Laboratory analysis of cadmium in fertilizers

The presence of cadmium in phosphate fertilizers is a key issue for compliance, product quality and environmental risk management. The government plans to gradually lower the maximum content to 20 milligrams of cadmium per kilogram of phosphorus contained in fertilizers from 2030, compared with 90 mg/kg currently. Manufacturers, importers, distributors and fertilizer users must therefore have reliable analytical results to characterize their raw materials, monitor production and document their decisions to place products on the market.

The Filab laboratory supports industry stakeholders with their cadmium analysis in fertilizers, covering finished products, phosphate raw materials, blends, granules, powders and liquid formulations. This approach helps anticipate regulatory changes, compare sources of supply and secure quality specifications.

Cadmium is a metallic trace element that may be present in certain phosphate ores used to manufacture fertilizers. Its concentration can vary depending on the geological origin of the raw material, the processing methods and the final formulation. Analytical characterization of supplies helps identify variations between batches and suppliers.

Fertilizers have varied compositions: phosphates, sulfates, carbonates, mineral salts, trace elements and, where applicable, organic materials. The first step consists of homogenizing the sample and applying suitable preparation, generally based on controlled dissolution or mineralization. This step is critical to obtaining a representative fraction of the total cadmium being measured.

The test report indicates the measured cadmium concentration, usually expressed in mg/kg of sample. To assess the content per kilogram of phosphorus contained in the fertilizer, the relevant phosphorus content for the product must be available and the expected calculation basis must be specified.

Reliable cadmium analysis requires controlled sample preparation to properly solubilize the mineral matrix and avoid biases related to its heterogeneity. At the Filab laboratory, preparation and measurement conditions are defined according to the type of fertilizer, the expected content and the objective of the study.

Measurements can be performed by elemental spectrometry, particularly ICP-OES or ICP-MS when the required performance makes it necessary. Results are expressed in the unit relevant to your control, notably in mg/kg of fertilizer or relative to the amount of phosphorus. For additional needs relating to metal contaminants, discover the services offered by the cadmium analysis laboratory.

Cadmium testing helps establish product compliance with applicable requirements and prepare for changes to regulatory thresholds. It also provides objective data for procurement management, supplier qualification, production control and the preparation of technical files. The Filab laboratory can incorporate this measurement into a broader heavy metals analysis approach.

The Filab laboratory uses spectrometry equipment suited to metal measurements. ICP-OES enables the quantification of numerous elements in mineral matrices. ICP-MS offers high detection capabilities to meet the needs of low-level quantification. The choice of technique takes into account the matrix, the expected limits of quantification and any additional elements to be analyzed.

Comparing the result with a threshold requires verifying its scope, the regulatory unit considered, and the declared characteristics of the fertilizer. The Filab laboratory can discuss with your teams which technical information should be provided: product designation, physical form, composition, phosphorus content, and purpose of the analysis.

To initiate an analysis, provide the fertilizer designation, its physical form, the number of samples, the phosphorus content when known, and the purpose of the inspection. The Filab laboratory will then define the appropriate analytical conditions and inform you of the sample handling arrangements.