title: Evaluation of nickel-zinc interactions by means of bioassays with amphibian embryos.
abstract: The nickel hazard was evaluated by means of a 7-day toxicity test with Bufo arenarum embryos. The LC(50) values for this metal from 24 to 168 h diminished from about 26 to 1.8 mg Ni(2+)/L, respectively, but from 96 h onward, the LC(50) varied very slightly. Although a noticeable difference among the LC(50) and LC(10) or LC(90) was observed at 24 h of exposure, these parameters tended to a similar value at 168 h of exposure while the confidence intervals of LC(50) overlapped all other confidence interval values. These results, plotted as toxicity profile curves, are useful for determining time and concentration thresholds for Ni. Nickel-zinc interactions on B. arenarum embryos were evaluated by means of simultaneous treatments with both cations (Ni: 5-35 mg Ni(2+)/L; Zn: 0.5-130 mg Zn(2+)/L). As a general pattern, low Zn concentrations (0.5 mg Zn(2+)/L) did not have a clear-cut effect on Ni toxicity, higher Zn concentrations (2-20 mg Zn(2+)/L) enhanced Ni toxicity, and concentrations of 30 mg Zn(2+)/L and higher had a beneficial effect in most cases. The metal interaction studies provide a scientific basis for the establishment of water quality criteria for wildlife protection purposes.
authors.affiliation: Programa de Seguridad Química, Instituto de Ciencias Ambientales y Salud, Fundación PROSAMA, Paysandú 752/760, Buenos Aires, 1405, Argentina. herkovit@mail.retina.ar
authors.forename: J
authors.initials: J
authors.lastname: Herkovits
authors.forename: C S
authors.initials: CS
authors.lastname: Pérez-Coll
authors.forename: F D
authors.initials: FD
authors.lastname: Herkovits
mesh_terms: D000818:Animals; D001681:Biological Assay / Q000379:methods*; D002022:Bufo arenarum; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions / Q000502:physiology; D004625:Embryo, Nonmammalian / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D005260:Female; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D007928:Lethal Dose 50; D008297:Male; D009532:Nickel / Q000378:metabolism / Q000633:toxicity*; D015032:Zinc / Q000378:metabolism / Q000633:toxicity*
chemical_list: D009532:Nickel; D015032:Zinc