Assessing the exposure of Sidi M’Hamed Benali lake (Algeria) to Organo-chlorinated compounds and pesticides in fish

Sidi M’Hamed Benali lake (Algeria) is a reservoir used for recreational and fishing purposes that also harbors a rich fauna an flora. These are affected by use of pesticides in view of the increasing anthropogenic activities. In this study, levels of contaminants, polychlorinated biphenyls (PCBs), polybromo-diphényléthers (PBDEs), dichlorodiphenyltrichloroethanes (DDTs), and Lin-dane were measured using gas chromatography with electron capture detec-tion and gas chromatography mass spectrometry in four fish species (Cyprinus carpio, Barbus barbus, Hypophthalmichthys molitrix, Rutilus rutilus) of Sidi M'Hamed Benali lake. The results showed that PCBs, PBDEs and the insecticide Lindane contaminated the studied species but at concentrations, much lower that the guiding values. On the contrary, high levels of pp’DDE (p,p’dichlorodiphényldichloroéthylène) was recorded in all samples with values higher than the Maximum residue limit of 300 ng/g lipid weight (LW.) set by FAO with values as high as 3.87 x 103 ng/g LW (total DDTs) which indi-cated potential hazard not only to human consumers of the lake fishs but also a potential hazard expected to animals that prey on these fishes. 14 ng/g fresh weight (FW.) Canadian limit is also significantly lower than the values of fish from the studied lake (42-46 ng/g FW.). In light of these results, we conclude that this lake is exposed to organic pollution of anthropogenic origin and we encourage caution regarding the consumption of fish in this reservoir. It is time to make serious efforts to mitigate the lake pollution in order to protect aquatic wildlife for sustainable development.

The Influence of Temperature Increase on the Toxicity of Mercury Remediated Seawater Using the NanomaterialGraphene Oxide on the Mussel Mytilus galloprovincialis

Mercury (Hg) has been increasing in waters, sediments, soils and air, as a result of natural events and anthropogenic activities. In aquatic environments, especially marine systems (estuaries and lagoons), Hg is easily bioavailable and accumulated by aquatic wildlife, namely bivalves, due to their lifestyle characteristics (sedentary and filter-feeding behavior). In recent years, different approaches have been developed with the objective of removing metal(loid)s from the water, including the employment of nanomaterials. However, coastal systems and marine organisms are not exclusively challenged by pollutants but also by climate changes such as progressive temperature increment. Therefore, the present study aimed to (i) evaluate the toxicity of remediated seawater, previously contaminated by Hg (50 mg/L) and decontaminated by the use of graphene-based nanomaterials (graphene oxide (GO) functionalized with polyethyleneimine, 10 mg/L), towards the mussel Mytilus galloprovincialis; (ii) assess the influence of temperature on the toxicity of decontaminated seawater. For this, alterations observed in mussels’ metabolic capacity, oxidative and neurotoxic status, as well as histopathological injuries in gills and digestive tubules were measured. This study demonstrated that mussels exposed to Hg contaminated seawater presented higher impacts than organisms under remediated seawater. When comparing the impacts at 21 °C (present study) and 17 °C (previously published data), organisms exposed to remediated seawater at a higher temperature presented higher injuries than organisms at 17 °C. These results indicate that predicted warming conditions may negatively affect effective remediation processes, with the increasing of temperature being responsible for changes in organisms’ sensitivity to pollutants or increasing pollutants toxicity.

Broad diversity of bacteria degrading 17ß-estradiol-3-sulfate isolated from river sediment and biofilm at a wastewater treatment plant discharge

Conjugated estrogens, such as 17β-estradiol-3-sulfate (E2-3S), can be released into aquatic environments through wastewater treatment plants (WWTP). There, they are microbiologically degraded into free estrogens, which can have harmful effects on aquatic wildlife. Here, the degradation of E2-3S in environmental samples taken upstream, downstream and at the effluent of a WWTP was assessed. Sediment and biofilm samples were enriched for E2-3S-degrading microorganisms, yielding a broad diversity of bacterial isolates, including known and novel degraders of estrogens. Since E2-3S-degrading bacteria were also isolated in the sample upstream of the WWTP, the WWTP does not influence the ability of the microbial community to degrade E2-3S.

An outbreak of multidrug-resistant Salmonella Kentucky infection in long-nosed fur seals

An outbreak of salmonellosis occurred in a group of 7 long-nosed fur seals Arctocephalus forsteri undergoing rehabilitation after being found injured and malnourished on beaches along the northern New South Wales and southern Queensland coasts of Australia. Three of the 7 individuals developed clinical disease and died within 3 d. Clinical signs included profuse diarrhea, vomiting, depression, and lethargy. Salmonella enterica subsp. enterica serovar Kentucky (S. Kentucky) was cultured from 2 of the 3 deceased animals. The other 4 animals showed similar signs and recovered following treatment. S. Kentucky (antigenic formula 8,20:i:z6) was isolated from the survivors and tissues recovered from post-mortem samples of deceased animals. The bacterium was susceptible to cephalothin and sulfamethoxazole/trimethoprim and resistant to amoxicillin-clavulanate, ampicillin/amoxicillin, tetracycline, and enrofloxacin. This organism has the potential to cause disease in aquatic wildlife, as well as posing a zoonotic threat to people who utilise the aquatic environment.