title: Comparative toxicity of Euphorbia milii latex and synthetic molluscicides to Biomphalaria glabrata embryos.
abstract: Plant molluscicides have been regarded as possible alternatives to the costly and environmentally hazardous molluscicides currently available. This study was undertaken to compare the developmental toxicity of a plant molluscicide (Euphorbia milii latex, LAT) with that of three synthetic molluscicidal compounds. Biomphalaria glabrata egg masses (0-15 h after spawning) were exposed to molluscicides for 96 h and thereafter examined up to the 14th day after spawning. Embryo deaths, abnormal embryo development (malformations) and the day of hatching were recorded. Although exhibiting a weak ovicidal effect, LAT markedly impaired the development of snail embryos at concentrations 1000 microg L(-1) and produced anomalies (EC(50)=2040 microg L(-1)) such as abnormal shells, hydropic embryos, cephalic and non-specific malformations. Embryolethal potencies of molluscicides were as follows: triphenyltin hydroxide (TPTH; LC(50)=0.30 microg L(-1))>niclosamide (NCL; LC(50)=70 microg L(-1))>copper sulphate (CuSO(4); LC(50)=2190 microg L(-1)) >>> LAT (LC(50)=34030 microg L(-1)). A few malformations were recorded in embryos exposed to concentrations of TPTH within the range of lethal concentrations, while almost no anomalies were noted among those treated with NCL or CuSO(4). A hatching delay (hatching on day 10 after spawning or later) was observed among LAT-exposed embryos. The effects of NCL, TPTH and CuSO4 on hatching were to some extent masked by their marked embryolethality. The no-observed effect concentrations (NOEC) for embryotoxicity were as follows: TPTH, 0.1 microg L(-1); NCL, 25.0 microg L(-1); CuSO(4), 500.0 microg L(-1) and LAT, 500.0 microg L(-1). Results from this study suggest that, although LAT was not acutely embryolethal after a short-term exposure, it markedly disrupted snail development. The marked embryotoxicity of E. milii possibly contributes to its effectiveness as a molluscicide.
authors.affiliation: Laboratory of Environmental Toxicology, Department of Biological Sciences, National School of Public Health, FIOCRUZ, Rio de Janeiro, RJ 21040-361, Brazil.
authors.forename: Eduardo C
authors.initials: EC
authors.lastname: Oliveira-Filho
authors.forename: Barbara R
authors.initials: BR
authors.lastname: Geraldino
authors.forename: Deise R
authors.initials: DR
authors.lastname: Coelho
authors.forename: Rosângela R
authors.initials: RR
authors.lastname: De-Carvalho
authors.forename: Francisco J R
authors.initials: FJ
authors.lastname: Paumgartten
mesh_terms: D000818:Animals; D001700:Biomphalaria / Q000187:drug effects* / Q000196:embryology; D019327:Copper Sulfate / Q000633:toxicity; D004625:Embryo, Nonmammalian / Q000187:drug effects*; D047108:Embryonic Development / Q000187:drug effects; D028481:Euphorbia / Q000633:toxicity*; D007840:Latex / Q000633:toxicity*; D008975:Molluscacides / Q000633:toxicity*; D009534:Niclosamide / Q000633:toxicity; D009947:Organotin Compounds / Q000633:toxicity; D010947:Plants, Toxic / Q000633:toxicity; D013723:Teratogens / Q000633:toxicity; D018675:Toxicity Tests
chemical_list: D007840:Latex; D008975:Molluscacides; D009947:Organotin Compounds; D013723:Teratogens; D009534:Niclosamide; C007567:triphenyltin hydroxide; D019327:Copper Sulfate