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Doctoral thesis, 2002

Biomonitoring of cadmium in cattle, pigs and humans

Olsson, Ing-Marie

Abstract

For the general non-smoking population food, and especially cereals, is the main source of exposure to cadmium (Cd), a nefrotoxic element. Cd exposure was studied in livestock and humans, and different indicators were evaluated for biomonitoring of Cd. Sampling of the outer part of cattle and pig kidney cortex was the optimal sampling technique to detect small differences between groups. Organically raised cows had lower levels of Cd in kidney, liver and mammary tissue than conventionally raised cows. The lower levels in the "organic" cows may be explained by a lower input of Cd to the soil, and lower levels in roughage, different feed composition, or a lower bioavailability of Cd in the feed. Long-term studis in well-defined systems are required to clarify if organic farming can lower the amount of Cd reaching the food chain. Cd was followed in the chain from soil via crops and feed, to pig blood and kidney and human blood and urine. The levels of Cd in pig kidney were significantly related to the levels in feed, however, there was no relationship to the locally produced cereals, the main ingredient in the feed. Thus, Cd in pig kidneys did not reflect available Cd in the local environment. The Cd content in non-locally produced feed ingredients constitutes an external source of Cd to the local circulation via excretion in feces and application of manure to arable soils. Food of vegetable origin contributed the major part (83%) of the human Cd exposure. The contribution of locally produced food to the total Cd intake was relatively low and varying. The dietary intake of Cd was higher in males than females living at the same farm, but the women had 1.8 times higher blood Cd (BCd) and 1.4 times higher urinary Cd (UCd) levels than the men. Cd levels in kidneys from pigs, fed locally produced cereals, could not be used to predict BCd and UCd in humans. However, males living in areas with low soil-Cd was not correlated with BCd or UCd. The higher female BCd and UCd are probably explained by higher absorption due to low iron status. BCd and UCd both increased with age and were higher in former-smokers than in never-smokers. Even at the relatively low exposure levels in this study there was an indication of effect on a biochemical marker (β₂-microglobulin-creatinine-clearance) of renal function, an effect that remained also when age was allowed for.

Keywords

Monitoring; environment; sustainable; food chain; couples; bovine; porcine; zinc; metallothionein; quality control

Published in

Acta Universitatis Agriculturae Sueciae. Veterinaria
2002, number: 118
ISBN: 91-576-6356-4
Publisher: Swedish University of Agricultural Sciences

Authors' information

Olsson, Ing-Marie
Swedish University of Agricultural Sciences, Department of Pharmacology and Toxicology

UKÄ Subject classification

Animal and Dairy Science

URI (permanent link to this page)

https://res.slu.se/id/publ/117368