Avaliação da exposição de trabalhadores de casas-de-farinha ao ácido cianídrico proveniente da mandioca, Manihot esculenta, Crantz, no agreste alagoano

Abstract

Exposure of cassava processing workers to hydrogen cyanide from Manihot esculenta, Crantz, in Alagoas, Brazil Cassava used for flour production contains high amounts of cyanogenic glycosides, compounds that, after degradation, release hydrogen cyanide (HCN) which provide toxicity to these type of root. A suitable cassava processing results in the degradation of cyanogenic glycosides and in the production of a safety flour for consumption as food, which generates the hypothesis of HCN release during the process. In this context, the present study aimed to evaluate the HCN exposure of workers engaged in cassava processing, as well as, to identify possible clinical and laboratory alterations related to this exposure. It was included in the study 4 cassava processing facilities placed on Alagoas state, Brazil. It was conducted the determination of HCN in air samples according to the method 6010 proposed by NIOSH. Each industry was monitored in three points: two on workers respiratory zone and one static. A total of 36 male volunteers, distributed between the 4 facilities were included in the study. Each participant was submitted to urine sampling, been one before and other after work shift, and to one blood sampling before work shift. Urinary thiocyanate (SCN-) was spectrophotometrically determined, whereas the remaining biochemical evaluation was conducted in a commercial clinical laboratory. The results indicated that the cassava processors are chronically exposed to HCN at levels between 0,464±0,02 and 3,328±3,85 mg/m³, in the work environment. The comparison between the levels determined at the present study with the Occupational Exposure Limits (OEL) established by NIOSH and ACGIH indicated that cassava processors may be exposed to HCN levels capable of causing adverse health effects. The mean levels of urinary thiocyanate (10,62-before shift and 8,76-after shift), were significantly higher than the reference value for non smokers and also for the history mean obtained from the laboratory employed for SCNanalysis, during 2008-2010. The results of laboratorial evaluation indicated increase in the serum activity of alkaline phosphatase in cassava processors exposed to HCN, with a prevalence of 93,3%. The workers were submitted to clinical evaluation and it was not detected any alteration typical of HCN exposure.

Vulnerabilidades, trabalhadores e casas de farinha: Cenário de riscos no agreste pernambucano

“…Ainda assim, os homens que manuseiam as máquinas de prensar declararam o incômodo com o ruído e com o forte odor da manipueira, líquido que sobra da prensagem da mandioca de elevadíssima carga orgânica e de ácido cianídrico, que tem provocado náuseas e dores de cabeça nos trabalhadores. Zacarias (2011) em minucioso estudo em quatro casas de farinha localizadas no Agreste Alagoano, microrregião de Arapiraca concluiu que os trabalhadores estão expostos cronicamente ao ácido cianídrico (HCN) devido à liberação deste gás durante o processamento da mandioca e que pode resultar na ocorrência de efeitos adversos à saúde dos trabalhadores.…”