The endocrine-disrupting effect and other physiological responses of municipal effluent on the clam Ruditapes decussatus.
In order to document the potential endocrine disrupting and toxic effect of the municipal wastewater effluents discharged into the Sfax coastal area (South of Tunisia), specimens of clam R. decussatus were collected from a reference site and were in vivo exposed to treated sewage effluent for 30 days. To this end, estrogenic and androgenic activities were measured in the gills to assess potential accumulation and regulation of active compounds. After effluent exposure androgenic activity in organic extracts increased up to fivefold compared to controls and remained elevated, while estrogenic activity was not significantly affected by exposure. As a consequence, remarkable disruptions in the gametogenesis activity, glycogen content, and Vitellogenin-like protein levels in male clams were observed. A parallel analysis of heavy metals in clam tissues was determined. A significant uptake of Ni, Zn, and Pb in soft tissues of exposed clams was observed. The significant increase of malondialdehyde (MDA) concentrations as a function of exposure time implies that clams have been exposed to an oxidative stress probably due to the presence of high metal concentrations in sewage effluent. Correlation analysis has revealed a statistically significant and positive relationship between MDA levels and metal concentrations in clams' tissues. The acetylcholinesterase activity was not significantly affected by exposure. Altogether, these results showed that a short-term exposure to a mixture of chemical compounds released by the Sfax wastewater treatment plant induce adverse physiological and reproductive effects in R. decussatus. Further studies are underway in order to evaluate its long-term impacts on aquatic wildlife in the gulf of Gabes area.
Unit of Marine and Environmental Toxicology, Sfax University, IPEIS, BP 1172, 3018, Sfax, Tunisia. mezghani.sawssen@tunet.tn.|Normandie Université, UMR-I-02 SEBIO, BP 540, 76058, Le Havre, France. mezghani.sawssen@tunet.tn.
Sawssan
S
Mezghani-Chaari
Unit of Marine and Environmental Toxicology, Sfax University, IPEIS, BP 1172, 3018, Sfax, Tunisia.
Monia
M
Machreki-Ajmi
Normandie Université, UMR-I-02 SEBIO, BP 540, 76058, Le Havre, France.
Gauthier
G
Tremolet
CNRS INEE-FRE3484 BioMEA, Université de Caen Basse-Normandie, 14032, Caen-Cedex, France.
Kristell
K
Kellner
Université de Reims Champagne-Ardenne, UMR-I 02 SEBIO, Campus Moulin de la Housse, B.P. 1039, 51687, REIMS cedex, France.
Alain
A
Geffard
Normandie Université, UMR-I-02 SEBIO, BP 540, 76058, Le Havre, France.
Christophe
C
Minier
Unit of Marine and Environmental Toxicology, Sfax University, IPEIS, BP 1172, 3018, Sfax, Tunisia.
Amel
A
Hamza-Chaffai
D000818:Animals; D049872:Bivalvia / Q000187:drug effects* / Q000378:metabolism; D052244:Endocrine Disruptors / Q000032:analysis / Q000633:toxicity*; D005880:Gills / Q000378:metabolism; D008297:Male; D008315:Malondialdehyde / Q000032:analysis; D019216:Metals, Heavy / Q000032:analysis; D018384:Oxidative Stress; D012098:Reproduction / Q000187:drug effects; D014416:Tunisia; D014819:Vitellogenins / Q000032:analysis; D062065:Wastewater / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000633:toxicity*
D052244:Endocrine Disruptors; D008315:Malondialdehyde; D019216:Metals, Heavy; D014819:Vitellogenins; D062065:Wastewater; D014874:Water Pollutants, Chemical
Androgenic and estrogenic activities; Biomarkers; Endocrine disruption; Municipal wastewater effluents; R. decussatus; Reproduction