This study aimed to determine mutagen contamination, to compare the differences between inlet and outlet distribution, and the possible impacts on public health. Water samples were collected from four different waterworks in Guangzhou, China. The Ames test was conducted to investigate the potential mutagenicity caused by organic extracts from drinking water sources and peripheral water. Organic content was extracted with XAD-2 resin column and organic solvents, and toxicity was tested in three doses of extract equivalent, 0.2, 0.4 and 0.8 L source water. The results of the Ames test showed that all the organic extracts from water samples could induce different levels of mutagenic potentials in the absence of S9 mix, which indicated mutagenicity and strain. Comparing with TA98, TA100 was more sensitive in genotoxicity. Mutagenic enhancement factors were found in both drinking water sources and peripheral water. Water treatment technologies with different disinfection ways could increase the mutagenicity of water, but the biological significance of mutagenicity of the organic extracts remained to be further confirmed. The results suggested that it was necessary to concern the relationship between source water, water treatment unit and the mutagenicity factors of water.

Wastewater treatment plants (WWTPs) face great challenges in developing countries, such as China, due to increasingly strict integrated wastewater discharge standard, especially for ammonium. Thus, it is very important to understand the limiting factor for ammonium removal in WWTPs. In this study, samples from 8 full-scale municipal WWTPs with different treatment processes in Pearl River Delta (PRD) area were evaluated. Bacterial and archaeal communities were investigated by high-throughput sequencing, activity of aerobic ammonium and nitrite oxidation, denitrification and anammox processes were evaluated. Nitrite, nitrate and TP concentration were strongly correlated with bacterial and archaeal composition in WWTPs based on canonical correspondence analysis (CCA). Aerobic ammonium oxidation activities were over 10 times lower than aerobic nitrite oxidation, denitrification and anammox activities in WWTPs samples, which indicated nitrogen removal activities in WWTPs were limited by aerobic ammonium oxidation, because of lack of nitrite/nitrate for denitrification and anammox. Moreover, a technology-dependent shaping of microbial diversity and nitrogen removal activity was observed. The highest bacterial diversity and nitrogen removal activities were achieved in sequencing batch reactor (SBR) and Modified Anaerobic-Anoxic-Oxic (MAAO) processes, which implied the advantage of these two treatment technologies in nitrogen removal. Therefore, this study suggested enhancing activity of aerobic ammonium oxidation might be a potential solution, for promoting ammonium removal and benefiting sustainable management of WWTPs in future.

A novel psychrotroph Cryobacterium sp. GCJ02 was isolated and characterized, which showed gorwth well at 4 ºC. The assembled whole genome of strain GCJ02 is 4.39 Mb, including 4,139 protein coding genes with G+C content of 68.41mol%. In this study, we report the complete genome sequence of a novel strain of the genus Cryobacterium, affording feasibility to elucidate the molecular mechanism of cold adaptation, and facilitate genetic manipulation of this bacterium.

At present, the problem of heavy metal pollution is a hot topic in the world. There are significant differences in the types and concentrations of metal ions distributed in each contaminated sites. In China, due to the vast territory and diverse ecoenvironments, the pollution situation is complex and variable, and the composite pollution is particularly obvious. Overall, pollution in the southern provinces is relatively higher than in other provinces, and Cd, Hg, Pb, Cr, As and Ni are listed as the priority pollutants for control. The metals have different physical or chemical specificity that allows them to be treated differently. Toxic Cr(VI) needs to be reduced to non-toxic Cr(III) before removal, whereas Cd(II) can form an insoluble Cd compound precipitate under alkaline conditions. Nevertheless, the characteristics of the soil itself such as pH, humidity, mineral composition, etc., are the hurdles in the process of remediation. Therefore, this review systematically summarizes the characteristics of heavy metal contaminated soil in major areas of China. It also proposes appropriate restoration methods and schemes such as phytoremediation and microbial remediation, which provides a theoretical basis for the elimination of heavy metals from a polluted land.

Analytical chemistry allows an accurate quantification of the total concentrations of a range of chemicals in different media of the ecosystems and contaminated sites, but the numerical values do not have direct relevance to the toxicity of them because the measured concentrations do not represent the active fraction that imposes toxic effects on organisms. It is apparent that an assessment of pollutant concentrations in ecosystems shall be made with new innovation to obtain the organism exposed concentrations so that the subsequent toxicological effects based on these data can provide reliable estimate on toxicity for management decision accordingly. Applied Toxicology, e.g., Ecotoxicology, and Environmental Toxicology, therefore shall have a different scientific framework to adopt the use of a new concentration term for pollutants to establish a close relationship between the effective concentration in the ecosystem and the toxicity to the organisms to make a meaningful understanding of the ecotoxicology and environmental toxicity. In addition, the choice of the organisms as indicators for chemical toxicity assays is another critical issue and the organism shall be selected with an international consensus to establish a solid baseline for comparable results from different laboratories around the world. Doing this way, the Applied Toxicology can make great advancement and contributes to the society better on a more competitive level based on exact science similar to physical sciences today. A greater opportunity is ahead and effective action needs to be taken collectively and immediately to advance the new knowledge of this research subject.