Sami Abidli - Academia.edu (original) (raw)

Papers by Sami Abidli

Bulletin of Environmental Contamination and Toxicology, 2011

Imposex and tributyltin (TBT) body burden were quantified in the gastropod Hexaplex trunculus col... more 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.

Journal of The World Aquaculture Society, 2010

Spawning, intracapsular development, and juvenile growth of Hexaplex trunculus were investigated ... more Spawning, intracapsular development, and juvenile growth of Hexaplex trunculus were investigated in the laboratory. Each female deposited nightly an average of 138.83 ± 58.70 yellowish egg capsules per spawn. Each capsule contained 358.57 ± 102.45 eggs with an average diameter of 207.23 ± 18.18 µm. Observations on the intracapsular development showed that H. trunculus is a spiralian unequal-cleaving gastropod, with polar lobes being extruded at early segmentation. Embryos develop within the egg capsule through the provision of nurse eggs as an extraembryonic source of nutrition. Hatching occurred after 52 d of incubation. However, the hatchlings were not completely metamorphosed because velum was still present. At this moment, the average of shell length was 1.04 ± 0.13 mm (n = 107). The average number of hatchlings per capsule was 14.73 ± 4.40 including 3.4% malformed individuals. During the first 5 mo of life, juveniles rapidly grew in shell length (growth rate = 3.56 mm/mo). However, in the remaining period (26 mo), growth rhythm decreased considerably (growth rate = 0.64 mm/mo). The weight growth rhythm was irregular with alternation between fast and slow increases observed over the rearing experiment. This kind of data could be useful for assessing the potential of this species for future molluscan aquaculture programs.

Journal of Environmental Sciences-china, 2011

Imposex and butyltin burden were assessed in Nassarius nitidus, Bolinus brandaris and Hexaplex tr... more Imposex and butyltin burden were assessed in Nassarius nitidus, Bolinus brandaris and Hexaplex trunculus collected at five stations in the Bizerta lagoon. Biological analysis showed that imposex followed type (a) in N. nitidus (distal evolution), against type (d) in the two muricids (proximal evolution). Imposex indices were higher in sites located nearby sources of tributyltin and N. nitidus was the least affected species of the five sites, followed by B. brandaris and H. trunculus. Butyltin analysis showed lower accumulation in N. nitidus followed by H. trunculus and B. brandaris. This study has allowed the gathering of data on imposex in a snail studied for the first time in Tunisia (N. nitidus). It suggests the possibility of using such snail as a complementary species for organotin monitoring programs in the Mediterranean and further confirmed that H. trunculus is the most suitable species for such investigations.

Environmental Monitoring and Assessment, 2011

The imposex incidence and butyltin concentration i.e. tributyltin with its di- and mono-substitut... more 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.

Journal of The Marine Biological Association of The United Kingdom, 2009

Tributyltin (TBT) exposure experiments at 5 and 50 ng l 21 concentrations were carried out in the... more Tributyltin (TBT) exposure experiments at 5 and 50 ng l 21 concentrations were carried out in the laboratory on female Hexaplex trunculus collected during the reproductive season from a site weakly-affected by imposex (12.1%). The imposex intensity estimated by the imposex incidence or frequency (I%), the average length of the vas deferens (VDL), the average length of female penis (FPL) and the vas deferens sequence index (VDSI) showed significant variation with TBT concentration. The number of spawning females decreased with TBT concentration. TBT had no effect on the number of egg-capsules laid per female nor on the number of eggs per capsule. The egg-capsules laid in the control and 5 ng TBT l 21 aquaria showed harder texture of the wall compared to those exposed to 50 ng TBT l 21 . The mortality rate increased proportionally with TBT concentration and duration of exposure.

Journal of Shellfish Research, 2009

Journal of Environmental Monitoring, 2009

We have assessed for the first time the current status of tributyltin (TBT) contamination in Hexa... more 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.

Marine Biology Research, 2010

Imposex and butyltin concentrations were assessed in Hexaplex trunculus, Conus mediterraneus, Cyc... more 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.

American Malacological Bulletin, 2008

Hexaplex trunculus (Linnaeus, 1758) is a gonochoric marine gastropod. Previous studies demonstrat... more Hexaplex trunculus (Linnaeus, 1758) is a gonochoric marine gastropod. Previous studies demonstrated that the biocide TBT (tributyltin) induced a sexual abnormality known as imposex (superimposition of male sexual characters onto females) in this whelk. Our study showed imposex in 19 stations out of 20 along the Tunisian coast. The frequency of imposex ranged from 0 to 100%. Among the 19 sites where the condition was found, 8 were considered as highly affected by imposex (VDSI > 3.7), 6 were moderately affected (VDSI > 1.3), and 4 were slightly affected (VDSI > 0). The most affected population was observed in the Bizerta Channel where the highest boating traffic was recorded; no imposex features were found in the Sea of Zarat where boating traffic was very low. Significant differences in imposex levels were obtained among sites with low, moderate, and high boating traffic. All the imposex indices values (I%, RPSI, RPLI, VDSI, FPL, and VDL) were significantly more elevated at sites with high boating traffic compared with sites with low and moderate boating traffic. Malformations of the penis were observed only in five stations and in very low rates, but where imposex rates were high. The incidence of penis malformation in males was significantly related to the boating traffic, I%, and VDSI. However, in females, a correlation was obtained only for the RPLI. The present study provides data on imposex level and penis malformations in H. trunculus from the Tunisian Coast that could be used as a starting point for future monitoring programs and for temporal trend surveillance related to TBT pollution in Tunisia where the use of TBT is not yet banned.