Displacement of five metals sorbed on kaolinite during treatment with modified Fenton's reagent

The displacement of sorbed metals during the treatment of soils and groundwater with modified Fenton's reagent was investigated using five common metal contaminants (cadmium, copper, lead, nickel, and zinc) and kaolinite as a model sorbent. Modified Fenton's conditions included three H(2)O(2) concentrations (0.9, 1.8, 2.7 M) and two catalysts: soluble iron (III) at pH 3 and iron (III)-NTA chelate at pH 6. Iron (III)-catalyzed Fenton's reactions released significant amounts of zinc, cadmium, and copper. Modified Fenton's reactions catalyzed by iron (III)-NTA released zinc, cadmium, copper, and lead, and resulted in greater amounts of metals release than the iron (III)-catalyzed reactions. Metals release may have been mediated by transient oxygen species, such as superoxide, generated by propagation reactions, which become dominant at the relatively high hydrogen peroxide concentrations used. Metals release from kaolinite was undetectable when sufficiently low hydrogen peroxide concentrations were maintained to minimize propagation reactions. These results indicate that using dilute concentrations of hydrogen peroxide for Fenton's ISCO may minimize potential metals mobility when treating contaminated soils and groundwater containing a mixture of organic and metal contaminants.     

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.     

Trace metals in the soft tissues of scaup ducks (Aythya marila L.) wintering in Gdańsk bay,Baltic sea

The concentrations of iron, zinc, manganese, copper, lead, cadmium, cobalt and nickel were determined in 107 pooled tissues of scaup ducks (Aythya marila L.). Distinct differences in concentrations of some metals in various tissues were observed; no significant sex-related variations for any of the metals were noted. Results obtained in this study show that kidney contained the maximum concentration of cadmium, while liver had the highest levels of cooper and manganese. Both liver and stomach were characterized by maximum levels of zinc; iron was detected, sometimes at highly elevated levels, in lung and liver. Transfer of metals analysed along a food chain from prey represented by molluscs to predator, i.e. scaup duck, was quantified with a transfer factor.     

Particle size distribution and atmospheric metals measurements in a rural area in the South Eastern USA

Atmospheric particle mass concentrations were measured at a site adjacent to Lake Hartwell, GA, during six dry sampling events in February-March 2003. The overall average PM2.5 mass concentration was 9.5 microg/m3 and the overall average total suspended particles mass concentration was 19.1 microg/m3. Particulate matter was collected on a deposition plate mounted onto a specially designed wind vane and was subsequently analyzed to determine the particle size distribution. The average geometric particle diameter was found to be 2.8 microm. Particulate matter collected was found to be closely approximately at log-normal distribution, with a count median diameter of 1.5 mum and a geometric standard deviation of 1.8. Individual metal concentrations present in airborne particulate matter were determined for cadmium, chromium, copper, iron, lead, manganese, nickel, and zinc using inductively coupled plasma-mass spectrometry analysis of samples collected on Teflon filters. Ambient metal concentrations were found to range from 0.8 ng/m3 for cadmium to 512 ng/m3 for iron. The dry deposition flux of metals was estimated to be in the range of 0.17 mg/(m2 year) for cadmium to 102 mg/(m2 year) for iron. More samples need to be collected and analyzed, both temporally and spatially, in order to establish atmospheric metals fluxes onto surfaces.     

The effect of surfactants on the extraction-atomic absorption spectrophotometric determination of copper, iron, manganese, lead, nickel, zinc cadmium and cobalt

Nine surfactants representing pure cationic, anionic and non-ionic detergents, three industrially prepared detergents. sodium pyrophosphate. sodium tripolyphosphate, and a soap were investigated for their effect on the extraction-atomic absorption spectrophotometric determination of copper. iron, manganese and lead. Some results are also given for nickel, zinc, cadmium and cobalt. Cations were extracted into 10 ml of MIBK as APDC chelates. To Avoid emulsion formation, maximum concentration of LAS was 1 mg 1⁻¹, and for formulated and non-ionic detergents and washing powders it was 5 mg 1⁻¹.A standard addition procedure was used to obtain correct results for copper and nickel. Two extractions of iron, cobalt and lead, and one extraction of manganese, zinc and cadmium gave a recovery of 100 ± 5%. Soap gave high recoveries for iron and copper. NTA in concentrations up to 25 mg l⁻¹ did not interfere. EDTA in concentrations up to 25 mg l⁻¹ interfered with iron and nickel determinations, but the addition of 3 mg of aluminium removed the EDTA interference in the determination of copper, manganese, lead, zinc, cadmium and cobalt.For the determination of trace metals in polluted natural waters the amount of 4% APDC was increased to 10 ml and for manganese to 25 ml. An addition of 3 mg aluminium as nitrate after the addition of buffer with subsequent 20 min reaction time is required for the determination of all eight metals by the recommended procedures. The effect of humic acid was also investigated.     

Uptake of cadmium, zinc, copper, lead and chromium in the pacific oyster. Crassostrea gigas. Grown in the tamar river. Tasmania

Hundreds of oysters and mud samples from 15 sites along the Tamar River were analysed for cadmium, copper, zinc, lead and chromium. The widely accepted concept of enrichment factors of up to several hundred thousand, describing accumulation by oysters of cadmium, zinc and copper from seawater has been found to be grossly misleading. Concentrations found for these three metals in oysters were only 10–40 times the concentrations in inhabited muds. Concentrations of metals in muds may be used to indicate whether a potential oyster bed would produce oysters that were grossly contaminated. Approximately 1 ppm cadmium in mud could result in oysters containing at least 25 ppm, i.e. 4–5 ppm wet wt. Similarly. 100 ppm zinc in mud could produce oysters containing at least 4000 ppm. i.e. 800–1000 ppm wet wt. Three heavy metal accumulation processes were discernible. Copper and chromium appeared to be absorbed up to a maximum weight that was limited by the size of the oyster and was independent of the amount of metal in the mud. Lead was not absorbed through any physiological demand, but was randomly incorporated at sites containing high concentrations in the mud. Zinc and cadmium were accumulated by a process that depended primarily on the concentrations of these metals in the mud at each site. Mean dry wt concentrations of metals in oysters and mud samples ranged from: 4.2–134 ppm and 0·4 to 5·7 ppm cadmium; 200–1700 ppm and 3–224 ppm copper: 0 135 ppm and 4–1500 ppm lead: 1–37 ppm and 2–88 ppm chromium; 1700 14.000 ppm and 20–500 ppm zinc. respectively.     

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.     

Influence of prefreezing on heavy metal concentrations in Bluegill sunfish

Concern for possible changes in tissue metal concentrations due to freezing of fish specimens prior to analysis prompted this investigation. Bluegill sunfish (Lepomis macrochirus) were collected from a Virginia stream and prepared for analysis of zinc, cadmium and lead concentrations either fresh or after 1, 7, and 70 days of freezing. Intact specimens as well as bone and liver tissue were then analyzed. Zinc concentrations displayed a statistically significant (P < 0.05) negative trend with duration of freezing in whole-body, liver and bone samples. Lead and cadmium concentrations showed no consistent pattern which could be related to length of the freezing period in any of the tissues analyzed. However, median concentrations of zinc, cadmium and lead were 10–30% lower in prefrozen sunfish (aggregated over freezing periods) than in sunfish which were analyzed fresh in seven of the eight tissue-metal combinations examined. These results indicate that freezing of sunfish prior to sample preparation can depress metal concentrations in both tissues and whole fish. Programs to monitor heavy metal contamination in sunfish and other fishes may incur bias unless specimens are prepared for analysis fresh or all samples experience equivalent freezing regimes.     

Levels of antimony,arsenic, cadmium,copper, lead,mercury, selenium,silver, tin and zinc in bone tissue of industrially exposed workers

The contents of the elements antimony, arsenic, cadmium, copper, lead, mercury, selenium, silver, tin and zinc in bone tissue from autopsy specimens of the femur of workers who had been exposed to a large number of metals in a smeltery and refinery in Northern Sweden as well as of a control group have been quantitatively assayed.The analytical techniques used were atomic absorption spectrophotometry, neutron activation analysis and particle induced X-ray emission analysis (PIXE) in a proton microprobe. Increased levels of lead in the bone tissue of exposed workers compared to a non-exposed control group were observed. The median level of lead in the group of exposed workers exceeded the corresponding value of the control group about 5 times.Using the proton microprobe in the PIXE-mode, concentration profiles of copper, lead and zinc were examined within the Haversian system of the bone samples.     

Toxic and essential trace metals in muscle, liver and kidney of bovines from a polluted area of Morocco

Toxic and essential trace metals were measured in muscle, bone, liver and kidney of bovine grazing on the municipal wastewater spreading field of Marrakech City (Morocco). Bovines were found to be seriously contaminated by toxic metals, for metal bioaccumulation. The high cadmium content seemed to contribute to a reduction in zinc and copper levels. The arithmetic mean concentrations of zinc, especially cadmium, and levels were higher in liver and kidney, specific target organs copper and cadmium in liver and kidney, were respectively: 126, 112 and 5.1 microg/g in liver; 89, 33 and 10.3 microg/g in kidney.     

Trace metal depositional patterns from an open pit mining activity as revealed by archived avian gizzard contents

Archived samples of blue grouse (Dendragapus obscurus) gizzard contents, inclusive of grit, collected yearly between 1959 and 1970 were analyzed for cadmium, lead, zinc, and copper content. Approximately halfway through the 12-year sampling period, an open-pit copper mine began activities, then ceased operations 2 years later. Thus the archived samples provided a unique opportunity to determine if avian gizzard contents, inclusive of grit, could reveal patterns in the anthropogenic deposition of trace metals associated with mining activities. Gizzard concentrations of cadmium and copper strongly coincided with the onset of opening and the closing of the pit mining activity. Gizzard zinc and lead demonstrated significant among year variation; however, maximum concentrations did not correlate to mining activity. The archived gizzard contents did provide a useful tool for documenting trends in metal depositional patterns related to an anthropogenic activity. Further, blue grouse ingesting grit particles during the time of active mining activity would have been exposed to toxicologically significant levels of cadmium. Gizzard lead concentrations were also of toxicological significance but not related to mining activity. This type of “pulse” toxic metal exposure as a consequence of open-pit mining activity would not necessarily have been revealed through a “snap-shot” of soil, plant or avian tissue trace metal analysis post-mining activity.     

Heavy metals in aerosols over the seas of the Russian Arctic

A review of the data on heavy metals in aerosols over the seas of the Russian Arctic is presented. Results of heavy metal studies in aerosols obtained during 11 research expeditions in summer/autumn period from 1991 to 2000, and at Severnaya Zemlya and Wrangel Island in spring, in 1985-1989 are discussed. Concentrations of most heavy metals in the atmosphere in the marine boundary layer in the Russian Arctic are nearly of the same order as literature data from other Arctic areas. The content of heavy metals in the aerosols over the seas of the Russian Arctic shows an annual variation with maximal concentrations during the winter/spring season. In the summer/autumn period increased concentrations of heavy metals could be explained, in most cases, by natural processes (generation of sea salt aerosols, etc.). In some cases, aerosols from Norilsk and Kola Peninsula were detected. Particular attention was paid to estimation of horizontal and vertical fluxes of atmospheric heavy metals. We estimated annual variations in long-range transport of heavy metals into the Russian Arctic in 1986-1995. In winter and spring, up to 50% of the average air pollutant concentrations in the Russian Arctic are due to the Arctic atmospheric pollution itself. Moreover, the monthly and annual averaged fluxes of six anthropogenic chemical elements (arsenic, nickel, lead, vanadium, zinc and cadmium) onto the surface in the Arctic were estimated, and the values obtained were in reasonable agreement with the literature data available.     

Heavy metals in aquatic plants,clams, and sediments from the Chesapeake Bay,U.S.A. implications for waterfowl

Dry weight concentrations of cadmium, lead, copper and zinc were measured in clams, submerged aquatic macrophytes and sediments from several locations in the Chesapeake Bay region. Clam species included Macoma balthica, Mya arenaria, and Rangia cuneata; plant taxa included Najas spp., Potamogeton spp., Ruppia maritima, Vallisneria americana, and Zostera marina. Cadmium and lead concentrations were generally greater in whole plants than in soft tissues of clams, while the reverse was true for zinc; no marked trend was observed in copper concentrations. These results suggest that the changes occurring in the food habits of some Chesapeake Bay waterfowl towards increased clam utilization as a result of declining submerged plant abundances is not increasing ingestion of the nonessential metals cadmium and lead. Highest lead, copper and zinc concentrations were observed in sediments from the Patapsco River, which is probably due to the proximity of Baltimore Harbor. Highest cadmium concentrations were observed in sediments in the Port Tobacco River, a tributary of the Potomac River. These observations were generally consistent with high concentrations of the respective metal(s) in biota from these locations. Concentrations of the four metals in sediments were highly correlated to organic matter content.     

Concentrations of selected metals in honey consumed in Nigeria

The concentration of metals, cadmium (Cd), lead (Pb), nickel (Ni), chromium (Cr), copper (Cu), cobalt (Co), iron (Fe), manganese (Mn), and zinc (Zn) was measured in selected samples of honey in Nigeria with a view to providing information on the regional concentration profile of metals in these honeys. The honey samples were digested with a mixture of acids and analysed for metal concentrations using atomic absorption spectrophotometry. The concentrations of metals (mg kg^?1) in these honeys ranged from < 0.3 for Cd,<0.50–39.75 for Pb,<0.25–6.98 for Ni,<0.25–55.25 for Cr,<0.25–71.25 for Cu,<0.25–3.50 for Co,<5.0–163.15 for Fe,<11.0–31.75 for Mn and 1.0–31.0 for Zn. The concentrations of metals were relatively high but lower than their respective permissible limits in food except for Pb and Cu in some samples. The regional distribution patterns of metals indicated that honey samples from the Niger Delta region of Nigeria had higher mean concentrations of Ni, Cr, Co, Fe and Zn than honey samples from other regions. The honey samples from the northern region had higher mean concentrations of Pb and Cu.     

An assessment of natural concentrations of selected metals in the bone tissues of the femur head

The study was aimed at assessing the natural concentrations of copper, iron, potassium, lead and cadmium in the femur head using regression analysis. The material was collected during the operation of total hip arthroplasty from patients of southern and central Poland suffering from diagnosed coxarthrosis. In total, 197 samples were collected, including 68 samples of spongious bone, 59 samples of cortical bone and 70 samples of cartilage surface. After wet microwave digestion, the metal content in the samples was measured by atomic absorption spectrophotometry. The average concentrations of metals in the femur head were 67.30 microgFe/g, 760.58 microgK/g, 0.07 microgCd/g, 0.81 microgCu/g and 2.76 microgPb/g. A comparison of metal concentrations in bone tissues assessed by regression analysis to the findings of other authors revealed that the technique can be used to assess the natural concentration of elements in tissues and the results may provide a basis for the evaluation of metal concentrations in the human organism.     

Trace metal concentrations in Nigerian fruits and vegetables

Eight trace metals, namely cadmium, cobalt, copper, chromium, iron, manganese, nickel and lead, as well as sodium, potassium, calcium and magnesium were determined in fresh Nigerian fruit and vegetables. Soil samples were also analysed for trace metals. The results show that trace metals occurred at low concentrations, and seem to reflect background levels, although higher concentrations and wider distribution were observed in the vegetables than in fruit. Their sodium, potassium, calcium, magnesium and iron content compared well with, values reported for American fruit and vegetables.     

Natural variation of copper,zinc, cadmium and selenium concentrations in Bembicium nanum and their potential use as a biomonitor of trace metals

Copper, zinc, cadmium and selenium were measured in the gastropod mollusc Bembicium nanum at two uncontaminated locations, Jervis Bay and Rosedale, NSW, to determine natural variability of metals associated with gender, mass, shore position and temporal variability. Trace metals were also measured in B. nanum at three industrialised locations to determine the accumulation of trace metals in contaminated environments.Copper, zinc, cadmium and selenium concentrations were not significantly different between male and female B. nanum. No significant relationships were found between zinc, cadmium and selenium concentrations and mass. There was a significant relationship between copper concentration and mass but only 19% of the variation was explained by mass. Generally inherent variability within samples had a greater influence than gender or variations in mass on trace metal concentrations.No trend was found in cadmium and selenium concentrations with variation in shoreline position. Copper and zinc concentrations increased further away from the low tide mark, with a decrease in metal concentrations at the furthest site from the water. Variability in metal concentrations is attributable to variations in food source, food availability and different immersion times.Copper, zinc, cadmium and selenium concentrations varied over a 12-month period. Copper, cadmium and selenium were taken up and lost over time, as metal body burden followed the same trend as metal concentrations. Zinc concentrations were influenced by mass. Copper and cadmium concentrations fluctuated throughout the 12-month period but with no clear seasonal trends. Selenium concentrations peaked in spring (October), with concentrations remaining uniform over the other months. These differences in mean concentrations between months were most likely due to inherent trace metal variability associated with differences in food availability and changes in metabolic rates associated with changes in temperature during the study period.Measurement of trace metals in B. nanum at contaminated sites showed that B. nanum accumulates metals in response to contamination.B. nanum meets most of the requirements to be a biomonitor of trace metal contamination as they are abundant, sedentary, easy to identify, provide sufficient tissue for analysis, tolerate high concentrations of pollutants and they accumulate trace metals in response to contamination. However, as trace metal concentration can vary with mass, shoreline position and temporally, care must be taken to collect individual organisms with similar mass from similar shoreline positions and times.     

Chemical partitioning and remobilization of heavy metals from sewage sludge dumped in Dublin Bay

During the disposal of sewage sludge to the marine environment, chemical changes may alter the mobility of trace elements, thus affecting their potential toxicity and availability to marine organisms. Primary sludge from the Ringsend treatment plant in Dublin receives both domestic waste and trade wastes which contain heavy metals, and approx. 250,000 tons per annum is periodically dumped in Dublin Bay. The purpose of this study was to determine changes which may occur in the chemical partitioning of heavy metals in the sludge during disposal. Samples of sludge were collected from the treatment plant in July 1987. Sequential chemical extraction of heavy metals (Cu, Pb, Cd, Zn, Fe, Mn) was carried out in a nitrogen-filled glove box using 1 M ammonium acetate, 1 M sodium acetate, 0.1 M hydroxylamine HCl (pH 2), 0.2 M ammonium oxalate (pH 3), 30% hydrogen peroxide and concentrated HNO₃. Seawater-extractable metal was determined by mixing subsamples of sludge with filtered seawater from Dublin Bay for 2 h. Chemical partitioning of heavy metals among solid phases in the sludge residue was redetermined by sequential chemical extraction. Both sludge and dumpsite sediments were analysed for total heavy metal content and organic content. The sludge was found to be only slightly anaerobic with a water content of 88% and significant concentrations of some metals, notably copper and zinc. Most of the non-residual copper, lead and cadmium was found in the organic/sulphidic fraction of the sludge (hydrogen peroxide extract), while the dominant phase for zinc was the moderately reducible fraction (ammonium oxalate extract) and only iron and manganese had substantial proportions of metal in more labile phases. Agitation with seawater mobilized cadmium and manganese to a significant extent (56 and 43%, respectively) but negligible amounts of copper or lead (0 and 2%, respectively). However, significant changes in solid-phase partitioning of lead and zinc occurred resulting in mobilization from stronglybound to more labile fractions. No deleterious effects were found at the dumpsite but localized effects are possibly due to the increased mobility of zinc, lead and particularly cadmium.     

Characterization of sanitary landfill leachates

Composition of leachates from some sanitary landfills in Norway and in the U.S.A. is described. The wide range of compositions found was mainly attributed to the efficiencies of preventing water to enter the fills.

Organic acids were found to contribute almost 90% of the total organics in the high strength leachates. The ratio of carbonaceous BOD to COD increased significantly with the concentrations of organics. Thus a better biological treatability is expected for the high strength leachates. High concentrations of nitrogen mainly as ammonia prevailed in all the samples while the concentrations of phosphorus were low. Of the heavy metals, iron were high in all the leachates, zinc was found to be the next highest. The concentrations of chromium, nickel, copper, cadmium and lead were low.     

The discriminatory power of two biomonitors of trace metal bioavailabilities in freshwater streams

The relative discriminatory powers of two trace metal biomonitors in European streams (the amphipod crustacean Gammarus fossarum and mayfly larvae of the genus Baetis-B. rhodani and B. vernus) are compared by discriminant function analysis using data from streams draining a zinc and lead mining area of Upper Silesia, Poland. The mayfly larvae (whether or not distinguished into the two separate species) had the better discriminatory power to distinguish between sites on the basis of local bioavailabilities of cadmium, copper, iron, lead and zinc. The bioavailabilities of the two metals lead and cadmium were the major local contributing factors to the stronger discrimination shown by the Baetis larvae.