| Popis: |
Goldfish (Carassius auratus) were simultaneously exposed to p,p′-DDT from two sources—food ([36Cl]p,p′-DDT) and water ([14C]p,p′-DDT). The concentration of p,p′-DDT in food was maintained at about 1 μg g−1 while the water concentration of p,p′-DDT was varied for each experiment (2, 20 and 177 ng dm−3). In these experiments the contribution of p,p′-DDT from food to the total body residue varied over the duration of the exposure from 0 to 81% (water concentration about 2 ng dm−3) and from 3.8 to 4.8% (water concentration about 171 ng dm−3). The results from these experiments were compared with those of experiments in which some goldfish were exposed to DDT-contaminated food and others to DDT-contaminated water. Comparison suggested that goldfish exposed to DDT-contaminated food and water simultaneously, had accumulated p,p′-DDT from the two sources additively. The data supports the concept that p,p′-DDT residues in fish can be derived from both food and water. We suggest that the importance of each source is determined by its relative concentration over the period of exposure. p,p′-DDT taken up by goldfish was converted, slowly at first, then more rapidly to p,p′-DDE reaching a maximum of > 80% from both water and food sources after about 40 days. Dietary p,p′-DDT was converted to p,p′-DDD to a greater extent (max. 15.9%) than water-borne p,p′-DDT is converted to p,p′-DDD (max. 2.8%). |
