Comparison of a test battery for assessing the toxicity of a bleached-kraft pulp mill effluent before and after secondary treatment implementation

Abstract

Pulp and paper mill effluents may cause harmful effects to the aquatic environment due to the combined influence of physical factors, toxic compounds, and nutrient enrichment. In the present study, the effectiveness of secondary treatment in reducing the toxicity of an elemental chlorine-free bleached-kraft pulp mill effluent was evaluated. To characterize the toxicity of the effluent, before and after the implementation of secondary treatment, a battery of tests with organisms bearing different functions at the ecosystem level was used, namely Vibrio fischeri (5-min luminescence), Pseudokirchneriella subcapitata (72-h growth), Lemna minor (7-day growth), Daphnia magna (21-day reproduction and 24-h postexposure feeding), Chironomus riparius (9-day growth), and Danio rerio (28-day growth). For the effluent sample collected before the implementation of secondary treatment, P. subcapitata was the most sensitive organism followed by V. fischeri and D. magna, and no toxic effects were observed toward the other organisms. For the effluent sample collected after the implementation of secondary treatment, the effluent caused no toxic effects on any of the tested species. The present results demonstrated not only that secondary treatment efficaciously reduced effluent toxicity toward the selected test organisms but also the usefulness of a battery of tests to characterize the toxicity of pulp mill effluents.

Cleanup of atrazine-contaminated soils: ecotoxicological study on the efficacy of a bioremediation tool with Pseudomonas sp. ADP

“…Measured levels were comparable across treatments and not expected to have deleterious effects on the test organisms (Environment Canada 1992;OECD 1998;Guilhermino et al 1999;Rosa et al 2009). …”

“…WW 15-2521; Carolina Biological Supply Company, Burlington, NC, USA) and the cladoceran Daphnia magna (clone IRCHA, University of Sheffield, UK) were chosen, and their culturing procedures were as previously outlined (Rosa et al 2009). Both P. subcapitata and D. magna are key aquatic organisms in a wide range of habitats and are widely recommended for freshwater toxicity studies for which standard guidelines have been established (Environment Canada 1992;OECD 1984OECD , 1998.…”

“…Three 900-µl subreplicate cultures per replicated eluate/ leachate and a standard control with six replicates were set up and inoculated with 100 µl of algal inoculum. For further details on testing procedures see Rosa et al (2009). At the end of the 72-hour exposure, algal growth was estimated as the mean specific growth rate per day.…”

“…Twelve replicates were set up for the standard control and four subreplicates per replicated eluate, each with 50 ml of test solution and one juvenile (less than 24-hour old). A detailed description of the testing procedures is available (Rosa et al 2009). After the 9-day exposure period, reproduction was determined both as the time to release the first brood and the total number of juveniles released per female.…”

Sensitivity Study Comparing Daphnia obtusa (Kurz 1874) and Daphnia magna (Straus 1820) Exposure to Treated Kraft Mill Effluents, Diethylstilbestrol, and Androstenedione

“…In this sense the different sensibilities are exposed. It was observed that activated sludge treatment removed 100% of the acute toxicity (Belmonte et al 2006;Rosa et al 2010). Figure 1 shows the relationship between body length and body width of D. obtusa and D. magna exposed to DES and AED.…”