Avoidance Test Using Earthworms (Eisenia fetida) for Contaminated Sites Evaluation: Preliminary Results for Hydrocarbon Contamination

Abstract

Problems related to contaminated sites are increasing in Brazil. These sites can be represented by gas station, waste disposal areas, abandoned industrial facilities, etc. and in general are located in the neighborhood of important ecosystems, being cause of negative impacts. Evaluation of contaminated sites in Brazil has been done using only chemical parameters, without ecotoxicological studies. The aim of this study was initiate preliminary tests according to the draft of ISO that describes an avoidance test used to assess soil quality and toxicity from chemical to Eisenia fetida (earthworm). This test can be applied as a rapid screening test to determinate the bioavailability of chemicals or contaminants in soil to E. fetida, where the avoidance behaviour is used as indicator. In accordance to the results, it can be decided if reproduction test with the same species must be performed. Samples from contaminated sites with different hydrocarbons concentrations collected from a bus garage, a gas station and a contaminated oil spilling area were analysed. The results of the sample from the bus station showed that 96% of the organisms escaped from the contaminated sample section to the control soil section. This indicates that the sample can be considered toxic, presenting the habitat function limited. The toxicity of this sample was confirmed later by mortality and reproduction tests. The preliminary results indicated that avoidance test was a rapid indicator of sample toxicity and can be applied as a complement to evaluate hydrocarbons contaminated sites.

Ecotoxicological Tests as a Tool to Assess the Quality of the Soil

“…Acute toxicity tests (mortality test) assess contamination after short-term exposure to high contaminant doses (from 24 h to 14 days). Overall, acute toxicity test results showed that lethality is the main effect of contamination; however, other manifestations such as decreased mobility can be observed [36].…”

Bioensaios para avaliação da toxicidade aguda, reprodução e ganho de biomassa de minhocas (Eisenia fetida) ambientadas em lodo de esgoto doméstico

“…No Brasil, como mencionado no artigo de Sisinno et al (2006), não existem muitos estudos relatando a ecotoxicidade Parâmetros LED* Solo Teor de Umidade (% m/m) 47,90 (0,65) 21,20 (0,12) Teor de Matéria Orgânica (mg kg -1 ) 572500 (2000) 36900 (2000) CTC (cmol c kg -1 ) 24,54 (0,54) 2,66 (0,37) COT (mg kg -1 ) 310000 (23300) 15600 (600) NKT (mg kg -1 ) 24400 (300) 06400 (300) C/N 16,69 (1,21) 2,83 (0,08) Teor de P (mg kg -1 ) 11200 (900) 04800 (900) pH 4,45 (0,03) 4,88 (0,04) *LED = Lodo de esgoto doméstico; entre parênteses o erro para n = 5 tabela 1 -Caracterização química do LED e do solo utilizados no experimento.…”

Atividade microbiana e enzimática em solo após a aplicação de xisto retortado

“…Em geral, a quantidade de C na biomassa microbiana, o quociente metabólico (qCO 2 ) e a atividade enzimática do solo são indicadores sensíveis e precoces de distúrbios naturais e antropogênicos (Lambais & Carmo, 2008;Lagomarsino et al, 2009). Atualmente, testes ecotoxicológicos estão sendo incluídos em protocolos de monitoramento da contaminação dos solos (Sisinno et al, 2006). Assim, estudos nessa área são importantes para auxiliar na recomendação do uso do XR na agricultura.…”