Inorganic contaminants in bee pollen from southeastern Brazil

A set of experiments was carried out to validate a method for inorganic contaminants in honeybee-collected pollen, consisting of digestion of the samples in a closed microwave-assisted system and quantification of 10 inorganic contaminants by ICP OES. Forty-three samples of Brazilian bee pollen, collected in southeastern Brazil during one year, were analyzed. Determination of these analytes is important both as bioindicators of pollution and to verify the safety of consuming the pollen itself. The method had satisfactory performance, with good accuracy and precision. The ranges of the mean levels were 10.4-268.0 mg/kg for Al, <0.01-1.38 mg/kg for As, 2.78-17.63 mg/kg for Ba, 0.003-0.233 mg/kg for Cd, <0.01-1.11 mg/kg for Co, <0.01-2.32 mg/kg for Cr, <0.10-1.13 mg/kg for Ni, <0.01-0.44 mg/kg for Pb, <0.035-1.33 mg/kg for Sb, and <0.0004-0.0068 mg/kg for Hg. Contamination seemed to occur in the following decreasing order: Sao Paulo > Minas Gerais > Espirito Santo. Generally higher levels of all studied contaminants were observed in samples produced in an urban site, compared to those of a rural site. Al, Cd, Co, and Pb tended to have higher levels during the dry months (July-October). Ingestion estimates showed that Al and As would have the highest contributions to the adult diet, reaching 27 and 8%, respectively, of the provisional tolerable weekly intake (PTWI) values, considering a daily portion of 25 g.