Geographic information system-based source estimation of copper pollution in Lake Itezhi-tezhi and metal-accumulation profiles in Oreochromis spp. from both field and laboratory studies.
The Copperbelt region, upstream of the Kafue River, including Lake Itezhi-tezhi (ITT), in Zambia has extensive copper (Cu) mines. In our field study, geographic information system analysis in lake sediment indicated that the northern part of the lake, i.e., the Copperbelt region, could be the source of Cu pollution. Concentrations of Cu in stomach contents between fish species were not significantly different. However, Oreochromis spp. liver showed significantly greater Cu concentrations than those in other fish species. Log liver [Cu], standard length, and nitrogen stable isotope ratio were positively correlated only in Oreochromis spp. In the laboratory study, O. niloticus and O. latipes were exposed to Cu for 4 days, and recovery phases ≤ 28 days were examined. O. niloticus showed significantly greater concentrations of Cu compared with O. latipes at all sampling points. Significantly greater concentrations of Hg in Schilbe intermedius liver than for other fish species were observed, whereas O. macrochir showed significantly greater concentrations of cadmium. In conclusion, the northern part of the lake could be the source of Cu pollution in Lake ITT. Diet may not be the reason for high Cu accumulation in Oreochromis spp. Results from both field and laboratory studies imply that Oreochromis spp. contain high concentrations of Cu under normal physiological conditions.
Laboratory of Toxicology, Department of Environmental Veterinary Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, 060-0818, Japan.
Shouta M M
SM
Nakayama
Yoshinori
Y
Ikenaka
Kaampwe
K
Muzandu
Kennedy
K
Choongo
John
J
Yabe
Taro
T
Muroya
Shigeho
S
Ijiri
Masao
M
Minagawa
Takashi
T
Umemura
Mayumi
M
Ishizuka
D000818:Animals; D023681:Cichlids / Q000378:metabolism*; D003300:Copper / Q000032:analysis* / Q000378:metabolism; D004784:Environmental Monitoring / Q000379:methods*; D040362:Geographic Information Systems; D060106:Lakes / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000378:metabolism; D015024:Zambia
D014874:Water Pollutants, Chemical; D003300:Copper