World Congress of Malacology Antwerp ... - Unitas Malacologica

Toxic effects of water samples of Tietê River in adults and embryos of Biomphalaria glabrata
(Say, 1818)
Tallarico, L.F. 1,2 ; Grazzefe, V. 1 ; Okazaki, K. 2 ; Kawano, T.; Nakano, E. 1
1. Laboratório de Parasitologia/Malacologia, Instituto Butantan, Avenida Vital Brasil, 1500, CEP
05503-900, São Paulo, SP, Brazil,
Email: letallarico2@butantan.gov.br
2. Centro de Biologia Molecular, Instituto de Pesquisas Energéticas e Nucleares, IPEN-CNEN/SP,
Brasil
The potential impact of secondary effluent discharge on Tietê River was evaluated by analyzing acute
toxicity in Biomphalaria glabrata. Acute toxicity assays were conducted in adult specimens and
embryo at blastulae, gastrulae, trocophore and veliger stages of freshwater snails B. glabrata. Four
sites were chosen for sampling: in the river, 200 meters before the treatment station; the influent and
effluent of the municipal wastewater system; and in the river, 200 meters after the treatment station
discharge. The work was initiated in 2005 september and at least three additional sampling will be
performed. At september 2005, the station affluent was toxic for the snail B. glabrata with the
following LC50 values: 37.76% for adult snails and 13.99%, 20.09%, 23.15% and 23.80% for
embryos at blastulae, gastrulae, trocophore and veliger stages respectively. Only the raw sample of
the station effluent was toxic for embryos, but not for adult snails. Acute toxicity was remarkably
reduced at august 2006, as shown by the lower LC50 values found. – 44.19%, 41.91%, 58.58% and
60.76% for embryos at blastulae, gastrulae, trocophore and veliger stages respectively and 100% for
adult snails. The station effluent was not toxic for adult and embryos. Sampling at february 2007 was
toxic only for adult snails, with a LC50 value of 32,53%. The station effluent was not toxic for adult
and embryos. In all samplings, after discharged into the river, treated effluents were not toxic for B.
glabrata adult snails and embryos. In these study, the potential impact of effluent discharges to the
biota of Tietê River was showed. Biological treatment was quite efficient in reducing toxicity to B.
glabrata as shown by the low toxicity of the effluent plant samplings. With the dillution effect of the
river, acute toxicity to B. glabrata was eliminated. These results show the importance of the
biological treatment of effluents in reducing acute toxicity.
Financial Suport: FAPESP, CNPq. Technical Support: SABESP, Suzano, SPp
Revision of Paludinellassiminea (Caenogastropoda: Assimineidae) – preliminary report
Tatara, Yuki 1 ; Fukuda, Hiroshi 2
1. Department of Biology, Faculty of Science, Toho University, Funabashi 274-8510, Japan,
Email: ykui@msc.biglobe.ne.jp
2. Conservation of Aquatic Biodiversity, Faculty of Agriculture, Okayama University, Okayama 700-
8530, Japan,
Email: suikei1@cc.okayama-u.ac.jp
The genus Paludinellassiminea (type species: Omphalotropis japonicus) is distributed in Japan and
South Korea. They live under rocks and debris on the supratidal zones or the edge of costal forests.
They are likely to be threatened in Japan, because their habitats have rapidly been decreasing partly
through construction of concrete banks over excessive ranges of coasts and rivers.
Paludinellassiminea has been thought to be closely related to Omphalotropis (sensu lato – it may
need to be divided into several genera), based on the similarities of shell, operculum, head-foot and
penis. However, Paludinellassiminea differs from Omphalotropis in having the outer marginal teeth
with no secondly cusps in the radula. The internal anatomy of Paludinellassiminea is little known,
and its relationships to other genera remain unclear.
The purpose of this study is to revise the systematics Paludinellassiminea by thorough anatomy. We
have obtained the following primary results:
1) The kidney extends forward into the pallial cavity, as in some Omphalotropis spp., the kidney
consists of two slender lobes. The gill filaments are present.
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