Cyanide exposure evaluation of workers envolved in the production of cassava flour from cassava, Manihot esculenta Crantz in the city of Arapiraca, Alagoas

Abstract

Cassava used in the production of flour contains high concentrations of cyanogenic glycosides (compounds that releases cyanide), which may represent a threat to workers involved in processing it's flour. Cassava processing begins with the stripping of the roots followed by the steps of grating, pressing (generating liquid waste containing cyanide), new grating, drying and sieving. The final outcome of this process is the production of flour with low concentrations of this glycoside. During the process of grating, cyanogenic glycosides are degraded due to the rupture of the cell structure, occurring the release of hydrogen cyanide, which is highly volatile. Therefore, on the step of sieving the grated mass loses most of its toxicity by volatilization of the toxicant. Considering the above mencioned information, the possibility of exposure to hydrogen cyanide by the cassava processors must be taken into account. In most of Brazilian northeast the cassava flour is produced in an artisanal way in plants named "casas-de-farinha", which for centuries acquired little technology. In most of these plants, little attention is given to the hygiene and health criteria, which may increase risk of poisoning. This study aims to evaluate the workers occupational cyanide exposure from cassava processing through the determination of atmospheric concentrations of HCN in the work environment, as well as of their biological indicator of exposure, the urinary thiocyanate. (AU)