title: Toxicity of eight metals to Malaysian freshwater midge larvae Chironomus javanus (Diptera, Chironomidae).
abstract: Fourth instars larvae of freshwater midge Chironomus javanus (Diptera, Chironomidae) were exposed for a 4-day period in laboratory conditions to a range of copper (Cu), cadmium (Cd), zinc (Zn), lead (Pb), nickel (Ni), iron (Fe), aluminium (Al) and manganese (Mn) concentrations. Mortality was assessed and median lethal concentrations (LC(50)) were calculated. LC(50) increased with the decrease in mean exposure times, for all metals. LC(50)s for 96 hours for Cu, Cd, Zn, Pb, Ni, Fe, Al and Mn were 0.17, 0.06, 5.57, 0.72, 5.32, 0.62, 1.43 and 5.27 mg/L, respectively. Metals bioconcentration in C. javanus increases with exposure to increasing concentrations and Cd was the most toxic to C. javanus, followed by Cu, Fe, Pb, Al, Mn, Zn and Ni (Cd > Cu > Fe > Pb > Al > Mn > Zn > Ni). Comparison of LC(50) values for metals for this species with those for other freshwater midges reveals that C. javanus is equally or more sensitive to metals than most other tested dipteran.
authors.affiliation: School of Environmental and Natural Resource Sciences, Faculty of Science and Technology, National University of Malaysia (UKM), Selangor, Malaysia. shuhaimi@ukm.my
authors.forename: Mohammad
authors.initials: M
authors.lastname: Shuhaimi-Othman
authors.forename: Nadzifah
authors.initials: N
authors.lastname: Yakub
authors.forename: Nur Shahirul
authors.initials: NS
authors.lastname: Umirah
authors.forename: Ahmad
authors.initials: A
authors.lastname: Abas
mesh_terms: D000818:Animals; D004175:Diptera / Q000502:physiology*; D004784:Environmental Monitoring; D005618:Fresh Water; D007814:Larva / Q000187:drug effects*; D007928:Lethal Dose 50; D008136:Longevity / Q000187:drug effects; D008670:Metals / Q000493:pharmacokinetics / Q000633:toxicity*; D018675:Toxicity Tests; D014874:Water Pollutants, Chemical / Q000493:pharmacokinetics / Q000633:toxicity*
chemical_list: D008670:Metals; D014874:Water Pollutants, Chemical