Environmental Cadmium in the Food Chain : Sources, Pathways and Risks

Brussels (Belgium), 13-16 September 2000
Proceedings edited by J. K. SYERS and M. GOCHFELD

Held at the Belgian Academy of Sciences on 13-16 September, 2000, the workshop on " Environmental cadmium in the Food Chain" was organized by IMPHOS in close cooperation with the Scientific Committee on Problems of the Environment (SCOPE) and the financial support of the Royal Academies of Sciences of Belgium and the U.S. National Institute of Environmental Health Sciences.

The objectives of this workshop were :

	To review the current state of knowledge on the sources and cycling of Cd in the Environment ;
	To evaluate available information on the inputs and transfers of Cd in the food chain;
	To review current knowledge on linking dietary intake to human health, including studies of human exposure and toxicity, through a multidisciplinary approach ;
	To review and re-evaluate information relating to the risks associated with environmental Cd, with a  view to identifying gaps in current knowledge.

The proceedings include papers presented in plenary sessions : overview and summary papers, sources and cycling of cadmium, inputs and transfers of cadmium in the food chain, and linking dietary intake to human health. The specific details and recommendations provided in the following working group reports are also included:
1. Is soil cadmium balance achievable ?
2. Cadmium in tropical ecosystems
3. Bioavailability of cadmium in food
4. Susceptibility to cadmium
5. Temporal and spatial issues relating to cadmium inputs and balances
6. Soil-plant-animal-human transfers
7. Cadmium in aquatic systems

The main conclusions of the workshop are the following :
1. Imputs are mainly from atmospheric deposition, application of biosolids, use of phosphate fertilizer, and from effluents from cadmium-using and recycling industries.
2. These inputs to the environment can be subject to control methods which vary in their economic and social cost.
3. There are significant data gaps related to biodiversity and food chain transfers, particularly under tropical conditions.
4. Caution is needed in generalizing exposure estimates from the existing epidemiological studies, because of substantial differences between occupational exposure (primarily inhalation) and community exposure (primarily ingestion), as well as between cultures with different diets and perhaps susceptibilities.
5. The significance of low level proteinuria and its relationship to exposure duration and levels proved controversial and could not be resolved with the existing epidemiological data. This limitation precludes recommending specific Cd levels for the environment.
6. Identifying the susceptible subsets of the population is important, and many factors influencing susceptibility remain to be identified and quantified.
7. There remains significant data gaps in the area of ecological risk assessment, particularly at the ecosystem (rather than single species) level.
8. There is a need to prioritize risk reduction strategies for the major Cd sources
9. In addition to the uncertainties concerning food chain and biomedical issues, there remain uncertainties regarding the benefits, costs and potential risks associated with various cadmium management scenarios.
10. The growing populations imposing increasing energy demands and limited arable land(much with low natural fertility) of developing countries in tropical regions requires a special attention with regards to risk balancing.
11. There is an urgent need to support further research on the topics identified at the workshop as having high priority.

The workshop was attended by about 46 participants representing various scientific disciplines as well as the phosphate industry and decision-making bodies.

Further information is available at the Scope website :
http://www.icsu-scope.org