Lead Contamination of Urban Soils and Vegetation by Emissions from Secondary Lead Industries

The degree and extent of lead contamination of urban soils and vegetation in the vicinity of secondary lead industries are provided. These urban industries, a secondary smelter reprocessing lead from used batteries and scrap metal and a manufacturer of new storage batteries, were located near residential communities. Levels as high as 21,000 ppm of lead in the upper 5 cm of soil (based on air dried weight) and 3500 and 2700 ppm in willow foliage (not washed and washed, respectively, based on dry weight) were found adjacent to the secondary smelter, with the levels decreasing exponentially from the sources. The data on lead contamination of soils and vegetation at various distances and directions from the urban secondary lead industries were compared with levels of lead found in control urban and highway locations. In addition, arsenic levels in soil were examined as a tracer for the source of industrial lead emissions. High levels of lead found In both vegetation and soil in the vicinity of the urban industries reflected both historical and current emissions of lead in those areas. These studies were conducted for industrial abatement purposes; to assist medical related epidemiology studies; to define the areas of severe contamination for soil cleanup purposes; and to formulate guidelines for excessive levels of lead in soil and vegetation. Since lead in soil is persistent, concern arises with respect to pica for small children, contamination of edible vegetables grown in high-lead soil, and reentrainment of leaded particulate matter into the air.     

Factors affecting EDTA extraction of lead from lead-contaminated soils

The effects of solution:soil ratio, major cations present in soils, and the ethylenediaminetetraacetic acid (EDTA):lead stoichiometric ratio on the extraction of lead using EDTA were studied for three different Superfund site soils, one rifle range soil, and one artificially lead-contaminated soil. Extraction of lead from the lead-contaminated soils was not affected by a solution:soil ratio as low as 3:1 but instead was dependent on the quantity of EDTA present. Results of the experiments showed that the extraction efficiencies were different for each soil. If sufficiently large amount of EDTA was applied (EDTA-Pb stoichiometric ratio greater than 10), most of the lead were extracted for all soils tested except for a Superfund site soil from a lead mining area. The differences in extraction efficiencies may be due to the major cations present in soils which may compete with lead for active sites on EDTA. For example, iron ions most probably competed strongly with lead for EDTA ligand sites for pH less than 6. In addition, copper and zinc may potentially compete with lead for EDTA ligand sites. Experimental results showed that addition of EDTA to the soil resulted in a very large increase in metals solubility. The total molar concentrations of major cations extracted were as much as 20 times the added molar concentration of EDTA. For some of the soils tested, lead may have been occluded in the iron oxides present in the soil which may affect lead extraction. While major cations present in the soil may be one of the factors affecting lead extraction efficiency, the type of lead species present also play a role.     

motor vehicle emissions and atmospheric lead concentrations in the los angeles area

This paper is directed to those concerned with the effect of changes in lead consumption by motor vehicles on atmospheric lead concentrations. Atmospheric lead concentrations in the Los Angeles area have been found to be dependent on lead consumption, meteorology, and source-receptor relationships. Mathematical relationships between these variables for selected Los Angeles area sites are derived. Los Angeles County experienced a 50% reduction in annual average atmospheric lead concentrations between 1971 and 1976, which was found to be due to a decrease in vehicular emissions of lead. Seasonal variations in lead concentration were found to be mainly a product of seasonal variations in weather. Projections of atmospheric lead concentrations for the next decade show a continued downtrend, based on regulation of fuel lead content and introduction of additional catalyst equipped vehicles. By the mid-1980's most locations in the Los Angeles area are expected to attain the California and federal ambient air quality standards for lead, 1.5 micrograms per cubic meter, based on a monthly average.     

Alteration in uptake and translocation of essential nutrients in cabbage by excess lead

To observe the tolerance limit of lead phytotoxicity in cabbage (Brassica oleracea L.) var. Golden Aker plants were grown in refined sand with complete nutrient solution for 41 days. On 42nd day, pots with plants were separated into six lots. One lot was allowed to grow as such and was treated as control, in rest of the five lots, lead was applied at 0.1, 0.2, 0.4, 0.5 and 1.0 mM as lead nitrate. At d 75 (34 days after metal exposure), the lead toxicity symptoms as restricted growth was observed on plants at 1.0 mM lead supply. Excess lead (0.5 and 1.0 mM) developed interveinal chlorosis along the margins of young leaves. The affected leaves were reduced in size giving plant a rosette like appearance. Head size was markedly reduced at these (0.5 and 1.0 mM) levels of lead. At 0.5 mM the intensity of symptoms was markedly low. With an increase in lead supply, the concentration of lead and zinc was increased whereas that of P, S, Fe, Mn and Cu were decreased in various parts of cabbage. At 1.0 mM Pb, the concentration of lead was highest in roots and lowest in head. In leaves of cabbage the threshold of toxicity and toxicity values were 150 and 320 microg g-1 dry matter, respectively.     

Environmental lead pollution threatens the children living in the Pearl River Delta region, China

Introduction and purpose

The objective of this study is to determine children??s blood lead levels and identify sources of lead exposure. Childhood lead exposure constitutes a major pediatric health problem today in China. A blood lead screening survey program for children in the age group of 2?C12?years residing in Pearl River Delta region, south of China, was carried out from Dec 2007 to Jan 2008.

Methods

Blood lead levels and lead isotope ratios of a total of 761 participants were assessed by inductively coupled plasma mass spectroscopy. Measurements of urban environmental samples for source identification of children lead exposure were also performed.

Results and conclusions

The geometric mean value of the children??s blood lead levels was 57.05???g/L, and 9.6% of them were higher than 100???g/L. The blood lead levels were still much higher than those in developed countries. Based on the data of environmental lead source inventories, lead isotopic tracing revealed that there is about 6.7% past used gasoline Pb embedded in Shenzhen residential dust and about 15.6% in Guangzhou dust, respectively.     

江苏省典型铅酸蓄电池企业周围环境铅污染水平调查

目的调查江苏省典型铅酸蓄电池企业对周围环境的影响。方法按照国家相关标准和规范对该企业内、外的环境样品进行检测。结果下风向区土壤铅含量中位数均明显高于上风向区域(L相似文献   

Lead contamination of seabirds harvested with lead shot--implications to human diet in Greenland

Lead contamination of seabirds from the use of lead shot in Greenland was studied in thick-billed murre hunted at Nuuk in November 1998. In each bird shot pellets were located and counted using X-ray. The birds were skinned and viscera, head, wings and legs removed, after which the carcass was cooked. The soup and breast meat were then analyzed for lead after removal of visible shot pellets. In the soup the lead concentration was quite low, mean 6.3 micrograms/l (95% confidence interval between 4.4 and 8.2 micrograms/l), whereas breast meat lead values have a mean of 0.22 microgram/g (wet weight basis; 95% confidence interval between 0.10 and 0.36 microgram/g). This is more than 10 times higher than in birds not killed with lead shot. We found no correlation between lead concentration measured and number of pellets recorded in the whole bird or in the soup or in meat. The study indicates that lead in the meat exists as small lead fragments, left during the passage of pellets through the breast. Because of inhomogeneous lead distribution in samples, the uncertainty of estimated lead concentration in breast meat is high. Based on this study, it is concluded that birds killed with lead shot are a significant source of lead, probably the most important single source, of the diet of many people in Greenland. We estimate an intake of 50 micrograms lead from eating one boiled murre with soup. In addition people will occasionally eat whole lead shot pellets which have documented health effects. An intake of 50 micrograms lead is about twice as much as the daily average lead intake from all dietary sources in Denmark, about 25 times the daily lead intake from other marine food items in Greenland, and about one-fourth of the accepted tolerable daily intake.     

Biosorption of lead ion by chemically-modified biomass of marine brown algae Laminaria japonica

In this paper, marine brown algae Laminaria japonica was chemically-modified by crosslinking with epichlorohydrin (EC(1), EC(2)), or oxidizing by potassium permanganate (PC), or only washed by distilled water (DW). They were used for equilibrium sorption uptake studies with lead. As can be seen from the experimental results that biosorption equilibriums were rapidly established in about 2h. The lead adsorption was strictly pH dependent, and maximum removal of lead on biosorbents were observed at pH 5.3. The effects solid/liquid ratio on lead biosorption was also investigated. The maximum lead uptakes were 1.67 mmol g(-1), 1.62 mmol g(-1), 1.54 mmol g(-1) and 1.21 mmol g(-1), respectively for EC(1), EC(2), PC and DW. The order of maximum lead uptakes for different pretreated and raw alga was EC(1)>EC(2)>PC>DW. A comparison of different isotherm models revealed that the combination of Langmuir and Freundlich (L-F) isotherm model fitted the experimental data best.     

Uptake and accumulation of lead by plants from the Bo Ngam lead mine area in Thailand

A field survey of terrestrial plants growing on Bo Ngam lead mine area, Thailand, was conducted to identify species accumulating exceptionally high concentrations of lead. Plant and soil samples were collected from five areas. Lead concentrations in surface soil ranged from 325 to 142,400 mg/kg. The highest lead concentration in soil was found at the ore dressing plant area and lowest at a natural pond area. In different areas, the concentrations of lead in plants were different when comparing various study sites. A total of 48 plant species belonging to 14 families were collected from five sampling sites. Twenty-six plant species had lead concentrations more than 1000 mg/kg in their shoots. Three species (Microstegium ciliatum, Polygala umbonata, Spermacoce mauritiana) showed extremely high lead concentrations in their shoots (12,200-28,370 mg/kg) and roots (14,580-128,830 mg/kg).     

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.     

Temporal trends (1990-2000) in the concentration of cadmium, lead and mercury in mosses across Europe

The European heavy metals in mosses survey provides data on the concentration of 10 heavy metals in naturally growing mosses. The survey has been repeated at five-yearly intervals and in this paper we report on the temporal trends in the concentration of cadmium, lead and mercury between 1990 and 2000. Metal- and country-specific temporal trends were observed. In general, the concentration of lead and cadmium in mosses decreased between 1990 and 2000; the decline was higher for lead than cadmium. For mercury not enough data were available to establish temporal trends between 1990 and 1995, but between 1995 and 2000 the mercury concentration in mosses did not change across Europe. The observed temporal trends for the concentrations in mosses were similar to the trends reported for the modelled total deposition of cadmium, lead and mercury in Europe.     

The relationship between lead and cadmium levels and functional dependence among elderly participants

The adverse impacts of lead and cadmium exposure on health outcomes have been reported in the past. Few studies have been conducted on the relationship between lead and cadmium exposures and disability. We evaluated whether lead and cadmium exposures were associated with functional dependence including the total number of disabilities, activities of daily living (ADL), instrumental activities of daily living (IADL), leisure and social activities (LSA), lower extremity mobility (LEM), and general physical activities (GPA) in an elderly population. A total of 5513 eligible subjects were enrolled in the study from the National Health and Nutrition Examination Survey 2001–2006. Serum lead and cadmium exposure assessments were performed using atomic absorption spectrometry. Functional dependence was assessed by 19 structured questions. The relationships between lead and cadmium exposures and functional dependence were investigated using by multivariable linear regression models. Q2, Q3, and Q4 of lead exposure were significantly associated with the total number of disabilities, with β coefficients of ??0.62 (95% CI ??0.99, ??0.24), ??0.64 (95% CI ??1.02, ??0.26), and ??0.81 (95% CI ??1.19, ??0.42), respectively. This relationship remained significant in males. Furthermore, we analyzed the relationships between lead and cadmium exposure quartiles and various functional dependence metrics, and we determined that lead content was significantly associated with decreased ADL, LEM, and GPA (p?<?0.05) and cadmium content was inversely associated with ADL (p?<?0.05). Our study demonstrated a strong relationship between exposure to lead and cadmium and functional dependence in an elderly population.

     

硫化钠对土壤中铅镉的固定效果简

研究了硫化钠用于固定土壤中铅镉的可行性,考察了硫化钠用量及土壤pH、有机质对固定过程中土壤铅、镉赋存形态及固定效果的影响。结果表明,添加硫化钠可改变土壤中铅镉的形态分布,明显降低可交换态铅镉的含量。条件适当时,铅镉可交换态下降值分别为63%和73%。硫化钠在固定铅的过程中,固定效率对土壤pH、有机质含量的变化较为敏感,在有机质含量较低或酸性土壤中,硫化钠对铅固定效率较高;相对于铅,有机质含量和pH变化对镉的固定效率影响不是很大。     

Lead isotope ratios in the urban air of eastern and central Russia

In order to characterize airborne lead in eastern and central Russian cities in terms of lead isotope ratios, aerosol samples were collected at six selected cities and Moscow, and their lead concentrations and isotope ratios were studied by comparing them to the data of ore lead used in Russia. All eastern Russian cities (Vladivostok, Khabarovsk and Yakutsk) were found to have isotope ratios similar to those of ore leads in Kazakhstan, the major lead producer for Russia. Samples collected in Moscow also showed isotope ratios similar to those of eastern Russian cities. The contribution from coal combustion to airborne lead was considered to be small even in winter, in these cities. This observation suggested that the origin of lead in these Russian atmosphere regions is closely related to the lead products (e.g. leaded gasoline). The lead isotope ratios in three eastern Russian cities were very close to the value for Russian air mass reported previously in Japan, which were also in good agreement with the same observation in Sweden. However, considerably different lead isotope ratios were observed in central Russian cities, Kemerovo and Nizhnevartovsk, indicating that specific lead emissions, such as industrial activities using Precambrian-age ores or unique leaded gasoline, might contribute to the atmospheric lead.     

Airborne lead in the Springfield, Missouri, area during a 19-year period (1975-1993)

Concentrations of airborne lead at Springfield, Missouri, in 1975-1993 have been determined by analysis of particulate material collected on glass-fiber filters during the 19-year period. Nitric acid-soluble lead in 1100 samples collected at a total of 19 monitoring stations was determined by atomic absorption spectroscopy and by differential pulse polarography. Ambient concentrations of airborne lead were found to decrease steadily (by more than 90%) during this period in spite of increases in area population and in automobile traffic. The decrease is significantly correlated with national trends in total emissions of lead to the atmosphere and with US ambient lead levels. Airborne lead from a coal-fired power plant was small compared with that from gasoline burning.     

Organochlorine pesticide residues in catfish,Tachysurus thalassinus (Ruppell, 1835), from the South Patches of the Bay of Bengal

Twenty-one wild brown rats (Rattus norvegicus) were collected from four areas of Milan (Italy). Main organs were harvested from each rat, fixed in 10% neutral buffer formalin, and embedded in paraffin. Organ sections were stained with hematoxylin and eosin, kidney sections were also stained with the Ziehl-Neelsen method. Graphite furnace atomic absorption spectrophotometry was performed on all kidney samples. The presence of inclusion bodies and karyocytomegaly was scored. Six adult rats out of 21 (28.6%) showed kariocytomegaly and intranuclear inclusion bodies of the renal proximal tubules, characteristic of lead toxicity. The nuclear inclusion bodies were always Ziehl-Neelsen positive. The six rats which showed the characteristic histological alterations ascribed to lead, had lead concentrations statistically higher than the three control rats (4 microg/g wet wt. versus 0.09 microg/g wet wt., P<0.001) and than the captured wild rats. Intranuclear inclusion bodies were found in rats with kidney lead concentrations greater than 0.6 microg/g wet weight. There were significant differences between the four areas of capture. The incidence of intranuclear inclusion bodies and karyocytomegaly in proximal tubular cells was higher in rats with high lead levels detected by spectrophotometry. The present results indicate a renal lead concentration of 0.6 microg/g wet weight as a threshold to detect histologic kidney changes due to lead absorption. Results demonstrate that the examination of adult free-living rats may be considered an appropriate method to obtain a rapid, sensitive, easy, cost effective estimate of lead contamination in urban areas. Animal models allow us to evaluate potential human health risk associated with environmental contamination.     

纳米零价铁颗粒去除污染土壤HCl浸提液中的Pb

主要研究了纳米零价铁颗粒对土壤HCl浸提液中重金属Pb的去除效果。通过批实验探讨HCl浓度、纳米零价铁投入量以及处理时间对Pb去除率的影响。实验结果表明,纳米零价铁颗粒对浸提液中Pb的去除反应符合langmuir和freundlich等温吸附方程;反应遵循准一级反应动力学方程,标准化后的反应速率常数KSA=0.018 mL/(m2.min);反应30 min时,0.5 g纳米零价铁对1.0 mol/L的HCl所提取Pb(51.7 mg/L)的去除率达到91.8%。研究结果表明,纳米零价铁对土壤HCl浸提液中Pb具有良好去除效果,但相对于处理水溶液中的Pb,反应速率偏低。     

Study of calcium-dependent lead-tolerance on plants differing in their level of Ca-deficiency tolerance

The main aim of the study was to determine the role of calcium in the amelioration of lead toxic effects in plants with accordingly high/low level of Pb-tolerance and high/low Ca-deficiency tolerance. The study was performed on maize, rye, tomato and mustard. Plants were cultivated in modified Knop's solution. They were subjected to Ca-deficiency, and to lead nitrate administered in the presence of four calcium nitrate concentrations 3.0, 2.4, 1.2, 0.3mM. Lead-tolerance and tolerance to Ca-deficiency were determined, as were concentration of the studied elements in plant tissues, and the Pb deposition pattern at the ultrastructural level (electron microscopy study, X-ray microanalysis). In all studied plants, lead toxicity increased as medium calcium content decreased, however, only in the Ca-deficiency sensitive mustard with low Pb-tolerance was it accompanied by a rise in tissue lead concentration. In contrast, lead root and shoot levels did not increase in the highly Ca-deficiency tolerant tomato, mustard and rye with high Pb-tolerance irrespective of the Ca(2+) regimens applied. Thus, in these plants, lead's unfavourable effects resulted only from the higher toxicity of the same amount of lead in tissues at low calcium in the medium. Of particular relevance is the finding by electron microscopy and X-ray microanalysis, that under low calcium in both highly Ca-deficiency tolerant and Ca-deficiency sensitive plants, less efficient Pb(2+) detoxification was accompanied by the restriction of the formation of large lead deposits in cell walls. Obtained results are novel in demonstrating calcium involvement in the lead deposition in the cell wall, thus in the regulation of the internal lead detoxification.     

Lead biosorption and desorption by intact and pretreated spirulina maxima biomass

In order to search for locally available and untried biomaterials in China with high removal capacity of heavy metals from wastewater, the feasibility of Spirulina maxima as biosorbent for lead removal and recovery from aqueous solution was investigated. The lead biosorption was studied by using intact biomass and pretreated biomass of S. maxima. The effects of operational conditions (e.g. pH, contact time, biomass concentration etc.) on lead biosorption were investigated. The biosorption was solution pH dependent and the maximum adsorption was obtained at a solution pH of about 5.5. The adsorption equilibrium was reached in 60 min. The biosorption followed the Freundlich isotherm model. The maximum removal ratios of lead were about 84% in intact biomass and 92% in pretreated biomass. The lead adsorbed could be desorbed effectively by 0.1 M nitric acid, EDTA and hydrochloric acid. The results in this study indicated that pretreated biomass of S. maxima was a promising candidate for removing lead from wastewater.     

Changes in concentration of lead and cadmium in water from three rivers in Derbyshire

River water from three sites in different streams in Derbyshire was sampled during different periods within 1 year to evaluate fluctuations in cadmium and lead concentration. The results indicate that most of the cadmium was in solution, while most of the lead was associated with particles at all sites. Period of sampling appeared to have a greater effect on the concentration of cadmium and lead than flow rate: metal levels were higher in spring than in autumn. Nevertheless, the total lead concentration increased with flow rate, presumably because more particles were then brought into suspension; however, the lead concentration in the filtrate was reduced at higher flow rates, presumably due to dilution in the greater water volume. Dissolved cadmium concentration increased with rising flow rate at relatively low flow rates and was diluted at high flow rates. The data suggest that particles with which most of the lead is associated remain in suspension for a considerable time even when flow rate decreases.