Search

Heavy metal contamination, particularly lead (Pb), causes serious global health problems. The industrial use of Pb has resulted in broad environmental contamination and severe toxicity, including neurological illnesses, developmental problems in children, and chronic diseases. Natural processes as well as human activity such as smelting and battery production are major causes of Pb contamination. Children and pregnant women are especially vulnerable to Pb exposure, which has a wide-ranging impact on many organ systems. Recent advances in detection, such as atomic spectrometry and GIS, as well as remediation technologies, such as nanotechnology and artificial intelligence, have enhanced monitoring and mitigation of lead contamination. Biomonitoring employing biological indicators, as well as identifying biomarkers of exposure, effect, and susceptibility, are critical for developing tailored therapies to reduce Pb harm. Furthermore, biomonitoring and environmental monitoring are critical in finding the most effective remediation procedures. While current physical repair procedures are successful, they are frequently expensive and complicated. Microbe-based remediation is a potential, low-maintenance option. This review emphasizes interdisciplinary collaboration to defend against Pb contamination by leading remediation activities with precise biomonitoring and proposing management solutions. It incorporates recent improvements in monitoring and remediation technology, resulting in a strong foundation for efficiently addressing Pb exposure. These activities are intended to reduce dangers, protect human health, and assure environmental safety for future generations. [ABSTRACT FROM AUTHOR]

Introduction: Lead (Pb) pollution in agricultural soil has been accelerated by industrial development and human activities, and poses a major threat to agricultural ecosystems. Both biochar and arbuscular mycorrhiza (AM) fungi are considered to play an important role in remediation of Pb contaminated soil. Methods: The combined remediation effects of introduced AM fungi and biochar on soil properties, Pb availability, microbial community and functional profiles were systematically investigated in unsterilized Pb-polluted agricultural soil. Results: Results indicated that soil nutrients were significantly improved through the combined application of biochar and introduced AM fungi. The introduced AM fungi combined with biochar prepared at 400°C and 500°C promoted the transformation of Pb to a more stable state with low bioavailability. Moreover, the addition of AM fungi and biochar affected the relative abundances of dominant bacteria and fungi at the phylum and genus levels. Biochar mainly affected soil bacterial community and obviously increased the relative abundance of Actinobacteria and Blastococcus. The interactions between biochar and introduced AM fungi mainly affected fungal community, and increased the abundance of Ascomycota and Botryotrichum. Further, PICRUSt analysis indicated biochar amendment supported stronger bacterial metabolic functional potentials. Discussion: Therefore, the combined application of biochar and Therefore, the combined application of biochar and introduced AM fungi could improve soil nutrients, reduce Pb introduced AM fungi could improve soil nutrients, reduce Pb availability, availability, and show and show a positive effect on a positive effect on indigenous microbial communities and indigenous microbial communities and metabolic functions in metabolic functions in farmland soil. [ABSTRACT FROM AUTHOR]

Simple Summary: Lead (Pb) is an environmental pollutant with reported contamination from mammals to fish. In particular, birds are often reported to be poisoned, and populations of some avian species have even reduced. In this study, we examined the causal relationship between the effects on immune function, which is one of the biological effects caused by Pb pollution, and focused on the expression of avian influenza virus (AIV) antibodies. Among black-headed gulls (Chroicocephalus ridibundus) that migrate in winter, two populations were targeted in this study: one was overwintering in Tokyo Bay (Tokyo Bay population; TBP) and the other in Mikawa Bay (Mikawa Bay population; MBP). Pb pollution was evaluated based on blood lead levels (BLL) and antibody positive rate (infection history), and antibody titer was evaluated using serum. The results indicated that the antibody titer was significantly decreased owing to increased BLL in MBP. There were no significant year-to-year differences in BLL or antibody titer. In the wintering period, antibody titer was also significantly decreased owing to increased BLL in TBP. The findings of this study indicated that Pb pollution had a possible negative effect on the antibody production of AIV. Lead (Pb), an environmental pollutant, has been widely reported to have contaminated mammals, including humans and birds. This study focuses on the effects of Pb pollution on avian influenza virus (AIV) antibody production. A total of 170 black-headed gulls (Chroicocephalus ridibundus) were captured in Tokyo Bay (TBP) from January 2019 to April 2020 and in Mikawa Bay (MBP) from November 2019 to April 2021. The gulls were weighed, subjected to blood sampling, and released with a ring band on their tarsus. The samples were used to measure blood Pb levels (BLL) and AIV-specific antibodies. The BLL were compared using the Wilcoxon two-sample test between the period when black-headed gulls arrived and the wintering period, defined by the number of gulls counted in each area. A significant increase was found in the TBP. A decrease in BLL significantly increased antibody titer during wintering in TBP and MBP. Pb pollution had a negative effect on the production of AIV antibodies. These findings suggest that wild birds that were contaminated by Pb in the environment may facilitate the spread of zoonotic diseases, further increasing the possibility that environmental pollutants may threaten human health. [ABSTRACT FROM AUTHOR]

Abstract Assessing metal distributions in cities is an important aspect of urban environmental quality management. Western honeybees (Apis mellifera) and their products are biomonitors that can elucidate small‐scale metal distribution within a city. We compare range and variations in trace element (TE) concentrations and lead (Pb) isotopic compositions of honey, bee tissue, bee pollen, and propolis collected throughout Metro Vancouver (BC, Canada). Honey, bee, and bee pollen results have similar TE and isotopic trends; samples collected in urban and industrialized areas exhibit elevated concentrations of anthropogenically influenced TE (e.g., Pb, Zn, V, and Ti) and a less radiogenic Pb isotopic composition (i.e., lower 206Pb/207Pb and elevated 208Pb/206Pb) relative to their suburban and rural counterparts. For example, 206Pb/207Pb, 208Pb/206Pb in honey range from 1.126, 2.131 and 1.184, 2.063; extremes measured in honey from urban and suburban/rural areas, respectively. Except for propolis, measured and interpolated (kriged) results in all materials reflect the immediate zoning or land use setting near the hive, providing kilometer‐scale geospatial resolution, suitable for monitoring urban systems. Statistical analysis reveals that no systematic variations or intra‐ or inter‐annual trends exist in TE concentrations or Pb isotopic compositions, including among sampling and field methods (i.e., old vs. new hive equipment and honey from the brood nest box vs. honey super). The results of this systematic study using honeybees and hive products in Metro Vancouver provide a robust, current baseline for future comparison of local land use and environmental policy change.

The use of bryophytes as an indicator of environmental quality has been addressed on numerous occasions and in different places of the world under a variety of conditions. However, in Latin America their use is still limited. In the study described here, the presence and distribution of the bioaccumulation of lead in bryophytes has been evaluated in both contaminated and uncontaminated sites in Villavicencio (Colombia) and its surroundings. Villavicencio is a medium-sized city that is similar in size to many other cities in Latin America. A total of 52 samples of bryophytes were collected, of which 43 belong to points distributed in urban areas of the city (residential, commercial, highway), and the remaining nine are from uncontaminated areas (reference) taken in the surroundings of the city. The samples were treated with acid (nitric and hydrochloric) and subsequently measured by atomic absorption spectrometry. It was found that Pb concentrations in the commercial sector are between 1 and 6 times higher than in the residential and highway sectors. Spatial distribution maps of lead over the sampled territory were created using Arc-GIS 10.1. It is noteworthy that the values obtained are higher than those found in European cities. [ABSTRACT FROM AUTHOR]

Assessing metal distributions in cities is an important aspect of urban environmental quality management. Western honeybees (Apis mellifera) and their products are biomonitors that can elucidate small‐scale metal distribution within a city. We compare range and variations in trace element (TE) concentrations and lead (Pb) isotopic compositions of honey, bee tissue, bee pollen, and propolis collected throughout Metro Vancouver (BC, Canada). Honey, bee, and bee pollen results have similar TE and isotopic trends; samples collected in urban and industrialized areas exhibit elevated concentrations of anthropogenically influenced TE (e.g., Pb, Zn, V, and Ti) and a less radiogenic Pb isotopic composition (i.e., lower 206Pb/207Pb and elevated 208Pb/206Pb) relative to their suburban and rural counterparts. For example, 206Pb/207Pb, 208Pb/206Pb in honey range from 1.126, 2.131 and 1.184, 2.063; extremes measured in honey from urban and suburban/rural areas, respectively. Except for propolis, measured and interpolated (kriged) results in all materials reflect the immediate zoning or land use setting near the hive, providing kilometer‐scale geospatial resolution, suitable for monitoring urban systems. Statistical analysis reveals that no systematic variations or intra‐ or inter‐annual trends exist in TE concentrations or Pb isotopic compositions, including among sampling and field methods (i.e., old vs. new hive equipment and honey from the brood nest box vs. honey super). The results of this systematic study using honeybees and hive products in Metro Vancouver provide a robust, current baseline for future comparison of local land use and environmental policy change. Key Points: Honeybees and their products can help monitor metal distributions in urban environmentsPb isotopes and trace element concentrations in hive matrices are geospatially and temporally reproducible over several yearsTypical hive management practices (reusing equipment or splitting hives) do not hinder biomonitoring utility of hive products [ABSTRACT FROM AUTHOR]

Abstract Wide application of TiO 2 nanoparticles (nTiO 2) and ubiquitous lead (Pb) pollution in natural environment enhance the chance of co-exposure of humans to Pb and nTiO 2. We investigated the effects of nTiO 2 on Pb-induced toxicity in human lung epithelial (A549) cells. Results showed that nTiO 2 was not toxic to A549 cells. Conversely, Pb-induced cytotoxicity and oxidative stress in A549 cells were evidenced by cell viability reduction, cell membrane damage, reactive oxygen species generation and depletion of antioxidants. The Pb was also found to alter the regulation of apoptotic genes and cell cycle. Interestingly, in co-exposure group (nTiO 2 + Pb), nTiO 2 effectively attenuated the cytotoxicity, oxidative stress and apoptotic responses of Pb in A549 cells. Cellular uptake experiments demonstrated that nTiO 2 increased the bioaccumulation of Pb in cells. However, due to strong adsorption of Pb on nTiO 2 , free Pb ions were not available even inside the cells. Hence, nTiO 2 significantly prevented the bioavailability and toxicity of Pb in A549 cells. This is the first report providing insight into understanding the mechanism of nTiO 2 mediated prevention against Pb-induced toxicity in human cells. This study warranted further research on co-exposure effects of nTiO 2 and Pb at in vivo mammalian models. Highlights • Combined effects of TiO 2 nanoparticles and Pb in A549 cells were investigated. • TiO 2 nanoparticles were not toxic to A549 cells. • Pb-induced cytotoxicity, oxidative stress and apoptosis in A549 cells • Interestingly, TiO 2 nanoparticles effectively prevented the Pb-induced toxicity. • TiO 2 nanoparticles decreased bioavailability of Pb through adsorption of Pb ions. [ABSTRACT FROM AUTHOR]

Poly-γ-glutamic acid (γ-PGA) can be used as a chemical stabilizer to chelate heavy metals in polluted soils. We investigated the effects of γ-PGA on cucumber seedlings under Cd and Pb stresses. γ-PGA effectively reduced the growth inhibitory effects of Cd and Pb on cucumber seedlings. Cd and Pb absorption in cucumber seedlings was also decreased. Further, γ-PGA decreased the malondialdehyde content, and increased the proline content and the total antioxidant capacity of cucumber seedlings in a dose-dependent manner. Infrared spectral characterization of γ-PGA-Cd and γ-PGA-Pb showed that Cd2+ and Pb2+ bind to free carboxyl groups on γ-PGA. Furthermore, γ-PGA-Cd and γ-PGA-Pb were degraded by 22.02 and 24.68%, respectively, within 28 weeks. The chelating rate of γ-PGA-Pb and γ-PGA-Cd reached 27.26 and 14.28%, respectively. Further, γ-PGA alleviated the negative effects of Cd and Pb on soil microorganisms. Thus, γ-PGA can effectively reduce the accumulation of heavy metals in crops caused by heavy metal pollution of farmland, and has significant application value. [ABSTRACT FROM AUTHOR]

This study assessed the level of Pb in soil and five wild plant species (Calotropis procera, Datura alba, Parthenium hysterophorus, Cenchrus ciliaris and Ricinus communis) during all the four seasons. Two busy roads varying in age and traffic volume were selected i.e., Faisalabad–Sargodha road (FSR) and Pindi Bhattian to Lillah (M-2) in the Punjab, Pakistan. Results showed raised levels of Pb in both plants and soil samples along both roads. The range of Pb concentration in plants was 0.08–3.98 and 1.95–4.74 mg kg− 1 for soil. Higher Pb contamination was recorded along FSR road as compared to M-2. Among seasons, the higher Pb concentration was found during summer, probably due to very high temperature. Among all the plants studied, Calotropis procera accumulated the highest level (3.98 mg kg− 1 dry wt.) of Pb; Thus, it can be used as good biomonitor/phytoremediator at Pb contaminated areas. [ABSTRACT FROM AUTHOR]

Medicinal teas (MT) were popular in Asian countries for its various effective components. However, Pb pollution poses a serious threat to MT consumption due to the irreversible effect on enzyme activity and neurodegenerative disease. Owing to its toxicity and matrix interference, a rapid screening method for Pb at trace level with high sensitivity and accuracy is urgent for MT consumers. Herein, a simple and ultra-sensitive AuNPs/MWCNTs-MB/DNA-GCE quadruplex biosensor was developed and investigated. Specifically, the monitoring technology of scanning electrochemical microscope was utilized to analyze the assembly and application process for screening key parameters in complex matrix, through in-situ characterization of the microstructure changes on stepwise modified sensors. According to the combined results of electrochemical test and Randles-Sevcik equation, the proposed sensor showed a wide linear range from 5.0 * 10−15 to 5.0 * 10−13 M with LOD of 0.9 fM. In addition, the optimized sensor exhibited an excellent selectivity under the inference of metals and medicinal components. The proposed biosensor was successfully implemented for the ultrasensitive monitoring Pb pollution in MT while its water infusions recoveries maintained within acceptable range (81–118 %, 82–129 %). In all, AuNPs/MWCNTs-MB/DNA-GCE provided a new insight into the design, optimization, application and mechanism analysis of sensor for reliable sensing in controlling MT pollution and consumption safety. • An AuNPs/MWCNTs-MB/DNA-GCE was developed with high sensitivity and antijamming capability. • Switching configuration was discussed by in-situ monitoring and theoretical calculations. • The reasons for good performance were analyzed by SECM, SEM, SWSV and XPS. • The detection limit of Pb2+ is as low as 0.90 fM (S/N = 3). • Trace Pb screening is significant for environment safety and human health. [ABSTRACT FROM AUTHOR]

Batch-type experiments were used to study cadmium (Cd) and lead (Pb) sorption/desorption on forest soil, vineyard soil and pyritic material samples, on the by-products mussel shell, oak ash, pine bark and hemp waste, and on forest soil, vineyard soil and pyritic material amended with 48 t ha-1 of oak ash, mussel shell, and hemp waste. The main results were that the forest soil showed higher Cd and Pb retention than the vineyard soil and the pyritic material. Regarding the byproducts, sorption was in the following order: oak ash > mussel shell > hemp waste > pine bark, with desorption following an inverse sequence. The pH was the parameter that most influenced Cd and Pb sorption. Cd and Pb sorption curves showed better fitting to the Freundlich than to the Langmuir model, indicating the dominance of multilayer interactions. Oak ash and mussel shell were the amendments causing higher increase in Cd and Pb sorption on both soils and the pyritic material (close to 100% with the oak ash amendment), as well as more a pronounced decrease in desorption. These results could be used to favor an effective management of the by-products studied, which could retain Cd and Pb in soils and degraded areas, preventing water pollution. [ABSTRACT FROM AUTHOR]

• Magnetic biohybrid is formed via in situ grown AGS with the help of magnetite. • The M-AGS exhibits large surface area and abundant function groups. • The M-AGS favors methane production and is conducive to Pb adsorption. • Pb binding to M-AGS is via complexation, precipitation, and lattice replacement. • The M-AGS promotes Pb stabilization in the contaminated soil. The development of magnetic adsorbents with high capacity to capture heavy metals has been the subject of intense research, but the process usually involves costive synthesis steps. Here, we propose a green approach to obtaining a magnetic biohybrid through in situ grown anaerobic granular sludge (AGS) with the help of magnetite, constituting a promising adsorbent for sequestration and immobilization of Pb in aqueous solutions and soils. The resultant magnetite-embedded AGS (M-AGS) was not only capable of promoting methane production but also conducive to Pb adsorption because of the large surface area and abundant function groups. The uptake of Pb on M-AGS followed the pseudo-second order, having a maximum adsorption capacity of 197.8 mg gDS−1 at pH 5.0, larger than 159.7, 170.3, and 178.1 mg gDS−1 in relation to AGS, F-AGS (ferrihydrite-mediated), and H-AGS (hematite-mediated), respectively. Mechanistic investigations showed that Pb binding to M-AGS proceeds via surface complexation, mineral precipitation, and lattice replacement, which promotes heavy metal capture and stabilization. This was evident from the increased proportion of structural Pb sequestrated from the aqueous solution and the enhanced percentage of the residual fraction of Pb extracted from the contaminated soils. [Display omitted] [ABSTRACT FROM AUTHOR]

Lead (Pb) contamination continues to contribute to world-wide morbidity in all countries, particularly low- and middle-income countries. Despite its continued widespread adverse effects on global populations, particularly children, accurate prediction of elevated household dust Pb and the potential implications of simple, low-cost household interventions at national and global scales have been lacking. A global dataset (∼40 countries, n = 1951) of community sourced household dust samples were used to predict whether indoor dust was elevated in Pb, expanding on recent work in the United States (U.S.). Binned housing age category alone was a significant (p < 0.01) predictor of elevated dust Pb, but only generated effective predictive accuracy for England and Australia (sensitivity of ∼80%), similar to previous results in the U.S. This likely reflects comparable Pb pollution legacies between these three countries, particularly with residential Pb paint. The heterogeneity associated with Pb pollution at a global scale complicates the predictive accuracy of our model, which is lower for countries outside England, the U.S., and Australia. This is likely due to differing environmental Pb regulations, sources, and the paucity of dust samples available outside of these three countries. In England, the U.S., and Australia, simple, low-cost household intervention strategies such as vacuuming and wet mopping could conservatively save 70 billion USD within a four-year period based on our model. Globally, up to 1.68 trillion USD could be saved with improved predictive modeling and primary intervention to reduce harmful exposure to Pb dust sources. [Display omitted] • Household indoor dust can contain elevated Pb concentrations, posing a health risk. • Predictive modeling reveals insights to important explanatory variables of dust Pb concentrations. • Housing age groups are effective at predicting elevated Pb concentrations in the U.S., U.K., and Australia. • Low-cost household intervention, such as vacuuming, can save billions of USD from Pb exposure. [ABSTRACT FROM AUTHOR]

Lead (Pb), as a heavy metal element, has become the most important metal pollutant of the environment. With allocating a relatively higher proportion of its biomass in roots, maize could be a potential important model to study the phytoremediation of Pb-contaminated soil. Here we analyzed the maize root transcriptome of inbred lines 9782 under heavy metal lead (Pb) pollution, which was identified as a non-hyperaccumulator for Pb in roots. In the present study, more than 98 millions reads were mapped to define gene structure and detect polymorphism, thereby to qualify transcript abundance along roots development under Pb treatment. A total of 17,707, 17,440, 16,998 and 16,586 genes were identified in maize roots at four developmental stages (0, 12 h, 24 h and 48 h) respectively and 2,825, 2,626, 2161 and 2260 stage-specifically expressed genes were also identified respectively. In addition, based on our RNA-Seq data, transcriptomic changes during maize root development responsive to Pb were investigated. A total of 384 differentially expressed genes (DEGs) (log2Ratio ≥ 1, FDR ≤ 0.001) were identified, of which, 36 genes with significant alteration in expression were detected in four developmental stages; 12 DEGs were randomly selected and successful validated by qRT-PCR. Additionally, many transcription factor families might act as the important regulators at different developmental stages, such as bZIP, ERF and GARP et al. These results will expand our understanding of the complex molecular and cellular events in maize root development and provide a foundation for future study on root development in maize under heavy metal pollution and other cereal crops. [ABSTRACT FROM AUTHOR]

Lead (Pb) pollution is appearing as an alarming threat nowadays. Excessive Pb concentrations in agricultural soils result in minimizing the soil fertility and health which affects the plant growth and leads to decrease in crop production. Plant growth promoting rhizobacteria (PGPR) are beneficial bacteria which can protect the plants against many abiotic stresses, and enhance the growth. The study aimed to identify important rhizobacterial strains by using the 1-aminocyclopropane-1-carboxylate (ACC) enrichment technique and examine their inoculation effects in the growth promotion of maize, under Pb pollution. A pot experiment was conducted and six rhizobacterial isolates were used. Pb was added to 2 kg soil in each pot (with 4 seeds/pot) using Pb(NO) at the rate of 0, 100, 200, 300, and 400 mg kg Pb with three replications in completely randomized design. Rhizobacterial isolates performed significantly better under all Pb levels, i.e., 100 to 400 Pb mg kg soil, compared to control. Comparing the efficacy of the rhizobacterial isolates under different Pb levels, rhizobacterial isolates having both ACC-deaminase and nitrogen-fixing activities (AN8 and AN12) showed highest increase in terms of the physical, chemical and enzymatic growth parameters of maize, followed by the rhizobacterial isolates having ACC-deaminase activity only (ACC5 and ACC8), and then the nitrogen-fixing rhizobia (Azotobacter and RN5). However, the AN8 isolate showed maximum efficiency, and highest shoot and root length (14.2 and 6.1 cm), seedling fresh and dry weights (1.91 and 0.14 g), chlorophyll a, b, and carotenoids (24.1, 30.2 and 77.7 μg/l), protein (0.82 mg/g), proline (3.42 μmol/g), glutathione S-transferase, peroxidase and catalase (12.3, 4.2 and 7.2 units/mg protein), while the lowest Pb uptake in the shoot and root (0.83 and 0.48 mg/kg) were observed under this rhizobial isolate at the highest Pb level (i.e., 400 Pb mg kg soil). The results revealed that PGPR significantly decreases the deleterious effects of Pb pollution and increases the maize growth under all Pb concentrations, i.e., 100-400 Pb mg kg soil. PGPR chelate the Pb in the soil, and ultimately influence its bioavailability, release and uptake. The PGPR having both ACC-deaminase and nitrogen-fixing abilities are more effective and resistive against Pb pollution than PGPR having either ACC-deaminase or nitrogen-fixing activity alone. The ACC enrichment technique is an efficient approach to select promising PGPR. [ABSTRACT FROM AUTHOR]

Abstract: Dating of sediment cores from the Baltic Sea has proven to be difficult due to uncertainties surrounding the 14C reservoir age and a scarcity of macrofossils suitable for dating. Here we present the results of multiple dating methods carried out on cores in the Gotland Deep area of the Baltic Sea. Particular emphasis is placed on the Littorina stage (8 ka ago to the present) of the Baltic Sea and possible changes in the 14C reservoir age of our dated samples. Three geochronological methods are used. Firstly, palaeomagnetic secular variations (PSV) are reconstructed, whereby ages are transferred to PSV features through comparison with varved lake sediment based PSV records. Secondly, lead (Pb) content and stable isotope analysis are used to identify past peaks in anthropogenic atmospheric Pb pollution. Lastly, 14C determinations were carried out on benthic foraminifera (Elphidium spec.) samples from the brackish Littorina stage of the Baltic Sea. Determinations carried out on smaller samples (as low as 4 μg C) employed an experimental, state-of-the-art method involving the direct measurement of CO2 from samples by a gas ion source without the need for a graphitisation step – the first time this method has been performed on foraminifera in an applied study. The PSV chronology, based on the uppermost Littorina stage sediments, produced ten age constraints between 6.29 and 1.29 cal ka BP, and the Pb depositional analysis produced two age constraints associated with the Medieval pollution peak. Analysis of PSV data shows that adequate directional data can be derived from both the present Littorina saline phase muds and Baltic Ice Lake stage varved glacial sediments. Ferrimagnetic iron sulphides, most likely authigenic greigite (Fe3S4), present in the intermediate Ancylus Lake freshwater stage sediments acquire a gyroremanent magnetisation during static alternating field (AF) demagnetisation, preventing the identification of a primary natural remanent magnetisation for these sediments. An inferred marine reservoir age offset (ΔR) is calculated by comparing the foraminifera 14C determinations to a PSV & Pb age model. This ΔR is found to trend towards younger values upwards in the core, possibly due to a gradual change in hydrographic conditions brought about by a reduction in marine water exchange from the open sea due to continued isostatic rebound. [Copyright &y& Elsevier]

Historical changes of anthropogenic Pb pollution were reconstructed based on Pb concentrations and isotope ratios in lake and peat sediment profiles from Ny-Ålesund of Arctic. The calculated excess Pb isotope ratios showed that Pb pollution largely came from west Europe and Russia. The peat profile clearly reflected the historical changes of atmospheric deposition of anthropogenic Pb into Ny-Ålesund, and the result showed that anthropogenic Pb peaked at 1960s–1970s, and thereafter a significant recovery was observed by a rapid increase of 206Pb/207Pb ratios and a remarkable decrease in anthropogenic Pb contents. In contrast to the peat record, the longer lake record showed relatively high anthropogenic Pb contents and a persistent decrease of 206Pb/207Pb ratios within the uppermost samples, suggesting that climate-sensitive processes such as catchment erosion and meltwater runoff might have influenced the recent change of Pb pollution record in the High Arctic lake sediments. [Copyright &y& Elsevier]

Within a more general study on marine sediments in the Gulf of Palermo (Sicily, Italy), the 210Pbex dating method (using a model with constant sedimentation rate) has been applied to one sediment core. The main goal of the research was to study the Pb pollution chronology. Dating of the core has allowed evaluating the time evolution of the gulf lead concentrations. Specific activities of 137Cs have also been measured in the sediment core sections as an independent confirmation of the chronology derived by the 210Pbex method. The time scale has then been used to correlate lead concentrations in core sections to estimated lead emissions in air due to gasoline combustion. A good correlation between the two data series has been obtained. [ABSTRACT FROM AUTHOR]

Abstract: Lead pollution was investigated in environmental matrices and biological indicators collected from two typical subtropical coastal ecosystems in the southeast Gulf of California, Mexico. Lead concentrations and isotopic compositions (206Pb/207Pb and 208Pb/207Pb) were measured using high resolution inductively-coupled plasma-mass spectrometry (HR-ICP-MS) and thermal ionization mass spectrometry (TIMS), respectively. Lead in surface estuary sediments (10.0–34.2μgg−1) and particulate Pb (25.0–128.7μgg−1, >98% of total Pb) in the water column were significantly higher than levels in natural bedrock soils (15.1±8.3μgg−1) and river runoff (1.9±1.4μgg−1). Aquatic plants had Pb concentrations between 2.5 and 7.2μgg−1, while those in macroalgae ranged from 3 to 5μgg−1. The ranges of mean Pb concentrations in the aquatic animals studied (ranges in μgg−1) were as follows: zooplankton 32±3, mussels 2.3–3.9, oysters 1.9–7.9, snail 2.0–7.7, barnacles 0.1–18.5, fish 1.4–8.9, crab 6.3–40.2 and polychaetae 8.5–16.7. Pb values in 20–40% of oyster and fish samples and in all samples of crab exceeded acceptable levels for a food source for human consumption. Pb isotope ratios 206Pb/207Pb, 208Pb/207Pb in biota ranged from 1.188 to 1.206 and 2.448 to 2.470, respectively. A plot of 206Pb/207Pb versus 208Pb/207Pb for the environmental and biological samples collected from two study areas indicates that they contain lead from ores mined in Mexico and used in the past to produce leaded gasoline in use until 1997, natural Pb weathered from the Sierra Madre Occidental mother rock, and the later influence of inputs from a more radiogenic source related to industrial activity in the United States. Statistical software IsoSource results revealed that the Pb contained in environmental matrices and biomonitors is mostly derived from gasoline (20–90%) and US emissions (10–40%). [Copyright &y& Elsevier]

Heavy metals in soils are of great environmental concern, in order to evaluate heavy metal contents and their relationships in the surface soil of industrial area of Baoji city, and also to investigate their influence on the soils. Soil samples were collected from 50 sites, and the concentration of Pb, Zn, Cu, Cr, Ni heavy metals and the contents of characteristics in soil from industrial area of Baoji city were determined with X-ray fluorescence method. The concentrations of Pb, Zn, Cu, Cr and Ni in the investigated soils reached the amount of 2,682.00–76,979.42, 169.30–8,288.58, 62.24–242.36, 91.96–110.54 and 36.14–179.28 mg kg−1, respectively. The major element Pb contents of the topsoils were determined. to highlight the influence of ‘anthropic’ features on the heavy metal concentrations and their distributions. To compare, all values of elements were much higher than those of unpolluted soils in the middle of Shaanxi province that average 16.0–26.5, 67.1–120.0, 17.8–57.0, 46.9–65.6 and 24.7–34.6 mg kg−1 for Pb, Zn, Cu, Cr and Ni, respectively. An ensemble of basic and relativity analysis was performed to reduce the precipitate of Pb in soil was extremely high and greatly relativity with other elements. Meanwhile, Pb, Zn, Cu, Cr, Ni heavy metals were typical elements of anthropic activities sources, so it was easy to infer to the tracers of anthropic pollutions from the factorial analysis, which was coming from the storage battery manufactory pollutions. The pollutant distributions were constructed for the urban area which identified storage battery manufactory soot precipitate as the main source of diffuse pollution and also showed the contribution of the topsoils of industrial area of Baoji city as the source point of pollution. Consequently, the impact of heavy metals on soil was proposed and discussed. These results highlight the need for instituting a systematic and continuous monitoring of heavy metals and other forms of pollutants in Baoji city to ensure that pollution does not become a serious problem in the future. [ABSTRACT FROM AUTHOR]

Abstract: The content and the isotopic composition of lead (Pb) were studied in a peat deposit on the ridge of the Brdy Hills, in the vicinity of the Příbram metallurgical works, in the Czech Republic. Quadrupole ICP MS was employed to determine the elemental composition and 206Pb/207Pb and 208Pb/206Pb isotope ratios. The individual layers were dated using α spectrometric measurement of the 210Pb activity. The historical time period covered by the studied cores reached back to the 18th century. The Pb concentration in the studied profiles varied from 10 to 550 mg kg−1. The 206Pb/207Pb ratio varied in the range from 1.154 to 1.194 in the individual parts of the profile. The metallurgy of the Pb ores (206Pb/207Pb∼1.16), lithogenic Pb (206Pb/207Pb∼1.2), metallurgical processing of automobile batteries (206Pb/207Pb∼1.17) and the combustion of coal (206Pb/207Pb∼1.17–1.19) yield isotopic signatures that determine the isotope compositions of the individual profiles. Deposition rates between 15 mg m−2 year−1 at the beginning of the 19th century and 320 mg m−2 year−1 in the 1980s were determined in the dated profiles. The increased deposition rates determined on the dated profiles correspond to the increasing production of Pb ores in the Příbram mining area at the turn of the 19th and 20th centuries. The maximum for metallurgical production corresponds to the highest deposition rates recorded in 1960s and 1970s. The current deposition rate of 5–89 mg m−2 year−1 Pb is related to erosion of contaminated soils and waste dumps. [Copyright &y& Elsevier]

Abstract: We determined Pb contents together with Pb isotopic compositions in coral skeletons (Porites spp.) collected from the western Pacific and adjacent seas to examine distribution of Pb in sea surfaces. Temporal records of Pb were also investigated using coral skeletons from Hainan and Ogasawara Island, located in China and Japan, respectively. The spatial distribution of Pb showed a clear dilution pattern of Pb from Asian continent to the open ocean. Also the similar trend was found in the Java Sea from Jakarta to the offshore. In addition to the spatial distribution, Pb contents in Ogasawara coral have gradually increased during last 108years. It may be attributed to Pb emission mainly from industrial activities in Asian countries. Hainan coral, which provided 10years record of Pb, showed a remarkable decline around 1997 probably due to the partial introduction of unleaded gasoline in China. [Copyright &y& Elsevier]

In this study, the relationship between some physico-chemical properties of soils and lead contamination in soil due to emission from industrial operations in Samsun province of Turkey was investigated. The extent of timely contamination was studied by comparing the obtained results with the results of the study conducted in the same region in 1998. An area of 225 km2 (15 km × 15 km), which was divided into 1000 × 1000 m grid squares (16 lines in the east and south directions), was selected within the industrial area. The total of 256 grid points was obtained and soil samples were collected from three depths (0–5, 5–15, and 15–30 cm) of each grid center in 2004. The total Pb concentrations of soil samples were determined as 65.84–527.04 μg g−1 at 0–5 cm in depth, 58.50 – 399.54 μg g−1 at 5–15 cm in depth, and 44.65–330.07 μg g−1 at 15–30 cm in depth. DTPA-extractable Pb concentrations of soils were found to be in the range of 1.52–9.03 μg g−1, 0.54–7.09 μg g−1, 0.19–6.13 μg g−1 at 0–5, 5–15, and 15–30 cm depths, respectively. There were significant relationships between both total or DTPA-extractable Pb concentrations and selected physico-chemical properties of soil. According to enrichment factor (EF) values calculated from the total Pb concentrations, 11.3% of the study area (225 km2) was enriched with Pb in high level, but 77% of the area was in significant enrichment level with Pb. The average total and DTPA-extractable Pb concentrations increased as 11 and 13%, respectively in comparison with the results of 1998. [ABSTRACT FROM AUTHOR]

Southeastern Missouri has been a major Pb mining region since 1720 AD. Missouri mines produce a Pb ore that has a distinctive elevated 206Pb/207Pb isotopic ratio (>1.30) that is easily recognized in Pb-contaminated sediments. Five 210Pb dated sediment cores from Horseshoe Lake, Madison County, Illinois were examined to reconstruct Pb-contamination of the site from southeastern Missouri mines and from a local Pb smelter located adjacent to the lake. Pb concentrations increased in the cores from 5 ppm in the early 1800’s to approximately 350 ppm in the late 1940’s and 1950’s. Pb concentrations in recently deposited sediment range from 100 to 300 ppm depending on the location within the lake. Throughout the 1800’s and early 1900’s the 206Pb/207Pb ratios in the sediment cores increased indicating contamination from southeastern Missouri (mean = 1.243). After the local smelter began recycling lead-acid storage batteries in the 1950’s, the 206Pb/207Pb ratio declined (mean = 1.224) suggesting contamination of Horseshoe Lake with Pb from sources elsewhere around the world. The results of this study demonstrate how isotopic ratios of Pb can be used to reconstruct historical anthropogenic contamination. [ABSTRACT FROM AUTHOR]

With a rapid development of road systems and an associated drastic increase in number of automobiles, the traffic has induced more and more obvious environmental pollution such as noise, dust, emission and heavy metal contamination. Lead, as one of the most harmful heavy metal contaminants, can execute a significant impact on soil quality and plant growth, depending on its form, as well as its transport and accumulation in soil. This paper describes the source and characteristics of Pb contaminant in soil along a road, and reviews the results of research on remediation of Pb-contaminated soils, aiming at identifying promising approaches to soil remediation along roads. [ABSTRACT FROM AUTHOR]

The outer bark being enveloped by and grown into the tree trunk (bark pocket), acts as a passive biomonitor which readily accumulates pollution on its surface. Analysed with stable lead isotopes, these environmental historical archives are very strong candidates for unwinding pollution history. The Røros sulphide ore district, central Norway, has a well-documented mining activity which started in 1647 and the quarrying and smelting in Røros was easily monitored from the middle of the 18th century until the smelting stopped in 1977. Thereafter other sources, like the increase in use of leaded gasoline and further on its outphasing, can be followed.In southern Norway analyses of bark pockets show a good correlation with Pb isotope data from peat cores and tree rings. This region has not been dominated by a single source for many centuries. From the 17th century until about 1925 coal firing and ore smelting in England and on the continent were the dominating sources of pollution in southwestern Norway. From about 1925 and until about 1950 other sources like waste burning contributed, and from about 1950 onwards the pollution has been a mixture of mainly leaded gasoline, coal and coke firing, and incineration of waste.The main objective of this study is to demonstrate the historical changes of environmental pollution in Norway during the last several hundred years up to the present time using tree bark pockets as pollution time capsules. Analyses of stable lead isotopes makes it possible to trace and identify lead from different sources of pollution and atmospherically transported lead deposited in central and southern Norway. Of special interest is the relationship between the industrialization of Europe and the global environmental pollution. Understanding this evolution is of considerable value for evaluating the present day situation. [Copyright &y& Elsevier]

The source and the extent of Pb pollution in the urban environment of Hong Kong were investigated at five different urban settings selected on the basis of their annual average daily traffic (AADT) varying from less than 100 to 61,700. In addition, a small distant island without any traffic was selected to establish the possible baseline values. The surface environmental samples studied consisted of street and tunnel dusts, gully sediments, and a limited number of roadside topsoils. The analytical results clearly indicated variable degrees of Pb contamination in these urban settings. However, the level of contamination varied significantly among different types of samples collected at the same location. Pb concentrations of roadside topsoils (79±22 μg/g) and gully sediments (278±88 μg/g) were lower than those of the corresponding road dusts (327±54 μg/g). The Pb isotope compositions in different urban settings varied considerably. The bedrock in the small island had the lowest Pb concentration (12 μg/g) but with the highest 206Pb/207Pb ratio (1.2206), whereas the tunnel ceiling dusts with the highest level of Pb (1410 μg/g) had the lowest 206Pb/207Pb ratio (1.1062). Despite the significant differences in vehicle types and traffic volumes, and the presence of several different petroleum retailers in Hong Kong, the Pb isotope ratios of road dusts (206Pb/207Pb: 1.1553±0.0043, 208Pb/207Pb: 2.4408±0.0084) varied within a relatively narrow range among all the five urban sampling sites. On the other hand, the Pb isotopic compositions of gully sediments (206Pb/207Pb: 1.1515±0.0145, 208Pb/207Pb: 2.4322±0.0198) varied noticeably within the same setting, but were reasonably comparable across the different study sites. In general, the 206Pb/207Pb ratios of road dusts can be used to estimate the direct contribution from automobile emissions, whereas those of gully sediments might reflect the effects of the mixing of different anthropogenic sources. The Pb isotope signatures in the urban environment of Hong Kong clearly suggested that anthropogenic Pb in the environment originated from Pb ore with a low 206Pb/207Pb ratio (such as the Australian Pb ore and similar sources in Southeast Asia) were significantly different from those of the anthropogenic Pb present in the neighboring Pearl River Delta (PRD) region. [Copyright &y& Elsevier]

The annual growth rings and bark pockets of a 250-year-old Japanese oak (Quercus crispula), collected from the Nikko National Park, Japan in 2000 ad, were analysed by ICP mass spectrometry. The annual rings, sampled in 5-year increments, recorded Pb concentrations from 0.01 to 0.1 mg kg−1 and there was no significant change in concentration with time. In contrast, bark pocket samples dating from 1875 to the present showed a progressive increase in Pb concentration with time, from approximately 0.1 to 10 mg kg−1. Shoots of epiphytic moss growing on the tree trunk contained 17 mg kg−1 Pb. The bark pockets recorded historical increases in airborne Pb pollution accompanying the industrialisation of Japan, which was initiated by the opening of Japan''s borders from 1854. This increase was not reflected by the annual rings. The 206Pb/207Pb isotope ratio of the bark pockets decreased from approximately 1.18 to 1.16 from 1964 to the present, indicating changes in the sources of Pb pollution. The 206Pb/207Pb isotope ratio of the moss shoots was similar to the current bark (1.16). The data showed bark pockets to be more effective than annual rings for recording historical change in airborne lead pollution. [Copyright &y& Elsevier]

Two ombrotrophic peat bogs in Northwestern Spain provided a history of 4600 years of Pb accumulation. Highest Pb concentrations (84–87 μg g−1) were found near the bogs’ surface, but there were also other significant peaks (6–14 μg g−1), indicating pre-industrial atmospheric pollution. The enrichment factors (EFs) in both cores show a remarkably similar record. Atmospheric Pb pollution dates back to at least approximately 2500 years ago, reaching a first maximum during the Roman period. For the last 300 years, Pb EFs significantly increased due to industrial development, but the uppermost samples of the bogs show decreasing Pb EFs, probably due to the phasing out of leaded gasoline. These results are also supported by 206Pb/207Pb isotope ratios, as they continuously decrease from ca. 3000 BP until 2000 BP (from 1.275 at 4070 14C years BP to 1.182), indicating the growing importance of non-radiogenic Pb released from Iberian ores by ancient mining. Peat samples at a 3–5-cm depth are even less radiogenic (206Pb/107Pb=1.157), indicating the strong influence of leaded gasoline. Despite the common history shared by the two bogs, striking differences were found for Pb enrichment, whether this was calculated by normalising to the Pb/Ti ratio of the upper continental crust or to the Pb/Ti ratios of peats from pre-anthropogenic times. This effect seems to be related to differences in Ti accumulation in both bogs, possibly due to physical fractionation of the airborne dust during wind transport. Enrichment has to be carefully considered when comparing the results obtained for different bogs, since our results suggest that normalising to crustal proportions is meaningless when the bulk of the deposition in an area is strongly influenced by short- and medium-range dust transport. [Copyright &y& Elsevier]

In the present study we assessed how modified rhizosphere pH and root exudation (total carbon (C) and soluble proteins released) affected lead (Pb) solubility as well as plant growth and Pb accumulation. A pot experiment with Pb polluted agricultural soils was performed, which involved growing two species, Capsicum annum (pepper) and Tagetes minuta , with the latter being a native herb indicated as potential phytoextractor of Pb, in monocrop and co-cropping conditions. Changes in plant growth, metal uptake as well as rhizosphere soil parameters (pH, EC) and total C and protein exudation were determined. In addition, the metal extraction efficiency of exudates released under mono- and co-cropped conditions were investigated. Results showed that in contrast to the control soil (with low Pb concentration), total C exudation was higher in co-cropping systems in Pb contaminated soils which lead to increases in Pb uptake in both species. Exudates originating from T. minuta were more efficient in solubilizing Pb than exudates from pepper when grown under mono-cropping conditions. Exudates derived from co-cropping both species were either equally or less efficient in mobilizing Pb than exudates from T. minuta. The capacity of exudates to mobilize metals was dependent not only on the species specific quality of root exudates released, but also on its quantity, with the metal extraction efficiency increasing with C concentration in exudates. However, the role of exuded proteins in Pb solubilization was found to be negligible. Biochemical interactions in the rhizosphere under co-cropping conditions favored metal solubilization, and consequently Pb accumulation. The co-cropping conditions could allow accumulation of Pb to levels in pepper that pose risks when the plants are used as a food source. [Display omitted] • Carbon exudation was increased in co-cropping in Pb polluted soils. • Carbon exudation played a major role in Pb, Cu, Zn, and Mn mobilization. • Protein exudation was not related to Pb solubilization in soils. • T. minuta root exudates were more efficient than C. annum to solubilize Pb in monocrop. • Co-cropping affected growth and favored Pb accumulation in highly polluted soils. [ABSTRACT FROM AUTHOR]

• Morphometrics detected an increase in variation of cells exposed to low Pb levels. • The symmetric variation and asymmetry were sensitive indicators of Pb pollution. • Fluctuating asymmetry between cellular lobules increased as a result of Pb pollution. Lead (Pb) contamination of surface waters caused by its gradual release from soils has been reported in acidic wetlands located near industrial regions that experienced significant atmospheric Pb deposition during the 19th and 20th centuries. The green algae belonging to Desmidiales are typically one of the dominant components of the phytobenthos in these habitats, and experimental studies have shown that morphogenesis of desmid cells can be significantly affected by increased Pb concentrations in the environment. This study focused on an analysis of the shape variation in cells of the model desmid species Micrasterias compereana exposed to low chronic levels of Pb contamination. The geometric morphometrics of biradial symmetry and asymmetry of cellular lobes detected a significant increase in the shape variation corresponding to the Pb exposure of populations. However, the sensitivity of this relation was considerably different in the individual subspaces of the symmetric variation and asymmetry. The symmetric variation of the lateral lobes among the cells and the asymmetry between two opposite semicells were the most sensitive components to Pb exposure. Conversely, the left–right asymmetry between two cellular halves across the vertical axis and the transversal asymmetry between the lateral lobes were considerably less sensitive. In addition, the bilateral fluctuating asymmetry in the shapes of two adjacent cellular lobules was also susceptible to increased Pb contamination. Thus, the results showed that quantitative changes in the morphological variation of desmid populations evaluated by the biradial symmetry and asymmetry of cells might be used as sensitive biological indicators for the detection of Pb pollution in dystrophic freshwater habitats, such as peatbogs and acidic fens. [ABSTRACT FROM AUTHOR]