Geographical and temporal variation in levels of organochlorine contaminants in marine mammals.

During the past few decades, increasing concern about environmental pollution has led to many investigations on heavy metals and their distribution
in the sea, air or biological materials. The distribution of xenobiotics in the
marine environment is not homogeneous and a considerable variation of the
concentrations may occur regionally and temporally. The use of bioindicators
offers a useful alternative for pollution monitoring studies. Marine mammals appear to be potentially valuable indicators of the level of heavy metals
accumulated in the marine environment: according to their top position in
the trophic network, their long life span and their long biological half-time
of elimination of pollutants, these animals accumulate high levels of chemicals
such as organochlorines (Kamrin and Ringer, 1994; Tanabe et al., 1994),
or heavy metals (Bouquegneau and Joiris, 1988, 1992; Andre et al., 1991a;
Dietz et al., 1998). The increased interest in studying contaminants in marine
mammals is due to large-scale die-off (Sarokin and Schulkin, 1992; Forcada
et al., 1994) or impaired reproduction (De Guise et al., 1995), which could
lead to population declines of some pinniped and small cetacean species in
Europe and North America, and the ﬁnding of relatively large contaminant
burdens in these animals. In many cases, morbillivirus infections were
the primary cause of the disease outbreaks (Heide-Jorgensen et al., 1992;
Thompson and Hall, 1993; de Swart et al., 1995a). These mass mortalities
among seals and dolphins inhabiting contaminated marine areas have led to
speculation about the possible involvement of immunosuppression associated
with environmental pollution.

/pdf/heavy-metals-in-marine-mammals-5avf279zbe.pdf

Heavy metals in marine mammals

Concentration and subcellular distribution of trace elements in liver of small cetaceans incidentally caught along the Brazilian coast.

Concentrations of HCB, DDTs and PCBs in the tissues andorgans of cetaceans ( Stenella coeruleoalba, Tursiops truncatus, Balaenoptera physalus, Steno bredanensis}, Grampus griseus} and Globicephala melaena) strandedalong the Italian coasts in the period 1987–1993 are reported. The values are compared between speciesand between specimens of the samespecies. Chlorinated hydrocarbon (CH) levels were found toincrease in relation to the quantity andtype of lipids in each tissue and organ. Differences inaccumulation encountered in the differentspecies are principally due to different feeding habitats.Remarkable differences found between malesand females of each species confirm that during gestation andlactation, females undergo disintoxication by passing much of their total burden of CHs to their young.

David Obendorf

Papers

A review of heavy metal and organochlorine levels in marine mammals in Australia.