Analysis of toxicity from the effluent generated in a furniture industry spray booth using the species Lactuca sativa and Allium cepa

Abstract

This study evaluated the toxicity of effluent generated in a furniture industry spray booth, before and after treatment in a system composed of an anaerobic sequencing batch (ASBR) followed by an aerobic sequencing batch reactor (SBR). The toxicity tests were carried out with raw (with and without dilutions) and treated effluent to evaluate the toxic potential using Allium cepa and Lactuca sativa as bioindicators.  The toxicity tests, using Allium cepa and Lactuca sativa, indicated that the anaerobic-aerobic treatment performed was efficient to reduce the toxicity of the paint booth effluent. The raw effluent, undiluted and diluted (at 1:10; 1:8 and 1:6 dilutions), showed toxic effect on the root growth of Allium cepa, as it inhibited root growth by 100%. In the tests with Lactuca sativa seeds, there was partial inhibition, between 44% and 63%, for 1:10 and 1:8 dilutions, but for the 1: 6 dilution and without dilution of effluent the inhibition was 100%. The treated effluent, in an ASBR followed by an SBR, presented a small percentage of inhibition for tests with Allium cepa (13%) and Lactuca sativa seeds (4%). The effluent treated by the anaerobic system followed by aerobic presented low toxicity without generating lethal or sub-lethal effects to the test organisms, which indicates the efficiency of the treatment process.