Cadmium in the Environment
Scientific Advisory Committee
Chair: Michael
Gochfeld (USA); Co-chair: Keith
Syers (Thailand); Members: Minora Kasuya (Japan),
Curtis Klaassen (USA), Werner Klein
(Germany), Michael McLaughlin (Australia), Jerome Nriagu (USA)
Concerns regarding the health risks of environmental cadmium are not
new, but knowledge of the relative importance of the various pathways
for human exposure is changing. Concerns are increasing largely because
of greater uncertainties of the key transfers in these exposure pathways.
Existing gaps in knowledge give rise to uncertainties regarding human
health and environmental risks from cadmium. The SCOPE cadmium project
focused on ecological and health risks as well as management issues.
Some conclusions
of the project:
Exploring environmental
cadmium can serve as a model for the complexities that certain other
ecotoxicologic contaminants present to researchers and policy makers—particularly
where competing risks must be balanced. The fact that the risks and
benefits are felt in different countries, in different ways and to varying
extents, emphasizes the generic nature of the issues that must be explored
and the equitable resolutions that must be achieved.
Remaining important
uncertainties in the human risk assessment for cadmium need to be resolved
by future epidemiologic research. Namely: if proteinuria is the most
sensitive biomarker of cadmium effect in humans, at what level of exposure
does irreversible proteinuria occur? Recent results on the impact of
cadmium on osteoporosis suggest that the proteinuria uncertainties may
be moot, and point to the importance of maintaining cadmium exposure
as low as reasonably achievable. Research on human carcinogenicity and
dose response is proceeding, and although some contribution of cadmium
exposure to additional cancer risk will no doubt be published, it appears
that the potency as a carcinogen is not likely to be high for most receptors.
Human exposure to
cadmium is largely driven by cadmium in staple food crops, e.g., cereals
and tubers, which originates from cadmium in the soil. Of the several
potential sources of soil cadmium, that in phosphate fertilizers has
received particular attention. However, the project found no conclusive
evidence of adverse impact of cadmium in phosphate fertilizers on human
health. This is the case even in Australia where there is a long history
of application of high cadmium-containing fertilizers.
Workshop I (Brussels,
Belgium, September, 2000) focused on biomedical and ecological issues
related to cadmium. Workshop II (Ghent, Belgium, 3-6 September, 2003)
directed attention to the sociopolitical and economic issues related
to cadmium regulation, particularly with regard to the cadmium content
of phosphate fertilizer. The papers and syntheses produced have been
made widely available to policy makers and regulatory agencies.
The first Environmental
Cadmium workshop, held at the Belgian Academy of Sciences, undertook
to review and assess knowledge on the sources and cycling of cadmium
in the environment; the inputs and transfers of cadmium in the food
chain; linking dietary intake of cadmium to human health, including
studies of human exposure and toxicity; and the risks associated with
environmental cadmium.
The abstracts of
the workshop papers and an Executive Summary of the meeting results
are available (click here).
The Proceedings of the Brussels Workshop were published by SCOPE as
a soft-cover volume in July 2001.
Workshop II (Ghent,
Belgium, September 2003) comprised an interdisciplinary approach to
risk assessment and management that involves the setting of standards,
the development and implementation of policies, and the balancing of
risk for cadmium in relation to meeting global food needs, with special
reference to the developing world. It also aimed to identify the research
needs and opportunities for risk assessment and management in the context
of environmental cadmium. The meeting working papers are available (click
here) and have been submitted to STOTEN (Science of the Total Environment).
SCOPE and IMPHOS
(World Phosphate Institute) are presently planning an international
conference in East Africa in April 2009 where policy and economy decision
makers will discuss specific regional aspects of the Cd situation in
Africa with scientific experts.
Last
up-dated May 2008