Ecotoxicological assessment of timber-industry wastewater based on bioassays conducted with lettuce seeds (Lactuca sativa L.)

Abstract

Due to the worldwide growth in the consumption of reforested wood, Brazil has the timber industry as one of the main activities in the sector of the national economy. Among the products made from wood are laminated plywood. The production of these materials is responsible for the generation of wastewater with highly polluting characteristics, therefore, their toxicological knowledge becomes essential, which can be acquired from bioassays using Lactuca Sativa L. seeds, which is the objective of the present study. When the growth of the seedling radicle in contact with the different concentrations of effluent is evaluated, there is a marked growth due to the increase in concentration, which is possibly linked to the high presence of organic material and phosphorus which favor its growth. When the germination of the seeds was evaluated, there was a normality until it reached the concentration of 75%, in this condition, about 20% of the seeds had the germination inhibited, already when 100% of the effluent in the sample was used, 40% of the seeds were inhibited, having as possible responsible for this, the presence of chemical compounds such as phenol and other inorganic compounds. Therefore, toxicological bioassays using Lactuca Sativa seeds proved to be efficient in obtaining knowledge of possible environmental impacts in a simple, reliable and inexpensive way.