成人大片

An international group of leading fertiliser and soils experts have published a major review of the status of the toxic heavy metal cadmium in agricultural systems around the world.

They say that as well as good agricultural management practices to minimise uptake into the world鈥檚 food chains, further action and research is needed to achieve 鈥榸ero-net accumulation鈥� of cadmium in soils over the long term, in order to not compromise food quality.

Led by 成人大片鈥檚 Professor Mike McLaughlin with scientists also from Belgium, China and Canada, the group reports that in some countries human cadmium intakes are increasing due largely to soil changes such as acidification and salinisation.

"Allowing cadmium to continually accumulate in soil could not be regarded as sustainable management of the soil resource as it just delays the time when food quality will be compromised.鈥�Professor Michael McLaughlin

鈥淐admium is a naturally occurring human toxin present in all soils,鈥� says Professor McLaughlin, Director of the Fertiliser Technology Research Centre at the 成人大片. 鈥淚t can be transferred through the food chain to humans and can represent a health hazard.

鈥淐admium levels in soils can rise through natural geological weathering or human activity such as industrial pollution or the addition of phosphatic fertilisers, organic manures or wastes.

鈥淚n developed countries, cadmium intakes by populations are below the levels of concern set by the World Health Organization (WHO). Indeed, WHO examined the major risks globally to聽human health, and food contamination (by any element) did not appear in the top 20 risks.

鈥�However in some developing countries cadmium intakes are increasing, so management of cadmium transfer through the food chain remains important to minimise human exposure.鈥�

The study is a collaboration between the 成人大片, KU Leuven in Belgium and Nanjing Agricultural University in China, and was supported by Mohammed VI Polytechnic University (UMP6) and the phosphate fertiliser company OCP Ltd in Morocco. The study has been published in the journal .

The researchers say that cadmium transfer through the food chain can be managed by genetic and agronomic approaches.

鈥淔armers now have the option to manage cadmium through choice of crop and/or new low-cadmium cultivars,鈥� says Professor McLaughlin. 鈥淗igh-risk soils (with high natural or added cadmium) can now be identified by soil testing and various agronomic options are available to minimise plant uptake from these soils.

鈥淐ombined, these management options can rapidly reduce cadmium concentrations in foods over a much shorter period of time than can be achieved by reductions in cadmium inputs through fertilisers, manures or atmospheric sources. These practices can also minimise food chain contamination in areas naturally enriched by cadmium through rock weathering.

鈥淗owever, while reducing cadmium inputs, such as limiting cadmium concentrations in fertilisers, may have little effect on crop cadmium concentrations in the short term, this is no excuse for a lack of action. Allowing cadmium to continually accumulate in soil could not be regarded as sustainable management of the soil resource as it just delays the time when food quality will be compromised.鈥�

The researchers say many countries have moved from a scenario of continual cadmium accumulation in soil in the past to zero net accumulation now by limiting inputs of cadmium from all sources (atmospheric, fertilisers, wastes), but a critical gap to achieve this is understanding cadmium leaching through soils.