Bioassays with Caged Hyalella azteca to Determine Aquatic Toxicity Downstream of Two Saskatchewan, Canada, Uranium Operations

2007 ◽  
Vol preprint (2007) ◽  
pp. 1
Author(s):  
Erin Robertson ◽  
Karsten Liber
Keyword(s):  
Aquatic Toxicity ◽  
Hyalella Azteca

Chemical characterization and biotreatability of effluents from an integrated alkaline-peroxide mechanical pulping/machine finish coated (APMP/MFC) paper mill

1997 ◽  
Vol 35 (2-3) ◽  
pp. 7-14 ◽  
Author(s):  
A. Schnell ◽  
M. J. Sabourin ◽  
S. Skog ◽  
M. Garvie
Keyword(s):  
Activated Sludge ◽  
Aquatic Toxicity ◽  
Wood Chip ◽  
Chemical Characterization ◽  
Toxicity Testing ◽  
Sampling Period ◽  
Paper Mill ◽  
Alkaline Peroxide ◽  
Conventional Activated Sludge ◽  
Treated Effluent

As part of an extensive audit of the Alkaline-Peroxide Mechanical Pulping (APMPTM) plant at the Malette Quebec Inc. mill in St. Raymond, Que., effluents were sampled from various stages of the process for comprehensive chemical characterizations, aquatic toxicity testing and anaerobic biotreatability assessments. In addition, untreated and secondary treated combined effluent from the integrated paper mill were sampled to determine the effectiveness of a conventional activated sludge process at the mill site. During the one-day sampling period, the APMP plant processed a mixed wood furnish consisting of 50% spruce/balsam fir and 50% aspen, with a chemical charge of 3.5% sodium hydroxide and 3.8% hydrogen peroxide on oven-dry fibre, while the Machine Finish Coated (MFC) paper production rate was 100 odt/d (oven dry metric tonnes per day). Measured production-specific contaminant discharge loadings from the novel APMP process were 56 kg BOD5/odt and 155 kg COD/odt in a combined effluent flow of 28 m3/odt. Sources of process effluent were chip washing, three stages of wood chip pretreatment and chemical impregnation (i.e., Impressafiner stages), interstate washing and pulp cleaning. The three Impressafiner pressates were found to be the most concentrated (i.e., 12-26 g COD/L) and toxic streams. Microtox testing of the pressates revealed EC50 concentrations of 0.07-0.34% v/v. The warm and concentrated effluents generated by the non-sulphur APMP process were found to be highly amenable to anaerobic degradation as determined by batch bioassay testing. Filterable BOD5 and COD(f) of the process effluents were reduced by 87-95% and 70-77%, respectively, with corresponding theoretical methane yields being attained. Acid-soluble dissolved lignin compounds exhibited biorecalcitrance, as revealed by limited removals of 34-55%, and were the main constituents contributing to residual COD(f), while resin and fatty acids (RFA) were reduced by 80-94%. The conservatively operated full scale activated sludge treatment process achieved a similar high 74% COD(f) removal from the whole mill effluent, while BOD5 and RFA reductions were virtually complete and the treated effluent was non-toxic, as measured by Microtox.

scholarly journals Aquatic Toxicity of Photocatalyst Nanoparticles to Green Microalgae Chlorella vulgaris

Water ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 77
Author(s):  
Cristina Adochite ◽  
Luminita Andronic
Keyword(s):  
Chlorella Vulgaris ◽  
Advanced Oxidation Process ◽  
Growth Parameters ◽  
Aquatic Toxicity ◽  
Basal Medium ◽  
Inhibitory Effect ◽  
Synthesis Methods ◽  
Potent Inhibitory Effect ◽  
Density Surface ◽  
The Impact

In the last years, nanoparticles such as TiO2, ZnO, NiO, CuO and Fe2O3 were mainly used in wastewater applications. In addition to the positive aspects concerning using nanoparticles in the advanced oxidation process of wastewater containing pollutants, the impact of these nanoparticles on the environment must also be investigated. The toxicity of nanoparticles is generally investigated by the nanomaterials’ effect on green algae, especially on Chlorella vulgaris. In this review, several aspects are reviewed: the Chlorella vulgaris culture monitoring and growth parameters, the effect of different nanoparticles on Chlorella vulgaris, the toxicity of photocatalyst nanoparticles, and the mechanism of photocatalyst during oxidative stress on the photosynthetic mechanism of Chlorella vulgaris. The Bold basal medium (BBM) is generally recognized as an excellent standard cultivation medium for Chlorella vulgaris in the known environmental conditions such as temperature in the range 20–30 °C and light intensity of around 150 μE·m2·s−1 under a 16/8 h light/dark cycle. The nanoparticles synthesis methods influence the particle size, morphology, density, surface area to generate growth inhibition and further algal deaths at the nanoparticle-dependent concentration. Moreover, the results revealed that nanoparticles caused a more potent inhibitory effect on microalgal growth and severely disrupted algal cells’ membranes.

The contribution of detoxification pathways to pyrethroid resistance in Hyalella azteca

2021 ◽  
Vol 284 ◽  
pp. 117158
Author(s):  
Courtney Y. Fung ◽  
Kun Yan Zhu ◽  
Kaley Major ◽  
Helen C. Poynton ◽  
Kara E. Huff Hartz ◽  
...  
Keyword(s):  
Pyrethroid Resistance ◽  
Hyalella Azteca ◽  
Detoxification Pathways
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