GOLD-MINING EFFECTS ON HEAVY METALS IN STREAMS,CIRCLE QUADRANGLE,ALASKA1

Placer gold mining, which extracts gold from buried or exposed alluvia, is often conducted on or near streams. Such mining has the potential to adversely affect water quality. Other heavy metals associated with the gold (such as arsenic, cadmium, lead, zinc, and copper) may be freed to enter streams. Mercury may also enter streams if miners are using it to recover fine particles of gold. These heavy metals are toxic and thus may be harmful to the aquatic life of the streams receiving effluent or runoff from placer mines. In 1982 we sampled two streams intensively - one heavily mined and one unmined - for total recoverable arsenic, mercury, lead, zinc, and copper. Only mercury was not significantly higher in concentration in the mined streams. In 1983 we sampled two stream pairs three times, and 10 other sites at least once, for total and dissolved arsenic, cadmium, mercury, lead, zinc, and copper. Mercury and cadmium were not significantly elevated in mined streams, but the concentrations of total arsenic, lead, zinc, and copper, and dissolved arsenic and zinc were significantly higher in streams below active placer mining sites than in these that were not being mined or those that had never been mined. Additionally, total arsenic, lead, zinc, and copper and dissolved arsenic and copper became elevated after mining began in 1983 on a previously unmined stream.     

Metals distribution and interactions in tissues of shrews (Sorex spp.) from copper- and zinc-contaminated areas in Poland

To assess the risk from heavy metal accumulation to insectivorous species exposed to different pollutants, shrews [Sorex araneus (Linnaeus 1758) and Sorex minutus (Linnaeus 1766)] were collected in the Olkuski Ore Region (OOR; a Zn and Cd smelter area), Legnicko-G?ogowski Copper Mine Region (LGCR; a copper ore-mining area), and Bia?owieza Forest (BF; a control area). A few sites were chosen in each region and a total of 57 animals were collected from them. The liver and kidneys were dissected from the animals, dried, and digested in a 4:1 mixture of HNO3 (nitric acid) and HClO4 (perchloric acid). Cadmium, lead, zinc, copper, and iron were determined in the samples by flame or flameless atomic absorption spectrometry. The interactions between toxic and essential metals were calculated for each tissue. The data showed that accumulation of metals by insectivores is high; shrews accumulated much higher amounts of cadmium and lead than bank voles, studied by other researchers, from the same areas. The expected high tissue accumulation of copper at LGCR and zinc at OOR was not seen, but the levels of both elements were higher in the tissues of shrews from OOR than from LGCR. The lowest copper concentrations were in the tissues of shrews from BF. The highest cadmium and lead concentrations were found in the tissues of shrews from OOR. Some significant correlations were found between the tissue concentrations of xenobiotic and essential metals (e.g., between cadmium and zinc and between lead and iron).     

Comparison of trace metal contents of sediments and mussels collected within and outside Tolo Harbour,Hong Kong

Sediments collected from Tap Mun (within Tolo Harbour) and Yim Tin Tsai (outside Tolo Harbour) were extracted sequentially and the copper, cadmium, and chromium contents were determined. Total contents of copper, cadmium, chromium, and arsenic were also detected by acid digestion. The level of heavy metal extracted was higher in sequential extraction (which extracted all forms of metal ions) than total acid digestion. Among the four heavy metals studied, only copper showed a significantly higher (P<0.001) level in samples collected from Yim Tin Tsai (16.10 mg/kg) than that from Tap Mun (3.19 mg/kg). Such a difference in copper level is mainly attributed to the significantly higher (P<0.05) levels of copper in the organic, carbonate, and sulfide forms, whereas there was no significant difference (P>0.05) in the exchangeable and sorbed forms. Green-lipped mussel (Perna viridis) samples collected from the two sites were dissected into seven parts (gill, byssus, siphon, shell, digestive gland, soft tissue, and adductor muscle) and the concentrations of copper, cadmium, chromium, and arsenic were measured. The highest concentration of copper was obtained in the byssus. A higher concentration of copper was also noted in the mussels collected from Yim Tin Tsai than those collected from Tap Mun. No specific trend was revealed for the other metals tested. Chromium and arsenic concentrations were found to be independent of the body size of the mussels. Copper had a lower concentration in larger mussels and cadmium level was found to decrease with size. In addition, the mussels collected from Tap Mun were much larger than those collected from Yim Tin Tsai.     

Determination and Evaluation of Cadmium, Copper, Nickel, and Zinc in Agricultural Soils of Western Macedonia, Greece

The objective of this study was to determine the levels of major phytotoxic metals―including cadmium (Cd), copper (Cu), nickel (Ni), and zinc (Zn)―in agricultural soils of Western Macedonia, Greece. We also wanted to determine the possible relationships among elements and between soil properties and elemental concentrations. Surface soil samples, n = 570, were collected and analyzed. The results of the elemental analysis showed that the mean metal concentrations were consistent with reported typical concentrations found in Greek agricultural soils in the cases of Zn and Cu. Cd exhibited lower and Ni higher mean concentrations than the typical levels reported in the literature. Metal concentrations in the majority of the examined samples (>69%) were found to be higher than the respective critical plant-deficiency levels. However, only 0.4% and 0.2% of the analyzed soil samples, respectively, exhibited Cd and Ni concentrations higher than the levels that cause plant toxicity, as referenced by other investigators. These results suggest that the soils studied can be considered as unpolluted with respect to the examined food-chain metal contaminants. However, the levels of the metal concentrations in some of the soil samples, and the low correlation of the metals with soil properties, suggest an anthropogenic rather that lithogenic origin.     

Biosorption of copper(II) and lead(II) onto potassium hydroxide treated pine cone powder

Pine cone powder surface was treated with potassium hydroxide and applied for copper(II) and lead(II) removal from solution. Isotherm experiments and desorption tests were conducted and kinetic analysis was performed with increasing temperatures.As solution pH increased, the biosorption capacity and the change in hydrogen ion concentration in solution increased. The change in hydrogen ion concentration for lead(II) biosorption was slightly higher than for copper(II) biosorption. The results revealed that ion-exchange is the main mechanism for biosorption for both metal ions. The pseudo-first order kinetic model was unable to describe the biosorption process throughout the effective biosorption period while the modified pseudo-first order kinetics gave a better fit but could not predict the experimentally observed equilibrium capacities. The pseudo-second order kinetics gave a better fit to the experimental data over the temperature range from 291 to 347 K and the equilibrium capacity increased from 15.73 to 19.22 mg g^?1 for copper(II) and from 23.74 to 26.27 for lead(II).Activation energy was higher for lead(II) (22.40 kJ mol^?1) than for copper(II) (20.36 kJ mol^?1). The free energy of activation was higher for lead(II) than for copper(II) and the values of ΔH* and ΔS* indicate that the contribution of reorientation to the activation stage is higher for lead(II) than copper(II). This implies that lead(II) biosorption is more spontaneous than copper(II) biosorption.Equilibrium studies showed that the Langmuir isotherm gave a better fit for the equilibrium data indicating monolayer coverage of the biosorbent surface. There was only a small interaction between metal ions when simultaneously biosorbed and cation competition was higher for the Cu-Pb system than for the Pb-Cu system. Desorption studies and the Dubinin–Radushkevich isotherm and energy parameter, E, also support the ion-exchange mechanism.     

Exploration and discovery of Australia's copper,nickel, lead and zinc resources 1976–2005

Examination of copper, nickel, lead and zinc (base metals) exploration expenditure and discovery in Australia over the period 1976–2005 reveals some significant trends. Australia's base metal resource inventory grew substantially as a consequence of successful exploration over the period, both through addition of resources at known deposits and new discoveries, notably a small number of very large deposits that underpin the resource base. In 2005, Australia had the world's largest economic demonstrated resources (EDR) of nickel, lead and zinc, and the second largest EDR of copper. Growth in nickel resources has been especially strong owing to discovery of large laterite resources in the late 1990s. Resource life, in average terms based on current EDR and production, is approximately 30 years for lead and zinc, 40 years for nickel sulphide (120 years for all nickel EDR) and 50 years for copper. Despite this success, major increases in production over the period (copper, nickel and zinc output increasing 3–4 fold, lead output doubling) and a fall in discovery rates during much of the 1990s means that resource life for lead and zinc is lower and nickel sulphide comparable now to that in 1976; only the resource life of copper has grown substantially over the period. Current published ore reserves are sufficient for at least 15 years operations at current production levels, but only a small number of the largest deposits currently being mined are likely to still be in production in 20 years. However, several mines have substantial inferred resources that may allow production beyond current mine reserves and there is a substantial number of undeveloped deposits that may provide the foundation for extended or new mining operations. The discovery record is strongly cyclical with resource growth for all the base metals punctuated by the discovery of giant (world-class) deposits each decade: these underpin current and future production. Recent higher metal prices and renewed interest in base metals, especially nickel, has reversed a 10 year decline in base metal exploration attended by reduced rates of discovery and resulted in record expenditure, new nickel, copper and zinc discoveries, and increased resources at a number of existing deposits, notably the Olympic Dam copper–uranium–gold deposit. With the exception of the Prominent Hill copper–gold and West Musgrave nickel–copper deposits, most of the recent discoveries, especially zinc (-lead) deposits, are of small tonnage (some of high grade). Nevertheless, these new discoveries have helped stimulate further exploration and also highlight the potential for further discoveries in little-explored provinces, especially those under regolith and shallow sedimentary cover.     

INPUTS OF COPPER‐BASED CROP PROTECTANTS TO COASTAL CREEKS FROM PASTICULTURE RUNOFF1

ABSTRACT: Inputs of copper‐based crop protectants from tomato fields grown under plastic mulch agriculture (plasticulture) to an estuarine creek were investigated. Copper was measured in runoff from diverse land‐uses including conventional agriculture, plasticulture, residences, and natural areas. Water column and sediment copper concentrations were measured in plasticulture and control (nonagriculture) watersheds. Copper concentrations in plasticulture‐impacted creeks exceeded background levels episodically. High concentrations occurred during or immediately after runoff‐producing rains. Concentrations of 263 μg/L total copper and 126 μg/L dissolved copper were measured in a tidal creek affected by plasticulture; concentrations exceeded the shellfish LC₅₀ values and the water quality criteria of 2.9 μg/L dissolved copper. Control watersheds indicated background water column levels of ≤ 4 μg/L dissolved copper with similar copper levels during periods with and without rain. The copper concentrations in tomato plasticulture field runoff itself contained up to 238 μg/L dissolved copper. Copper concentrations in runoff from other land‐uses were less than 5 μg/L dissolved copper. Creek sediment samples adjacent to a plasticulture field contained significantly higher copper concentrations than sediments taken from nonplasticulture watersheds.     

Trace metal contents of the pacific oyster (Crassostrea gigas) purchased from markets in Hong Kong

Arsenic, cadmium, chromium, and copper concentrations of the Pacific oyster,Crassostrea gigas, purchased from four different markets were determined in this project. In general, gill tissue had the highest proportion of metal contents (34%–67%) when compared with other tissue parts (mantle, viscera, and adductor muscle), except for arsenic, which showed the highest level in adductor muscle (44%). Smaller oysters (longitudinal length of soft body part less than 6 cm) had higher metal levels than larger ones (longitudinal length of soft body part more than 6 cm), except copper. None of the four metals examined showed an obvious seasonal trend, although cadmium levels seemed to be higher in autumn and winter months. Arsenic, cadmium, and copper levels in oysters purchased from different markets and different months obtained in the present study were higher when compared with past reports. Cadmium levels, as high as 10.98 mg/kg (dry weight basis) have been obtained. This approaches the safety limit that may be hazardous to human health. Continual monitoring of cadmium and other trace metals of toxicological significance to man in Hong Kong seafood is recommended.     

FACTORS INFLUENCING ACUTE TOXICfrY OF COAL ASH TO RAINBOW TROUT (SALMO GAIRDNERI) AND BLUEGILL SUNFISH (LEPOMIS MACROCHIRUS)1

ABSTRACT: The potentially toxic components in coal ash (ash particles, heavy metals) were evaluated in laboratory static, acute (96 hr) bioassays, both separately and in various combinations with extreme pH (5.0 and 8.5), using rainbow trout (Salmo gairdneri) and bluegifi sunfish (Lepomis macrochirus). Ash particle morphology and metal distribution anlaysis, using electron microscopy and surface-subsurface analysis by ion microscopy, showed that metals could be either clumped or evenly distributed on the surface of fly ash. Surface enrichment on fly ash particles from electrostatic precipitators, as measured by ion microscopy, was found for cadmium, copper, chromium, nickel, lead, mercury, titanium, arsenic, and selenium. Bottom (heavy) ash was not acutely toxic to either fish species at concentrations of up to 1500 mg/l total suspended solids (TSS) at pH 5.0, 7.5, or 8.5. Fly ash particles were not acutely toxic to blue-gill at levels up to 1360 mg/l TSS. Rainbow trout were highly sensitive to fly ash (25 to 60 percent mortality) at concentrations of 4.3 to 20.5 mg/I TSS when dissolved metal availability was high but were not sensitive at higher particulate concentrations (58 to 638 mg/I TSS) when dissolved metals were low. When metals were acid-leached from fly ash prior to testing, no rainbow trout mortality occurred at TSS concentrations of up to 2,350 mg/l TSS. When the percent of dissolved metal was high (e.g., 50–90 percent of the total), fish mortality was increased. Rainbow trout were nearly two orders of magnitude more sensitive than bluegill when subjected to a blend of cadmium, chromium, copper, nickel, lead, and zinc. The two species were similar in their acute sensitivity to acidic pH at levels at or below 4.0 and alkaline pH of 9.1. If the pH of coal ash effluent is contained within the range 6.0 to 9.0, acute toxicity to fish can be attributed to trace element availability from fly ash but not heavy ash. Control of holding pond and effluent pH and maximizing pond residence time are important strategies for minimizing effects of ash pond discharges on fish.     

Reclamation of wastes contaminated by copper,lead, and zinc

Waste materials containing toxic levels of copper, lead, and zinc, such as mine and smelter wastes, present difficult conditions for the establishment of vegetation. This article reviews the many attempts which have been made to reclaim these wastes. Inert wastes from mining and quarrying operations, such as slate quarry waste and certain colliery shales, seem to be good materials for reclaiming wastes contaminated by copper, lead, and zinc. Organic wastes, such as sewage sludge and domestic refuse, may provide only a temporary visual improvement and stabilization of the toxic materials.Nontolerant plant materials may often be planted directly on modern waste materials, which are less toxic than they were in the past. However, tolerant plant materials are needed for revegetating waste materials produced by early and more primitive extraction methods.     

Determining contamination level of heavy metals in road dust from busy traffic areas with different characteristics

This study identified the levels and sources of heavy metal contamination in road dust from busy traffic areas in a typical industrial city in Korea. This study compared the total concentrations, as determined by aqua regia digestions and atomic absorption spectroscopy, of cadmium (Cd), copper (Cu), lead (Pb), zinc (Zn) and nickel (Ni) in the road dust from areas with different characteristics such as traffic rotaries, downtown areas, circulation roads, and asphalt and concrete highways. The contamination levels of the heavy metals in the road dust were evaluated using the contamination factor and the degree of contamination. The contamination levels of the heavy metals in the road dust were highly dependent on traffic volume and atmospheric dispersion from traffic rotaries. Industrial emissions and the frequency of brake use and vehicles coming to a complete stop were additional factors that affected the contamination levels in downtown areas. The concrete highway had higher contamination levels of the heavy metals than the asphalt highway. Vehicle speed was also a strong contributing factor to the degree of contamination of heavy metals in the road dust from the circulation roads and highways.     

CHARACTERIZING GROUND WATER FLOW IN THE MUNICIPAL WELL FIELDS OF CEDAR RAPIDS,IOWA, WITH SELECTED ENVIRONMENTAL TRACERS1

ABSTRACT: Cedar Rapids obtains its municipal water supply from a shallow alluvial aquifer along the Cedar River in east-central Iowa. Water samples were collected and analyzed for selected isotopes and chlorofluorocarbons to characterize the ground-water flow system near the municipal well fields. Analyses of deuterium and oxygen-18 indicate that water in the alluvial aquifer and in the underlying carbonate bedrock aquifer was recharged from precipitation during modern climatic conditions. Analyses of tritium indicate modern, post-1952, water in the alluvial aquifer and older, pre-1952, water in the bedrock aquifer. Mixing of the modern and older waters occurs in areas where (1) the confining layer between the two aquifers is discontinuous, (2) the bedrock aquifer is fractured, or (3) pumping of supply wells induces the flow of water between aquifers. Analyses of chlorofluorocarbons were used to determine the date of recharge of water samples. Water in the bedrock aquifer likely was recharged prior to the 1950s. Water in the alluvial aquifer likely was recharged from the 1960s to 1990s. Biodegradation or sorption probably affected some of the ground water analyzed for chlorofluorocarbons. These processes reduce the concentrations of CFCs, which results in older than actual calculated dates of recharge.     

Levels of lead in blood in residents of Kuwait

Following an examination of blood samples from 1000 persons from Kuwait, a number of important differences in the levels of lead in the blood were noted. There were significant differences between the sexes living in the same residential area. Certain significant lead in blood differences were also found between females and males who dyed their hair, and between smokers and non-smokers. Lead in blood concentrations were also tested for the various blood groups of the respondents. It was noted that O⁺ blood group respondents were found to have higher lead levels than those of other major blood groups.     

SUSPENDED SEDIMENT AND METALS REMOVAL FROM URBAN RUNOFF BY A SMALL LAKE1

ABSTRACT: A small lake in the Chicago Metropolitan Area was from 91 to 95 percent efficient in removing suspended sediment and from 76 to 94 percent efficient in removing copper, iron, lead, and zinc from urban runoff. Sediments accumulated in the lake in the form of an organic-rich mud at an average rate of 20 millimeters per year; this reduced lake storage and covered potential habitat for aquatic organisms. Copper, lead, and zinc concentrations were closely associated with suspended-sediment concentrations and with silt- and clay-sized fractions of lake sediment. Although concentrations of mercury and cadmium were near detection limits in runoff, measurable concentrations of these metals accumulated in the lake sediments.     

pH-dependent release of cadmium,copper, and lead from natural and sludge-amended soils

The pH-dependent release of cadmium, copper, and lead from soil materials was studied by use of a stirred flow cell to quantify their release and release rates, and to evaluate the method as a test for the bonding strength and potential mobility of heavy metals in soils. Soil materials from sludge-amended and nonamended A horizons from a Thai coarse-textured Kandiustult and a Danish loamy Hapludalf were characterized and tested. For each soil sample, release experiments with steady state pH values in the range 2.9 to 7.1 and duration of 7 d were performed. The effluent was continuously collected and analyzed. Release rates and total releases were higher for the Hapludalf than the Kandiustult and higher for the sludge-amended soils than the nonamended soils. With two exceptions the relative release rates (release rate/total content of metal in soil) plotted vs. steady state pH followed the same curves for each metal, indicating similar bonding strengths. These curves could be described by a rate expression of the form: relative release rate = k[H+]a, with specific a (empirical constant) and k (rate constant) parameters for each metal demonstrating that metal release in these systems can be explained by proton-induced desorption and dissolution reactions. With decreasing pH, pronounced increases in release rates were observed in the sequence cadmium > lead > copper, which express the order of metal lability in the soils. The flow cell system is useful for comparison of metal releases as a function of soil properties, and can be used as a test to rank soils with respect to heavy metal leaching.     

Copper, Cobalt, Nickel and Manganese Availability from Land-based Endowments A Perspective

Estimates of land-based demonstrated resources of cobalt, copper, manganese, and nickel would indicate adequate supply for many years to come based on current levels of annual consumption. However, when these resource estimates are disaggregated, much of this resource is found to occur in a limited number of producing mines. Almost all of the cobalt in these resources coexists with either nickel or copper, and as such, will be available only to the degree extraction of these two metals from existing mines is economical. Finally, current projections of excess capacity in existing mines for all four metals, coupled with additional inferred resources at these mines and yet to be exploited resources in known economical deposits, would lead one to conclude that, from this perspective, the mining of sea bed nodules is not likely to occur until well into the next century.     

Predicting estuarine sediment metal concentrations and inferred ecological conditions: an information theoretic approach

Empirically derived relationships associating sediment metal concentrations with degraded ecological conditions provide important information to assess estuarine condition. Resources limit the number, magnitude, and frequency of monitoring activities to acquire these data. Models that use available information and simple statistical relationships to predict sediment metal concentrations could provide an important tool for environmental assessment. We developed 45 predictive models for the total concentrations of copper, lead, mercury, and cadmium in estuarine sediments along the Southern New England and Mid-Atlantic regions of the United States. Using information theoretic model-averaging approaches, we found total developed land and percent silt/clay of estuarine sediment were the most important variables for predicting the presence of all four metals. Estuary area, river flow, tidal range, and total agricultural land varied in their importance. The model-averaged predictions explained 78.4, 70.5, 56.4, and 50.3% of the variation for copper, lead, mercury, and cadmium, respectively. Overall prediction accuracies of selected sediment benchmark values (i.e., effects ranges) were 83.9, 84.8, 78.6, and 92.0% for copper, lead, mercury, and cadmium, respectively. Our results further support the generally accepted conclusion that sediment metal concentrations are best described by the physical characteristics of the estuarine sediment and the total amount of urban land in the contributing watershed. We demonstrated that broad-scale predictive models built from existing monitoring data with information theoretic model-averaging approaches provide valuable predictions of estuarine sediment metal concentrations and show promise for future environmental modeling efforts in other regions.     

GEOCHEMICAL CHARACTERIZATION OF SHALLOW GROUND WATER IN THE EUTAW AQUIFER,MONTGOMERY, ALABAMA1

ABSTRACT: Ground water samples were collected from 30 wells located in, or directly down gradient from, recharge areas of the Eutaw aquifer in Montgomery, Alabama. The major ion content of the water evolves from calcium‐sodium‐chloride‐dominated type in the recharge area to calcium‐bicarbonate‐dominated type in the confined portion of the aquifer. Ground water in the recharge area was under saturated with respect to aluminosilicate and carbonate minerals. Ground water in the confined portion of the aquifer was at equilibrium levels for calcite and potassium feldspar. Dissolved oxygen and nitrite‐plus‐nitrate concentrations decreased as ground water age increased; pH, iron, and sulfate concentrations increased as ground water age increased. Aluminum, copper, and zinc concentrations decreased as ground water age and pH increased. These relations indicate that nitrate, aluminum, copper, and zinc are removed from solution as water moves from recharge areas to the confined areas of the Eutaw aquifer. The natural evolution of ground water quality, which typically increases the pH and decreases the dissolved oxygen content, may be an important limiting factor to the migration of nitrogen based compounds and metals.     

PRESENCE AND DISTRIBUTION OF TRACE ELEMENTS IN NEW JERSEY STREAMBED SEDIMENTS1

ABSTRACT: The distribution of trace elements in New Jersey streambed sediments is described with respect to physiographic provinces and major drainage areas. Samples were collected during 1976–1993 at 295 sites distributed throughout New Jersey. Copper, chromium, lead, and zinc were detected with the greatest frequency and at the highest concentrations of the elements. Concentrations of most trace elements were significantly higher in streambed sediments from the New England (glaciated) and Piedmont physiographic provinces - the provinces with the lowest and highest percentages of urban land use, respectively - than in sediments from the other provinces. High trace-element concentrations in the New England (glaciated) province reflect previous mining of extensive magnetite deposits, whereas those in the Piedmont province most likely reflect urban land use. Significantly lower trace-element concentrations in streambed sediments from the Coastal Plain are attributable to the low pH of the streamwater, the lack of iron and manganese available to form coatings that scavenge trace elements, and the relatively low percentage of urban land use in the province. Trace-element concentrations were related to land use, population, or point sources in the drainage basin specific to the sampling location by using logistic regression. Results of this analysis indicate a relation between arsenic and agricultural land use; chromium and physiographic province; and copper, lead, and zinc and population density.