title: Dose-dependent effects of dietary Pb and Zn on feeding and growth rates of the landsnail Helix engaddensis.
abstract: Dose-dependent effects of dietary lead and zinc on feeding and growth rates of adult Helix engaddensis snails were studied over a 1-month period followed by a 2-week recovery period. Snails were fed on an artificial diet containing the following lead or zinc concentrations= 0, 20, 100, 500, 2500, and 12,500 microg/g dry food. At the end of the 6 weeks, mortality rate among snails fed on Pb-contaminated diet was 18.3% (11/60) and the respective value for Zn-contaminated diet was 50% (30/60). Both metals significantly reduced growth and feeding rates. Snails were found to be sensitive to zinc but tolerant to lead. During the recovery period, snails fed on Zn-contaminated diet failed completely to feed or grow normally, whereas snails fed on Pb-contaminated diet showed signs of slow improvement in terms of feeding and growth rates. The NOEC and LOEC for lead were 100 and 500 microg/g (-1), respectively, while the respective concentrations for zinc were 20 and 100 microg/g (-1).
authors.affiliation: Department of Biology and Biochemistry, Birzeit University, Birzeit, West Bank, Palestine. kswaileh@birzeit.edu
authors.forename: K M
authors.initials: KM
authors.lastname: Swaileh
authors.forename: A
authors.initials: A
authors.lastname: Ezzughayyar
mesh_terms: D000284:Administration, Oral; D000818:Animals; D001522:Behavior, Animal; D004032:Diet; D004305:Dose-Response Relationship, Drug; D004785:Environmental Pollutants / Q000008:administration & dosage / Q000009:adverse effects*; D005247:Feeding Behavior / Q000187:drug effects*; D006372:Helix, Snails / Q000187:drug effects / Q000254:growth & development*; D007854:Lead / Q000008:administration & dosage / Q000009:adverse effects*; D019055:No-Observed-Adverse-Effect Level; D015032:Zinc / Q000008:administration & dosage / Q000009:adverse effects*
chemical_list: D004785:Environmental Pollutants; D007854:Lead; D015032:Zinc