Toxicological Chemistry and Biochemistry, Third Edition

The speciation and physico-chemical forms of metals in surface waters and sediments

“…as a free ion -the form most toxic to living organisms; as an ion bound to different ligands -complex compounds are formed; as the precipitated molecule of a compound, suspended in the liquid phase or adsorbed on the surface of suspended or colloidal matter (Manahan, 2003).…”

“…The same applies to soluble hydrophobic forms of Cd, the quantity of which is a function of the salinity, the total dissolved organic carbon (DOC) and the availability of suitable organic ligands. Highly characteristic of cadmium is the lowering of the partition coefficient K D (EPA, 402-r-99-004b ch5a) between the bottom sediment and the water with increasing salinity: this is due to the competitive adsorption of divalent cations, e.g., Ca 2 þ and Mg 2 þ , and complexation by Cl À (Turner, 1996;Cenci and Martin, 2004 [H 3 CCd þ ] has been found in the surface layer of the North Atlantic and also in Arctic snowmelt, in which more than half of the Cd content was in the form of the monomethylcadmium ion (Manahan, 2003).…”

Effect of Cadmium on DNA Changes in Ipomoea aquatica Forssk.

“…Y R = 101.64X + 306.31 (R² = 0.99) (1) Y S = 38.539X + 946.76 (R² = 0.87) (2) Y L = 10.183X + 505.63 (R² = 0.91) (3) …where Y R , Y S , and Y L are the Cd concentrations in the roots, stems, and leaves, respectively, and X is the concentration of Cd in the soil.…”

“…Based on the high level of Cd accumulation in I. aquatica, plants that grow in contaminated soils are not recommended for human consumption. Cd toxicity can pose direct threats to human health via the food chain, and it can cause disease (e.g., itai-itai disease, cancer), damage to the skeletal system, adverse cardiovascular events, enzyme inhibition, DNA damage in humans [1], and chronic toxicity in animals [2]. An example of the RAPD banding patterns observed in RAPD fingerprinting experiments is shown in Fig.…”

“…Cd contamination in agricultural soils is unlikely to affect plant growth, but Cd is easily transferred from soil to the human food chain. Moreover, an excess of toxic heavy metal ions induces several cellular stress responses and damages different cellular components of the plant, such as membranes, proteins, and DNA [1,6]. Ipomoea aquatica is a popular vegetable in northeastern Thailand and other Asian countries.…”