Spatial Assessment of Heavy Metals in Surface Soil from Klang District (Malaysia): An Example from a Tropical Environment

Heavy metals (Al, Cd, Co, Cr, Cu, Fe, Pb, Zn) in surface soil of Klang district were determined and multivariate analysis was used to understand their potential sources. The total and bioavailability of concentrations were used in identifying the potential risks to the ecology and human health. The means for the total heavy metal concentrations were found to be in the order of Fe > Al > Zn > Pb > Cu > Cr > Co > Cd, while the means for the bioavailability concentrations were found to be in the order of Al > Fe > Zn > Cu > Co > Cd > Pb > Cr. Principal Component Analysis showed Principal Component 1 as being of natural origin whereas Principal Components 2, 3, and 4 were associated with mixed anthropogenic sources, such as traffic and industrial emissions, organic matter, and granulometric fractions. Potential ecological risk assessment indicated an overall low ecological risk. Spatial assessment of non-carcinogenic risks showed that the Hazard Index values were more than one in Johan Setia, due to biomass burning of peat swamps exploited for agricultural development. While for spatial assessment of carcinogenic risks, the Lifetime Cancer Risk values were in the limit (1 × 10^?5), indicating low cancer inducing risks. Nevertheless, with intense development pressure in the Klang district could overlap pollution inputs in the future.     

Hydrologic and biogeochemical controls on trace element export from northern Wisconsin wetlands

Wetlands play an important role in determining the water quality of streams and are generally considered to act as a sink for many reactive species. However, retention of chemical constituents varies seasonally and is affected by hydrologic and biogeochemical processes including water source, mineral weathering, DOC and SPM cycling, redox status, precipitation/dissolution/adsorption, and seasonal events. Relatively little is known about the influence of these factors on trace element cycling in wetland-influenced streams. To explore the role of wetlands with respect to the retention/release of trace elements to streams, we examined temporal and spatial patterns of concentrations of a large suite of trace elements (via ICP-MS) and geochemical drivers in five streams and wetland rivulets draining natural wetlands in a northern Wisconsin watershed as well as in their groundwater sources (terrestrial recharge, lake recharge, and older lake recharge). We performed principal components analyses of the concentrations of elements and their geochemical drivers in both the streams and rivulets to assist in the identification of factors regulating trace element concentrations. Variation in trace and major element concentrations among the streams was strongly related to the proportion of terrestrial recharge contributing to the stream. A dominant influence of water source on rivulet chemistry was supported by association of groundwater-sourced elements (Ba, Ca, Cs, Mg, Na, Si, Sr) with the primary statistical factor. DOC appeared in the first principal component factor for the streams and in the second factor for the rivulets. Strong correlations of Al, Cd, Ce, Cu, La, Pb, Ti, and Zn with DOC supported the important influence of DOC on trace metal cycling. A number of elements in the rivulets (Al, La, Pb, Ti) and streams (Al, Ce, Cr, Cu, La, Pb, Ti, Zn) had a significant particulate cycle. Redox cycling and precipitation/dissolution reactions involving Fe and Mn likely impacted Cu and Mo as evidenced by the low levels in the rivulets. Variance in Fe, Mn and the metal oxy-anions was associated with factors related to redox cycling and adsorption reactions in the wetland sediments. In streams, DOC and metals with a high affinity for DOC were associated with a factor which also included negative loadings for groundwater-sourced elements, reflecting the importance of seasonal hydrologic events which flush DOC and metals from wetland sediments and dilute groundwater sourced metals. Redox processes were of secondary importance in the streams but of primary significance in the rivulets, documenting the importance of anoxic conditions in wetland sediments on groundwater en route to the stream.     

The effects of eight trace metals in acid soft water on survival, mineral uptake and skeletal calcium deposition in yolk-sac fry of brown trout, Salmo trutta L.

Recently hatched fry of brown trout were exposed to each of eight trace metals (Al, Cd, Cu, Fe, Mn, Ni, Pb, Zn) and to a mixture of all eight, at concentrations typical of soft acid waters, in flowing artificial soft water medium at pH 4·5 and 6·5, for 30 days. At pH 4·5, in the absence of trace metals, net uptake of Ca, Na and K and skeletal calcification were impaired but mortalities were low (10%). At pH 4·5, in the presence of Al, Cu, Pb and Zn individually and the mixture, mortalities were high (87–100%). Cd, Fe, Mn and Ni at pH 4·5 each caused some mortalities (17–43%) and impaired skeletal calcification. At pH 6·5, each of Al, Cd, Cu, Fe, Mn, Pb and the mixture of metals impaired net Ca uptake and (except Al, Fe and Pb) skeletal calcification. Net K uptake was impaired by Al and by the mixture, and less severely by Cu and by Fe. Net Na uptake was impaired by Al and by the mixture, and less severely by Fe and by Mn. The role of trace metals other than Al in fisheries'decline in soft acid waters is discussed.     

Environmental impact of former gold mining on the Orangi river,Serengeti N.P., Tanzania

The Orangi river is an important all-year source of water for wildlife in the northern part of the Serengeti National Park. At two points along the river in the Banagi area, tributaries draining the adit and tailings of the Kilimafeza mine impact the Orangi. The former Au-Cu mine is subject to occasional wet season flooding leading to the release of iron ochres from the adit and physical as well as chemical mobilization of tailings material. The unpolluted river chemistry is essentially Na-Ca-HCO ₃ ^– and well-buffered. Drainage water; from the tailings are characterized by low pH (2.3) and high concentration of sulphate (up to 3280 mg/l), aluminium (275 mg/l), arsenic (324 mg/l), copper (125 mg/l), iron (622 mg/l), lead (21 mg/l), manganese (65 mg/l), and zinc (126 mg/l). Adit-drainage waters are typically of a lower pH (4.6) and have a lower concentration of sulphate (up to 1840 mg/l) and metals (up to 25 mg/l Al, 92 mg/l As, 42 mg/l Cu, 258 mg/l Fe, 9.6 mg/l Pb, 53 mg/l Mn, and 102 mg/l Zn). Mixing of these acidic waters with the alkaline river leads to rapid metal precipitation as Fe-ochre coatings on clastic sediment. This effect is more noticeable in the dry season. Consequently, although the tributaries draining the two sources are heavily contaminated, the effective buffering of the mine drainage waters restricts any potential pollution to within 1 km of the mine workings. Faecal coliforms show an antipathetic relationship to low pH and high metal conditions. The only mobile metals in the water outside this area are Mn and Zn and their contamination can be biologically monitored using a protozoan-based bioassay.     

Trace elements in the Upper Fly River, Papua New Guinea

SUMMARY. Measurements were made of calcium, magnesium and eight trace elements (Cu, Zn, Fe, Mn, Ni, Pb, Cd, Co) in waters, sediment and biota at eight sites in the Upper Fly River, Papua New Guinea. Determinations from streams draining an area rich in copper ore showed relatively low values for soluble copper and this was attributed to the small amount of ore exposed to weathering, heavy rainfall and high pH of water associated with the limestone bedrock. More iron was transported in a soluble form down a headwater tributary (Alice River) than in the Fly River but higher iron concentrations were associated with particulate matter in the Fly than in the Alice. The geochemistry of the catchment and the distance from the headwaters were important influences on the amount of particulate iron and its distribution between soluble and particulate forms.
Levels of metals in the biota generally reflected the background concentrations of metals encountered at each site. Concentrations of Cu, Cd, and Zn were lower in starved invertebrates compared with unstarved individuals but no consistent changes were observed in Fe or Mn content.     

Impacts of Yellow River Irrigation Practices on Trace Metals in Surface Water: A Case Study of the Henan-Liaocheng Irrigation Area,China

Large-scale irrigation practices may disturb local hydrologic cycles and distribute trace metals throughout the environment. Reported here is the spatial pattern of trace metals and associated health risks in an agricultural area of China, which has a long history of irrigation with water from the Yellow River. Multivariate statistical analyses and a risk-assessment model were employed to interpret the environmental data. It indicated that Zn, Se, B, Ba, Fe, Mn, Mo, Ni, V, Al, Li, Sr, Be, Cd, Cr, Cu, and Pb were all detected in the surface waters. Compared to drinking water guidelines, the primary trace metal pollution components (Al, Fe, Se, B, Mn, and Zn) exceeded drinking water standards by 40.7%, 14.8%, 29.6%, 25.9%, 11.1%, and 14.8%, respectively. Except for one site that exhibited anomalous metal concentrations, landscape features of trace metals identified a uniform distribution of trace metals for all sample sites. The calculated mean value of Hazard Quotients (HQs) exceeded the USEPA's recommendations by a factor of 2.9 times the threshold value. Primary sources of trace metals were associated with natural deposition, industrial and agrochemical processes, and a mixed source of both geogenic and anthropogenic origins.     

Zooplankton from a North Western Mediterranean area as a model of metal transfer in a marine environment

We monitored the concentration of 21 trace elements in zooplankton samples collected in a Northwestern Mediterranean coastal ecosystem (Italy). In the last 20 years, this area has been the target of important anthropogenic impacts including maritime traffic and substantial industrial activities. Zooplankton contributes to the transfer of trace metals to higher trophic levels and constitute one of the recommended groups for the baseline studies of metals in the marine environment. The essential trace elements (As, Cu, Mn, Zn, Fe, Mo, Co, Cr, Se, Ni) and the nonessential trace elements (Al, Be, Cd, Pb, Sb, Sn, V) were generally found at concentrations of no concern in the analyzed zooplankton samples, but showed important variations between seasons and different water depths. The zooplankton was found to be a significant accumulator of metals, and bioaccumulation factors were in the range of 28 (Co) to 10,9015 (Fe) in marine surficial waters, with increasing values at increasing water depth. Zooplankton is a useful bioindicator to assess metal contamination and its impact in the marine environment.     

Bioaccumulation and health risk assessment of trace metal contamination in the musculature of the trahira fish (Hoplias malabaricus) from two neotropical rivers in southeastern Brazil

BackgroundFish are an important source of nutrition for humans. Artisanal fishing plays a fundamental role in Brazil fish production. In Brazil, the unrestrained increase, diffusion, and little importance for environmental causes of other economic activities, such as the agricultural industry, has caused irreparable damage, leading to the contamination of water bodies. Among the countless pollutants that reach water bodies, trace metals are extremely problematic. Here, we evaluated the bioaccumulation and health risk of trace metal contamination in the musculature of the trahira fish (Hoplias malabaricus), collected from two rivers in southeastern Brazil.MethodsDuring the period from May 2017 to November 2019, 90 fish were collected, 45 from each river. River water samples were also taken during the same collection periods. From fish, muscle tissue samples were taken, and together with river water samples, analyzed for the recovery of trace metals (Al, Cr, Mn, Fe, Ni, Cu, As, Cd, and Pb) through the technique of Inductively Coupled Plasma Mass Spectrometry (ICP-MS).ResultsIn general, fish as well as the waters of the Jacaré-Guaçú River had higher concentrations of metals. The elements Al, Cr and Cd stood out from the others analyzed metals for having a hazard index (HQ) above 1 (Al), for being up to 10 times above the concentrations allowed by Brazilian legislation (Cr) and for having a high bioconcentration factor (Cd), indicating a biomagnification process through the food chain.ConclusionIn general, trace metal concentrations in the waters and fish of the Jacaré‐Guaçú were higher than in the Jacaré-Pepira, which shows that the Jacaré‐Guaçú is the one that suffers more anthropogenic action between the two rivers. In addition, some elements such as Al, Cr and Cd, due to its high concentrations, should receive some attention as they can pose risks to the health of fish, which can jeopardize the survival of their populations, and especially to humans who use these animals as a food source.     

Comparison of measured and modelled copper binding by natural organic matter in freshwaters

Fifteen freshwater samples containing significant concentrations of dissolved organic carbon-[DOC]-were titrated with copper under standardised conditions (pH 6 and 7), and concentrations of Cu(2+)-[Cu(2+)]-were measured with an ion-selective electrode. Measured values of [Cu(2+)], which were in the range 10(-11)-10(-5) moll(-1), were compared with those simulated using Humic Ion-Binding Models V and VI. It was assumed that copper speciation was controlled by the organic matter, represented by fulvic acid (FA), together with inorganic solution complexation (calculated with an inorganic speciation model). The models were calibrated by adjusting a single quantity, the concentration of FA. The optimised value-[FA](opt)-was that giving the best agreement, according to least squares, between measured and simulated [Cu(2+)]. The calculations took into account competition by other dissolved (filterable) metals (Mg, Al, Ca, Fe(II), Fe(III), Zn); in the case of Fe(III) it was assumed either that all the dissolved metal was truly in solution, or that the activity of Fe(3+) was controlled by equilibrium with Fe(OH)(3). The assumption about Fe(III) had relatively small effects on the fitting of Model V, but was significant for Model VI, because Model VI represents low-abundance, high-affinity binding sites in humic matter, which are sensitive to Fe(III) competition. Because of its inclusion of the high-affinity sites, Model VI provided better fits of the data than did Model V. Furthermore, Model VI with Fe(3+) activity controlled by Fe(OH)(3) gave smaller variation in the ratio of [FA](opt) to [DOC] than Model VI with all Fe(III) assumed to be in solution. The average [FA](opt)/[DOC] found from the Cu titrations was 1.30, which implies that 65% of the organic matter is 'active' with respect to metal binding. The average ratio of 1.30 is in reasonable agreement with ratios obtained by applying the model to field data sets for charge balance (1.22), Al speciation (1.56) and base titrations of Cu-amended waters (1.45). It is concluded that Model VI/Fe(OH)(3) provides the most reliable predictions of dissolved metal speciation in natural waters; at a total Cu concentration of 1 microM, the predicted concentration of Cu(2+) is expected to be correct to within a factor of 3.6 in 95% of cases.     

Effects of six trace metals on calcium fluxes in brown trout (Salmo trutta L.) in soft water

Summary Calcium fluxes were measured simultaneously in brown trout fry maintained in an artificial soft water medium of [Ca] 20 mol·l^-1 and pH 5.6, and exposed to each of six trace metals (Al, Cu, Fe, Ni, Pb, and Zn). The trace metal concentrations represented typical and maximum levels found in acid waters experiencing declining fishery status. In the absence of trace metals, evidence is presented which suggests that ca. 91% of Ca taken up from the external medium was by extraintestinal active transport. Calcium efflux was stimulated by both concentrations of Al, Cu, Fe, and Pb. Efflux was also stimulated by [Ni] 170 nmol·l^-1 and [Zn] 3000 nmol·l^-1. In some cases, response to increased efflux was stimulation of influx. Lack of stimulation of influx resulted in negative net Ca fluxes. Net Ca losses were recorded at both concentrations of Al, Pb, and Ni, lower concentrations only of Fe, and higher concentrations only of Cu and Zn.Abbreviations J _in influx - J _net net flux - J _out efflux Henceforward in this paper, chemical elements are referred to by their chemical symbols rather than by full names     

Human Health Risk of Metals in Drinking-Water Source Areas from a Forest Zone after Long-Term Excessive Deforestation

The concentrations of 10 metals (As, Cd, Cr, Cu, Fe, Hg, Mn, Pb, Se, Zn) were determined in drinking water in Khingan, China, a forest zone after long-term excessive deforestation. These metals’ concentrations in water exceeded background values of metals in some other regions of the world, indicating that there were other metal sources contributing to such high levels of metals in Khingan. Arsenic was the only metal whose concentration exceeded the maximum levels allowed in drinking water. Principal component analysis showed that As, Cd, Cu, and Se originated from anthropogenic sources and exhibited significantly high concentrations in north Khingan, while Fe and Mn derived from natural formation and showed significantly high concentrations in central Khingan. Health risks from metals were evaluated by a model recommended by the U.S. Environmental Protection Agency. Ingestion was the predominant pathway of exposure to metals in water for local residents. Arsenic was also the only metal causing both noncarcinogenic hazard and carcinogenic risk in Khingan. The high risks occurred mainly in north Khingan and are associated with coal combustion. This study indicates that long-term excessive deforestation may increase As concentration considerably in drinking water and then pose health risks to local residents.     

Heavy Metals in Sediments of the Gold Mining Impacted Pra River Basin,Ghana, West Africa

Total concentrations of Hg, Al, Fe, As, Pb, Cu, Cr, Ni, Mn, Co, V, and Zn were determined in surface sediments collected from 21 locations within the gold mining impacted Pra River basin in southwestern Ghana. Samples were collected during both the rainy and dry seasons. We hypothesized that in the rural southwestern portion of Ghana, the lack of industrial activities makes artisanal gold mining (AGM) by Hg amalgamation the main source of water resource contamination with heavy metals. Therefore, metals showing concentration trends similar to that of Hg in the studied system are likely impacted by AGM. We found that total-Hg (THg) concentrations in riverine sediments are rather low as compared to other aquatic systems that are impacted by similar mining activities. Measured THg concentrations ranged from 0.018 to 2.917 mg/kg in samples collected in the rainy season and from about 0.01 to 0.043 mg/kg in those collected during the dry season. However, the determination of the enrichment factor (EF) calculated using shale data as reference background values showed signs of severe contamination in most of the sampled sites. In the dry season, THg concentrations correlated positively and significantly to the concentrations of As (r = 0.864, p < 0.01), Cu (r = 0.691, p < 0.05), and Ni (r = 0.579, p < 0.05). Based on our previously stated hypothesis, this could then be an indication of the impact of AGM on ambient levels of these 3 elements. However, the determined concentrations of Cu, and Ni co-varied significantly with Al, suggesting that natural sources do account for the observed levels. Accordingly, both AGM and metal inputs from weathered natural deposits are likely co-responsible for the observed levels of Cu and Ni. In contrast, the lack of correlation between As and Al tends to suggest an impact of AGM on As levels. Overall, our data suggest that besides Hg and to some extent As, the impact of AGM on ambient levels of investigated metals in the gold mining impacted Pra River remains negligible. Finally, the increase in metal concentrations from the dry to the rainy season underlines the impact of changes in hydrologic conditions on levels and fate of metals in this tropical aquatic system.     

Enrichment in Trace Metals (Al,Mn, Co,Cu, Mo,Cd, Fe,Zn, Pb and Hg) of Macro-Invertebrate Habitats at Hydrothermal Vents Along the Mid-Atlantic Ridge

The present study describes several features of the aquatic environment with the emphasis on the total vs. filter-passing fraction (FP) of heavy metals in microhabitats of two typical deep-sea vent organisms: the filter-feeder, symbiont-bearing Bathymodiolus and the grazer shrimps Rimicaris/Mirocaris from the Mid-Atlantic Ridge (MAR). The concentration of 10 trace elements: Al, Mn, Co, Cu, Mo, Cd, Fe, Zn, Pb and Hg was explored highlighting common and distinctive features among the five hydrothermal vent sites of the MAR: Menez Gwen, Lucky Strike, Rainbow, Saldanha, and Menez Hom that are all geo-chemically different when looking at the undiluted hydrothermal fluid composition. The drop off in the percentage of FP from total metal concentration in mussel and/or shrimp inhabited water samples (in mussel beds at Rainbow, for instance, FP fraction of Fe was below 23%, Zn 24 %, Al 65%, Cu 70%, and Mn 89%) as compared to non-inhabited areas (where 94% of the Fe, 90% of the Zn, 100% of the other metals was in the FP fraction) may indicate an influence of vent organisms on their habitat’s chemistry, which in turn may determine adaptational strategies to elevated levels of toxic heavy metals. Predominance of particulate fraction over the soluble metals, jointly with the morphological structure and elemental composition of typical particles in these vent habitats suggest a more limited metal bioavailability to vent organisms as previously thought. In addition, it is evoked that vent invertebrates may have developed highly efficient metal-handling strategies targeting particulate phase of various metals present in the mixing zones that enables their survival under these extreme conditions.     

Phosphorus Retention at the Redox Interface of Peatlands Adjacent to Surface Waters in Northeast Germany

It is demanded currently in public discussions to rewet peatlands and re-establish their function as nutrient sinks. But due to high phosphorus (P) concentrations in the pore water of rewetted peatlands (40–420 μM) it is hypothesized that they can act as a surplus P source for adjacent surface waters and consequently support the eutrophication of such waters. Our detailed investigations of processes at the redox interface in four fens with different geochemical character show the dependence of P retention from the chemistry of the pore water. The precipitation of Fe(III) oxyhydroxide led to high retention of phosphorus and other substances such as DOC and sulphate in the eutrophic fens. When molar Fe/P ratios were larger than about 3 the initially high P concentrations in the anaerobic pore water (20–210 μM) decreased to concentrations below 1 μM under aerobic conditions. Thus, after rewetting high pore water concentrations of P do not automatically result in an increased P load to adjacent surface waters compared to pre-rewetting conditions. An enhanced P export to adjacent surface waters from eutrophic fens can be expected when the Fe/P ratio is smaller than 3 in the anaerobic pore water. In our investigations of natural, oligotrophic to mesotrophic fens the precipitation of Fe(III) oxyhydroxide was inhibited by the formation of stable dissolved Fe ∼ humic complexes. P retention in these fens was only related to the DOC concentrations at the redox interface, so that lower DOC concentrations concurred with higher P retention. The P equilibrium concentrations in an aerobic environment can be higher than that of eutrophic fens with Fe/P ratios larger than about 3 in the anaerobic pore water.     

Trace Metal Fractionation by the Sequential Extraction Method in Sediments from the Lis River (Portugal)

The extractable contents of Zn, Pb, Cu, Cr, Mn, Ni, Fe and Al were evaluated in sediments from the Lis River (Portugal) using the three-step sequential extraction procedure described by Community Bureau of Reference (BCR, now the Standards, Measurement and Testing Programme) of the European Union. The distribution of trace metals among the exchangeable, water and acid soluble, reducible, oxidizable and residual fractions was determined. The highest metal concentrations were observed in samples collected at the most polluted river sites (animal husbandry, domestic, industrial and agricultural wastes). Pb, Cu, Cr, Ni, Fe and Al were found mainly associated with the residual and organic fractions. High concentrations of Zn and Mn were found in the exchangeable/acid soluble fraction.     

Determination of water quality,and trace metals in endemic Sarotherodon linellii,Pungu maclareni and Clarias maclareni,in crater Lake Barombi Mbo,Cameroon

Considering water pollution as a potential threat to some endemic cichlids of Lake Barombi Mbo, Cameroon, an investigation was done in 2011 to determine trace metals in its water, linking their uptake in gills and liver of fish to water chemistry. ICP-MS and ICP-OES analyses of trace metals based on total concentration of unfiltered lake water samples showed the presence of trace metals. All fish species accumulated Al, Mn and Sr in the highest concentrations in their gills, with Cu, Cd, Co, Cr, Pb and U highest in the liver. Pungu maclareni accumulated Al, Cr, Co, Sr and Pb in the highest concentrations. The highest mean gill Al concentration of 140 µg g^?1 dry weight was measured in P. maclareni gills, this being one of the critically endangered cichlids of the lake. Stable isotope analyses of carbon δ¹³C and nitrogen δ¹⁵N showed that P. maclareni had the highest mean δ¹³C (?30.2‰) and highest concentrations of Cr, Co, Pb and U in liver, probably linking the carbon source to the accumulation of metals. Though trace metal levels in the lake water were low, their presence in fish tissues suggest they are bioavailable, bioaccumulate and may pose a threat to the aquatic biota, and therefore should be monitored.     

Distribution and Contamination Risk Assessment of Dissolved Trace Metals in Surface Waters in the Yellow River Delta

This study investigated the dissolved trace metal contamination levels of Zn, Sr, B, Al, Ba, Fe, Mn, Li, V, Be, Cd, Cr, Cu, Mo, Ni, Se, and Pb in 23 surface waters of the Yellow River Delta (YRD) in China. Coefficients of variation with 66–260% reflected large spatial variations of concentrations of metals. Compared to drinking water guidelines established by the World Health Organization and the U.S. Environmental Protection Agency, the primary trace metal pollution components (Al, B, V, and Zn) were above drinking water standard levels by 82.6%, 47.8%, 52.2%, and 52.2%, respectively. Preliminary risk assessments were determined via the Hazard Quotient (HQ) to evaluate the human health risk of these metals. HQ_ingestion of V indicated potential deleterious health effects for residents. Hierarchical cluster results revealed that clusters 1, 2, and 3 were primarily affected by pollution from industrial and domestic activities, natural and agriculture activities, and oil fields, respectively. Principal component analysis results indicated Fe, Mn, Al, and Ba were controlled by natural sources, whereas anthropogenic activities led to high pollution levels of Al, B, V, Zn, and Sr.     

Metal concentrations in Sargassum algae from coastal waters of Nha Trang Bay (South China Sea)

The concentrations of metals, viz., Fe, Mn, Cu, Zn, Cd, Pb, and Ni, were investigated in brown algae of the genus Sargassum collected in the coastal waters of Nha Trang Bay (South China Sea). Metal concentrations in algae growing in the zone of influence of the city of Nha Trang were higher than those in macrophytes collected to the south and north of the city. Similar levels of Cu and Fe concentrations were observed in macrophytes from the urbanized coastal areas of Nha Trang Bay and in algae from the Peter the Great Bay (Sea of Japan). This is suggestive of comparable metal inputs from the anthropogenic sources of the cities of Nha Trang and Vladivostok (Peter the Great Bay). However, the concentrations of Pb, Ni, and Cd in algae from the coastal waters of Nha Trang Bay were lower than in macrophytes from the inshore zone of Vladivostok. The high level of pollution of sea water with Zn compounds near Nha Trang was local. The metal levels in macrophytes from background areas reflect the geochemical features of the environment. Sargassum algae from Nha Trang Bay had lower concentrations of Zn, Cd, and Ni and higher concentrations of Mn than algae from Peter the Great Bay. The background concentrations of Cu, Pb, and Fe in macrophytes from both bays were virtually the same.     

Impact of Simulated Acid Rain on Trace Metals and Aluminum Leaching in Latosol from Guangdong Province,China

Acid rain is one of the most serious ecological and environmental problems worldwide. This study investigated the impacts of simulated acid rain (SAR) upon leaching of trace metals and aluminum (Al) from a soil. Soil pot leaching experiments were performed to investigate the impacts of SAR at five different pH levels (or treatments) over a 34-day period upon the release of trace metals (i.e., Cu, Ni, Pb, Zn, and Fe) and Al from the Latosol (acidic red soil). The concentrations of trace metals in the effluent increased as the SAR pH level decreased, and were highest at the SAR pH = 2.0. In general, the concentrations of Cu, Pb, Fe, and Al in the effluent increased with leaching time at the SAR pH = 2.0, whereas the concentrations of Zn, Fe, and Al in the effluent decreased with leaching time at the SAR pH ≥ 4.0. The increase in electrical conductivity (EC) with leaching time at five different SAR pH levels was primarily due to the concentrations of Al and Fe in the effluent. There were good linear correlations between the effluent Al concentrations and the effluent pH at the SAR pH = 2.0 (R² = 0.87) and pH = 3.0 (R² = 0.83). More soil trace metals and Al were activated and released into the soil solution as the SAR pH level decreased.     

Trace metals in Swedish natural fresh waters

Water samples were collected from unpolluted waters in southern and northern Sweden to show the range of natural trace metal concentrations. The results do not indicate any significant differences in metal levels between the two study areas. Negative correlations with pH exist for total concentrations of Cd, Pb, Al, Mn and Zn. The dissolved (dialysable) metal fractions also increase with increasing acidity. The concentration of humic substances influences the distribution of Fe, Mn, Al, Pb, Cr, Co and As, as shown by positive correlations with water colour.Increasing alkalinity has a limiting effect upon concentrations and annual fluctuations of Cd and Pb, and to some extent on Zn, in running waters.