Elevated atmospheric deposition and dynamics of mercury in a remote upland forest of southwestern China

Mt. Gongga area in southwest China was impacted by Hg emissions from industrial activities and coal combustion, and annual means of atmospheric TGM and PHg concentrations at a regional background station were 3.98 ng m⁻³ and 30.7 pg m⁻³, respectively. This work presents a mass balance study of Hg in an upland forest in this area. Atmospheric deposition was highly elevated in the study area, with the annual mean THg deposition flux of 92.5 μg m⁻² yr⁻¹. Total deposition was dominated by dry deposition (71.8%), and wet deposition accounted for the remaining 28.2%. Forest was a large pool of atmospheric Hg, and nearly 76% of the atmospheric input was stored in forest soil. Volatilization and stream outflow were identified as the two major pathways for THg losses from the forest, which yielded mean output fluxes of 14.0 and 8.6 μg m⁻² yr⁻¹, respectively.     

不同因素对人工湿地基质脱氮除磷效果的影响

在人工配制的污水中投入一定量的基质,不同条件下振荡培养,评价沸石、炉渣和陶瓷滤料3种基质在不同因素影响下对氨氮(NH4+-N)和总磷(TP)的吸附能力。结果表明,不同吸附时间时,沸石对NH4+-N的吸附效果最好,陶瓷滤料对TP的吸附效果最好;进水浓度对沸石吸附NH4+-N的影响较大,其吸附量随进水浓度的增大而增大,进水浓度对炉渣和陶瓷滤料吸附NH4+-N及炉渣吸附TP影响不大;3种基质对NH4+-N和TP的吸附量均是随吸附剂量的增加而降低,要达到较好的去污效果,应根据实验结果考虑基质投入量;pH值对沸石吸附NH4+-N影响显著,pH值6～7范围内吸附效果最好,pH值8～12的碱性条件有利于基质对TP的吸附。     

粉状活性焦在双层滤料颗粒床中的脱硫试验研究

在双层滤料颗粒床模型试验台上对粒径为300～400目的粉状活性焦进行了脱硫试验,研究了温度、O2和水蒸气体积分数、气体流速、再生次数对脱硫效果的影响.试验结果表明.温度为120℃、O2体积分数为8%、水蒸气体积分数为10%条件下,脱硫效果最好;粉状活性焦在双层滤料颗粒床中经过7次重复吸附.达到硫饱和吸附量为66.2 mg/g.粉状活性焦再生试验表明,随着再生次数的增加.粉状活性焦的脱硫性能呈下降趋势.     

In vitro biotransformation of PBDEs by root crude enzyme extracts: Potential role of nitrate reductase (NaR) and glutathione S-transferase (GST) in their debromination

In order to investigate the enzyme transformation of PBDEs and to track the key enzymes involved in PBDE degradation in plants, in vivo exposure of plants of ryegrass, pumpkin and maize and in vitro exposure of their root crude enzyme extracts to PBDEs were conducted. Degradation of PBDEs in the root crude enzyme solutions fit well with the first order kinetics (R² = 0.52–0.97, P < 0.05), and higher PBDEs degraded faster than the lower ones. PBDEs could be transformed to lower brominated PBDEs and hydroxylated-PBDEs by the root crude enzyme extracts with debromination as the main pathway which contributed over 90% of PBDE depletion. In vitro and in vivo exposure to PBDEs produced similar responses in root enzyme activities of which the nitroreductase (NaR) and glutathione-transferase (GST) activities decreased significantly, while the peroxidase, catalase and cytochrome P-450 activities had no significant changes. Furthermore, higher enzyme concentrations of NaR and GST led to higher PBDE debromination rates, and the time-dependent activities of NaR and GST in the root crude enzyme extracts were similar to the trends of PBDE depletion. All these results suggest that NaR and GST were the key enzymes responsible for PBDE degradation. This conclusion was further confirmed by the in vitro debromination of PBDEs with the commercial pure NaR and GST.     

环境因素对长寿湖底泥释磷影响的模拟实验研究

肥水养殖显著增加了长寿湖底泥中的磷含量。为了解肥水养殖积累在湖泊底泥中磷的释放情况,以长寿湖大坝口枯水期底泥为实验材料,模拟研究了不同环境条件(上覆水pH、温度、DO含量和扰动)下湖泊底泥的释磷特征。结果表明,在弱碱性条件下,底泥释磷量随上覆水pH的升高而升高;温度升高有利于底泥磷的释放,温度每升高5℃,第21天时底泥释磷量增大0.0045～0.0074 mg/L;DO含量降低有利于底泥中铁/铝结合态磷的释放;扰动对底泥磷的释放没有明显影响。研究表明,网箱养殖增加了底泥中的有机磷含量,促进有机磷向无机磷转化,增大了底泥中磷的释放风险。     

太湖水质指标相关性与富营养化特征分析

为研究太湖第一阶段治理水质富营养化的特征，根据1999年10月采样数据，对总磷、总氮等与富营养化相关的水质指标进行了统计分析。发现透明度与叶绿素a之间并未表现出显著的相关性，而在聚类图中，悬浮物与总磷、总氮显示出密切关系。指出农村面源仍是太湖中营养物质的重要来源。     

Bioaccumulation and tissue distribution of organochlorine pesticides (OCPs) in freshwater fishes: a case study performed in Poyang Lake,China’s largest lake

Concentrations and tissue distribution of organochlorine pesticides (OCPs) in different tissues of freshwater fish, silver carp (Hypophthalmichthys molitrix) and bighead carp (Aristichthys nobilis), collected from Poyang Lake, China’s largest shallow lake, and were studied. OCPs were detected with the observed concentrations ranging from 280.67 to 1,006.58 ng/g wet weight (ww) for bighead carp and from 67.28 to 930.06 ng/g ww for silver carp. Composition analysis demonstrated OCPs in both fish were from the same polluted environment, and then, the species-specific bioaccumulation might be mainly due to the different fish age as well as the different feeding habits elucidating from the stable carbon (δ¹³C) and nitrogen (δ¹⁵N) isotope analysis. Tissue distribution indicated that dietary intake was the major exposure route of OCPs for both fish and higher accumulation potency of OCPs by the hepatobiliary-related tissues (such as liver, kidney, bile, and heart). The higher metabolic activities of these tissues elucidating from the higher values of δ¹⁵N might be the potential-determined factor responsible for the tissue-specific accumulation.     

A real-time,dynamic early-warning model based on uncertainty analysis and risk assessment for sudden water pollution accidents

A real-time, dynamic, early-warning model (EP-risk model) is proposed to cope with sudden water quality pollution accidents affecting downstream areas with raw-water intakes (denoted as EPs). The EP-risk model outputs the risk level of water pollution at the EP by calculating the likelihood of pollution and evaluating the impact of pollution. A generalized form of the EP-risk model for river pollution accidents based on Monte Carlo simulation, the analytic hierarchy process (AHP) method, and the risk matrix method is proposed. The likelihood of water pollution at the EP is calculated by the Monte Carlo method, which is used for uncertainty analysis of pollutants’ transport in rivers. The impact of water pollution at the EP is evaluated by expert knowledge and the results of Monte Carlo simulation based on the analytic hierarchy process. The final risk level of water pollution at the EP is determined by the risk matrix method. A case study of the proposed method is illustrated with a phenol spill accident in China.     

矸石基X型分子筛对水中Co2+、Cu2+、Cd2+和Cr3+的去除

以煤矸石为原料,采用碱熔后水热合成法制备X型分子筛并进行XRD、SEM、BET和Zeta电位分析。研究其对水中Co2+、Cu2+、Cd2+和Cr3+4种离子的吸附性能,包括吸附等温线、吸附动力学以及初始金属离子浓度、pH值对吸附性能的影响。所合成的矸石基X型分子筛的BET比表面积为676.02 m2/g,微孔孔容为0.263 cm3/g。吸附实验表明,矸石基X型分子筛能有效去除上述4种离子,同时实现煤矸石的资源化和金属离子的去除。4种离子的平衡吸附量均随初始浓度的增大而增大,相同条件下平衡吸附量的大小顺序为Cd2+>Cr3+>Cu2+>Co2+。准二级动力学模型能很好地描述4种离子的吸附动力行为。Langmuir模型对Co2+、Cu2+和Cd2+吸附的拟合较Freundlich模型高,说明其主要表现为物理吸附过程。4种离子的吸附速率均由液膜扩散和颗粒内扩散共同控制。     

聚糖菌的代谢机制及生物学特性研究进展

强化生物除磷(EBPR)是一种经济、高效、可持续的除磷工艺之一,然而聚糖菌(GAO)的过量生长将导致EBPR系统恶化甚至完全失效.介绍了GAO的厌氧/好氧代谢机制,重点总结了两种GAO(Competibacter和类Defluviicoccus vanus细菌)的生物学特性,分析了碳源、pH、温度等影响GAO生长的关键因素,并对今后的研究进行了展望.