroborating the data of imposex analysis. These results confirmed that B. brandaris could be used as a bioindicator species of butyltin pollution in the studied areas. In addition, this study provided baseline data that could serve for long-term monitoring of TBT pollution in Tunisia, since legislation to reduce the use of TBT-based antifouling paints has not been introduced yet.
Bulletin of Environmental Contamination and Toxicology, 2011
Imposex and tributyltin (TBT) body burden were quantified in the gastropod Hexaplex trunculus collected from the Bizerta channel between 2002 and 2010. Except for the imposex frequency that remained maximal (100%), all the other imposex indices decreased throughout the study period. Similarly, TBT levels also decreased over time, being the less frequent compound among butyltins, with a proportion of 22.2%, against 42.9% for dibutyltin (DBT) and 34.9% for monobutyltin (MBT). These findings reflect the effectiveness of new generation of TBT-free antifouling paint introduced in the Tunisian market and global ban of TBT on reducing the environmental impact of this biocide.
Marine Pollution Bulletin, 2007
Specimens of Nassarius nitidus were collected in seven stations of the Venice Lagoon to assess the levels of tributyltin (TBT) and its metabolites monobutyltin and dibutyltin in the tissues and monitor their effect on organisms, in particular the phenomenon of imposex (superimposition of male sexual characteristics on females). The following values of population indices were found: vas deferens sequence: 1.2 ± 0.7-4.0 ± 0.5; relative penis length: 6-47%. The least impacted station was situated in the northern part of the Lagoon, where females without imposex were found and Butyltin (BuTs) concentrations in the organisms (average sum of BuTs = 43 ± 14 ng Sn g À1 w.) were significantly lower than in the other stations (range of average sum of BuTs: 101 ± 22-217 ± 27 ng Sn g À1 d.w.). Population indices were found to be related to the TBT content in the tissues. In particular VDSI had a significant logarithmic correlation: r = 0.95, n = 8, p < 0.05.
Biomonitoring organotin pollution with gastropods and mussels
Marine Ecology-progress Series, 2005
In order to compare their performance for the biomonitoring of organotin (OT) pollution, Galician (NW Spain) populations of gastropods Nassarius reticulatus and mussels Mytilus galloprovincialis were sampled in 2000. Imposex (a set of sexual anomalies) in snails as well as the bioaccumulation of several OT species (mainly tributyltin [TBT]) in both invertebrates were determined. Imposex was related to TBT in female gastropod tissues in a biphasic manner, the slope changing markedly at around 200 ng Sn g -1 dry wt. OT compounds in both animal species were significantly correlated, mussels consistently accumulating more than gastropods; in addition, correlation coefficients considerably increased when outliers were excluded from computation with the aid of fine chemical speciation analyses. The expected decline of OT pollution can satisfactorily be recorded by means of monitoring concentrations in either mussels and/or gastropods. However, the use of the latter is favoured because their imposex response is an easily determined biomarker, which additionally provides useful insights into the biological impact of TBT.
Journal of Environmental Monitoring, 2009
We have assessed for the first time the current status of tributyltin (TBT) contamination in Hexaplex trunculus along Tunisian coastal waters. Two sampling campaigns have been performed in July 2004 and July 2007 at seven different sites. The snails were analyzed for imposex status, i.e. Imposex incidence, Relative Penis Length Index (RPLI) and Vas Deferens Sequence Index (VDSI), followed by the quantification of butyltins in their tissues. Imposex was detected in six populations from the 2004 samples and in five populations from the 2007 samples. The imposex incidence ranged from 0 (no imposex) to 100%, the RPLI from 0 to 56.7 and the VDSI from 0 to 4.4. TBT was also detected in six populations in 2004 and five populations in 2007. The concentrations ranged from 1.5 to 73.7 ng Sn g -1 dw in 2004 samples and from 1.2 to 23.9 ng Sn g -1 dw in 2007 samples. Temporal comparison of the data indicates some evidence of imposex recovery in most affected populations. Improvements in reduced body concentrations of TBT in both sexes were also seen in most stations. These TBT concentrations were only significantly correlated to imposex indices in samples from 2007 (r > 0.8, n = 7, p < 0.05). The present results will serve as a reference for long-term monitoring of butyltin contamination in the Tunisian coast, where TBT restrictions were not yet implemented.
Butyltins concentration levels and imposex occurrence in snails from the Sicilian coasts (Italy)
Chemosphere, 2003
Two sampling campaigns have been carried out along the Sicilian coasts within the frame of a European project (Hic-TBT) financed by the LIFE programme. Snails and sediments have been sampled at 5 stations, characterised by very low (Ustica natural sea reserve), low (Ustica harbour), intermediate (Castellamare and Termini Imerese) and high shipping densities (Palermo). Biological and chemical analyses were carried out in order to evaluate the incidence of imposex occurring in snails, and the concentration levels of organotins in sediment and snail samples. Despite the low organotin concentration levels in sediment and snail samples, the results show that imposex is widespread around Sicily. In four locations almost all female snails were affected by imposex at advanced development stages, even in areas with a fairly low shipping density. Only in the natural sea reserve of Ustica Island imposex was relatively less severe. Finally a logarithmic correlation between TBT and imposex stages was observed.
Ecotoxicology and Environmental Safety, 2016
Butyltin (TBT, DBT, and MBT) effects on molluscs, especially endocrine disruption in bivalves and gastropods, have been widely investigated. Imposex, the superimposition of male characters onto female gonochoristic Caenogastropods, is the most studied biological effect of TBT. TBT compounds are among the priority hazardous substances within Directives 2000/60/EC (WFD) and 2008/105/EC. The Environmental Quality Standards (EQSs) set by the WFD for TBT are quite difficult to quantify by means of chemical analysis, without the use of expensive and high performance methods. Assuming that EQSs set for TBT were derived from evidence of imposex development at very low concentrations, this specific biomarker could be used as an indirect measure of assessing levels of bioavailable BTs. Therefore, this study aims to validate the use of imposex development as an investigative tool to monitor the bioavailable fraction of BTs within the WFD, by comparing imposex levels and BT concentrations in Nassarius nitidus from the Venice Lagoon. BT concentrations and imposex levels in N. nitidus, collected in 2013, had decreased when compared to previous studies in the same area. Both VDSI and RPLI correlated positively with BT body burden in females, confirming that imposex is a valid tool to monitor bioavailable BTs. However, TBT is still a matter of concern in the Venice Lagoon, as TBT concentrations were still higher than its degradation products suggesting recent fresh TBT inputs in the studied area. To propose imposex levels as an indicator of the impact of BTs within the WFD, classification class boundaries and Ecological Quality Ratios were introduced. As a preliminary attempt, imposex levels were also compared to the OSPAR Commission EcoQOs which linked imposex levels in Nassarius reticulatus with TBT concentrations in water. Based on this comparison the degree of imposex development in the Venice Lagoon suggested that TBT concentrations in water should be over the EQS-AA concentration and, at one site, also over the EQS-MAC. From all the results obtained in this work, it appears that imposex evaluation in N. reticulatus could give information about the ecological status regarding BT compounds under the WFD and also be used to monitor their effects and support chemical analyses until more sensitive methods become available.
Chemosphere, 2008
Two monitoring surveys were repeated in Galicia (NW Spain): one in 2003 concerned the rocky shore gastropod Nucella lapillus (19 populations, the reference campaign in 1996), the other dealt in 2005 with the infaunal snail Nassarius reticulatus (25 sites, the previous one in 2000). Samples were subject to a standard protocol to determine the concentrations of butyltins (BTs) in tissues. Results show that pollution in most populations has considerably decreased over the last decade: for N. lapillus the mean descent ranged from 37% (for tributyltin -TBT-) to 66% (for monobutyltin -MBT-), and TBT concentrations were on average halved in N. reticulatus. However, derivatives generally increased in this latter species, to the extent that dibutyltin -DBT-in several 2005 samples exceeded the aggregate of all three BTs in 2000. As a consequence, a major change in the bioaccumulation patterns becomes evident, particularly when computing the butyltin degradation index [BDI: (DBT + MBT)/TBT]. This shift is most marked at sites where pollution has always been lowest, and it shows significant negative correlation between both gastropods. Since sources other than antifouling paints are not important in the area, it is proposed that observations are due to BT desorption from sediments through some interplay involving the different characteristics of the chemicals and the contrasting biology of the animals.