Ecological toxicity of reactive X-3B red dye and cadmium acting on wheat (Triticum aestivum)

Ecological toxicity of reactive X\|3B red dye and cadmium in both their single form and their combined form on wheat was studied using the experimental method of seed and root exposure. The single factor exposure indicated that the inhibitory rate of wheat root elongation was significantly increased with the increase in the concentration of the dye in the cultural solution, although seed germination of wheat was not sensitive to the dye. The toxicity of cadmium was greatly higher than that of the dye, but low concentration cadmium (<40 mg/L) could promote the germination of wheat seed. Interactive effects of the dye and cadmium on wheat were complicated. There was no significant correlation between the inhibitory rate of seed germination and the concentrations of the dye and cadmium. Low concentration cadmium could strengthen the toxicity of the dye acting on root elongation. On the contrary, high concentration cadmium could weaken the toxicity of the dye acting on root elongation.

Rapid ecotoxicological assessment of heavy metal combined polluted soil using canonical analysis

Quick, simple to perform, and cheap biomarkers were combined in a rapid assessment approach to measure the effects of metal pollutants, Cu, Cd, Pb and Zn in meadow burozem on wheat. Analysis of orthogonal design showed that the significant zinc factor indicated both the inhibition rate of shoot mass and that of root elongation were affected by zinc(P<0.05 and P<0.01, respectively). The first toxicity canonical variable (TOXI), formed from the toxicity data set, explained 49% of the total variance in the toxicity data set; the first biological canonical variable(BIOL) explained 42% of the total variation in the biological data set. The correlation between the first canonical variables TOXI and BIOL (canonical correlation) was 0.94 (P<0.0001). Therefore, it is reliable and feasible to use the achievement to assess toxicity of heavy metal combined polluted soil using canonical analysis. Toxicity of soil combined polluted by heavy metals to plant community was estimated by comparing the IC 50 values describing the concentration needed to cause 50% decrease with grow rate compared to no metal addition. Environmental quality standard for soils prescribe that all these tested concentration of heavy metals in soil should not cause hazard and pollution ultimately, whereas it indicated that the soils in second grade cause more or less than 50% inhibition rates of wheat growth. So environmental quality standard for soils can be modified to include other features.

Zebrafish embryo toxicity of 15 chlorinated, brominated, and iodinated disinfection by-products

Disinfection to protect human health occurs at drinking water and wastewater facilities through application of non-selective oxidants including chlorine. Oxidants also transform organic material and form disinfection by-products（DBPs）, many of which are halogenated and cyto-and genotoxic. Only a handful of assays have been used to compare DBP toxicity,and researchers are unsure which DBP（s） drive the increased cancer risk associated with drinking chlorinated water. The most extensive data set employs an in vitro model cell,Chinese hamster ovary cells. Traditionally, most DBP research focuses on the threat to human health, but the effects on aquatic species exposed to DBPs in wastewater effluents remain ill defined. We present the developmental toxicity for 15 DBPs and a chlorinated wastewater to a model aquatic vertebrate, zebrafish. Mono-halogenated DBPs followed the in vivo toxicity rank order： acetamides 〉 acetic acids 〉 acetonitriles ~ nitrosamines, which agrees well with previously published mammalian in vitro data. Di-and tri-halogenated acetonitriles were more toxic than their mono-halogenated analogues, and bromine-and iodine-substituted DBPs tended to be more toxic than chlorinated analogues. No zebrafish development effects were observed after exposure to undiluted or non-concentrated,chlorinated wastewater. We find zebrafish development to be a viable in vivo alternative or confirmatory assay to mammalian in vitro cell assays.

Characterization,occurrence,environmental behaviors,and risks of nanoplastics in the aquatic environment:Current status and future perspectives

Microplastics(MPs)are emerging contaminants that have attracted worldwide attention in recent years.Compared with MPs,nanoplastics(NPs)may exhibit greater toxicity and higher potential risks because of their unique physiochemical nanoscale properties.However,the environmental fate,ecosystem toxicity,and potential risks associated with NPs have been less explored.This study summarizes the current research status of NPs through a comprehensive bibliometric analysis.The research hotspots and future trends of NPs were identified.We comprehensively searched the Web of Science Core Collection scientific database from its inception(2004)to November 26,2020.The results showed that the number of papers on NPs has increased significantly since 2014.The keywords used in NP research were divided into three clusters.Cluster 1 related to the physical,chemical,and biological behaviors of NPs in aquatic environments.Cluster 2 represented a relatively new and hot research field concerning the exposure,accumulation,and toxicity of NPs in organisms.Cluster 3 corresponded to the identification and quantification of NPs in marine environments and sediments.Moreover,we systematically elaborated the main areas of NP research,such as the characterization,occurrence,environmental behavior,ecological toxicity,and human health risks of NPs.The results showed that the quantification of NPs at environmentally relevant concentrations remains a challenge.Most studies have investigated polystyrene NPs,spherical NPs,and NPs in marine environments,while few studies have examined the aggregation,deposition,and ecological toxicity of NPs under environmentally relevant conditions.In addition,much less is known about the human health risks associated with NPs because little research has been conducted on estimating the overall human exposure to NPs and its effect.Finally,the current challenges and future perspectives of NP research are discussed.

Occurrence of polycyclic aromatic hydrocarbons in the estuarine sediments of the Taihu Lake and their associated toxic effects on aquatic organisms

Polycyclic aromatic hydrocarbons(PAHs)are ubiquitous toxic organic pollutants in the natural environment that are strongly associated with socioeconomic activities.Exploring the distribution,sources,and ecological toxicity of PAHs is essential to abate their pollution and biological risks.The 16 priority PAHs in different lakeside city estuarine sediments in the northern Taihu Lake in China were determined using gas chromatography-mass spectrometry.Results showed that total concentrations of PAHs(ΣPAHs)ranged from 672.07 to 5858.34 ng g^(^(-1)),with a mean value of 2121.37 ng g^(^(-1)).High-molecular-weight PAHs(4-6 rings)were dominant,accounting for 85%of theΣPAHs detected.Due to the barrier of gate/dam in the estuarine area,the concentrations of PAHs in the sediments were significantly different between the river mouth and lake side.Changes in total organic carbon(TOC)content and the spatial distribution of PAHs in the sediments were consistent.Sediment pollution assessment explored using the fuzzy evaluation model indicated 75%of slight PAH pollution.Some estuarine sediments(22%)concentrated in the east of the Wuli Lake in the Meiliang bay of the Taihu Lake were moderately or heavily polluted.The PAHs may lead to occasional detrimental biological consequences in the area.Diagnostic ratios and principal component analysis-multiple linear regression suggested vehicle emission and natural gas combustion as the primary PAH contributors(81%).