Analysis of mercury and methylmercury concentrations, and selenium:mercury molar ratios for a toxicological assessment of sperm whales (Physeter macrocephalus) in the most recent stranding event along the Adriatic coast (Southern Italy, Mediterranean Sea).

Mass stranding of sperm whales (Physeter macrocephalus) is a rare event in the Mediterranean Sea. In September 2014, a pod of seven sperm whales became stranded along the Adriatic coast of Southern Italy. This is the seventh occurrence of this type since 1555 in this sea basin. Total concentrations of mercury (T-Hg), methylmercury (MeHg) and selenium (Se) were measured from brain, muscle, liver and kidney of three female sperm whales, which died in this event. Analyses showed considerable, age-dependent variations in Hg and Se concentrations in the different organs. The contamination levels of T-Hg in the liver (up to 200 mg kg(-1)) and brain (up to 21 mg kg(-1)) samples were markedly higher than those in the kidney and muscle samples. The liver and brain also showed the highest Se levels. Se:Hg molar ratios ⩾1 were observed in all the organs of the three sperm whales, suggesting that Se could protect the animals from Hg toxicity. The risk of Hg-associated neurotoxicity was assessed by comparing our values to thresholds set for neurotoxicity in mammals, and the role of Se in the detoxification process of T-Hg/MeHg is discussed herein.

Heavy metals distribution in muscle, liver, kidney and gill of European catfish (Silurus glanis) from Italian Rivers.

The accumulation of heavy metals in freshwaters has direct consequences to man and ecosystem. Thus, in this study, the concentrations of mercury, cadmium, lead, arsenic and chromium in organs of the predator European catfish (Silurus glanis) were investigated. Samples were collected annually in five sites covering the area of the Po River (North Italy) between 2007 and 2009. Metals were differently distributed in the various organs, the highest concentrations of Hg were found in muscle and liver, Cd in kidney, Pb in gill and liver, as in muscle, and of Cr in gill and liver. Our survey found Hg exceeding the Maximum Levels (MLs) of 0.5 ppm in 18% of samples, while Pb and Cd were lower than the MLs set by European regulations in muscle tissues (1881/2006/EC and 629/2008/EC). Hg concentrations were significantly related to sampling stations studied, according to the presence of many industrial activities in the catchment area of Bormida and Tanaro Rivers. The finding that Hg did not fit food fish legislation limits indicated that S. glanis flesh might not be utilised for human consumption. A close monitoring of metals pollution is strongly recommended especially in piscivorous fish, cause their bioaccumulation capacity.

Heavy metals in Mugil cephalus (Mugilidae) from the Ligurian Sea (North-West Mediterranean, Italy).

Pb, Cd and Hg in muscles of flathead mullet (Mugil cephalus), collected from Bocca di Magra, La Spezia (Ligurian Sea, Mediterranean Sea, Italy), were determined using graphite furnace atomic absorption spectrometry after microwave digestion for Pb and Cd and direct mercury analyser for Hg. Average Pb concentrations varied in the range 0.20-0.24 mg/kg, whereas Cd and Hg levels were negligible. None of the tested 200 samples exceeded the European regulatory limits as set by EC 1881/2006 and 420/2011. Metal concentrations in fish muscles were assessed for human consumption according to provisional tolerable weekly intake. The estimated values of Pb, Cd and Hg in M. cephalus's edible parts in this study were below the values established by the Joint WHO/FAO Expert Committee on Food Additives. Therefore, it can be concluded that there is no health problem in human consumption.