Association of trace metals with various sedimentary phases in dam reservoirs

In the present study sediment and water samples collected from Kowsar Dam reservoir in Kohkiluye and Boyerahmad Province, southwest of Iran, are subjected to bulk digestion and chemical partitioning. The concentrations of nickel, lead, zinc, copper, cobalt, cadmium, manganese and iron in water and bed sediment were determined by atomic absorption spectrometry. The concentrations of metals bounded to five sedimentary phases were estimated. On this basis, the proportions of natural and anthropogenic elements were calculated.The anthropogenic portion of elements are as follows: zinc (96 %)> cobalt (88 %)> iron (78 %)> magnesium (78 %)> nickel (78 %)> copper (66 %)> lead (63 %)> cadmium (59 %). The results show sediment contamination by nickel, cadmium and lead, according to the world aquatic sediments and mean earth crust values. Manganese and copper have strong association with organic matter and are of high portion of sulfide bounded ions. Finally, The degree of sediment contamination was evaluated using enrichment factor, geo-accumulation index (Igeo) and pollution index (IPoll). The sediments were identified to be of high cadmium and lead pollution index. The pattern of pollution intensity according to enrichment factor is as follows; manganese (1.25) < copper (1.63) < zinc (1.93) < cobalt (2.35) < nickel (3.83) < lead (12.63) < cadmium (78.32). Cluster analysis was performed in order to assess heavy metal interactions between water and sediment. Accordingly, nickel, cadmium and copper are earth originated. Zinc, copper and manganese are dominated by pH. All the elemental concentrations in water and sediment are correlated except for sedimental copper.     

Heavy metal contamination and its indexing approach for river water

The objective of the study is to reveal the seasonal variations in the river water quality with respect to heavy metals contamination. To get the extend of trace metals contamination, water samples were collected from twelve different locations along the course of the river and its tributaries on summer and the winter seasons. The concentrations of trace metals such as cadmium, cromium, copper, cobalt, iron, manganese, nickel, lead, mercury and zinc were determined using atomic absorption spectrophotometer. Most of the samples were found within limit of Indian drinking water standard (IS: 10500). The data generated were used to calculate the heavy metal pollution index of river water. The mean values of HPI were 36.19 in summer and 32.37 for winter seasons and these values are well below the critical index limit of 100 because of the sufficient flow in river system. Mercury and chromium could not be traced in any of the samples in the study area.     

Trace metals in surface seawaters and sediments from various habitats of the Red Sea coast of Yemen

The purpose of this study was to determine and assess the concentrations of trace metals in surface seawaters and sediments from different coastal habitats of the Red Sea coast of Yemen. Surface seawater and sediment samples were collected, treated and analyzed for cadmium, cobalt, manganese, chromium, lead, iron, nickel, copper, zinc and vanadium by the atomic absorption spectrometric analysis. The concentrations were high for cadmium, cobalt and lead and low or consistent with the natural background concentrations for the rest of the metals. However, the coastal habitats of the Red Sea coast of Yemen are still considered unpolluted, it is concluded that the cadmium cobalt and lead levels in surface seawaters are high and could have negative effects on marine life of the sites. Further studies are needed to characterize the sources fate, biogeochemical processes and impacts of these trace metals on coastal habitats and marine life of the region.     

Geochemical distribution of trace metal pollutants in water and sediments of downstream of an urban river

A study was conducted to investigate the trace metal pollution of water and sediments of downstream of Tsurumi River, Yokohama, Japan. Twenty samples of water and sediments were collected from the river starting from Tokyo bay side up to the junction point of the Yagami River. Results show that the mean concentrations of chromium, cupper and nickel in water greatly exceed (>100 times) the surface water standard. The concentration of molybdenum and lead was also higher than standard values while iron and manganese was lower than that of surface water standard. The mean concentration of zinc, cupper, cadmium, lead, chromium, vanadium, bromine and iodine was 381.1, 133.0, 1.0, 40.8, 102.9, 162.0, 71.5 and 10.6 μg/g sediments, respectively and was greatly exceed the average worldwide shale concentrations and average Japanese river sediment values. However, mean concentration of arsenic, nickel and strontium was 11.0, 36.6 and 164.6 μg/g sediments, respectively which was lower than the average shale value. Other analyzed trace metals, including barium, zirconium, rubidium, yttrium, tin, antimony, cesium, lanthanum, cerium, praseodymium and neodymium were detected in river sediments; the concentration of which was close to the Japan’s river sediment average values. Pollution load index values of the sites of the studied area ranged from 1.24 to 7.65 which testify that the river sediments are polluted. The PLI value of the area was, however, high (6.53) as the concentration of trace metals like zinc, cupper, cadmium, lead and chromium were very high and were the major pollutants.     

Distribution of heavy metals in the core sediments of a tropical wetland system

Five sediment cores from the fresh water region of the Vembanad wetland system were studied for the trace element contents The average concentration of iron, manganese, nickel, copper, zinc, cadmium, lead, mercury and chromium were determined. The core samples were collected using gravity type corer, digested with a mixture of nitric acid and perchloric acid and analyzed by atomic absorption spectrophotometry. Heavy metals such as iron, copper, nickel and zinc reported enrichment towards the surface of the core sediment sample collected from the centre of the lake. Lead, cadmium and mercury showed uniform distribution through out the core. Quality of the sediments were evaluated based on sediment quality guidelines, pollution load index, sum of toxic units and with effect range low/effect range median and threshold effect level/probable effect level values of Environmental Protection Agency guidelines. The degree of contamination for each station was determined. The concentration of different heavy metals has been compared with the world average concentration of shale values. Results of the analysis showed that Vembanad lake is facing serious metal pollution with increased rate of deposition.     

Heavy metals contamination of the Quaternary coral reefs, Red Sea coast, Egypt

In order to assess pollutants and impact of environmental changes along the Egyptian Red Sea coast, seven recent and Pleistocene coral species have been analyzed for Zn, Pb, Mn, Fe, Cr, Co, Ni, and Cu. Results show that the concentration of trace elements in recent coral skeletons is higher than those of Pleistocene counterpart except for Mn and Ni. In comparison with recent worldwide reefs, the present values are less than those of Central America coast (iron), Gulf of Aqaba, Jordan (lead, copper), Gulf of Mannar, India (chromium, zinc, manganese), Costa Rica, Panama (chromium, nickel), North-west coast of Venezuela and Saudi Arabia (copper). The present values are higher than those of Gulf of Aqaba, Jordan (iron, zinc, manganese), Gulf of Mannar, India (lead, cobalt, nickel), North-west coast of Venezuela (lead, zinc, chromium, manganese), Australia (copper, nickel, zinc, manganese). The highest values were recorded in Stylophora pistillata (iron, lead and copper), Acropora cytherea (cobalt), Pocillopora verrucosa (zinc) and the lowest concentrations were recorded in Goniastrea pectinata (iron, chromium, copper and nickel), Favites pentagona (lead, zinc and manganese), and Porites lutea (cobalt). The differences in metals content among the studied species are attributed to differences in microstructure and microarchitecture.     

Minor elements in sediments of Great Bay estuary,New Hampshire

Concentrations of copper, zinc, chromium, lead, cadmium, and phosphorus were obtained from 81 samples of unconsolidated estuarine sediment from Great Bay, New Hampshire. Dispersal of aqueous chromium from localized industrial effluent is believed responsible for an increase in sediment chromium throughout the entire estuary. High phosphorus concentrations exist in sediment near the outfalls from several waste-water treatment plants. There is no evidence for any increase of copper, zinc, lead, or cadmium in this estuary, except for localized high concentrations close to industrial outfalls. Fine-grained sediments and organic carbon correlate highly with all the elements studied, except for chromium. This suggests that conventional agents of sedimentary adsorption are not adequate to explain the incorporation of chromium into sediment under the conditions of heavy industrial discharge which exist in this estuary. Sediment phosphorus correlates highly with minor elements, suggesting that it is an adsorption agent, similar to more typical sedimentary parameters such as organic matter and clay minerals. In such a capacity phosphorus may enhance the sedimentary uptake of other aqueous species, and account for higher chromium sediment concentrations. Comparative data from other sedimentary environments emphasize the environmental significance of these elements in Great Bay.     

Use of Siam weed biomarker in assessing heavy metal contaminations in traffic and solid waste polluted areas

The ability of Chromolaena odorata to accumulate and serve as biomarker to lead and cadmium metals pollution load had been revealed by this study. Samples of soils and Siam weed were collected to assess impacts of solid waste disposal and traffic density on the environment. Composite sample were collected from a solid waste dumpsite, three traffic polluted areas with varying traffic density and a background site distant from traffic. Concentration of eight elements: cadmium, cobalt, chromium, copper, iron, nickel, lead and zinc were determined in soil and plant samples and correlated together. Accumulative factors like pollution load index, transfer factor, contamination factor, enrichment factor were calculated for the metals in both plants and soils and used as basis for interpreting the state of the environment and ability of C. odorata to accumulate metals. The accumulative factors of plants were generally greater than that of soil samples indicating increased accumulative capacity of the plant. The accumulations of lead and cadmium in C. odorata were remarkable with contamination factor 10.51 and 23.50, respectively and mean enrichment factors 3.52 and 6.93, respectively. Other metals had lower accumulative factors. The distribution of metals and calculated factors placed solid waste disposal site as the most polluted site while the trend observed in areas with traffic pollution depicts the ability of C. odorata to clean up metal pollution by accumulating them. It can therefore be suggested that solid waste disposal negatively affects the environment more than traffic pollution subject to the volume of traffic.     

Trace metal levels in edible wild fungi

Metal levels (cadmium, cobalt, chromium, copper, iron, nickel, lead and zinc) of seventeen different edible wild fungi species (Agaricus campestris, Calocybe gambosa, Coprinus comatus, Hericium coralloides, Hydnum repandum, H. repandum var. rufescens, Lactarius deliciosus, L. salminocolor, Macrolepiota procera, Pleurotus ostreatus, P. ostreatus var. columbinus, Ramaria aurea, R. stricta, Rhizopogon luteolus, Sparassis crispa, Suillus bovinus, Tricholoma terreum) growing in Bolu-Turkey were measured by inductively coupled plasma optical emission spectrocopy. The obtained data were analyzed with “statistical package for the social sciences” statistics program. In addition, relation between metal concentrations in both soil and fungi samples were investigated. The highest metal concentrations in Bolu District, Turkey were measured in A. campestris (cadmium 0.270, chromium 2.735 and zinc 7.683), C. comatus (iron 160.12), M. procera (copper 15.990, cobalt 0.352 and nickel 3.645), R. luteolus (Pb 4.756) mg/kg dw (dry weight). As a result of the measurements, it was observed that metal uptake is related with the species of fungi and is also affected by pH and organic contents of the soil.     

Metal accumulations in acidic waters from gold mines in South Africa

Heavy metal contents have been investigated in sediment and water samples from gold and platinum mining areas of South Africa. Waste waters from Witwatersrand and Orange Free State gold mines exhibit characteristically low pH-values due to the formation of sulphuric acid by oxidation of sulphide ore minerals. Acid leaching of iron, manganese, nickel, cobalt, copper and zinc effects a 1,000–10,000-fold increase of metal concentrations as compared to the respective values in unpolluted river water. Lack of carbonate buffering prevents rapid immobilization and may lead to widespread distribution of toxic metals in the aquatic systems. These findings illustrate that modern ore refining techniques have little effect on the water quality as long as unchecked hydrometallurgical processes take place outside the production plant.     

Depositional environment of mudflats and mangroves and bioavailability of selected metals within mudflats in a tropical estuary

Four sediment cores representing adjacent mudflat and mangrove sub-environments of middle estuary (Shastri) were analyzed for sand, silt, clay, and organic carbon. Total metal concentration of iron (Fe), manganese (Mn), nickel (Ni), zinc (Zn), chromium (Cr), copper (Cu), cobalt (Co), and lead (Pb) and chemical speciation of Fe, Mn, and Co on selected samples was also carried out on mudflat cores. The sediments in the upper middle estuary were found to be deposited under highly varying hydrodynamic energy conditions; whereas lower middle estuary experienced relatively stable hydrodynamic energy conditions with time. The tributary joining the river near the upper middle estuary is found to be responsible for the addition of enhanced organic carbon and metal concentrations. Speciation study indicated Fe and Co are from natural lithogenic origin while Mn is derived from anthropogenic sources. Higher Mn and Co than apparent effects threshold can pose a high risk of toxicity to organisms associated with these sediments.     

Inorganic pollution of the sediments of the River Torrens, South Australia

The River Torrens plays a vital role in the economic, social and environmental life of South Australia. The river rises on the Adelaide Hills and flows west across the Adelaide Plains, bisecting the city of Adelaide and reaching the sea at the Gulf of St Vincent. The bed sediments of the Torrens were sampled from its headwaters to the coast and analysed for cadmium, chromium, copper, lead, phosphorus and zinc. With the exception of chromium, the concentration of every metal investigated lies above the national trigger value for sediment quality at some point along the course of the river. The sediments of the headwaters exhibit high values of copper and zinc, although these probably reflect natural background conditions rather than pollution. By contrast, in the residential areas that dominate the Adelaide Plains, almost every site is contaminated by lead and zinc, some to well beyond the point of biological damage. Several residential sites, notably those downstream of the city of Adelaide, are also polluted by cadmium. Within the industrial zone around the city, every site is contaminated by lead and zinc, with concentrations at some locations far beyond the threshold for ecological damage. Several industrial sites are also polluted by cadmium and copper. There are no national guidelines against which to assess the phosphorus content of the sediments. However, there is strong evidence that human activities have had a significant impact on phosphorus levels in the river. Major cyanobacterial blooms along the lower Torrens have been linked to the release of nutrients from the sediments, and phosphorus concentrations in the water have reached dramatic levels. Much of this contamination appears to be a consequence of past pollution practices. In particular, the severe pollution along the reach immediately to the west of the city may be largely attributed to the former concentration of metallurgical and chemical industries in that area. These problems are likely to persist indefinitely as modifications to the flow behaviour of the river mean that bed sediments are neither being moved downstream and flushed out of the system nor diluted by mixing with relatively uncontaminated deposits.     

Chemical speciation of fine particle bound trace metals

This study reported quantifications of fine particle bound trace metals and their potential health risks for residents in Guangzhou, a rapidly developing and most populated city in South China. The fine particle samples were collected from October 29^th. to November 8^th. of 2006 at two different elevations in a mainly residential area and analyzed for the total concentration of aluminum, iron, zinc, lead, manganese, copper, arsenic, chromium, nickel, cadmium, molybdenum and cobalt. Results showed that the fine particle concentrations ranged from 95.8μg/m³to 194.7 μg/m³ at the ground and 83.3-190.0 μg/m³ on the roof, which were much higher than the 24 h fine particle standard (35 μg/m³) recommended by USEPA. The total concentrations of zinc, lead, arsenic, chromium and cadmium in fine particle were 504.8, 201.6, 24.3, 7.7 and 4.4 ng/m³, respectively, which were comparable to other major cities of China, but much higher than major cities outside of China. A sequential extraction procedure was used to fractionate these fine particle bound metals into four different fractions. Results indicated that most toxic metals were mainly distributed in bioavailable fractions. For instance, about 91 % of cadmium, 85 % of lead and 74 % of arsenic were in bioavailable forms. Risk calculations with a simple exposure assessment model showed that the cancer risks of the bioavailable fractions of arsenic, chromium and cadmium were 3 to 33 times greater than usual goal, indicating serious health risks to the residents in this urban area.     

A geochemical assessment of the middle and lower Mvoti river system,KwaZulu-Natal,South Africa

This paper presents one of the first investigations into the geochemical enrichment of the middle and lower Mvoti river system. Chemical elements are naturally present in aquatic sediments, but their concentrations tend to rise to potentially toxic levels via both natural and anthropogenic processes. This study evaluated the concentrations of aluminum, arsenic, boron, barium, cadmium, calcium, cobalt, chromium, copper, iron, lead, magnesium, manganese, molybdenum, nickel, phosphorous, selenium, silicon, strontium, titanium, vanadium and zinc, using inductively coupled plasma optical emission spectroscopy. The levels of elements present were used to assess their spatial distribution within the river and to determine the contamination factors and enrichment factors for each element. The pollution load index (PLi) is another contributing parameter that was calculated to determine the degree of pollution at each site. The results indicate that the sediments of the Mvoti are low to moderately polluted and deteriorating with time (average PLi value of 5.19), and that a major contributing factor to this contamination is natural sources.     

Geochemical and statistical approach for evaluation of heavy metal pollution in core sediments in southeast coast of India

Industrialization coupled with urbanizaton has led to stress in the Buckingham Canal which runs parallel to Bay of Bengal at a distance of around 1 km from the coastline. 4 sediment cores were collected along Ennore — Pulicat stretch to determine acid leachable trace metal concentration. Core samples were collected using gravity corer. The cores were sliced horizontally at 2.5 cm to determine the grain size, sediment composition, pH, organic matter, calcium carbonate, acid leachable trace metals; cadmium, chromium, copper, lead, zinc. The trace metals were extracted using acid mixture containing hydro fluoric acid, nitric acid and sulphuric acid and analysed by atomic emission spectrophotometer. In an attempt to infer anthropogenic input from geogenic input, several approaches including comparison with sediment quality guidelines — ecotoxicological sense of heavy metal contamination and classification by quantitative indexes such as geoaccumalation index, anthropogenic factor, enrichment factor, contamination factor and degree and pollution load index was attempted. Grain size analysis and sediment composition of core samples shows Ennore is sandy in nature having a neutral pH. Organic matter enrichment is observed to a higher extent in core 3. Core 2 at a depth of 5 cm shows organic matter of 9.4 %. calcium carbonate is totally absent at the surface sediments in core 2. Cores collected within the canal showed a higher heavy metal concentration than the cores collected from Pulicat lagoon and 2 km into the Ennore Sea. The trace metal concentration for cadmium, lead and zinc in Ennore does not pose a threat to the sediment dwelling fauna whereas chromium and copper are likely to pose a threat. Quantitative indexes place Ennore under moderately polluted. Ennore is likely to face a serious threat of metal pollution with the present deposition rates unless stringent pollution control norms are adopted.     

Mathematical models to predict soil heavy metal toxicity in the 2012 Olympic site

Heavy metal concentrations in samples collected from the London 2012 Olympic Village were determined using a three-step sequential extraction and a rapid extraction method. Metal toxicity was measured by employing the Microtox^? solid phase analysis. Both extraction methods produced comparable results (p?=?0.996), but the rapid method produced higher readings. A number of heavy metals were detected using the two extraction methods, including aluminum, arsenic, cadmium, chromium, copper, iron, nickel, lead and zinc; beryllium, molybdenum, niobium and titanium were also found in low concentration ranging between 0.16 and 27.10?mg/kg in the total acid digestion. The total metal levels in all the soil samples were within the UK Soil Guideline Value (SGV) except for lead which ranged between 62.9 and 776.2?mg/kg. The 30?min EC₅₀ of different soil fractions was 2?C5.8?g/L. In the absence of any of heavy metals in the SGV, the Dutch Guideline values were referred. Mathematical models for a number of metals were generated based on the changes in EC₅₀ values between each (F1, F2 and F3) soil fractions and the initial toxicity in the non-fractionated samples. The resulting models produced good R² values (>96%) for predicting the change in toxicity of lead, cadmium, zinc and copper by measuring their changes in concentrations. These models could substantially reduce the time requires to determine the toxicity in the samples; they would be a useful tool in the clean up process where monitoring of metal toxicity is required.     

电感耦合等离子体发射光谱法同时测定铜铅锌矿石中铜铅锌钴镍等元素方法确认

文章在修订GB/T 14353—1993《铜矿石、铅矿石和锌矿石化学分析方法》研究工作中,建立了电感耦合等离子体发射光谱同时测定铜铅锌矿石中铜铅锌钴镍等元素的标准分析方法。通过控制试样量和制备试样溶液的体积,可实现主量元素铜、铅、锌与次量元素钴、镍的同时测定。测定范围为铜0.002%~8.5%,铅0.01%~5%,锌0.005%~3%,钴0.001 5%~0.5%,镍0.003%~0.5%。按照相关国家标准对测量方法与结果的准确度进行8个实验室协同参加的准确度试验,统计参数结果表明在限定水平范围内方法偏倚不显著;利用方法重复性限参数,计算可能产生的最大相对偏差。分析方法精密度满足《地质矿产实验室测试质量管理规范》的要求。     

Isolation and characterization of metal-resistant bacterial strain from wastewater and evaluation of its capacity in metal-ions removal using living and dry bacterial cells

A novel strain of the genus Micrococcus isolated from wastewater was studied for resistance to seven heavy metals and forty antibiotics. Its capacity to accumulate metal ions was also realized at different pH. The strain exhibited high minimal inhibitory concentration values for metal ions tested and resist to 15 antibiotics. The living cells of the bacterial strain show a largest uptake capacity at pH 6–8.5 for copper, nickel, and zinc with values ranging from 51.45 to 83.90 %, 52.59 to 78.81 %, and 59.55 to 78.90 %, respectively. It was also able to absorbed 59.81–80.08 % of chromium and 58.09–79.41 % of cobalt at pH 7.3–8.5. The maximum lead uptake was obtained at pH 5.5–8.5 with an amount of 55.28–91.06 %. The significant absorption of cadmium was shown at pH 6.5 with 38 %. In 25 µg mL-1 zinc, chromium, and nickel solutions, dead cells of the isolate were able to biosorbed 20.46, 22.5, and 23.98 µg mL^?1, respectively, after 30 min of contact. In other solutions with higher concentrations 50 and 100 µg mL^?1, the amount of each metal immobilized was, respectively, as follows: 38.02 and 90.21 µg mL^?1 for zinc, 39.78 and 89.23 µg mL^?1 for chromium, and 47.19 and 86.83 µg mL^?1 for nickel. Due to its high-metal accumulation capacity in aerobic conditions, these Gram-positive bacteria may be potentially applicable in situ bioremediation of heavy metals contaminating aqueous systems.     

Metal accumulation in surface salt marsh sediments of the Bay of Fundy,Canada

We measured the amount of arsenic, chromium, copper, lead, nickel, vanadium, and zinc accumulated over a five-year period from 1997 to 2002 in surface sediments of seven salt marshes along the New Brunswick coast of the Bay of Fundy, Canada. Study sites extended from outer to inner Bay, spanning a gradient in tidal range (6–12 m) and mean sediment deposition rate (0.27–1.76 cm yr⁻¹). In each study site, metal concentrations were measured in low and high marsh areas. Concentrations of chromium, nickel, and zinc appear to be within their natural range, while arsenic, lead, and vanadium are enriched in some sites. Calculated sediment metal loadings rates showed variability among marsh sites that closely followed sediment deposition patterns, suggesting sediment deposition rate is the driving factor of short-term metal accumulation in Fundy marshes. The value of salt marshes as a sink for metals may be enhanced by high sedimentation rates.     

The retention of heavy metals in sewage sludge applied to a freshwater tidal wetland

The hypothesis that freshwater tidal wetlands act as sinks for heavy metals was tested using sewage sludge applied biweekly from March to October 1981 at low treatment (25 g m^?2 wk^?1) and high treatment (100 g m^?1) levels. No differences in aboveground macrophyte standing crop were found except in June when high and low treatment sites had significantly higher (p=0.05) standing crops than control sites. Except for chromium, metal standing stocks in the vegetation on treatment sites did not increase as a result of sludge application. The March litter had significantly higher (p=0.05) concentrations of chromium, copper, lead, and nickel at all sites than the October vegetation, but only high and low treatment litter chromium levels were significantly higher (p=0.05) than control litter. When sludge application terminated in October, the top 5 cm of soil at the high and low treatment sites had retained, respectively, 47 and 43% of the cadmium, 53 and 28% of the chromium, 52 and 0% of the copper, 51 and 0% of the zinc, 31 and 0% of the lead, and 0 and 0% of the nickel applied; only cadmium (15 and 46%, respectively) and chromium (12 and 28%, respectively) were still retained the following March. Thus, freshwater tidal wetlands can retain significant quantities of heavy metals associated with sewage sludge. The vegetation and litter play minor roles while the soil plays a major role in heavy metal retention.