Copper, selenium and zinc content of canned and non- canned beverages in Nigeria

Abstract

The levels of copper, selenium and zinc in beverages purchased in Nigeria were studied. Fifty samples of these beverages were digested in nitric acid and were analyzed using the Atomic Absorption Spectrophotometer (AAS). The zinc levels ranged from 0.0 - 1.34 mg/L for the canned and 0.01 - 1.11 mg/L for the non-canned beverages. All had zinc levels below the maximum contaminant level (MCL) of 5.0 mg/l set by United States Environmental Protection Agency (US EPA). The selenium levels ranged from 0.24 - 1.67 mg/L for the canned and 0.07 - 1.23 mg/L for non-canned beverages. 20 out of 21 (95%) canned beverages had selenium levels that exceeded the MCL whereas 90% of the non-canned products had selenium levels above the MCL. The copper levels ranged from 0.04 - 3.55 mg/L for the canned and 0.04 - 3.20 mg/L for non-canned beverages. 11 out a total of 21 (52%) canned beverages had copper levels that exceeded the MCL. 45% of the non-canned products had copper levels above the MCL. The mean and median values of copper and selenium exceeded the MCL in the beverages whereas the zinc levels did not exceed the MCL. The calculated amount of copper, selenium and zinc in three beverages were 14.57, 5.96 and 5.31 mg respectively. The worst-case scenario is assumed here to estimate the weekly intakes of Cu, Se and Zn, and results seem to pose some concern. 48 and 92% of the 50 beverages studied in March 2005 in Nigeria failed to meet the US EPA criteria for acceptable copper and selenium levels in consumer products. Key words : Copper, selenium, zinc, contaminants, beverages, Nigeria.