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Growing male pigs were exposed to cadmium (Cd) at levels around 1 and 10 mg kg–1feed for up to 12 weeks, administered as CdCl2or Cd-cysteine (CdCys). Pigs exposed to 10 mg kg–1showed decreased growth during the last 3 weeks. Liver and kidney concentrations of Cd continuously increased over the entire 12-week exposure, exceeding the European Union limits of 1.0 mg kg–1(kidney) and 0.5 mg kg–1(liver) within 3 weeks at the feed level of 10 mg kg–1. A switch to clean feed after 3 weeks for 5 or 9 weeks resulted in steadily decreased levels in kidney and liver, which could be completely attributed to organ growth. At the lower feed level, the level in kidney exceeded the limit almost twofold after 12 weeks, but not after 3 weeks. Liver levels remained below the limit. Metallothionein (MT) levels in livers showed a steady decrease in both untreated and treated animals over time. In kidney such a decrease was only observed in control animals, whereas in the highest-dosed animals the MT concentrations steadily increased. The observed carryover of Cd from feed to liver and kidney was modelled by means of a simple transfer model relating levels in feed via MT levels to accumulation of Cd. Using this model, it was shown that the exposure period of growing pigs to feed containing the European Union limit of 0.5 mg kg–1feed should be less than 12 weeks in order to prevent Cd levels in the kidneys to exceed the European Union limit. [ABSTRACT FROM PUBLISHER]

The carbamoyloxime pesticides methomyl, oxamyl and aldicarb, together with the oxidation products of aldicarb, are known to break down much more rapidly in certain anaerobic subsoils than in the aerobic topsoils from the same site. Ferrous ions have now been shown to be involved in this reaction. Oxamyl was degraded in aqueous solutions at 30°C containing 250 μg ml−1 Fe2+ with a half-life of about 10 h, independent of pH in the range of 5.65-7.66; the observed products of this reaction were N,N-dimethyl-l-cyanoformamide and methanethiol. These same products, rather than the oximino hydrolysis product observed from degradation in aerobic soils, were rapidly and quantitatively formed from oxamyl in suspensions of anaerobic reduced subsoils (Fe2+ concentration 27-41 μg ml−1 soil water), but oxamyl was rather stable in water-saturated Vredepeel subsoil (Fe2+ concentration 0.65 μg ml−1) in which the redox potential was much higher. Methomyl behaved similarly. The rates of reaction in the suspensions of anaerobic subsoils were greater than expected from the concentrations of Fe2+ in the soil water, but most of the Fe2+ present in soil was bound to the soil particles by cation exchange and this bound Fe2+ may have participated. Breakdown of aldicarb was accelerated both in solutions of Fe2+ and in the suspensions of anaerobic reduced subsoils, though the rate enhancement was less than observed with methomyl and oxamyl; 2-methyl-2-methylthiopropionitrile and 2-methyl-2-methylthiopropionaldehyde were the observed products from aldicarb in anaerobic soil but only the former was produced in Fe2+ solutions; the corresponding nitriles and aldehydes were also yielded by aldicarb sulphoxide and aldicarb sulphone in the anaerobic, reduced subsoils. [ABSTRACT FROM AUTHOR]