For snails, adding the soil characteristics in the regression models
improved the assessment of metal accumulation in viscera for Cd, Cr,
Ni and Zn. This increased the adjusted coefficients of correlation of
approx. 10%, 22%, 12% and 10% for Cd, Cr, Ni, Zn respectively. Beside
total element contents in soils, the main parameters that modulated
metal accumulation were the SEC (for Ni and Zn), the organic carbon
content (for Cd) and the pH and CaCO 3 content (for Cr). On the other
hand, for As and Pb no significant influence of the soil parameters was
observed. Lastly for Cu, no significant model was found.