How Can We Use the Red Fox as a Bioindicator of Organochlorines?

Abstract

The exposure of red foxes to hexachlorobenzene (HCB), dichlorodiphenyltrichloroethan (DDT), DDT derivatives, and polychlorinated biphenyls (PCBs) in central Italy was determined by analyzing muscle and adipose tissue samples from 57 red foxes collected in 1992-1993 in three areas of Tuscany, each characterized by different levels of anthropization. Chemical analysis showed that HCB occurred in low concentrations, ranging from an average of 0.08 microg/g lipid basis in fat of foxes from Pisa, the least agricultural area, to 1.06 microg/g in muscle of those from Grosseto, the least industrialized area. DDTs were calculated as the sum of the op' and pp'DDT isomer concentrations and the DDT derivatives DDE and DDD. The lowest values of DDTs were found in foxes from Pisa, with mean values in muscle of 0.55 microg/g and 0.14 microg/g in fat. In the outskirts of Siena, the corresponding values were 1.16 microg/g and 0.49 microg/g. Higher values were found in the Grosseto area: 4.17 microg/g in muscle and 0.67 microg/g in fat. The most abundant DDT was pp'DDE in all areas, constituting more than half of total DDTs. Mean and standard deviations of PCB concentrations (calculated as the sum of the 31 identified and quantified congeners), were 20.2 microg/g in muscle and 7.2 microg/g in fat of red foxes from the Siena area. Values in the Pisa area were lower (7. 6 microg/g in muscle and 1.8 microg/g in fat), whereas the highest levels were found in the Grosseto area (38 microg/g in muscle and 7. 5 microg/g in fat). PCB fingerprints showed that hexa- and heptachlorobiphenyls were the most common congeners, although amounts differed between the three localities and the two tissues considered. As far as PCB composition is concerned, detailed observation revealed that although the three areas highly differed between each other, the most abundant congeners were the 22'344'5' (PCB 138) and 22'44'55' (PCB 153) hexachlorbiphenyls and 22'33'44'5 (PCB 170) and 22'344'55' (PCB 180) heptachlorobiphenyls; these accounted for over 60% of total PCB residues in muscle and fat. Concentrations of the remaining PCB congeners were all lower than 5% of total PCBs, with the exception of octachlorobiphenyl 22'33'44'55' (PCB 194) in fat tissue. Foxes may be suitable biological indicators to detect organochlorine contamination in the environment because of their catholic food habits. This information may be used to select specific bioindicators for assessing the relative level of pollutants in that area.

Age- and sex-dependent distribution of persistent organochlorine pollutants in urban foxes.

“…For several years, remobilization of existing pollutants and their constant circulation in the environment and food web has been considered to represent the major source of PCB contamination in Switzerland (Müller 1994). In agreement with the general reduction of PCB exposure, we found a considerably lower PCB content in our study, conducted with samples obtained in 1999-2000, than in similar reports from neighboring countries (Germany and Italy) based on foxes collected during 1983(Brunn et al 1991Corsolini et al 1999Corsolini et al , 2000Georgii et al 1994). No adverse health or reproductive responses are expected to occur from this low burden of organochlorine contamination, and in fact, the local fox population in Zürich has been growing steadily during the last years.…”

“…Organochlorine concentrations were assessed in samples of homogenized kidney using a validated procedure that follows the method by Corsolini et al (2000) with several modifications. Samples were extracted in the presence of a mixture of n-hexane and dichloromethane at a ratio of 4:1.…”

“…A convenient alternative species that lives in close vicinity to humans is provided by the increasing colonization of suburban and urban habitats by the red fox (Vulpes vulpes). Indeed, red foxes have already been used to monitor anthropogenic pollutants in rural habitats (Ansorge et al 1993;Brunn et al 1991;Bukovjan 1997;Corsolini et al 2000;Georgii et al 1994). Being a highly opportunistic species that adapts to a multitude of different environmental conditions and food supplies (Nowak 1991), red foxes have progressively invaded the cities and suburbs of many European countries (Schöffel et al 1991;Willingham et al 1996), where these animals are exposed, at least in part, to the same pollutants and contaminants as the local human population.…”

Carrion dependence and food habits of the red fox in an Alpine area

“…to estimate the level of pollutants in an area, Corsolini et al, 2000). If so, the overall similarity between the spectrum of food habits in Leinati et al (I960) and our study could suggest that modest changes have occurred in the habitats within this large protected area.…”

Use of Honeybees as Bio-Indicators of Environmental Pollution in the Kurdistan Province of Iran

“…Several animal species have been suggested to be suitable for the monitoring of environmental pollution. Mussels (Dreissena polymorpha) (Binelli et al, 2001;Szefe et al, 2002); herrings (Clupea harengus), and partridges (Alectoris rufa) (Herrera et al, 2000) or even mammals such as cattle (López-Alonso et al, 2002) and fox (Corsolini et al, 2000) have been suggested for the monitoring of environmental pollution. Since 1970, honeybees (Apis mellifera) have increasingly been used to monitor heavy metal environmental pollutants as reported in some studies (Porrini et al, 2002;Bromenshenk et al, 1985).…”