Combined pollution of arsenic and Polymyxin B enhanced arsenic toxicity and enriched ARG abundance in soil and earthworm gut microbiotas

Polymyxin B (PMB) is considered as the last line of antibiotic defense available to humans. The environmental effects of the combined pollution with PMB and heavy metals and their interaction mechanisms are unclear. We explored the effects of the combined pollution with PMB and arsenic (As) on the microbial composition of the soil and in the earthworm gut, as well as the spread and transmission of antibiotic resistance genes (ARGs). The results showed that, compared with As alone, the combined addition of PMB and As could significantly increase the bioaccumulation factor and toxicity of As in earthworm tissues by 12.1% and 16.0%, respectively. PMB treatment could significantly increase the abundance of Actinobacteria in the earthworm gut (from 35.6% to 45.2%), and As stress could significantly increase the abundance of Proteobacteria (from 19.8% to 56.9%). PMB and As stress both could significantly increase the abundance of ARGs and mobile genetic elements (MGEs), which were positively correlated, indicating that ARGs might be horizontally transferred. The inactivation of antibiotics was the main resistance mechanism that microbes use to resist PMB and As stress. Network analysis showed that PMB and As might have antagonistic effects through competition with multi-drug resistant ARGs. The combined pollution by PMB and As significantly promoted the relative abundance of microbes carrying multi-drug resistant ARGs and MGEs, thereby increasing the risk of transmission of ARGs. This research advances the understanding of the interaction mechanism between antibiotics and heavy metals and provides new theoretical guidance for the environmental risk assessment and combined pollution management.     

除尘脱硫系统带水原因及解决对策

对燃煤烟气除尘脱硫系统容易产生引风机带水问题进行了分析和研究，改进了传统的除尘脱硫器水位控制箱和溢水槽，有效解决了常用的冲击水浴式和旋风水膜式除尘脱硫系统风机带水问题。     

Effects of anionic hydrocarbon surfactant on the transport of perfluorooctanoic acid (PFOA) in natural soils

Environmental Science and Pollution Research - The widespread usage of per- and polyfluoroalkyl substances (PFASs) has led to their ubiquitous co-existence with hydrocarbon surfactants in the...     

根分泌物对根际重金属动态的影响

介绍了采用上，下分根试验，使水稻根系下部生长在不同浓度铁营养液中，研究不同供铁处理对不同品种水稻吸收生金属和微量元素及其在体内转移和运输的影响。结果表明缺铁处理时常优８７－８８品种的植株地下部铁含量仅为正常供铁处理的５８％，而Ｃｄ，Ｚｎ的含量却比正常供的植株高１．４倍；缺铁时远诱一号和科长８９－１１３两个品种植株地上部含铁量也比正常供铁时低，但差异不如常优８７－８８明显，Ｃｄ，Ｚｎ含量比正常供铁时     

人工湿地反硝化外加固体碳源选择研究

为了筛选合适的固体碳源,以玉米秸秆、污泥作为研究对象进行碳源释放规律及预处理实验研究,并从碳源释放量,释放速率、释放C/N比等方面探讨其做为碳源的可行性。结果表明,碱加热预处理后的玉米秸秆碳元素平均释放量为10.31 mg/(g·d),较酸加碱加热预处理方式高0.91 mg/(g·d),但二者氮元素平均释放量相同,均为0.20 mg/(g·d)。污泥经预处理后,碳、氮元素平均释放量分别为8.98 mg/(g·d)、0.21 mg/(g·d)。考虑到污泥作为反硝化碳源可以实现污泥的资源化、减量化和无害化。所以污泥和碱加热处理的玉米秸秆均可作为人工湿地外加碳源。     

Monitoring and control methods of harmful algal blooms in Chinese freshwater system: a review

Environmental Science and Pollution Research - Harmful algal blooms (HABs) are a worldwide problem with substantial adverse effects on the aquatic environment as well as human health, which have...     

Trichloroethylene degradation by PVA-coated calcium peroxide nanoparticles in Fe(II)-based catalytic systems: enhanced performance by citric acid and nanoscale iron sulfide

Environmental Science and Pollution Research - In this study, the enhanced trichloroethylene (TCE) degradation performance was investigated by polyvinyl alcohol coated calcium peroxide...     

沈阳市黑臭水体溶解性有机物组分及其光学特征

以沈阳市5条黑臭水体作为研究对象,其中支流I和支流II为重度黑臭,支流III、IV和V为轻度黑臭。运用三维荧光光谱结合平行因子方法对黑臭水体中水溶性有机物(DOM)组分进行了表征,并通过与光谱数据相结合的方法,建立了DOM各组分最大荧光强度(Fmax)与归一化遥感反射率的一元线性回归方程。三维荧光分析结果显示,DOM分为2个类别3种不同组分,分别为类蛋白荧光组分C1(235 nm/360 nm)、类腐殖质荧光组分C2(220 nm/430 nm)和C3(255 nm/520 nm)。水体光谱分析结果表明：在250~800 nm处,有色可溶性有机物吸收系数(ag)、总悬浮物吸收系数(ap)曲线均随着波长的增大逐渐减小,空间变化特征明显;在特征波长440 nm处,轻度黑臭水体的有色可溶性有机物吸收系数总体上大于重度黑臭水体,重度黑臭水体总悬浮物吸收系数总体大于轻度黑臭水体。与正常水体相比,在可见光波段,沈阳市黑臭水体遥感反射率普遍较低,出现3个反射峰和1个反射谷。但支流I与其他黑臭水体不同,表面呈白灰色,导致其遥感反射率(Rrs)呈现与正常水体类似的明显的波峰和波谷,是一类特殊的黑臭水体。线性回归分析表明,由归一化遥感反射率比值R688/R555与DOM组分最大荧光强度所建立的线性模型估算精度最理想。R688/R555与轻度黑臭水体DOM组分Fmax的拟合程度好于重度黑臭水体。进一步研究表明,R688/R555与色氨酸类物质拟合程度较好,与腐殖质类物质没有明显的线性关系。     

次氯酸钠降解水中萘普生的效果

探究了次氯酸钠(NaClO)对萘普生(NPX)的氧化降解效果。分析了次氯酸钠投加量对NPX去除率和体系总有机碳(TOC)的影响,同时分析了此过程中次氯酸钠投加量与次氯酸钠利用效率之间的关系。结果表明,NPX的降解率随着次氯酸钠投加量增加而增加,直至NPX的降解率达100%。溶液中TOC去除率随NaClO与NPX摩尔比的增大先增加后趋于平缓,最后溶液中TOC去除率稳定在22.5%左右。次氯酸钠的利用效率会随NaClO与NPX摩尔比的增大先增后减,在NaClO与NPX摩尔比为7.5:1时,次氯酸钠的利用效率达最大值。同时研究了不同pH对NPX氧化降解反应的影响,实验显示,溶液处于较低的pH更有利于NPX被氧化降解。最后通过对比实验,研究了医用萘普生胶囊中所添加辅料对NPX的氧化反应的影响,结果表明,萘普生医用药品中所添加成分对NPX的氧化降解有一定的抑制作用。     

Occurrence of perfluoroalkyl substances in matched human serum, urine, hair and nail

The purpose of this study was to determine perfluoroalkyl substances(PFASs) in human serum, urine, hair and nail from general populations, and to investigate the possibility for human urine, hair and nail used as the biomonitoring sample for PFASs exposure. We detected the concentrations of PFHx A, PFOA, PFNA, PFDA, PFUn DA, PFDo A, PFHx S and PFOS in 39 matched human serum, urine, hair and nail samples from Shenzhen in China. The detection frequency and the median level of PFOS were all higher than that of the other PFASs in four matrices. The median concentration of PFOS in serum, urine, hair, and nail were 9.24 ng/mL, 13.96 ng/L, 0.58 ng/g and 0.63 ng/g, respectively. The results of spearman correlation test indicated that nail was an ideal matrix for biomonitoring PFOS rather than human urine and hair in general populations for the non-invasive sampling.