Heavy metals other than lead in flaked paints from buildings in Eastern Nigeria

Cadmium, chromium, iron, zinc, and copper levels of flaked paints collected from fifty buildings of four major cities - Enugu, Onitsha, Aba, and Port Harcourt in Eastern Nigeria were studied. Fifty samples of the flaked paints were ground with laboratory pestle and mortar, 2 g of fine ground paints that could pass through a 0.5-mm sieve were digested with 15 ml concentrated nitric acid and perchloric acid at a ratio of 1:1 and analyzed for cadmium, chromium, iron, zinc and copper using atomic absorption spectrophotometer 500. Cadmium ranged from 9.032 +/- 0.000 to 10.575 +/- 0.000 and 6.845 +/- 0.000 to 10.028 +/- 0.002 mg/kg in Enugu and Onitsha, respectively. In Aba and Port Harcourt, the levels of cadmium ranged 7.464 +/- 0.002-9.343 +/- 0.002 and 7.293 +/- 0.002-9.395 +/- 0.000 mg/kg, respectively. Chromium levels were significantly lower in Enugu (range 0.940 +/- 0.000-12.793 +/- 0.002 mg/kg) when compared with the values from other cities namely Onitsha (range 1.613 +/- 0.002-15.140 +/- 0.000 mg/kg), Aba (range 15.206 +/- 0.000-39.215 +/- 0.000 mg/kg) and Port Harcourt (range 33.118 +/- 0.002-55.418 +/- 0.002 mg/kg). The highest levels (mg/kg) of iron (11908.150 +/- 0.000), zinc (31.508 +/- 0.002) and copper (7.588 +/- 0.002) were seen in buildings from Enugu aged 11 years and above. The iron level (mg/kg) ranged from 1391.750 +/- 0.000 to 10 476.845 +/- 0.000, 1450.176 +/- 0.000 to 11580.750 +/- 0.000 and 3314.913 +/- 0.002 to 8162.333 +/- 0.002 in Onitsha, Aba, and Port Harcourt, respectively. Zinc levels were significantly lower in Onitsha than in Aba and Port Harcourt. Age of building did not seem to affect the levels of these metals namely iron, zinc and copper from these cities. This study shows that flaked paints increase the environmental heavy metal burden in Nigeria.