Resumo:
Background: Manganese (Mn) is an important essential micronutrient
involved in bone mineralization, especially for growing children. However,
it can also be a neurotoxin if high exposure levels surpass the body
homeostatic mechanisms. Objective: To detect the manganese
concentration in food crops grown in the vicinity of a ferro-alloy plant in
order to evaluate the quality of products cultivated in such impacted area
and food also supplied by the Government to the day care-school of
Cotegipe, district of Simões Filho - Bahia. Methods: Mn levels in banana
(Musa paradisiaca L.), acerola (Malpighia punicifolia) and in fermented manioc
(Manihot utilissima) flour were determined by electrothermal atomic
absorption spectrometry. Food crops were sampled (n=20 of each) in two
areas between 2007-2008: Cotegipe de baixo (Cb) close to the plant (avg.
distance 1.5 km) and Cotegipe de cima (Cc) a hill area a little bit further
and not in the wind direction (avg. distance 2.5 Km). Results: Mean Mn
levels in acerola were 18.69±8.79 mg.Kg-1 and 28.13±13.57 mg.Kg-1
, for
CC and CB, respectively. In banana, mean Mn levels were 93.60±41.03
mg.Kg-1 and 66.73±62.23 mg.Kg-1
for CC and CB, respectively. In manioc
flower, locally known as "puba", mean Mn levels were 2.26±1.29 mg.Kg-1
and 2.64±1.51 mg.Kg-1 in CC and CB, respectively. Mn contents in fruits
grown in Cotegipe Village are very high when compared to literature
values 0.7 mg.Kg-1
for acerola and 4.2-6.7 mg.Kg-1 for banana). It is also
approximately 4 to 5 times higher in manioc flower when compared to
reported values (0.5 mg.Kg-1
). Statistical difference in mean Mn levels
between products from the two localities was only observed for acerola
(p=0.015). Conclusion: The results show that the Mn levels in food
product locally grown in the vicinity of a ferro-alloy plant are vey high,
reaching Mn contents that surpass the estimated safe daily ingestion of
Mn (2-5 mg/day).
