IMPHOS Concerted Actions On Cadmium in Fertilizers

Since its creation, in the early 1970s, IMPHOS has concerted its Members action in order to meet the various challenges that the industry has been facing. For example, shortly after the World Health Organization issued in 1972 some provisional limits on cadmium dietary intake by man, IMPHOS started a number of activities to collect and disseminate information in order to clarify misperceptions about the role of phosphate fertilizer in introducing cadmium into the food chain.
Despite the fact that they account for only a minor fraction of the total cadmium input to agricultural soils, mineral phosphate fertilizers have been the main target of restrictive measures in the European Union (EU). A first draft of an EEC Directive was elaborated in 1982 to limit the content of cadmium and other undesirable elements in industrial wastes. The Directive was published in 1983, and required reductions of the amounts of cadmium spread with the phosphogypsum, (formed as a waste in phosphoric acid production). As soon as the Directive was introduced, some companies with IMPHOS backing established a strategy for the minimization of cadmium and the elimination of some of the attributed undesirable effects. The strategy included both literature review (starting in 1982) and the launching of a research program aiming at the identification of feasible technical methods for cadmium removal from phosphate rock and phosphoric acid (in 1984). This program was funded successively by the Wold Bank and the Commission of European Communities (CEC).
Later on, IMPHOS has made a considerable number of contributions to the promotion and development of the scientific and technical knowledge about the cadmium issue in relation to the use of phosphate fertilizers in agriculture. Some examples of these contributions are listed below:

Literature review : In cooperation with the EU, several literature reviews covering different aspects of the "cadmium issue" were undertaken, including sources of cadmium in environmental exposure of man, inventories of studies and processes for cadmium removal from phosphate rock and phosphoric acid, …etc.
Cadmium removal : In cooperation with the EU, the major member company OCP, developed in 1993-95 a process for cadmium removal from phosphoric acid by co-precipitation with anhydrite. The co-crystallization process operates with diluted acid by altering conditions for the acid production (such as the concentration and temperature) which induce the precipitation of the anhydrate. Co-crystallization with anhydrite has been tested in laboratory and it is considered the most promising technique, both from an economical and technical point of view, for producing low cadmium phosphoric acid. This process still needs to be further tested at pilot-scale and industry scale.
International events : IMPHOS cosponsored two important meetings on cadmium transfer:

The "Symposium on Cadmium in Soils, Plants and the Food Chain", was held 1997 at the University of California, Berkeley, USA; 1997. The symposium dealt with cadmium in soils and plants, the environmental chemistry of cadmium, the chemistry of cadmium in the soil solution, and solid phase of cadmium and reactions of aqueous cadmium within soil. The symposium concluded that cadmium may accumulate in crops to levels that are of concern in the diet, but this accumulation is influenced by crop genetics and Cd activity in the soil solution. It emphasized that management practices can be used to reduce the level of cadmium in edible portion of crops and its bioavailability to mankind (see Proceedings).

Workshop on "Environmental Cadmium in the Food Chain: Sources, Pathways, and Risks" held in Brussels; September, 2000. The workshop concluded that there are significant data gaps related to biodiversity and food chain transfers, in addition to the uncertainties regarding the benefits, costs and potential risks associated with various cadmium management scenarios(see Proceedings).

Studies : Although relatively few European countries currently impose very restrictive limits on fertilizer cadmium, more uniform severe European restrictions are expected in the near future, as part of the EU drive to harmonize state policies in this regard. Information is being collected that will serve as a basis for a decision on whether there is a need for an EU-wide, harmonized regulation on cadmium in fertilizers, as the European Union Commission (EC) is decided on reviewing Article 7 of the Fertilizers Directive (76/116/EEC) regarding cadmium. In anticipation of the EU move, IMPHOS sought to develop counter-arguments in a study on "Cadmium in phosphate fertilizers-Consequences of an eventual European Standard Limit", which it has entrusted to Lars Landner et al, AF-IPK(MFG), Stockholm, Sweden in May 2000.
The study recommended to IMPHOS to demonstrate to the European Commission that EU-wide limits on cadmium in fertilizers are not urgent, i.e. such regulations should wait until it has been convincingly shown that they are scientifically justified, cost-effective and are not causing unacceptable, harmful side-effects ( e.g. economic, social and environmental impacts) in countries outside the Union. Time is needed to design an optimal scheme that will minimize negative side-effects. It warned that addressing cadmium exclusively in fertilizers will not lead to the sought-after result, but other measures focussed on cadmium in crops for human consumption, may be much more cost-effective.

To summarize, most of the IMPHOS activities on cadmium have focused on collecting and compiling scientifically based, i.e. objective and reliable, information about the risks to human health associated with the fluxes of cadmium from phosphate rock via phosphate fertilizers and agricultural soils to the human food chain. Moreover, they have contributed to preparing the industry to meet the challenges of new and stricter regulations and standards on cadmium in fertilizers by backing and promoting efforts to develop technically and economically feasible de-cadmiation processes.
These activities clearly show that IMPHOS is aware of the problem of cadmium influx with phosphate fertilizers to agricultural soils. They show equally that IMPHOS Member Companies are keen to take a responsible attitude to matters of public concern and, in case it can be demonstrated scientifically that it is justified to introduce more restrictive regulation with regard to cadmium in fertilizers, they will do their best to meet such new European and /or global standards. Indeed, in the guided and coordinated effort by IMPHOS, the associated phosphate industry has made investments to comply with European environmental standards and regulations.
In spite of this basically positive attitude of the industry towards the need for continuous progress in environmental performance, IMPHOS has expressed concern about the negative impact on the profitability and trade volume of its Member Companies, if such standards become more restrictive than is motivated from public health point of view.