This report describes the role and use of and the risks associated with the chelating agents DTPA and EDTA in the production of pulp and paper. The background for the present study is the criteria set by the Nordic Swan Ecolabel for the use of chemicals in the pulp and paper processes.
n the present report, DTPA and EDTA are described from several aspects: chelating functions, their role in the pulp and paper making process, degradation, effects in aquatic environment and teratogenic effect. Analyses of DTPA and EDTA in several pulp and paper products are presented. The results show that <2 percent of added chelating agent is found in the final products. An exception is when DTPA is added at the last stage of the process with the aim of reducing formation of odor and flavor generating substances that can harm what is packaged in the product. In this type of product, all added DTPA is found in the final product. Earlier performed studies on aqua-toxicity of DTPA and EDTA show no observed effects from the low amounts emitted to recipient from pulp and paper mills in Sweden. To protect pregnant women working in the pulp and paper mills, there are already regulations in place that include actions such as changing to work tasks not presenting certain risks. Exposure to DTPA and EDTA can easily be included among such risk factors. Calculations performed on earlier results regarding DTPA and EDTA in recipient water together with results from reproductive toxicity tests show that a volume of 700 L of water in immediate proximity to a mill effluent has to be ingested in order to pose any risk to the unborn child. Calculations based on DTPA content in paper-based food packaging (paper mug) regarding DTPA intake through hot beverage consumption show that such exposure is by far below levels supposed to present any risks to the unborn child. No technically feasible alternatives to EDTA and DTPA are available today – despite intense research. Furthermore, these two chelating agents are not completely exchangeable with each other. The economic consequence of a ban of DTPA above 0.05 kg/tonne in the production process is estimated to be between 5 and 10 billion SEK for the Swedish pulp and paper sector. Based on the above, the authors recommend that a continued exception for DTPA and its salts is given in the Nordic Ecolabel criteria for use of chemicals in pulp and paper products.
Report number: B2245E
Authors: Louise Staffas, Mikael Remberger, Magnus KarlssonDownload publication