Lead concentration profiles in lead-210 dated Lake Ontario sediment cores

Lead concentrations were measured in sediment cores from four sites distributed among the three major sedimentary basins — Niagara, Mississauga and Rochester — of Lake Ontario for which sedimentation rates had been previously determined by ²¹⁰Pb dating.Around 90% of the total lead present in fine-grained surface sediments was removed by CH₃CO₂H/NH₂OH · HCl leaching, concentrations ranging from 137 μg/g in surface sections to a constant background of 12–13 μg/g at unpolluted depths. Lead-210 dating indicated that increases in lead concentrations commenced ca. 1850–1875 with 5, 10, 35 and 50% of the total “excess” lead inventory in the sediment column being assigned to the pre-1900 period and successive 25-year intervals during the 20th Century, respectively. Anthropogenic inputs of lead from such sources as the combustion of leaded gasoline and coal are responsible for these increases.About 10 μg/g lead remained in the sediment residue after leaching. The total natural lead flux to the sediments ranged from 0.4–1.3 μg/cm²/yr while “excess” lead of anthropogenic origin varied from 1.2–6.7 μg/cm²/yr and totalled 0.5–1.5 g/m² at the four sites.Various potential modes of introduction of anthropogenic lead and of ²¹⁰Pb to the lake are considered in conjunction with the ratio of Pb/²¹⁰Pb fluxes to the sediment.     

Stable lead isotopic characterisation of the historical record of environmental lead contamination in dated freshwater lake sediment cores from northern and central Scotland

Sediment cores from three Scottish freshwater lakes, Loch Ness in the remote north and Loch Lomond and the Lake of Menteith, much closer to the heavily populated and industrialised central belt were analysed for 210Pb, 137Cs, Pb and stable Pb isotopic composition (206Pb/207Pb). The radionuclide data were used to establish chronologies for the Loch Ness and Loch Lomond cores, but a chronology could not be developed for the Lake of Menteith core, in which the surface sediment had been subject to intense mixing. Although Pb concentrations generally started increasing during the mid-17th Century, a small peak occurred for Loch Ness in the early 16th Century, perhaps attributable to the influence of medieval mining and smelting in mainland Europe. Temporal trends in the pattern of Pb accumulation were similar for Loch Ness and both sites in Loch Lomond, with 40-50% of the anthropogenic Pb deposited prior to the 20th Century. Fluxes of anthropogenic Pb to the lake sediments peaked during the 1950s at all locations where chronologies could be established. The 5-fold increase in anthropogenic Pb inventory for the southern basin of Loch Lomond relative to Loch Ness reflected geographical proximity to the main polluting sources. The 206Pb/207Pb data for anthropogenic Pb in the sediments from Loch Ness and Loch Lomond exhibited largely similar trends related to five different time periods. Pre-1820, the 206Pb/207Pb ratio was close to that for coal (1.181). From 1820 to 1900, a fairly constant 206Pb/207Pb ratio of approximately 1.17 probably resulted from a combination of emissions from the smelting of indigenous Pb ore (1.170) and coal burning (1.181) in Scotland, and industrial activity to the south in England, where Australian Pb of characteristically low 206Pb/207Pb ratio (1.04) was already in use. From 1901 to 1930, the 206Pb/207Pb ratio declined by <0.01, due to the increasing influence of Australian Pb. From 1931 to 1975/1985, the 206Pb/207Pb ratio of anthropogenic Pb declined by a further 0.03 to 0.04, to minimum values from approximately 1975 to 1985, primarily a consequence of car-exhaust emissions of Pb arising from the introduction of alkyl Pb petrol additives (206Pb/207Pb approximately 1.06-1.09). From 1975/1985 to the mid-1990s, the 206Pb/207Pb ratio of anthropogenic Pb increased by up to 0.015, a consequence of a reduction in car-exhaust emissions of Pb, resulting from reductions in the maximum permitted concentration of Pb in petrol, and the introduction and increasing uptake of unleaded petrol. Source apportionment calculations, on the basis of 206Pb/207Pb values in surface sediment, suggested that the contribution of Pb emissions from the use of leaded petrol was 27-40% of the atmospheric burden by the mid-1990s, in line with estimates from rainwater 206Pb/207Pb data.     

Levels of heavy metals in outdoor and indoor dusts in Muscat,Oman

The concentrations of lead, copper, nickel, zinc and chromium in outdoor and indoor dusts collected from different sites in Muscat, Oman, were determined by flame atomic absorption. Results showed a wide range of concentrations, the means in the outdoor dust being, 65?±?50, 124?±?316, 47?±?45, 930?±?666 and 64?±?26 mg kg^??1 for lead, zinc, copper, nickel and chromium, respectively. The 2001 Omani phasing out of leaded fuel resulted in low levels of lead in outdoor dust compared to those reported in the literature. Outstanding was the high nickel concentration in outdoor dust when compared to that in the literature, the reason being natural soil pollution due to the local geology of the northern parts of Oman. The concentrations of chromium, copper and zinc are lower than or comparable to these in other cities around the world. The results also showed that the industrial activities in Muscat do not contribute significantly to metal pollution in street dusts.

On the other hand, the mean concentrations of lead, zinc, copper, nickel and chromium in indoor dust were 108?±?65, 753?±?1162, 108?±?91, 130?±?125 and 34?±?14 mg kg^??1, respectively. In general, zinc and nickel levels are higher than those reported in the literature while lead, copper and chromium levels are lower or comparable.

When outdoor and indoor dusts were correlated, the ratios between indoor–outdoor mean concentrations revealed that lead, zinc, and copper were generated internally, while nickel and chromium were from external sources.     

Heavy metals in the lagos lagoon sediments

Concentrations of cadmium, cobalt, copper, chromium, iron, manganese, nickel, lead and zinc were determined in surface sediments of the Lagos Lagoon, Nigeria. The results revealed largely anthropogenic heavy metal enrichment and implicated urban and industrial wastes and runoff water transporting metals from land‐derived wastes, as the sources of the enrichment. Higher levels (F < 0.05) of cadmium, iron, manganese, nickel and zinc occurred in sediment samples collected near industrialized‐urban areas than in those from unindustrialized‐rural areas only in the wet season. While iron constituted about 1% of dry sediment by weight, the other metals were present in trace amounts.     

陶瓷地理标志产品微量元素迁移量检测研究

利用电感耦合等离子体质谱仪对20种陶瓷地理标志产品中的砷、镉、铬、镍、铅、锑、锌、铜、锰等9种微量元素迁移量情况进行检测。结果显示,镉、铬、锑在20种地理标志产品陶瓷中均未检出;铅、锌、铜、锰迁移量在有釉瓷（陶）器的多数种类中检出,其中锌迁移量突出;砷、镍迁移量在无釉陶器中检出。     

Distribution of 23 elements in the kidney,liver and lungs of workers from a smeltery and refinery in north Sweden exposed to a number of elements and of a control group

The levels of antimony, arsenic, cadmium, caesium, chromium, cobalt, copper, gold, iron, lanthanum, lead, manganese, mercury, molybdenum, phosphorus, rubidium, scandium, selenium, silver, tellurium, tin, tungsten and zinc in the kidney, liver and lungs of autopsy specimens from exposed workers in North Sweden, as well as from a control group, have been assayed quantitatively. The workers had been exposed to several elements and their compounds, e.g. lead, mercury, arsenic and cadmium, for long periods in arsenic, lead or selenium plants and in a lead or copper smelter.The chemical analysis was by neutron activation analysis and atomic absorption spectrophotometry.Median levels of antimony, arsenic, cadmium, chromium, cobalt, lanthanum, lead or selenium in kidney, liver or lungs in the exposed worker group were found to be about 2 to 16 times as great as the corresponding levels for the control group. Long biological half-life values were observed for these elements, especially in lung tissue.     

The effect of heavy metals on laboratory populations of two polychaetes with comparisons to the water quality conditions and standards in Southern California marine waters

Polychaetous annelid assays were performed with laboratory inbred cultures of juvenile and adult Neanthes arenaceodentata and Capitella capitata to cadmium, chromium, copper, lead, mercury, and zinc in sea water. Data were presented as 96-h and 28-day LC₅₀ concentrations. Mercury and copper were the two most toxic with zinc and chromium generally the next most toxic followed by lead and cadmium. The adult stages of both species were more tolerant to these metals than the juveniles. Comparisons of these six metals present in the two large domestic sewage outfalls in Los Angeles County indicate that the amount of copper and zinc present in the effluent exceeds the 28-day LC₅₀ of these two polychaetes. The results were compared to the water quality standards for discharges in the State of California.     

An investigation of trace element losses during lyophilization of marine biological samples

Trace element losses during lyophilization of selected macroalgae and marine flesh tissues were investigated. No significant losses (p > 0.1) of arsenic, cadmium, copper, iron, mercury, manganese, nickel, lead, selenium, tin and zinc were found. Significant losses of chromium (3–15%) occurred from several specimens. An all-glass freeze drying apparatus is also illustrated.     

Sorption and accumulation of cadmium in the sediment of the Tama River

Cadmium contents in the water and the sediment samples collected from the Tama River and several branches were measured. Cadmium (above 0.005mgl⁻¹) was detected in only four of the water samples, while the sediment samples showed cadmium content of 1.0–9.8 μg g⁻¹ dry sediment. Cadmium concentration in the sediments of the main stream was correlated against ignition loss of the samples and it was found that 1 g of ignition loss (organic matter) corresponded to 35 μg of cadmium.The batch adsorption experiment in the laboratory using an aqueous solution of cadmium for 14 sediment samples with a higher concentration of cadmium indicated that the amount adsorbed by the sediment is highly dependent on the ignition loss. The amount adsorbed on unit mass of ignition loss q_IL could be correlated by a Freundlich-type equilibrium relation as where C is the equilibrium concentration in the aqueous phase ranging between 7 × 10⁻³ and 10 mg l⁻¹, while k_IL and n are equilibrium constants.The adsorption rate measurement showed that the intraparticle diffusion coefficient of cadmium in the sediment was about 1.1 × 10⁻⁶ cm²s⁻¹, which is of a reasonable order of magnitude assuming the pore diffusion mechanism inside the particle.The results suggest that suspended solid particles of high organic content in flowing water contribute significantly to the transport of cadmium along the river.     

Heavy metal conservation in Lake Cadagno sediments: Historical records of anthropogenic emissions in a meromictic alpine lake

Currently, pollution by heavy metals is one of our most serious environmental problems. Metals such as lead and cadmium enter the biosphere through biogenic and anthropogenic emissions and have been steadily accumulating in soils and sediments. We report on a remote mountain lake in the Swiss Alps where the unusual conditions present have led to the accumulation of several heavy metals in the sediments. The sulfide rich environment contains precipitates of cadmium, lead and zinc. The anoxic conditions and prevalence of sulfate reducing bacteria in the water column have prevented the remobilisation of the metals leaving them trapped in the sediments. This has resulted in the formation of surprisingly “stable” metal profiles which have been correlated to levels of human and industrial activity and provide the means of reconstructing a record of human impact and pollution over the past 50 to 100 years. We suggest that such metals in sediment profiles can also be used as chronological markers in cases where cost or sampling difficulties preclude the use of radiological ¹³⁷Cs and ²¹⁰Pb dating. Stable metal profiles are valuable sources of environmental data, they reveal pertinent information on the atmospheric transport of contaminants and are relatively simple to analyse.     

Contaminant fluxes from sediment due to tubificid oligochaete bioturbation

The release of the hydrophobic organic compounds pyrene, dibenzofuran and phenanthrene from bioturbated freshwater sediments was studied in laboratory microcosms. Initial Tubificid oligochaete densities of 0, 6700 and 2.67 × 10⁴ individuals · m⁻² were employed. Under oxygen saturated conditions, the difference between the contaminant fluxes from the high-density bioturbated microcosms and controls remained essentially constant at 37 and 70 ng · cm²⁻² · d⁻¹ for pyrene and phenanthrene, respectively, corresponding to effective mass transfer coefficients of 0.16 and 0.37 cm/y. Under hypoxic conditions, worm defecation on the sediment surface increased and led to significantly increased fluxes to a maximum of 380, 490 and 940 ng · cm⁻² · d⁻¹, for pyrene, phenanthrene and dibenzofuran, respectively. Average bioturbation fluxes in the high-density microcosms of 246, 258 and 310 ng · cm⁻² · d⁻¹ for the respective compounds corresponded to effective mass transfer coefficients of 1.7, 3.2, and 7.5 cm/yr. Initial release rates from medium-density microcosms (25% of high density) were typically half the release rate of the high-density microcosms, indicating greater organism activity per individual at the lower density. The increased flux with the more soluble compounds likely reflects more rapid release at the sediment surface and the increased importance of porewater pumping over sediment particle reworking for migration of these compounds.     

Effects of chloride,sulfate and natural organic matter (NOM) on the accumulation and release of trace-level inorganic contaminants from corroding iron

This study examined effects of varying levels of anions (chloride and sulfate) and natural organic matter (NOM) on iron release from and accumulation of inorganic contaminants in corrosion scales formed on iron coupons exposed to drinking water. Changes of concentrations of sulfate and chloride were observed to affect iron release and, in lesser extent, the retention of representative inorganic contaminants (vanadium, chromium, nickel, copper, zinc, arsenic, cadmium, lead and uranium); but, effects of NOM were more pronounced. DOC concentration of 1 mg/L caused iron release to increase, with average soluble and total iron concentrations being four and two times, respectively, higher than those in the absence of NOM. In the presence of NOM, the retention of inorganic contaminants by corrosion scales was reduced. This was especially prominent for lead, vanadium, chromium and copper whose retention by the scales decreased from >80% in the absence of NOM to <30% in its presence. Some of the contaminants, notably copper, chromium, zinc and nickel retained on the surface of iron coupons in the presence of DOC largely retained their mobility and were released readily when ambient water chemistry changed. Vanadium, arsenic, cadmium, lead and uranium retained by the scales were largely unsusceptible to changes of NOM and chloride levels. Modeling indicated that the observed effects were associated with the formation of metal–NOM complexes and effects of NOM on the sorption of the inorganic contaminants on solid phases that are typical for iron corrosion in drinking water.     

Electrodeposition of six heavy metals on reticulated vitreous carbon electrode

Six heavy metals, copper, cadmium, chromium, lead, uranium and zinc were deposited on cathodes made of a newly developed form of carbon, Reticulated Vitreous Carbon, in a laboratory scale electrochemical reactor. Different metals varied in the extent of their removal with copper depositing 100% at a flow rate of 0.24 cm min⁻¹ in a single pass while it would require a maximum of 20 passes for 100% chromium deposition at a flow rate of 1.8 cm min⁻¹, initial concentrations for both metals being 50 μmol 1⁻¹.Experiments conducted using 0.5 × 10⁻³ M CuSO₄ in 0.5 M Na₂SO₄ supporting electrolyte resulted in a mass transfer coefficient of the order of 10⁻³ cm s⁻¹ and a current efficiency of 64% for the electrodeposition of copper at a cell voltage of 4.0V. Because of very high porosity, 97%, high specific surface area, up to 66 cm² cm⁻³ for RVC grade 100, and useful electrochemical characteristics, RVC can be advantageously used as electrode material for heavy metal removal from dilute industrial effluents.     

Trace elements in home-produced eggs in Belgium: Levels and spatiotemporal distribution

The purpose of this study was to evaluate the levels of arsenic, cadmium, lead, copper and zinc in home-produced eggs, soils and kitchen waste samples of private chicken owners in Belgium, and to determine spatiotemporal differences in trace element contents in eggs. Eggs were sampled in all provinces of Belgium in autumn 2006 and spring 2007. A total number of 59 private chicken owners participated in the study. Trace elements were determined by inductively coupled plasma-mass spectrometry except for mercury, which was determined by atomic absorption of mercury vapour. The mean fresh weight concentrations in eggs in autumn and spring respectively were < 8.0 and < 8.0 µg/kg for arsenic, 0.5 and < 0.5 µg/kg for cadmium, 116 and 74 µg/kg for lead, 0.43 and 0.52 mg/kg for copper, 20.3 and 19.2 mg/kg for zinc, and 3.15 and 4.44 µg/kg for mercury. Analysis of variance determined significant differences in some trace element concentrations in eggs among seasons and regions in Belgium. Average concentrations of arsenic, cadmium and mercury corresponded well with values measured in other countries, while copper and zinc concentrations were within the same order of magnitude as in other countries. Average lead concentrations were high compared to concentrations in eggs from other countries and correlated well with lead concentrations in soil, indicating that the soil is an important source. Other sources of trace elements in eggs might be home-grown vegetables and forage (grass and herbs), and indirectly, air pollution.     

Assessing the chelating ability of Aerva Lanata: Adsorption of chromium from tannery effluent and its toxicity measurement

The chelating ability of aqueous leaf extract of Aerva lanata was assessed in vitro. The aqueous leaf extract showed a dose dependent decrease in chelating ability using FeCl₂. The highest chelating ability of aqueous leaf extract was observed at 2 × 10^?5 g/mL (100 ± 0.00). The antioxidant activity of the aqueous leaf extract ranged from 42.13% to 88.66%. At 2 × 10^?5 g/mL concentration, a strong positive significant correlation was observed between chelating ability and total phenolics concentration (R = 0.94; P = 0.001). The chelating ability of aqueous leaf extract (2 × 10^?5 g/mL) showed a high positive significant correlation with antioxidant activity (R = 0.78; P = 0.001). Aqueous leaf extract removed the chromium from tannery effluent by 43 mg/g. Allium cepa toxicity test was performed on tannery effluent treated with aqueous leaf extract that increased the root length of onion.     

Arsenic in coastal waters of South Australia

Surface seawater samples from South Australian coastal locations were analysed for dissolved inorganic arsenic [As(III) + As(V)], arsenite [As(III)] and particulate arsenic.Dissolved inorganic arsenic concentrations ranged from 1.10 to 1.61 μg As l^?1 (average 1.3 ± 0.1 μg As l^?1) with 1.2–4.3% (average 2.7%) present as arsenite. Particulate arsenic concentrations were below the limit of detection (0.0006 μg As l^?1) at most sampling stations.     

Investigation of mangrove macroalgae as biomonitors of estuarine metal contamination

This study examined the potential use of macroalgae epiphytic on mangrove aerial roots as biomonitors of estuarine contamination. The metal concentrations of macroalgae were investigated in four estuaries in the vicinity of Sydney, Australia, and compared to water and sediment metal concentrations over three seasonal surveys. Macroalgal metal concentrations (copper, zinc, cadmium, chromium, lead, nickel, manganese and iron) appeared to be more associated with sediment metal concentrations than water concentrations, suggesting they may be useful biomonitors of estuarine sediment contamination. Algae in the more contaminated estuaries generally contained higher metal concentrations. However, concentrations of iron, nickel and manganese appeared to be similar in the algae despite the varying sediment concentrations, while accumulation of copper, zinc, lead and chromium appeared to be associated with ambient environmental concentrations. The uptake of metals also varied among the different species, suggesting that algal parameters, such as morphology, may also influence metal uptake and accumulation.     

Electrothermal atomic-absorption determination of copper and zinc in mineral waters and peloids

The article presents the results of electrothermal atomic-absorption determination of copper and zinc in mineral waters and peloids.¹ The article contains metrological control of the techniques and confirms the possibility of their use during the analysis of these natural objects. The detection limit of copper and zinc constitutes respectively 0.6 ad 0.7 μg/dm³, relative error of determination being ± 0.05 and ± 0.03.     

A stable lead isotopic investigation of the use of sycamore tree rings as a historical biomonitor of environmental lead contamination

The validity of the use of sycamore (Acer pseudoplatanus) tree-rings for the reconstruction of atmospheric lead pollution histories was investigated. Tree cores spanning 1892-2003 were collected from several sycamores from the eastern shore of Loch Lomond, Scotland, an area with no local point sources of lead emission. The lead concentration and 206Pb/207Pb profiles of the Loch Lomond region cores were compared with corresponding data for the 210Pb-dated loch sediment, and also with data for moss of known age from a Scottish herbarium collection. Two of the seven sycamore cores showed the same lead concentration trend as the lead flux to the loch, the rest having no similarity to either each other or the loch sediment record. Two further sycamore cores showed some similarity in their temporal 206Pb/207Pb trends to those seen in the sediment and moss records, but only in part of their profiles, whilst the 206Pb/207Pb ratios of the other sycamore cores remained relatively unchanged for the majority of the time covered, or exhibited an opposite trend. The 206Pb/207Pb ratios of the tree cores were also mostly higher than those of the previously established records for any given time period. Tree cores covering 1878-2002 were also collected along transects from Wanlockhead and Tyndrum, two areas of former lead mining and smelting associated with distinct 206Pb/207Pb ratios of 1.170 and 1.144, respectively. The Wanlockhead tree cores exhibited a generally decreasing trend in lead concentration with both time and distance from the lead mine. The characteristic 206Pb/207Pb ratio of 1.170 was observed in samples close to the mine but a decrease in the influence of the mine-derived lead was observed in more distant samples. The tree sampled at Tyndrum showed elevated lead concentrations, which decreased with time, and a fairly constant 206Pb/207Pb ratio of 1.15 reflecting input from the mine, features not observed in any other trees along the transect. Overall the data suggest that sycamore tree-ring analysis is an unsuitable method for obtaining records of historical lead deposition in areas with no large local lead input, although it can reveal some information about the temporal and spatial influence of point source emitters. The unsuitability probably arises from the number of active annual rings in a single year, the post-uptake radial translocation of elements, the relative importance of the different routes of uptake, and the soil depth(s) from which trees draw nutrients.     

The influence of heavy metals on a mixed bacterial population of sewage origin in the chemostat

A reproducible mixed continuous bacterial population has been cultured in the chemostat at a low dilution rate. Four species originally isolated from activated sludge were used to provide an inoculum. The influence of cadmium, chromium, copper and lead as shock doses has been examined at concentrations of 50 mg l⁻¹ and the response of the population was found to vary for each metal. The most toxic metal was copper followed by cadmium, lead and chromium. Continuous doses of chromium and lead have been studied, the latter over a range of concentrations. It appears that concentrations of lead as low as 5 mg l⁻¹ cause modifications in the individual population sizes. Some of the species studied were found to be more resistant to heavy metal toxicity than others.