Evaluation of chemical residues originated from automatic hematological analyzers in the Municipality of Guarulhos [State of São Paulo, Brazil]

Introduction: If incorrectly managed, dangerous chemical residues produced by clinical analysis laboratories are worrisome. These residues can represent serious environmental and human health hazards if disposed improperly in the sewage system. Currently, the laboratories take over strategies with the potential to minimize the negative environmental impacts and public health risks. To demonstrate the current scenario and contribute to the sustainable development of these laboratories, it is necessary to evaluate the toxicity of hematological equipment´s chemical residue effluents. Methods: A questionnaire was addressed to employees of 15 clinical analysis laboratories of the Municipality of Guarulhos, Sao Paulo / Brazil. All these laboratories dispose the hematological equipment’s residues into the sewage system. The objective of the questionnaire was to appraise the daily average hematological exams performed in 2012. Through the data collected with equipment suppliers and analysis of the concentration of dangerous chemical residues diluted in the municipal sewage network, it was possible to calculate the volume of dangerous chemical residues generated by this equipment. Results: The data showed a daily average of 2,800 examinations per laboratory, generating a daily disposal of 131,600 mL of chemical residues. Only formic acid was identified as dangerous chemical residue. About 1,680 mg per day of this residue is disposed. Diluted in the average daily sewage volume of 32,500 m 3 , it represents a concentration of 0.052 mg/m 3 or 5.2 x 10 -5 mg / L. Conclusion: Despite the large volume of chemical residues generated by hematological analyzers and disposed into the sewage system of Guarulhos, the data indicates low toxicity concentration in the sewage system. Therefore, there is no evidence of enough toxic residues to be responsible for creating environmental risks.