A new index for evaluation of cadmium pollution in birds and mammals

Abstract

The degree of cadmium (Cd) contamination in wildlife is often used as an indicator in the environmental monitoring of Cd poisoning. However, previous studies have not clarified the correlation between levels in wildlife and levels in the environment by comparing levels among different species of animals; therefore, assessing the level of pollution in this manner is not considered a reliably accurate indicator of levels in the environment. The aim of this study was to establish a new indicator for the non-polluted warm-blooded animals, one that is not species-dependent, which will facilitate using different species for Cd monitoring. First, the previous publications regarding Cd contents in wildlife, 27 reports in which Cd contents were represented as arithmetic means and described for both kidney and liver were selected. A regression line (CSRL) between Cd contents of kidney and that of liver was obtained in a high correlation coefficient (R (2) = 0.943, P < 0.01). The mean values from land and waterfowl, terrestrial mammals, seabirds, marine mammals, and non-polluted humans were located on the line and aligned in order. CSRL might allow an accurate determination of whether an animal is polluted by Cd. CSRL was confirmed using well-established and widely recognized pollution models such as Itai-itai patients and Cd-exposed experimental animals. The Cd contents from these models were located in different positions relative to CSRL depending on the level of contamination. Thus, this new indicator determining the Cd-pollution status of animals would be useful for environmental monitoring.

Metal interactions within and between tissues of nestling rooks Corvus frugilegus

“…Finally, bearing in mind earlier important findings on significant relationships of individual toxic metals (Cd or Pb) between different tissues, mainly between liver and kidney (review for Cd in Mochizuki et al 2008), and in lesser degree between liver and bone, in the case of Pb (Wayland et al 1999), we concluded that the lack of significant relationships of individual toxic metals (Cd or Pb) between examined tissues (Table 3) could result from high concentration of these elements (Or lowski et al 2012; c.f. Table 1).…”

“…This assumption coincides with the results of Larison et al (2000), who showed that in the white-tailed ptarmigan Lagopus leucurus (Richardson, 1831) from habitat with extremely high content of Cd, the linearity of the regression line between Cd concentration in kidney and liver was lost when the toxic levels were exceeded. Similarly, Mochizuki et al (2008) concluded that a linear relationship between Cd concentration in the liver and kidney occurs only in animals unpolluted by Cd. Hence, we conclude that an interpretation of metal interactions in animals requires the identification of toxicity threshold (in the case of toxic metals) or/and physiological level (in the case of essential and trace metals).…”

“…In most tests concerning multiple comparisons we accepted the significance level P < 0.01; however in the Results section (c.f. Table 1) we presented the raw values of statistical tests; we believe that such approach is useful to comparison with other published investigations on metal interactions in tissues in birds and threshold of toxic metals indicative of acute and chronic exposure or toxicosis, see papers in which the matrices of correlations between concentrations different metals are presented without Bonferroni adjusted P-value; e.g., Wenzel et al (1996), Woshner (2001a, b), Kalisińska et al (2004Kalisińska et al ( , 2007, Mochizuki et al (2008), Larison (2002). The accepted Bonferroni adjusted value agrees with the level of significance recommended for multiple comparisons (Chandler 1995).…”

“…According to Scheuhammer (1987) the con- centration of Cd greater than 3 ppm d.w. in liver and kidney would suggest hazardous environmental exposure to this element, although the concentration greater than 40 ppm in the liver and 100 ppm in the kidney are indicative for toxicosis (Degernes 2008). According to last review, the highest concentration of Cd (up to 179 ppm) found in the kidneys of marine and water birds; in the land bird the concentrations of Cd are generally lower, <16.4 ppm (Mochizuki et al 2008). In the light of these data, we believe that the level of Cd observed in examined nestling rooks can be defined as acute contamination (Or lowski et al 2012).…”

An Innovative Approach to Biological Monitoring Using Wildlife

“…This method was established using the significant regression lines obtained from the Cd content of kidney and that of liver (Mochizuki et al, 2008). Given that the data from animals were cited in various studies in which no particular contamination was described, we considered that these lines were indicative of normal metabolism in animals.…”