Ecological risk assessment of p-toluidine in freshwater, sediment, and soil media.

Para-toluidine (p-toluidine) is a high production volume chemical, of which about 5,000 tons/year are imported into Korea as of the 2018 registration. This substance is mainly used as an intermediate in the manufacture of paints, azo dyes, and pigments. In this study, an ecological risk assessment of p-toluidine was performed to investigate the risk to the environment assuming the worst-case exposure scenario.

Molecular toxicity identification evaluation (mTIE) approach predicts chemical exposure in Daphnia magna.

Daphnia magna is a bioindicator organism accepted by several international water quality regulatory agencies. Current approaches for assessment of water quality rely on acute and chronic toxicity that provide no insight into the cause of toxicity. Recently, molecular approaches, such as genome wide gene expression responses, are enabling an alternative mechanism based approach to toxicity assessment.

Acute toxicity of Ag and CuO nanoparticle suspensions against Daphnia magna: the importance of their dissolved fraction varying with preparation methods.

A variety of methods to prepare nanoparticle suspensions have been employed for aquatic toxicity tests, although they can influence the dispersion property and subsequent toxicity of nanoparticles. Thus, in this study, we prepared stock suspensions of silver (Ag) and copper oxide (CuO) nanoparticles using different methods and compared their acute toxicity against Daphnia magna. The results showed that the dispersion method, filtration and initial concentration largely affected their toxicity, when the toxicity was expressed as the total concentrations of Ag and Cu.

Identification of multi-level toxicity of liquid crystal display wastewater toward Daphnia magna and Moina macrocopa.

Toxicity-based regulations of industrial effluent have been adopted to complement the conventional discharge limits based on chemical analyses. In this study, multi-level toxicity including acute toxicity, feeding rate inhibition and oxidative stress of effluent from a liquid crystal display (LCD) wastewater treatment plant (WWTP) to Daphnia magna (reference species) and Moina macrocopa (native species) were periodically monitored from April 2010 to April 2011. Raw wastewater was acutely toxic to both D.

Potential risks of effluent from acid mine drainage treatment plants at abandoned coal mines.

The lethal and sublethal toxicity of effluent from three acid mine drainage treatment plants were monitored from August 2009 to April 2010 using Daphnia magna (reference species) and Moina macrocopa (indigenous species). Acute lethal toxicity was observed in Samma effluent due to incomplete neutralization of acid mine drainages by the successive alkalinity producing system (SAPS). Additionally, there was no significant difference in toxicity values (TU) between D.

A comparative study on toxicity identification of industrial effluents using Daphnia magna.

In this study, acute toxicity monitoring and toxicity identification evaluation procedures were applied to identify causative toxicants in industrial effluents. Effluents from a metal plating factory and a rubber products factory were acutely toxic toward Daphnia magna and the toxicity varied over different sampling events (2.9-5.

Using response surface methodology to assess the effects of iron and spent mushroom substrate on arsenic phytotoxicity in lettuce (Lactuca sativa L.).

The effects of iron (Fe) and spent mushroom substrate (SMS) arsenic (As) phytotoxicity towards lettuce in artificial soils were investigated to separate the adverse soil parameters relating to As toxicity using a response surface methodology. SMS induced the root elongation of lettuce in both control and As-treated soils. However, in phytotoxicity test using a median effective concentration (EC(50)) of As, Fe and the interaction between both parameters (Fe*SMS) significantly affected EC(50), which explained 71% and 23% of the response, respectively.

Quantification of water solubilized CdSe/ZnS quantum dots in Daphnia magna.

The relative transparency of Daphnia magna (daphnia) and the unique optical properties of quantum dots (QDs) were paired to study the accumulation potential and surface coating effects on uptake of amphiphilic polymer coated CdSe/ZnS QDs. Fluorescence confocal laser scanning microscopy was used to visualize and spectrally distinguish QDs from competing autofluorescent signals arising from the daphnia themselves and their food sources. QDs were found to accumulate within the digestive tracts of daphnia, as well as, in some cases, adhere to the carapace, antennae, and thoracic appendages.

A toxicity monitoring study on identification and reduction of toxicants from a wastewater treatment plant.

In this study, toxicity of effluents in a wastewater treatment plant and of receiving water in an adjacent stream was periodically monitored from November 2007 to June 2008, in order to trace and reduce sources of toxicants. The results showed that toxicity of final effluent (FE) changed greatly over different sampling events, and appeared to have impacts on toxicity of downstream water with a significant correlation (r(2)=0.87, p<0.

Toxicity identification in metal plating effluent: implications in establishing effluent discharge limits using bioassays in Korea.

Because of complexity and diversity of toxicants in effluent, chemical analysis alone gives very limited information on identifying toxic chemicals to test organisms. Toxicity identification evaluation (TIE) techniques have been widely used to identify toxicants in various samples including industrial wastewater as well as natural waters. In response to new regulation for effluent discharge in Korea, which will be effective from 2011, a necessity of studies emerges that investigates toxicity levels in industrial effluents.