Temporal and geographical variation in skeletal fluoride content of roe deer (Capreolus capreolus) from industrialized areas in Germany

In order to study temporal and spatial variation of environmental fluoride levels, we analyzed the mandibular bone fluoride content of 157 roe deer (age range: 1–11 years) from two industrialized regions (Ruhr area: n=76, sampling period 1955–1998; area W of Cologne: n=81, sampling period 1983–1998) in the federal state of North Rhine-Westphalia, Germany. Bone fluoride values (dry weight basis) ranged between 150 mg F/kg (2 year-old specimen taken in 1997) and 5724 mg F/kg (10 year-old specimen taken in 1957). In both study areas, a pronounced decline in mandibular bone fluoride concentrations occurred over the respective sampling periods. In consequence, bone fluoride content of animals (both study areas pooled) taken during the period 1990–1998 was significantly (P<0.00001) lower than that of roe deer from the period 1955–1989, while the two animal groups did not significantly differ in age. These findings are regarded as indicative of a considerable reduction of fluoride deposition into the animals’ habitats, due to effective emission control measures. Bone fluoride values for the period 1990–1998 in the roe deer from the Ruhr area significantly (P<0.005) exceeded those of the individuals from the study area W of Cologne, while the difference in age between the two groups was not significant. In both study areas, a significant (P<0.00001) positive correlation between age and mandibular bone fluoride content (Ruhr area: r_s=0.601; area W of Cologne: r_s=0.725) was found for animals taken during this period. The present study underscores the suitability of analyzing skeletal fluoride concentrations in wild roe deer in order to monitor the magnitude of environmental contamination by fluoride and thereby to assess the efficiency of measures taken to reduce fluoride emissions from industrial sources.