Toxicity Assessment of Contaminated Soil Using Seeds as Bioindicators

Ecotoxicology not only detects dangerous substances, but also biological effects from such substances that may harm the environment (Lynch, 2001). Thus, ecotoxicology integrate the synergistic and antagonistic effects of all contaminants and provide information on the bioavailable fraction of the contaminants only, which would be impossible to evaluate solely with chemical data. Hence, bioassays can serve as a complementary tool in environmental risk assessment of bioremediated places (Plaza et al., 2005; Repetto et al., 2001).

Ecotoxicity tests evaluate the effect of environmental contamination on organisms through assessment of survival, growth, reproduction and behavior. These tests help to determine whether the contaminant concentration at remediated sites is high enough to cause adverse effects on organisms (U. S. EPA, 1996).

Plants depend strongly on soil to germinate and grow, so any alterations in the seed development may reflect the presence of toxic substances in the soil. Germination test in ecotoxicological assays are considered short-term and evaluate acute toxicity effects (Banks & Schultz, 2005). Siddiquii et al. (2001) analyzed grass germination in soil contaminated with diesel oil, demonstrating its high toxicity. Saterbak et al. (1999) recommends various seeds germination as an effective evaluation of site contamination, since such tests present a narrow variability, good sensitivity and applicability to variety of soils.

Maila and Cloete (2002) consider Lepidium sativum germination as a potential PAHs bioindicator. On the other hand, Smith et al. (2006) report that none of the treatments with PAHs contaminated soil adversely affected germination. The findings of Lors et al. (2009) suggest a probable relationship between acute toxicity and low-molecular weight PAHs. Banks and Schultz (2005) supported using lettuce in germination toxicity assays in petroleum-contaminated soils. This seed showed sensitivity to contaminant.

 

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(Author: Jaqueline Matos Cruz, Paulo Renato Matos Lopes, Renato Nallin Montagnolli, Ivo Shodji Tamada, Natália Maria Maciel Guerra Silva, Ederio Dino Bidoia

Published by Macrothink Institute)