Trace elements in inorganic fertilizers: health risk assessment.

Trace Elements are generally present in inorganic fertilizers as by-products or contaminants. There are however some trace elements (e.g., Zn, Cu, Fe, and Mn) that are plant nutrients and are intentinally included in fertilizer formulations. It is acknowledged a priori that exposure to high levels of trace elements (nutrient or not) could pose a health risk to humans. Therefore, this evaluation tries to establish safe limits of trace elements, referred to a Risk Based Concentrations, in inorganic fertilizers that are applicate to Brazilian conditions. The methodology used to develop the risk based concentration is a back-calculation of health risks and is standard for a screening level risk evaluation. This work follows the same approach of the document prepared by The Fertilizer Institute (FI, United States) for the US scenario, entitled "Health Risk Evaluation of Selected Metals in Inorganic Fertilizers Post Application". The major purpose of this first attempt of establishing guideline values for concentration of trace elements in inorganic fertilizers in Brazil is to suggest limits (based on health risk assessment) that could be used as initial quidance for regulators seeking the protection of human in the current scenario of fertilizers use in Brazil. The results obtained indicate that trace elements do not cause harm to human health when considering post application of inorganic fertilzers in Brazil (based on information for phosphate as well as Zn-carryng fertilizers). This study also suggests that the limits currently established by the Brazilian legislation are safe in terms of health risk assessement. It should be highlighted the need to increase the database for the construction of the Brazilian scenario, especially with respect to information concerning the concentration of trace elements in fertilizers marketed in Brazil. However, as more data are being collected, a new comparison with the risk based concentrations suggested in this study could be done to make this scenario closer to the Brazilian reality. Similarly, as more data are generated with respect to the parameters that make up the equation used to calculate the risk based concentrations for the Brazilian scenario, then, a review of currently estimated risk based concentrations could be made.