Major Source Of Pb Research Articles

Mixed lead sources in tin metal: Implications for using lead isotopes to study tin artifacts

Methods for provenancing copper, lead, and silver using the isotopic composition of lead are well-established. Lead isotope analysis holds promise for the study of tin metal as well, as long as one accounts for the U-Th-Pb systematics of cassiterite (SnO2) and chaîne opératoire of tin production. Although Precambrian cassiterite may contain 10s of ppm Pb or more (predominantly radiogenic 206Pb), Phanerozoic examples typically contain only a few parts per million Pb. However, all but one of the 133 raw tin ingots excavated from European Bronze Age shipwrecks contains more Pb than could have come from cassiterite alone, as do six of the twelve analyzed tin objects interpreted to have been derived from the ores of southern Africa. Accordingly, almost all tin objects must contain Pb from external cassiterite sources and interpretation of LIA must account for this contamination. The nature of the contaminant (sulfides, U-Th-bearing minerals, silicates) can be inferred from patterns in Pb concentration and LI values. The 3 major sources of Pb that can typically be identified in tin artifacts are original Pb from the tin ore, radiogenic Pb produced in-situ due to U decay, and external Pb added during the cassiterite smelting and ingot production. As cassiterite has high U/Pb but low Th/Pb, the 208Pb/204Pb may be representative of the initial Pb incorporated in the mineral. This is assuming either that no external Pb is added during the ore processing or that the added Pb is from coeval sulfides from the same Pb ore provenance. In such cases 208Pb/204 Pb can be used to estimate a Pb model age, which in turn can be used for provenance estimate of the ingots. If the addition of Pb is from U-Th-mineral contaminants to the ore concentrate, then this will also increase 208Pb/204Pb and point to erroneously young model Pb ages. In such cases, the problem would be evident in positively correlated values of 206Pb/204Pb and 208Pb/204Pb. If Pb concentrations are above a certain threshold (approximately 5 ppm). LIA typical common Pb isotope ratios will be clear indication that external, non-cassiterite Pb, is added to the tin artifact. This tin could be from impurities in the ore (e.g., inclusions in cassiterite, impurities in the ore concentrate, or added during ore smelting and/or metal processing. Overall, elevated Pb concentrations accompanied with non-radiogenic Pb isotopes typical for common Pb, is a clear indication that significant amount of external (contaminant) Pb is added to the tin artifact.

Discrimination of metal contaminant sources in river sediments influenced by mining and smelting activities using stable Pb and Zn isotopes.

To determine the sources and pathways of lead (Pb) and zinc (Zn) in river sediments contaminated with metals from mining and smelting activities, metal concentrations and Pb and Zn isotope ratios were measured in river water and sediment, and potential metal contaminant samples (imported Zn concentrates, smelting wastes, soils around the smelter, mine ores, and riverside tailings). Zn and cadmium (Cd) concentrations in river water and sediment samples were 30- and 11-25-fold higher, respectively, near the smelter than upstream, while a 6-fold increase in sediment Pb concentrations was detected over the same region. Sediment samples near the smelter (207Pb/206Pb = 0.8638 and 208Pb/206Pb = 2.0960) were observed to have a different Pb isotopic composition from upstream of the smelter (207Pb/206Pb = 0.8322 and 208Pb/206Pb = 2.0502), with δ66Zn values increasing from -0.01 to 0.82‰. Analysis of Pb and Zn isotopes and concentrations revealed that dust-contaminated soils were a major Pb source, and baseline sediments were found to be contaminated by regional mining tailings. For Zn in sediments, the main Zn sources were groundwater-derived Zn (δ66Zn = 1.02 ± 0.43‰, n = 4), dust-contaminated soils (δ66Zn = -0.18 ± 0.08‰, n = 3), and tailings-contaminated sediments (δ66Zn = 0.01 ± 0.07‰, n = 10). Endmember mixing model results showed that dust-contaminated soils contributed 78% and 64% of sediment Pb and Zn, respectively, within 2km of the Zn smelter, decreasing to negligible levels after 47.1km downstream. Downstream of the smelter, groundwater-derived Zn contributed 54% of sediment Zn, whereas tailings contaminated sediments contributed 70% and 25% of Pb and Zn, respectively.

Exchange of Pb from Indian to Atlantic Ocean is driven by Agulhas current and atmospheric Pb input from South Africa

Using a spatiotemporal dataset of dissolved lead (dPb) from the subtropical oceans surrounding South Africa, this study quantifies the exchange of dPb between the Indian and Atlantic Oceans. Despite the absence of a major Pb source within the South Atlantic sector and the complete phase-out of leaded petroleum in Southern Africa, the ecologically important southeast Cape Basin shows an elevated surface dPb concentration (21–30 pmol kg−1). We estimated up to 90% of the measured dPb in surface waters of the Cape Basin was delivered from the Indian Ocean via the Agulhas Current (AC). Eddy dynamics and leakage at Agulhas retroflection result in an increased Pb flux from winter to summer, while a long-term (2008–2019) temporal change in dPb in the AC-derived water of Cape Basin was contemporaneous to a change in atmospheric Pb emissions from South Africa. The South African-origin atmospheric Pb, however, contributes first to the Agulhas waters in the West Indian Ocean, which is then transported to the South Atlantic, thereby regulating the dPb inventory of the Cape Basin. This indirect mechanism of Pb transfer emphasizes the importance of regulating Pb emissions from Southern Africa to protect rich fishing grounds associated with the Benguela marine ecosystem.

Boundary exchange completes the marine Pb cycle jigsaw

Material fluxes at the land-ocean interface impact seawater composition and global cycling of elements. However, most attention has been focused on the fluvial dissolved fluxes. For elements like lead (Pb), whose fluvial particulate flux into the ocean is two orders of magnitude higher than the dissolved counterpart, the role of particulates in elemental cycling is potentially important but currently less appreciated. Using both chemical analyses on samples collected from around equatorial Southeast Asia and model simulations, we show that particulate-dissolved exchange is an important mechanism controlling the concentration and isotopic composition of dissolved Pb in the ocean. Our model indicates that Pb contributed from particulate-dissolved exchange at ocean boundaries is larger than, or at least comparable to, other major Pb sources to the seawater before the Anthropocene, when the anthropogenic Pb was absent. Our work highlights the importance of boundary exchange in understanding marine element cycling and weathering-climate feedback.

Identifying the origin of lead poisoning in white-backed vulture (Gyps africanus) chicks at an important South African breeding colony: a stable lead isotope approach.

Elevated lead levels in scavenging raptors can originate from a variety of environmental and anthropogenic sources, including soil, water, mining activities and legacy lead from leaded fuel, but has mostly been attributed to fragments of lead-based ammunition embedded in the tissues of carcasses. To identify the origins of lead in the tissues of white-backed vulture (Gyps africanus) chicks at Dronfield Nature Reserve, South Africa, we used MC-ICP-MS to compare the isotopic composition of lead in blood samples to those of soil in the chicks' immediate environment, different mining activities in South Africa and lead ammunition commonly used in hunting and game management practices. The isotopic ratios in vulture blood samples ranged widely (207Pb/206Pb: 0.827-0.911), but fell within those measured for ammunition (0.761-0.938). Dronfield water can be excluded as a significant source, as the lead concentration for water was below detection limits. Uranium, coal, atmospheric Pb, legacy Pb from fuel and Pb mining can also be excluded as significant sources, based on the limited overlap with Pb isotopic ratios measured in vulture blood. Whereas 55% of chicks we sampled displayed isotopic ratios consistent with Dronfield soil, the low local Pb concentration and the low extractable Pb levels in South African soil in general, imply that soil Pb is unlikely the major source of Pb in WBV chicks, especially in birds with elevated blood Pb levels, i.e. > 20µg/dL. Our results, when considered in the context of vulture feeding ecology and low Pb levels in non-scavenging birds in South Africa, imply the major source of elevated Pb levels in WBV chicks to be fragments of lead-based ammunition embedded in the carrion fed to them by their parents.

Potentially toxic elements contents and the associated potential ecological risk in the bottom sedimentsof Hrazdanriver under the impact of Yerevan city(Armenia).

This research aims to assess the ecological status of the Hrazdan river (Armenia) section that flows through Yerevan. The distribution of potentially toxic elements (PTE) (Cr, V, As, Zn, Cu, Ni, Co, Mn, Pb, Ti, Mo, Fe, and Ba), the bottom sediments pollution level, and the ecological risk were assessed employing the single pollution index (SPI), the enrichment factor (EF), the geo-accumulation index (Igeo), and the potential ecological risk index (RI). On sampling sites, water quality parameters (turbidity, DO, electrical conductivity (EC), salinity, TDS, pH, temperature°C) were measured as well. The correlation analysis revealed a significant correlation between Zn-Cu, Pb; Cu-Pb, Mo; Co-Fe, Ti pointing out similar sources and origination of these elements. The results indicated that the content of the studied elements in the Hrazdan bottom sediments exceeded the background content in urban soils, which was due to a set of geological and anthropogenic factors. High contents of elements were determined on the sampling sites spatially confined to the residential and industrial areas. According to EF and Igeo data, the priority bottom sediment contaminants are As, Pb, Mo, Zn, V, and Cu. The RI value varies from 196 to 316 with the mean of 246 which corresponds to the moderate-level ecological risk. On the whole, a moderate (77.8%) and a considerable (22.2%) ecological risk was revealed. The major source of Pb, Cu, Zn, and Mo contents was identified as the surface runoffs in the urban environment. This was verified by the cluster analysis results.

Levels, Inventory, and Risk Assessment of Heavy Metals in Wetland Ecosystem, Northeast China: Implications for Snow Cover Monitoring

Snow cover is a unique environmental medium in cold regions that can cause potential risks to the ecological environment, due to the release of pollutants that are stored in it. In this study, the Qixing River wetland, located in the Sanjiang Plain of China, was taken as the target research area. Heavy metals in snow cover, including Cu, Ni, Cr, Cd, Pb, and Zn were measured at 19 sampling sites. The results showed that the average concentrations of heavy metals were: Zn (103.46 ± 39.16) > Pb (13.08 ± 4.99) > Cr (11.97 ± 2.82) > Ni (9.55 ± 4.96) > Cu (6.19 ± 1.79) > Cd (0.55 ± 0.25) μg·L−1. Cr and Zn were between Class I and Class II in the “Environmental Quality Standards for Surface Water” of China (GB3838-2002). Pb in snow exceeded the upper limit of Class II, and was significantly higher than concentrations measured in water samples from the Qixing River wetland (p < 0.05), indicating that atmospheric deposition during winter was the major source of Pb. The water pollution index (WPI) indicated that 61.0% of samples could be considered of “clean” status, while the contribution of Zn, Pb, and Cr to WPI were 33.3%, 21.0%, and 19.3%, respectively. A preliminary evaluation of heavy metal inventory in snow cover showed that the residue level of Zn was the highest (2313.57 ± 1194.67 μg·m−2), while Cd was the lowest (13.91 ± 10.45 μg·m−2). The areas with high residues of heavy metals were all located near the buffer zone of the wetland (except for Zn), where snow depth tended to be greatest. Exposure analysis indicated that the risks to winter resident birds from snow ingestion was minimal, but it should be noted that the exposure risk was higher in birds with lower bodyweights. This study provides important information and scientific knowledge on the pollution characteristics and residue inventory of heavy metals in wetland ecosystems, while the results can also provide a monitoring method, reflecting atmospheric environmental quality at a local or regional scale.

Gut Escherichia coli expressing Pb2+-adsorption protein reduces lead accumulation in grass carp, Ctenopharyngodon idellus.

Lead (Pb2+) is easy to accumulate in fish which become a major source of Pb2+ exposure to humans. In this study, a recombinant Escherichia coli strain expressing Pb2+-specific surface-binding protein anchored by the ice nucleation protein was introduced into grass carp (Ctenopharyngodon idellus) gut to investigate its protective effect against dietary Pb2+ exposure. Pb2+ mostly precipitated on the surface of the engineered strain through Pb2+-specific surface-binding protein, with a maximum adsorption efficiency of 73% and an adsorption capacity of 163μmol/g dry cells. The Pb2+ concentration in engineered bacteria-fed grass carp was reduced significantly, and the residual level of Pb2+ in feces was increased by 76%, compared with the control group. Meantime, the engineered bacteria were able to mitigate the oxidative stress and histological alterations of intestines and dysbiosis of gut microbiota induced by Pb2+exposure. Thus, the engineered bacterium that can effectively reduce Pb2+ residue in grass carp might be a useful tool for decontamintion of lead in aquatic organisms.

Chronic Exposure to Lead and Cadmium in Residents Living Near a Zinc Smelter.

This study aimed to measure lead (Pb) and cadmium (Cd) exposure levels in residents living near a zinc (Zn) smelter in Seokpo-myeon, Bonghwa-gun, South Korea, and identify factors affecting exposure. Residents aged ≥20 years living within 3 km and ≥30 km away from the smelter were classified as the exposure group (n = 549), and the control group (n = 265), respectively. Data were obtained through a questionnaire survey. Blood Pb levels in the exposure group (4.19 µg/dL) were higher than in the control group (2.70 µg/dL). The exposure group (1.32 µg/L) also had higher urinary Cd concentrations than the control group (0.80 µg/L). Male sex, older age, previous work at the smelter, smoking, and proximity to the smelter were associated with higher blood Pb levels on multivariate analysis; urinary Cd concentration was significantly higher in women, those who were older, those with experience of working in a Zn smelter or mine, those with proximity to the Zn smelter, and those who consumed locally grown vegetables. In conclusion, Zn smelters are major source of Pb and Cd pollution and require ongoing public health management to prevent potential adverse health effects.

Contribution of PM2.5-Pb in atmospheric fallout to Pb accumulation in Chinese cabbage leaves via stomata

Foliar uptake of Pb is especially important when Chinese cabbage (Brassica rapa spp. pekinensis), having a large leaf surface area, is cultivated in North China during seasons with heavy haze. However, the mechanisms of foliar Pb uptake via stomata by Chinese cabbage exposed to atmospheric fallout are unclear. A field experiment was conducted to explore the impacts of Pb in particulate matter with sizes ≤ 2.5 µm (PM2.5-Pb) from atmospheric fallout to Pb accumulation in cabbage leaves through stomata. Cabbage varieties with low-Pb-accumulation (LPA) and high-Pb-accumulation (HPA) were examined using inductively coupled plasma-mass spectrometry and scanning electron microscopy/energy-dispersive X-ray analysis. The 206Pb/207Pb and 208Pb/207Pb ratios of PM2.5, plants, and soil demonstrated that the major source of Pb in cabbage leaves was PM2.5. The average width and length of the stomatal apertures were 7.14 and 15.61 µm for LPA cabbage and 8.10 and 16.64 µm for HPA cabbage, which are large enough for PM2.5-Pb to enter the leaves. The HPA cabbage had significantly higher stomatal width-to-length ratios than the LPA cabbage, indicating that the former trapped much more PM2.5-Pb and accumulated more Pb. These results clarify the contributions of the stomatal characteristics to PM2.5-Pb accumulation in the edible parts of Chinese cabbage.

Tyre Weights an Overlooked Diffuse Source of Lead and Antimony to Road Runoff

Lead (Pb) remains elevated in road runoff and roadside dust, which has been attributed to legacy lead in surface soils from leaded petrol. However, “lead” tyre weights, an alloy of 95% Pb and 5% Sb, may be a relatively unrecognised diffuse source of Pb and Sb as they are still used in many countries. An unknown number of these weights drop off tyre rims and deposit on the road where they are abraded and dispersed, potentially causing adverse environmental effects. The type, number and weight of tyre weights lost from motor vehicles were characterised for a range of roading infrastructures and motor vehicle intensities in a 38 month long study of a 6.9 km length of road in Hamilton City, New Zealand. Overall, 1070 tyre weights with a combined mass of 18.6 kg were collected. About 96.4% of the collected weights were made of “lead”, which is an alloy of 95% Pb and 5% Sb, indicating tyre weights can be a major source of Pb and Sb in urban areas. The tyre weight distribution on roads used in this study depended mainly on traffic density and the prevalence of “start stop” patterns in traffic flow influenced by roundabouts and intersections. “Lead” tyre weights should be phased out and replaced with environmentally benign materials.

Assessing lead sources in fishes of the northeast Pacific Ocean

Abstract Industrial lead (Pb) emissions have changed oceanic Pb concentrations and isotopic compositions significantly over the last century. Asian industrial emissions are currently the dominant Pb sources in the northwest and central Pacific Ocean. This study investigated major Pb sources in the northeast Pacific Ocean (inland, coastal, and open ocean), where no comprehensive data exist currently. We measured Pb concentrations and isotopic compositions of a variety of shellfish and fish collected in British Columbia (BC) and used them for Pb source apportionment applications in the marine environment. We identified a clear trend in Pb isotopic compositions, from higher 206Pb/207Pb in inland fish to lower 206Pb/207Pb in open ocean fish, with coastal fish possessing mid-range values. These results indicate that natural sources of Pb dominate freshwater ecosystems in the central BC coast, whereas anthropogenic Pb sources prevail in western North America and the northeast Pacific. Pacific herring that forage along BC coast exhibit Pb isotopic composition that deviates toward the Chinese Pb regression line. We estimate an Asian origin for about one third of their total Pb. This study shows that Pb isotopes in aquatic organisms are valuable tools for assessing Pb sources across coastal and offshore regions of the northeast Pacific, with great potential for identifying primary foraging areas of marine organisms.

Source apportionment of heavy metal and their health risks in soil-dustfall-plant system nearby a typical non-ferrous metal mining area of Tongling, Eastern China

The agricultural land-atmospheric dustfall-plant system around the mining area is at high risks of heavy metal pollution caused by mining-smelting activities. In this study, 118 samples (including rhizospheric soils, background soils, soil-forming parent rocks, crops, vegetables, medicinal plants and atmospheric dustfall) were collected nearby Tongling Cu-Fe-Au mining area, Eastern China. We studied the concentrations, migration, sources, and health risks through consumption of two main crops (corn and rice), six kinds of vegetables, and medicinal plants (Fengdan, Paeonia ostii) for six metal elements (Cu, Zn, Cr, Cd, Pb and Hg). Results revealed Cr and Cd in soils, and Cd, Cr, Pb, Cu and Zn in dustfall showed a relatively high contamination degree. The mean contents of Cr and Pb in corn kernels, as well as Cd, Cr and Pb in rice grains and all vegetables, and Cr in Fengdan cortex moutan exceeded the corresponding food safety limits in China. The transfer capability of Cr in corn kernels and rice grains, Pb in edible vegetables, and Cd in cortex moutan were the strongest, respectively. Health risk assessment results showed Cr had the greatest non-carcinogenic risk, followed by Pb and Cd. The results of pearson's correlation analysis (CA), hierarchical cluster analysis (HCA), and principal component analysis (PCA) indicated Zn-Cr, Pb and Cd-Cu-Hg in the plants might derive from different geochemical end-members. Source apportionment based on lead isotope showed that mining-smelting activities were the major source of Pb in atmospheric dustfall and agricultural soils, with the average contribution rates of 66% and 50%, respectively. Vehicle emissions from diesel fuels (50%–68%) and mining-smelting activities (16%–25%) contributed mainly to Pb accumulation in plants. Hence, our study suggested the accumulations of Pb in plants might be mainly from the direct foliar uptake of atmospheric Pb related to vehicle emissions and mining-smelting activities.

Evaluation of atmospheric dry deposition as a source of nutrients and trace metals to Lake Tahoe

Atmospheric deposition can be an important source of nutrients and trace metals to oligotrophic alpine lakes, affecting their biogeochemistry. We measured trace metal concentrations and lead (Pb) isotope ratios in lake water, river water, ground water, and aerosol total suspended particles (TSP), as well as nutrient (NO3−, NH4+, PO43−) concentrations in TSP in the Tahoe Basin. The contribution of TSP deposition to the lake trace metal budget was assessed. Our results show seasonality in TSP and associated trace metal concentrations with higher concentrations during Oct – April. However, trace metal solubilities are higher during May – Sept, resulting in a higher contribution of soluble trace metals to the lake water. The source of most of the trace metals in TSP in the Lake Tahoe Basin is mineral dust; however, Zn, Cu, and Cd also have an anthropogenic origin. Among major nutrients, NO3− concentrations are slightly higher during Oct – April, while NH4+ and soluble reactive phosphorus (SRP) are higher during May – Sept. The distributions of trace metal concentrations and Pb isotopic ratios are homogenous throughout the lake water column, suggesting that the residence time of the trace metals in the lake is longer than the lake water mixing time. The contribution of atmospheric TSP deposition to the upper 20 m of lake water trace metal inventory is low, ranging from 0.03% for V to 5.7% for Mn. A triple-isotopes plot of Pb indicates that riverine and groundwater inputs are the major Pb sources, but aerosols still contribute some Pb to the lake.This article is part of a special issue entitled: “Cycles of trace elements and isotopes in the ocean – GEOTRACES and beyond” - edited by Tim M. Conway, Tristan Horner, Yves Plancherel, and Aridane G. González.

Horizontal migration process of Pb in bottom waters in Jiaozhou Bay 1989

This paper quantified the horizontal migration processes of Plumbum (Pb) in Jiaozhou Bay in 1989. Results showed that Pb contents in bottom waters in April and July 1989 were 8.15-10.10 μg L-1 and 3.39-7.15 μg L-1, respectively. The pollution level of Pb in bottom waters in April and July 1989 could be considered as heavy and moderate, respectively. In April 1989, Pb contents in bottom waters from the bay center to the bay mouth were decreasing from 10.10 μg L-1 to 8.15 μg L-1, indicating that the sedimentation rate was high in the bay center, yet was low in the bay mouth. In July 1989, Pb contents in bottom waters from the bay center to the bay mouth were decreasing from 7.15 μg L-1 to 3.39 μg L-1, also indicating that the sedimentation rate was high in the bay center, yet was low in the bay mouth. By means of source input and the vertical water’s effect, the sedimentation rate in the bay center was high via the rapid vertical sedimentation process. The major source of Pb were river runoff and atmosphere deposition, the sedimentation rate in the bay mouth was low due to the water exchange. By means of the vertical water’s effect and the water exchange process, Pb contents in marine bay were changing continuously.

Influence of vertical migration process on seasonal variation and horizontal distribution of Pb in marine bay

This paper analyzed the seasonal variation, vertical variation and horizontal distribution of Pb in Jiaozhou Bay using investigation data in April and July 1989. Results showed that Pb contents in surface and bottom waters April 1989 were 9.96-11.03 μg L-1 and 8.15-10.10 μg L-1, respectively, while in July 1989 were 6.47-15.17 μg L-1 and 3.39-7.15 μg L-1, respectively. The pollution level of Pb in bottom waters in April and July 1989 could be considered as heavy and moderate, respectively. The seasonal variations of Hg in both surface and bottom waters were summer > spring. Hence, the seasonal variations of Hg in surface and bottom waters were same. The vertical migration processes of Pb in waters in April and July 1989 revealed the accumulation effect and dilution effect. The seasonal variations of Pb contents in surface waters were determined by the changes of the major Pb sources, while in bottom waters were determined by both the source input and vertical water’s effect. The horizontal distributions of Pb in surface and bottom waters in April 1989 were opposite, yet the horizontal distributions of Pb in surface and bottom waters in July 1989 were consistent. The horizontal distributions of Pb contents in surface waters were determined by the changes of the major Pb sources, while in bottom waters were determined by both source input and the inputting time.

Distributions and pools of lead (Pb) in a terrestrial forest ecosystem with highly elevated atmospheric Pb deposition and ecological risks to insects

There is growing interest in how heavy metals in remote ecosystems are elevated and affect environmental health. However, no studies have investigated atmospheric lead (Pb) deposition influences on the Pb bioaccumulation in insects in forests. Here we measure Pb concentrations and pools in forest vegetation, litterfall, organic soil, mineral soil, as well as litterfall deposition fluxes in a region severely affected by atmospheric deposition. We also analyzed Pb in insects which feed in the polluted forest vegetation and litter. Assessment of high Pb loads causing potential ecological risk to insects was also studied. Total Pb pool in the vegetation was 0.12 g m−2 and annual litterfall deposition flux of Pb was 13.42 mg m−2, which was much higher than those in the background areas. Pools of Pb from litter to mineral topsoil averaged 4.3 g m−2, which accounted for 97.3% of total pools (biomass + soil) in the forest ecosystem. Pools of Pb in surface soils were correlated significantly with the pools of total organic matter and elevation. Atmospheric deposition was inferred the major source of Pb in the forest ecosystem, which can be supported by the highest Pb concentrations in the moss and overstory foliage. The maximum Pb concentration was showed in the dung beetle (12.1 mg kg−1) residing in the soils compared that in the longicorn and of cicada, which would potentially pose negatively influence to predators along food chains.

Combining emission inventory and isotope ratio analyses for quantitative source apportionment of heavy metals in agricultural soil

Two quantitative methods (emission inventory and isotope ratio analysis) were combined to apportion source contributions of heavy metals entering agricultural soils in the Lihe River watershed (Taihu region, east China). Source apportionment based on the emission inventory method indicated that for Cd, Cr, Cu, Pb, and Zn, the mean percentage input from atmospheric deposition was highest (62–85%), followed by irrigation (12–27%) and fertilization (1–14%). Thus, the heavy metals were derived mainly from industrial activities and traffic emissions. For Ni the combined percentage input from irrigation and fertilization was approximately 20% higher than that from atmospheric deposition, indicating that Ni was mainly derived from agricultural activities. Based on isotope ratio analysis, atmospheric deposition accounted for 57–93% of Pb entering soil, with the mean value of 69.3%, which indicates that this was the major source of Pb entering soil in the study area. The mean contributions of irrigation and fertilization to Pb pollution of soil ranged from 0% to 10%, indicating that they played only a marginally important role. Overall, the results obtained using the two methods were similar. This study provides a reliable approach for source apportionment of heavy metals entering agricultural soils in the study area, and clearly have potential application for future studies in other regions.

Atmospheric deposition having been one of the major source of Pb in Jiaozhou Bay

Many marine bays have been polluted by Pb due to the rapid development of industry, and identifying the major source of Pb is essential to pollution control. This paper analyzed the distribution and pollution source of Pb in Jiaozhou Bay in 1988. Results showed that Pb contents in surface waters in Jiaozhou Bay in April, July and October 1988 were 5.52-24.61 μg L−1, 7.66-38.62 μg L−1 and 6.89-19.30 μg L−1, respectively. The major Pb sources in this bay were atmospheric deposition, and marine current, whose source strengths were 19.30-24.61μg L−1 and 38.62 μg L−1, respectively. Atmospheric deposition had been one of the major Pb sources in Jiaozhou Bay, and the source strengths were stable and strong. The pollution level of Pb in this bay in 1988 was moderate to heavy, and the source control measurements were necessary.

Source and fate of plumbum in marine bay

Many marine bays bave been polluted by Plumbum (Pb) due to the rapid development of industry and the swift increasing of economic, and therefore understanding the source and fate of Pb is essential to environmental remediation in marine bays. This paper analyzed the source and fate of Pb in Jiaozhou Bay, Shandong Province, eastern China in 1989. Results showed that Pb contents in surface waters in April, July and October 1989 were 5.56-12.59 μg L-1, 1.73-15.17 μg L-1 and 0.50-11.57 μg L-1, and the pollution levels were heavy, moderate and slight/moderate, respectively. The major sources of Pb in this bay were atmosphere deposition, overland runoff and river discharge, and their source strengths were 15.17 μg L-1, 12.59 μg L-1 and 11.57-12.06 μg L-1, respectively. The three source input processes were defined that the longer migration processes, the larger loss of substance’s contents. Furthermore, fate of Pb from source to sink was also defined. These migration processes were demonstrated by two block diagrams, which were helpful to better understand the source and fate of Pb in marine bay.