Polonium (210Po) and lead (210Pb) in marine organisms and their transfer in marine food chains

The determination of ²¹⁰Po and ²¹⁰Pb was performed in marine organisms from the seashore to abyssal depths, encompassing a plethora of species from the microscopic plankton to the sperm whale. Concentrations of those radionuclides ranged from low values of about 5 × 10⁻¹ Bq kg⁻¹ (wet wt.) in jellyfish, to very high values of about of 3 × 10⁴ Bq kg⁻¹ (wet wt.) in the gut walls of sardines, with a common pattern of ²¹⁰Po > ²¹⁰Pb.These radionuclides are primarily absorbed from water and concentrated by phyto- and microzooplankton, and then are transferred to the next trophic level along marine food chains. Investigation in epipelagic, mesopelagic, bathypelagic and abyssobenthic organisms revealed that ²¹⁰Po is transferred in the marine food webs with transfer factors ranging from 0.1 to 0.7, and numerically similar to those of the energy transfer in the marine food chains. As ²¹⁰Po preferentially binds to amino acids and proteins, its transfer in food chains likely traces protein transfer and, thus, ²¹⁰Po transfer factors are similar to ecotrophic coefficients. ²¹⁰Pb is transferred less efficiently in marine food chains and this contributes to increased ²¹⁰Po:²¹⁰Pb activity ratios in some trophic levels.     

Heavy metals and couple fecundity, the LIFE Study

The effect of heavy metals at environmentally relevant concentrations on couple fecundity has received limited study despite ubiquitous exposure. In 2005-2009, couples (n = 501) desiring pregnancy and discontinuing contraception were recruited and asked to complete interviews and to provide blood specimens for the quantification of cadmium (μg L⁻¹), lead (μg dL⁻¹) and mercury (μg L⁻¹) using inductively coupled plasma-mass spectrometry. Couples completed daily journals on lifestyle and intercourse along with menstruation and pregnancy testing for women. Couples were followed for 12 months or until pregnant. Fecundability odds ratios (FORs) and 95% confidence intervals (CIs) were estimated adjusting for age, body mass index, cotinine, and serum lipids in relation to female then male exposures. FORs <1 denote a longer time to pregnancy. In adjusted models, reduced FORs were observed for both female cadmium (0.78; 95% CI 0.63-0.97) and male lead (0.85; 95% CI 0.73-0.98) concentrations. When jointly modeling couples’ exposures, only male lead concentration significantly reduced the FOR (0.82; 95% CI 0.68, 0.97), though the FOR remained <1 for female cadmium (0.80; 95% CI 0.64, 1.00). This prospective couple based cohort with longitudinal capture of time to pregnancy is suggestive of cadmium and lead’s reproductive toxicity at environmentally relevant concentrations.     

不同电极降解2-氯苯酚

采用电沉积法制备了4种钛基二氧化铅电极,并与商业化的钛基RuO2电极进行了对比。分别用XRD和阳极极化曲线对电极性能进行了表征,并以2-氯苯酚为目标污染物,考察了6种电极的电催化氧化性能。研究结果表明,以钛板为基体的系列电极的综合性能优于以钛网为基体的相应电极。以β-PbO2为活性外层的二氧化铅电极的综合性能优于以RuO2为活性外层的电极。6种电极对2-氯苯酚降解反应均遵循一级反应动力学规律。其中Ti/α-PbO2/β-PbO2电极析氧电位最高,电催化性能最好,对2-氯苯酚的去除率可达99.3%。     

Sources of PM10 and PM2.5 in Cairo’s ambient air

A source attribution study was performed to assess the contributions of specific pollutant source types to the observed particulate matter (PM) levels in the greater Cairo Area using the chemical mass balance (CMB) receptor model. Three intensive ambient monitoring studies were carried out during the period of February 21–March 3, 1999, October 27–November 27, 1999, and June 8–June 26, 2002. PM₁₀, PM_2.5, and polycyclic aromatic hydrocarbons (PAHs) were measured on a 24-h basis at six sampling stations during each of the intensive periods. The six intensive measurement sites represented background levels, mobile source impacts, industrial impacts, and residential exposure. Major contributors to PM₁₀ included geological material, mobile source emissions, and open burning. PM_2.5 tended to be dominated by mobile source emissions, open burning, and secondary species. This paper presents the results of the PM₁₀ and PM_2.5, source contribution estimates.     

Assessment of the quality of the air in the city of Palermo through chemical and cell analyses on Pinus needles

The influence of air pollution on the chemical composition of Pinus sp. needles was examined in polluted and control sites in and around the city of Palermo (Sicily). The chemical composition of needles indicated the extent of contamination of the trees, which were cytologically examined. Cell analysis was carried out on pine samples, including needles and pollens, from 15 different locations. Biostructural and spectrophotometric tests were performed. In particular, concentrations of toxic (Cd, Pb) and non-toxic metals (Fe,Cu, Zn) were determined, as well as injury caused by their accumulation in the needles. The more highly urbanised areas showed higher concentrations of metals (Pb, Cu. Zn, Fe); only the concentrations of Cd and Mn turned out to be constant in all the sites. Cell analysis revealed displasic cells and secondary metabolite accumulations in trees from polluted sites. These changes observed were most likely caused by the toxic effect of pollutants.     

Kinetic adsorption of application of carbon nanotubes for Pb(Ⅱ) removal from aqueous solution

The capability of carbon nanotubes (CNTs) to adsorb lead (Pb) in aqueous solution was investigated. Batch mode adsorption experiment was conducted to determine the effects of pH, agitation speed, CNTs dosage and contact time. The removal of Pb(Ⅱ) reached maximum value 85% or 83% at pH 5 or 40 mg/L of CNTs, respectively. Higher correlation coeffcients from Langmuir isotherm model indicates the strong adsorptions of Pb(Ⅱ) on the surface of CNTs (adsorption capacity Xm = 102.04 mg/g). The results indicates tha...     

长江水中泥沙及悬浮粒子对Pb2+的吸附作用研究

对长江水中泥沙与Pb2 的吸附作用进行研究.结果表明,长江水中泥沙与Pb2 进行阳离子交换反应,河水pH值是控制Pb2 与泥沙交换吸附的主要因素,泥沙浓度是控制江水中重金属迁移转化的主要因素;Pb2 初始浓度增大时,吸附作用增强.     

我国大气铅浓度水平与污染源排放特征

总结和评价了我国大气铅浓度水平、大气铅污染源的主要类型和排放特征,对今后我国大气铅污染发展趋势进行了说明.汽油无铅化以后,我国城市大气环境中的铅浓度有所下降,一般不超过国家标准的限值,但农村地区大气铅污染状况应引起高度重视.涉铅工业排放、燃煤排放和汽车尾气是大气铅污染的主要来源.我国大气铅污染源涉及行业和部门庞杂,伴随着铅产品的整个生命周期.     

废旧电路板上残留焊锡剥离液的研制

以硝酸-磺酸型退锡剂为基础配方,研制了一种脱除废旧电路板表面残留焊锡的剥离液.该剥离液以硝酸为氧化剂,氨基磺酸为稳定剂,苯并三氮唑为铜的缓蚀剂.实验结果表明:剥离液的最佳配比为硝酸浓度3 mol/L,氨基磺酸浓度0.4 mol/L,苯并三氮唑浓度0.08 mol/L;每升剥离液可处理3.5 kg废旧电路板,处理后电路板中的铅离子含量降至100 mg/kg以下.该剥离液处理后的电路板表面的铜箔保持完好,基本没有被剥离液浸蚀.     

Lead sorption by a Mexican,clinoptilolite-rich tuff

Goal, Scope and Background The retention of lead by a Mexican, clinoptilolite-rich tuff from Oaxaca (Mexico) at different pH values was evaluated and the lead sorption mechanisms on the zeolitic material in this work were discussed. Methods Isotherms were determined using lead nitrate solutions (initial pH values between 2 and 5) at 303 K. After the equilibrium was reached, the content of lead in the liquid phases was determined by atomic absorption spectrometry. The elemental composition of the clinoptilolite-rich tuff before and after the lead sorption process was evaluated by electron microscopy. Results The maximum ion exchange capacity of the Mexican, clinoptilolite-rich tuff for lead was 1.4 meq/g at pH 3, considering an ion exchange mechanism in the absence of any precipitated or hydrolyzed lead species in the sorption process or any change in the zeolite network. Langmuir and Freundlich isotherms were also considered in this work for comparison purposes. Discussion It is important to consider the nature of the sorption processes before choosing a model to describe the interaction between the metal ions and the sorbent. Conclusions The chemical lead speciation, the pH, as well as the characteristics of the clinoptilolite-rich tuff are important factors to be considered on the lead sorption process by natural zeolites. The chemical species involved in that process are Na⁺ from the zeolite and Pb²⁺ from the aqueous solution at pH 2 and 3, so that the ion exchange mechanism explains the lead sorption processes by the clinoptilolite-rich tuff through the ion exchange isotherms. The sodium, Mexican, clinoptilolite-rich tuff is a potential adsorbent for lead from aqueous solutions. Recommendations and Perspectives The natural zeolite-rich tuffs are very important as ion exchangers for the treatment of polluted water due to their sorption properties and low cost. The sorption behavior of each natural material depends on their composition. Mexican, clinoptilolite-rich tuff from Oaxaca (Mexico) could be used for the treatment of waste water contaminated with lead. It would be important to propose this material as an alternative as waste water treatment, because it shows good selectivity for the removal of heavy metals from water.