WHO-IRC和IAEA-AQCS国际比对样品的γ谱分析

报道了本实验室１９９１－１９９４年间参加ＷＨＯ－ＩＲＣ和ＩＡＥＡ－ＡＱＣＳ组织的环境样品放射性测量国际化对工作。用２台ＨＰＧｅγ谱仪,相对方法和效率曲线方法测量了土壤样品,用自吸收校正方法测量了生物样品。对ＷＨＯ－ＩＲＣ Ｎｏ．５７Ｖｉ３００号样品,在２８个报出实验室中,本实验室测量值与推荐值的平均相对偏差最小,为３．０４％。     

湘江流域岳麓山周边地区不同水体中氢氧稳定同位素特征及相互关系

不同水体中稳定同位素的差异性组成对认识区域水文过程,如水体的补给机制、不同水体间的相互作用具有重要意义。论文基于2010—2013年湘江流域岳麓山周边地区降水、地表水、浅层土壤水和地下水中δD和δ¹⁸O的逐日数据及相关气象资料,分析了不同水体中稳定同位素的组成,揭示了不同水稳定同位素间的相互作用关系。结果表明：地表水、浅层土壤水和地下水中δD和δ¹⁸O对日降水中δD和δ¹⁸O的响应存在时滞,地表水和浅层土壤水的滞后时间较短,地下水的滞后时间较长;在天气尺度下,降水中δD和δ¹⁸O存在很好的线性关系,二者的相关系数达0.98;地表水、浅层土壤水和地下水中δD和δ¹⁸O的线性相关系数分别为0.95、0.90和0.90,均超过0.001的信度;在δD-δ¹⁸O关系中,地表水水线（SWL）、浅层土壤水水线（SSWL）和地下水水线（GWL）的斜率及截距都小于长沙大气水线（LMWL）,表明降水是区域地表水、浅层土壤水和地下水的主要补给水源,且在补给过程中,存在一定程度的蒸发,同时与其他水体存在混合交换作用;在季节尺度下,同一水体的水线斜率与截距具有正比关系,即斜率越大,截距越大;但LMWL斜率和截距的关系存在季节和年际的差异;对比同一类水线旱雨季的斜率,仅有LMWL的斜率旱季小于雨季,反映出旱季干燥的大气条件下,降落雨滴云下二次蒸发强烈的特点。     

珠三角城市群典型城市土壤邻苯二甲酸酯污染特征

选择了经济相对发达的珠江三角洲城市群中的典型中小城市的菜园和果园表层土壤(0～20 cm)进行调查取样,采用气相色谱法,对土壤样品中的16种邻苯二甲酸酯(PAEs)进行了测定,分析了其分布特征,并初步探讨了本区域的PAEs的污染控制问题.结果表明:在珠三角城市中,东莞土壤的PAEs含量最高,各地土壤中的PAEs均值高低顺序依次为东莞＞深圳(珠海)＞中山(惠州);菜园土壤中的平均PAEs含量比果园高37%左右;从珠三角城市菜地和果园的平均PAEs分布来看,东莞和深圳的菜地PAEs明显高于果园;珠海、中山和惠州菜地的平均PAEs与果园基本持平.16种PAEs类化合物在珠江三角洲不同城市的分布的差异非常大,不同城市所受到的主要PAEs化合物污染的种类不同;与美国土壤PAEs控制标准相比,珠三角城市果园和菜地土壤的PAEs主要为DEP和DnBP超标,这两类PAEs化合物应该成为重点的污染控制对象.     

Characteristics of plankton Hg bioaccumulations based on a global data set and the implications for aquatic systems with aggravating nutrient imbalance

• Hg bioaccumulation by phytoplankton varies among aquatic ecosystems. • Active Hg uptake may exist for the phytoplankton in aquatic ecosystems. • Impacts of nutrient imbalance on food chain Hg transfer should be addressed. The bioaccumulation of mercury (Hg) in aquatic ecosystem poses a potential health risk to human being and aquatic organism. Bioaccumulations by plankton represent a crucial process of Hg transfer from water to aquatic food chain. However, the current understanding of major factors affecting Hg accumulation by plankton is inadequate. In this study, a data set of 89 aquatic ecosystems worldwide, including inland water, nearshore water and open sea, was established. Key factors influencing plankton Hg bioaccumulation (i.e., plankton species, cell sizes and biomasses) were discussed. The results indicated that total Hg (THg) and methylmercury (MeHg) concentrations in plankton in inland waters were significantly higher than those in nearshore waters and open seas. Bioaccumulation factors for the logarithm of THg and MeHg of phytoplankton were 2.4–6.0 and 2.6–6.7 L/kg, respectively, in all aquatic ecosystems. They could be further biomagnified by a factor of 2.1–15.1 and 5.3–28.2 from phytoplankton to zooplankton. Higher MeHg concentrations were observed with the increases of cell size for both phyto- and zooplankton. A contrasting trend was observed between the plankton biomasses and BAF_MeHg, with a positive relationship for zooplankton and a negative relationship for phytoplankton. Plankton physiologic traits impose constraints on the rates of nutrients and contaminants obtaining process from water. Nowadays, many aquatic ecosystems are facing rapid shifts in nutrient compositions. We suggested that these potential influences on the growth and composition of plankton should be incorporated in future aquatic Hg modeling and ecological risk assessments.     

Understanding the role of nano-TiO2 on the toxicity of Pb on C. dubia through modeling–Is it additive or synergistic?

• A two-compartment model is able to quantify the effect of nano-TiO₂ on Pb toxicity. • Nano-TiO₂ reduces Pb tolerance level and increased the killing rate for C. dubia. • Thus, nano-TiO₂ synergistically enhances Pb toxicity. • Algae reduce Pb transfer rate to the body tissue and the killing rate. Nano-TiO₂ can remarkably increase lead (Pb) toxicity in aquatic organisms. However, the mechanism of this toxicity, additive or synergistic, is not well understood. To explore this mechanism, we inspected the role of nano-TiO₂ in the toxicity of Pb on Ceriodaphnia dubia (C. dubia), a model water flea species typically used for ecotoxicity studies. The effect of algae, a diet for aquatic organisms, on the effect of this binary mixture was also investigated. A two-compartment toxicokinetic (TK)-toxicodynamic (TD) modeling approach was used to quantify the Pb toxicity under these complex conditions and to develop critical parameters for understanding the mechanism of toxicity. This two-compartment modeling approach adequately described the Pb accumulation in the gut and in the rest of the body tissue under different nano-TiO₂ concentrations, with and without algae, and predicted the toxicity response of C. dubia. It indicated that increasing the nano-TiO₂ concentration reduced the Pb tolerance level and concurrently increased the killing rate constant of C. dubia. Therefore, nano-TiO₂ synergistically enhanced Pb toxicity. Algae remarkably reduced the toxicity of this binary mixture through reducing the Pb transfer rate to the body tissue and the killing rate, although it did not affect the Pb tolerance level. This two-compartment modeling approach is useful in understanding the role of nanoparticles when assessing the overall toxicity of nanoparticles and other toxic elements in the environment.     

Occurrence of PAHs, PCBs and organochlorine pesticides in the Tonghui River of Beijing, China

Tonghui River, a typical river in Beijing, People's Republic of China, was studied for its water and sediment quality, by determining the levels of 16 polycyclic aromatic hydrocarbons (PAHs), 12 polychlorinated biphenyls (PCBs) and 18 organochlorine pesticides in water and sediment samples. Total PAHs, PCBs and organochlorine pesticides concentrations in water varied from 192.5 to 2651 ng/l, 31.58-344.9 ng/l and 134.9-3788 ng/l, respectively. The total PAHs, PCBs and organochlorine pesticides concentrations in surficial sediments were 127-928 ng/g, 0.78-8.47 ng/g and 1.79-13.98 ng/g dry weight, respectively. The results showed that the concentration of these selected organic pollutants in sediment was higher than those in surface water. It may be due to the fact that organic hydrophobic pollutants tend to stay in the sediments. The PAHs were dominated by 2-, 3-ring components in water samples and by 3- and 4-ring compounds in sediment. For organochlorines, alpha-HCH, delta-HCH, Heptachlor, Endosulfan II, DDT are the major organochlorine pesticides in water while Heptachlor, Dieldrin and DDE composed of 95% of total organochlorine pesticides in sediment. For HCHs (HCHs=alpha-HCH+beta-HCH+gamma-HCH+delta-HCH), the predominance of alpha-HCH of total HCHs were clearly observed in water and sediment. PCB18, PCB31 and PCB52 were predominant in water, on average these compounds collectively accounted for 67% of total PCBs. But in sediment, the predominant compounds were PCB28, PCB31 and PCB153, which accounted for 71% of total PCBs in sediment. The levels of micro pollutants in our study areas were compared with other studies.     

有机固体废物堆肥化处理的微生物学机理研究

由于符合持续发展的理念 ,利用微生物技术处理有机固体废物越来越受到人们的重视 ,其核心问题则是木质纤维素的生物降解。随着园林废物等高木质纤维素含量的城市生活垃圾的不断增加 ,以及对农业固体废物和食品工业废物再利用的需要 ,这一领域的研究取得了很大的进展。在研究中 ,针对好氧堆肥和厌氧发酵 2项主要的微生物处理技术 ,对其优势微生物菌群、不同降解底物和微生物降解动力学方面的最新研究进展进行了回顾和总结 ,并对环境微生物制剂的应用以及有机固体废物的微生物处理技术的发展做了合理的展望。     

Reactions of compost-derived humic substances with lead, copper, cadmium, and zinc

Thermodynamic stability constants of the formation of complexes from the reactions of humic substances with various metals are usually used as parameters to judge the reactivities of both humic substances and metals. However, in calculating the thermodynamic stability constants, complicated processes for the acquisition of activities of components in reactions are absolutely inevitable. In this study, we investigated the average conditional concentration quotients of the complexes formed from the reaction of metals with humic substances and the relations of these quotients to thermodynamic stability constants. The characterized humic substances including HA (MW>1,000), FA (MW>1,000), and FA (MW<1,000) extracted from a swine compost were prepared to react with Pb, Cu, Cd, and Zn at 25 degrees C and at pH 4.00 and 6.50. Reactions of HA (MW>1,000), FA (MW>1,000), and FA (MW<1,000) with the four metals were carried out at 1:0.1, 1:0.5, 1:1, 1:5, and 1:10 ligand:metal stoichiometry. The concentrations of the free ions of Pb, Cu, Cd, and Zn in the reaction systems of metal-HA suspensions and metal-FA solutions were measured by anodic stripping voltammetry (ASV). The sequence of the average conditional concentration quotients of the formed complexes from the reaction of humic substances with metals was FA(MW<1,000)>FA(MW>1,000)>HA(MW>1,000), showing the relative reactivities of the fractions of swine compost-derived humic substances. The sequence of reacting metals with humic substances was Pb>Cu>Cd>Zn, which is in good agreement with the sequence reported by judging the thermodynamic stability constants. The average conditional concentration quotients of the formed complexes from the reaction of humic substances with metals were thus useful parameters that can be directly related to thermodynamic stability constants and other parameters.     

重金属污染土壤植物修复及进展

土壤污染是当今面临的一个重要环境问题。常规的土壤污染物理化学治理技术 ,如客土换土法、冲洗法、热处理、固化、玻璃化、动电修复法等 ,由于其技术要求高或经济成本高昂 ,对土壤结构的扰动破坏较严重 ,因而 ,大规模推广应用存在较大问题。重金属超累积植物的不断发现 ,使人们认识到有可能利用植物于土壤污染的治理修复。自 2 0世纪 90年代起 ,植物修复成为环境污染治理研究领域的一个前沿性课题。研究表明 ,通过植物的吸收、挥发、根滤、稳定等作用 ,可以净化土壤或水体中金属污染物 ,达到净化环境的目的。近 10年来 ,在超累积植物的找寻培育、植物根际微生物共存体系研究、植物对重金属的耐忍性、超量吸收及其解毒机制以及植物修复的工艺技术方面已有不少研究 ,并取得长足的进展 ,现代分子生物学的发展以及基因工程技术的应用有可能使植物修复技术取得根本性的突破。     

剩余污泥对活性黑KN-B的吸附性能

用剩余污泥对活性黑KN-B进行吸附研究,考察了pH、吸附时间、温度、盐类和污泥量等对活性黑KN-B吸附的影响.结果表明,剩余污泥对活性黑KN-B的吸附是一个快速过程,吸附时间可控制在30 min;其吸附过程可以用准二级动力学模型进行描述和预测;温度对污泥吸附活性黑KN-B产生的影响较小;其吸附等温线,25℃、35℃时与Freundlich方程拟合良好,45℃时则可以由Langmuir方程更好地描述.未调pH的剩余污泥,对pH≤2的废水中活性黑KN-B吸附性能良好;剩余污泥pH为1时,对pH＜12的废水中活性黑KN-B均可有效吸附;氯化钠浓度低于500 mg/L或氯化钠和硫酸钠的混合盐浓度低于100 mg/L时,有利于吸附;氯化钠浓度高于500 mg/L、混合盐浓度高于100 mg/L或单独加入硫酸钠后,随盐浓度的增加,吸附量呈下降趋势.