Sublethal Effects of Chlorine-Free Kraft Mill Effluents on Daphnia magna

Abstract

The implementation of elemental chlorine-free (ECF) bleaching methods has drastically reduced the aquatic toxicity of Kraft mill effluents during the last decade. However, the residual toxicity of Kraft mill effluents is still a potential concern for the environment, even when subjected to secondary wastewater treatment. The aim of this study is characterize potential sublethal effects of ECF Kraft mill effluents using Daphnia magna as model species. D. magna exposed towards increasing concentration of ECF Kraft mill effluent showed a significant, dose-dependent reduction in feeding. Conversely, post-feeding assay, life history, and allometric growth analyses showed stimulatory, rather than inhibitory effects in exposed animals at low concentrations, while high concentrations of ECF Kraft mill effluents reduced their reproductive output. These results suggest a hormetic effect in which moderate concentrations of the effluent had a stimulatory effect with higher concentrations causing inhibition in some variables.

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

“…Also, organic compounds contained in BKMEs, such as β-sitosterol and stigmasterol, may be contributing to the allometry. Moreover, phytosterols per se are responsible for 12.9% and 8.1% of the deviation from the natural shape of D. magna, while the BKMEs account for 25.6% to 27.8% of shape deviation (López et al 2011;Chamorro and Vidal, 2014;Chamorro et al 2016b).…”

“…Previous studies of D. magna show that fertility, growth rate, maturity, and sex ratio are affected by organic compounds with chronic estrogenic activity López et al 2011;Chamorro et al 2016b). Also, the allometric growth rate of D. magna can be affected by estrogenic compounds (Olmstead and LeBlanc 2000).…”

Review of Constructed Wetlands for Acid Mine Drainage Treatment

“…Daphnia species (sp) have been used in standard toxicity tests for many years due to their high sensitivity, manageability, and high parthenogenetic reproduction rate, which ensures a uniform response [14,15]. Furthermore, these species play an important role in the aquatic food chain [16].…”

Endocrine disruption in aquatic species of Chile

“…Bioassays were used to evaluate the endocrine effects of kraft pulp mill effluent (KPME) from the Biobío river basin using the Daphnia magna Straus 1820 toxicity test (Chamorro et al 2016;López et al 2011;Xavier et al 2005), D. magna and Daphnia obtusa Kurtz 1875 (Xavier et al 2017), Yeast Estrogen Screen (YES), and Recombinant Yeast Assays (RYAs) (Chamorro et al 2010(Chamorro et al , 2013a(Chamorro et al , 2013b. Finally, YES was performed to measure estrogenic activity in river sediments and male T. areolatus tissues collected from the Chillán watershed (central-southern Chile) (Bertin et al 2020).…”

“…In another study using D. magna (sublethal and chronic toxicity test), the daphnids, when exposed to an increasing concentration of KPME, showed a significant dosedependent reduction in feeding. In contrast, post-feeding, life history, and AGR tests showed stimulating and noninhibitory effects in daphnids exposed to low concentrations (suggesting hormetic effect), while high concentrations of KPMEs reduced their reproductive output (Chamorro et al 2016). A study was conducted to determine the sensitivity of D. magna and Daphnia obtusa Kurtz 1875 exposed to KPME, diethylstilbestrol (DES), and androstenedione.…”