标题：Influência da Salinidade na Toxicidade de Sedimentos Dragados da Lagoa Rodrigo de Freitas e Baía de Guanabara (RJ): Efeitos Tóxicos em Minhocas
其他标题：Influence of Salinity on the Toxicity of Dredged Sediments from Estuarine Rodrigo de Freitas Lagoon and Guanabara Bay (RJ): Toxic Effects On Earthworms
摘要：A influência da salinidade na ecotoxicidade de sedimentos dragados de sistemas estuarinos, em cenário de disposição terrestre, foiestudada utilizando Eisenia andrei como bioindicador. Foram coletadas amostras de Latossolo e de Chernossolo e salinizadas com água domar para realização de bioensaios agudo e de fuga. Dados de salinidade e CL50 de sedimento (Lagoa Rodrigo de Freitas e Baía de Guanabara)foram compiladas da literatura, oriundos de bioensaios agudo com E. andrei. Quando a concentração de sal na mistura solo: sedimentoé próxima à CL50 de sal obtida experimentalmente com água do mar, considerou-se que o sal tem papel preponderante na toxicidade. Asconcentrações de sal ≥ 3 g/kg são significativamente letais aos organismos em ambos os tipos de solo. Respostas significativas de fugaforam constatadas a partir da dosagem de 2 g/kg. Os resultados indicam que para os sedimentos da APA de Guapimirim (inverno), LagoaRodrigo de Freitas (em Chernossolo), Porto do Rio (inverno), Porto de Niterói (verão) e foz do Rio Meriti (inverno), o sal marinho tem papelde suma relevância na toxicidade para as minhocas. Para as demais áreas estudadas, outros fatores, como as propriedades do sedimento,metais pesados e substâncias orgânicas, parecem desempenhar papel mais importante na toxicidade.
其他摘要：The role of salinity levels in the toxicity of dredged sediments from estuarine systems, in scenario of land disposal, was investigatedby using Eisenia andrei as bioindicator. Samples of ferralsol and chernosol were collected and salinized with seawater (2 and 12 g/kg of salt)and submitted to acute and avoidance bioassays with E. andrei. Data of salinity and sediment LC50 were extracted from the literature. Thesedata consists of results from acute bioassays with E. andrei applied to dredged sediments from Rodrigo de Freitas Lagoon and GuanabaraBay. The concentration of salt (g/kg) in soil:sediment mixture that corresponded to the LC50 was estimated by determining salt contents inpure soils and sediments. When such concentration is close to the LC50 obtained in laboratory using seawater, the influence of the salt in thetoxicity was considered preponderant. The results revealed that concentrations of salt ≥ 3g/kg are significantly lethal to the organisms in bothsoil types, but toxicity levels are higher in ferralsol (LC50 = 3,51 g/kg) than those observed in chernosol (LC50 = 4,03 g/kg). Concentrationsof salt ≥ 2g/kg were able to cause significant avoidance responses, but again the value of EC50 in ferralsol (2,77 g/kg) were lower than thatobtained in chernosol (2,99 g/kg). These observations are due to the abundance of expansive clay minerals in chernosol, with high cationicexchange capacity and that are able to reduce toxicity levels. The sediments whose salt concentrations in the sediment LC50 (soil:sedimentmixture) are close to the salt LC50 values determined in laboratory are the APA of Guapimirim (winter), Porto of Rio (winter), Port of Niterói(summer), Rodrigo de Freitas Lagoon (in chernosol) and the mouth of Meriti River (winter), suggesting that the concentrations of salts aresufficiently high to play a crucial role in the toxicity. Regarding the other study areas, other factors, such as the properties of the sediments,heavy metals and organic substances, may play an important role in the toxicity.
