Effects of copper on the egg development and hatching of a freshwater pulmonate snail Lymnaea luteola L.
A freshwater invertebrate egg development and hatching toxicity test with an Indian freshwater pulmonate snail, Lymnaea luteola, comprising the following developmental endpoints was described: mortality, development, formation of eyes and foot structure, heart rate, duration of different larval stages, and hatching time. Developmental stages were morula, and at third, fifth, and eighth days; the trochophore, veliger, and hippo larvae, respectively. At the age of about 9th to 11th days after egg laying; more than 95% young snail hatched in control laboratory conditions. To evaluate effects on embryonic development, the pulmonate snail eggs of 24-h old were exposed to a series of nominal copper concentrations. The percentage survival of embryos treated in 10-32 microg l(-1) of Cu after 240 h of exposure drops sharply at veliger and hippo stages. All embryos died at 100-320 microg l(-1) of Cu within 168 h of exposure at trochophore and early veliger stages. The detected abnormalities were malformation of foot, eyes, thinness and incomplete formation of shell, growth retardation, and slow rotation of embryo within the egg capsule as compared to control embryos. Lethal and sublethal effects in terms of mortality and significant delay in hatching could be found in the 3.2, 5.6 and 10 microg l(-1) of Cu concentrations. This species is widely distributed in the Indian subcontinent freshwater reservoirs and more sensitive to Cu than other tested aquatic test organisms; therefore, could be used as a test model of Cu and possibly other pollutants for rapid risk assessment of environmental pollutants. The snail egg embryo bioassay is simple, rapid, highly sensitive, cost-effective, and easy to test under standardized laboratory conditions.
Khangarot
B S
BS
Ecotoxicology Laboratory, Indian Institute of Toxicology Research, Mahatma Gandhi Marg, Lucknow 226 001, India. bkhangarot@hotmail.com
Das
Sangita
S
D000014:Abnormalities, Drug-Induced / Q000473:pathology; D000818:Animals; D001681:Biological Assay; D001724:Birth Weight; D003300:Copper / Q000633:toxicity*; D004625:Embryo, Nonmammalian / Q000187:drug effects*; D047108:Embryonic Development / Q000187:drug effects; D005123:Eye / Q000254:growth & development; D005618:Fresh Water; D006339:Heart Rate / Q000187:drug effects; D007194:India; D008195:Lymnaea / Q000502:physiology*; D008675:Metamorphosis, Biological / Q000187:drug effects; D010063:Ovum / Q000187:drug effects* / Q000254:growth & development*
D003300:Copper