Transcriptome and computational approaches highlighting the molecular regulation of Zacco platypus induced by mesocosm exposure to common disinfectant chlorine.

Chlorine (Cl) is a disinfectant often used in swimming pools and water treatment facilities. However, it is released into aquatic ecosystems, where it may harm non-targeted organisms. Here, we performed a mesocosm experiment exposing Zacco platypus (Z.

Transformation Products of Emerging Pollutants Explored Using Non-Target Screening: Perspective in the Transformation Pathway and Toxicity Mechanism-A Review.

The scientific community has increasingly focused on forming transformation products (TPs) from environmental organic pollutants. However, there is still a lot of discussion over how these TPs are generated and how harmful they are to living terrestrial or aquatic organisms. Potential transformation pathways, TP toxicity, and their mechanisms require more investigation.

Ecological Effects of Benzyl Chloride on Different Korean Aquatic Indigenous Species Using an Artificial Stream Mesocosm Simulating a Chemical Spill.

In this study, an artificial stream mesocosm consisting of a head tank, faster-flowing riffle section, gravel section, pool section, lower-run section, and tail tank was installed to simulate a chemical spill in a river. The responses of freshwater periphyton algae, crustacea (), freshwater worm (), benthic midge (), and fish ( and ) were observed after exposure to benzyl chloride (classified as an accident preparedness substance, APS) at concentrations of 1, 2, and 4 µL/L for 22.5 h.

Derivation of acute copper biotic ligand model-based predicted no-effect concentrations and acute-chronic ratio.

The copper biotic ligand model (BLM) can quantitatively describe the bioavailability depending on various environmental factors and has been used to derive the predicted no-effect concentrations (PNECs). The commonly employed acute BLM tool, HydroQual, which applies the biotic ligand constants of fathead minnow in the same model structure for all taxonomic groups, estimates lower acute copper toxicity values compared to the chronic copper PNECs of the European Union Risk Assessment Reports (EU-RAR), which are based on taxon-specific model structures and biotic ligand constants for vertebrates, invertebrates, and algae. In this study, the full-BLM approach was applied using an appropriate acute BLM for each taxonomic group to derive acute HC5s (fifth percentile value in the species sensitivity distribution [SSD]) and an acute-chronic ratio for copper.

Biomonitoring the effects of urban-stream waters on the health status of pale chub (Zacco platypus): A comparative analysis of biological indexes and biomarker levels.

The objective of this study was to biomonitor the effects of potential environmental pollutants in urban-stream waters, on fish health. Pale chub (Zacco platypus), a dominant species in the Korea urban stream waters, was chosen and biomonitoring indicators for the different spatial characteristics were tailored in an urban watershed. Biological responses including biotic-somatic index as well as gonadal development phase and plasma steroids levels, and the biochemical responses, ethoxyresorufin-o-deethylase (EROD) and acetylcholinesterase (AChE) activities, were measured.

Towards a multi-bioassay-based index for toxicity assessment of fluvial waters.

Despite their proven reliability for revealing 'acceptable' degrees of toxicity in waste- and reclaimed waters, bioassays are rarely used to assess the toxicity of hazardous contaminants present in natural waters. In this study, we used organisms from different trophic levels to assess the toxicity of water samples collected from four different South Korean rivers. The main objective was to develop a multi-descriptor index of toxicity for undiluted river water.

Development of water quality criteria of ammonia for protecting aquatic life in freshwater using species sensitivity distribution method.

Ammonia is deemed one of the most important pollutants in the freshwater environment because of its highly toxic nature and ubiquity in surface water. This study thus aims to derive the criteria for ammonia in freshwater to protect aquatic life because there are no water quality criteria for ammonia in Korea. Short-term lethal tests were conducted to perform the species sensitivity distribution (SSD) method.

A new approach of Integrated Health Responses (IHR(s)) modeling for ecological risk/health assessments of an urban stream.

The objective of this study was to evaluate the ecological health of an urban stream using Integrated Health Responses (IHRs). Water chemistry analysis, habitat health, and ecotoxicity tests were conducted in the stream along with analyses of molecular/biochemical, physiological biomarkers, and population-level responses in indicator species. Chemical stresses, measured as nutrient levels, ionic content and organic matter concentrations were significantly greater (p<0.

ZnO nanowire-based nonvolatile memory devices with Al2O3 layers as storage nodes.

Top-gate ZnO nanowire field-effect transistors (FETs) with Al2O3 gate dielectric layers as storage nodes were fabricated and their memory effects were characterized in this work. The Al2O3 layers deposited on the ZnO nanowire channels were utilized not only as gate dielectric ones but also as charge trapping ones. For a representative top-gate ZnO nanowire FET, its I(DS)-V(GS) characteristics for the double sweep of the gate voltages exhibit the counterclockwise hysteresis and the threshold voltage shift.

ZnO nanowire field-effect transistors with floating gate nodes of Au nanoparticles.

The memory characteristics of top-gate single ZnO nanowire-based field-effect transistors (FETs) with floating gate nodes consisting of Au nanoparticles on top of the nanowire channels were investigated in this study. Au nanoparticles, synthesized by a thermal deposition of Au thin film and by a subsequent thermal annealing procedure, were embedded in between Al2O3 tunneling and control gate layers deposited on ZnO nanowire channels. For a representative single ZnO nanowire-based FET with floating gate nodes consisting of Au nanoparticles embedded between Al2O3 layers, its drain current versus gate voltage (I(DS)-V(DS)) characteristics for a double sweep in the gate voltage range from -4 to 4 V exhibit a clockwise hysteresis loop with a threshold voltage shift of deltaV(th) = 1.

ZnO nanowire-based nano-floating gate memory with Pt nanocrystals embedded in Al(2)O(3) gate oxides.

The memory characteristics of ZnO nanowire-based nano-floating gate memory (NFGM) with Pt nanocrystals acting as the floating gate nodes were investigated in this work. Pt nanocrystals were embedded between Al(2)O(3) tunneling and control oxide layers deposited on ZnO nanowire channels. For a representative ZnO nanowire-based NFGM with embedded Pt nanocrystals, a threshold voltage shift of 3.

NOT and NAND logic circuits composed of top-gate ZnO nanowire field-effect transistors with high-k Al(2)O(3) gate layers.

Electrical characteristics of NOT and NAND logic circuits fabricated using top-gate ZnO nanowire field-effect transistors (FETs) with high-k Al(2)O(3) gate layers were investigated in this study. To form a NOT logic circuit, two identical FETs whose I(on)/I(off) ratios were as high as ∼10(8) were connected in series in a single ZnO nanowire channel, sharing a common source electrode. Its voltage transfer characteristics exhibited an inverting operation and its logic swing was 98%.

Stressor identification and health assessment of fish exposed to wastewater effluents in Miho Stream, South Korea.

This study evaluated the effects of an industrial wastewater treatment plant (IWTP) and a municipal wastewater treatment plant (MWTP) effluents on a variety of bioindicators ranging from biochemical, organism, and population-level responses in pale chub (Zacco platypus) and fish community structure. The Index of Biotic Integrity (IBI) indicated that the site upstream of these wastewater treatment plant discharges is in fair-good condition and downstream of the plant is in poor condition. The EROD (ethoxyresorufin-O-deethylase) activity, condition factor, and liver somatic index were significantly increased at the downstream site compared to those of the upstream site.

Assessing effects of stress across levels of biological organization using an aquatic ecosystem health index.

Multimetric approaches typically consider only one level of biological organization to assess the effects of environmental stressors on the health of aquatic ecosystems. The present study applied integrative star-plot analysis to evaluate effects of stressors over several levels of biological organization ranging from the sub-organism to the community level at study sites subjected to different levels of contaminant stress. An aquatic ecosystem health index (AEHI), based on the sum of all the star-plot areas over these levels of biological organization, was developed to reflect an integrative and holistic assessment of stressors on ecosystem health.