Variations In Heavy Metal Concentrations Research Articles

Concentration of heavy metals in the food chain components of the nearshore coastal waters of Kalpakkam, southeast coast of India

Kalpakkam, located on the southeast coast of India, has witnessed intense nuclear power plant activities resulting in a substantial increase in social and industrial development. This has prompted the study of the concentrations of heavy metals in water, sediment, zooplankton and fish in the coastal waters of Kalpakkam to understand their pattern of distribution and bioaccumulation. The concentrations of metals were in the order Fe > Zn > Pb > Cr > Mn > Ni > Cu > Cd > Co in water, Fe > Zn > Mn > Pb > Cr > Cu > Ni > Cd > Co in zooplankton, Fe > Zn > Cu > Mn > Cr > Pb in fish and Fe > Cu > Zn > Pb > Cr > Ni > Cd in sediment. Metal concentrations in plankton were much higher than those in water, sediment and fish. The results showed wide variations in heavy metal concentrations in four food web components. The major sources of metals on the Kalpakkam coast are land-based anthropogenic ones. The coastal sediment is moderately polluted with Cu & Cd. Relatively low dissolved metal concentrations were observed when compared to other coastal waters. However, the results indicated that dermal absorption (CDIdermal) of Fe might be a matter of concern due to its carcinogenicity. The summer season had higher Metal Pollution Index (MPI) values, than the rest of the year. Metal pollution indices indicated that southwest monsoon (SWM) and northeast monsoon (NEM) periods had lower contamination (MPI: 1.0–2.0; Class-III) than the summer season (MPI: 2.0–4.0; Class-IV). The bioaccumulation of metal is faster and the content is much higher in zooplankton than in fish. Bioconcentration factors (BCF) were significantly different for different metals. Amongst the toxic metals the BCF was highest for Cr for both zooplankton and fish tissue. The metal concentrations in the fish species studied were sufficiently low that the fish tissue was safe for human consumption.

Changes in the contents of strontium, barium, and lead in scales of bream Abramis brama from the Mozhaisk Reservoir over a quarter century.

The heavy metal contents in the scales of bream (Abramis brama) from the Mozhaisk Reservoir collected in the second half of the 1980s were compared to the current values. The concentrations of three out of the seven elements studied in the bream scales have changed severalfold during the past quarter century: that of strontium has decreased, and those of barium and lead have increased. Short-term variations of heavy metal contents have proved to be smaller than the observed long-term differences. There is grounds to believe that these long-term differences adequately reflect the changes that have occurred in the water body.

Self-organizing map for the detection of seasonal variations in Sidi Chahed Dam sediments (Northern Morocco)

ABSTRACTA database of 88 superficial sediment samples, distributed in space and time, was collected from the Sidi Chahed Dam (northeast of Meknes city, Morocco) and from four other reference stations (in the same region) located in supposedly uncontaminated environments. Analyses were focused on the physico-chemical characteristics and concentrations of heavy metals (Fe, Mn, As, Cu, Zn, Pb, Cr, Cd). The database was processed by advanced statistical analysis techniques. The method of classification by self-organizing maps (SOM) was used, permitting understanding and visualization of the spatial and temporal distribution of samples. Principal component analysis (PCA) and SOM hierarchical classification (SOM-HC) were used to validate the classification and detect seasonal variations in heavy metal concentrations. Dependencies between different metal tracers were considered and their spatio-temporal distribution is shown, together with the ranking of clusters, according to their pollution levels. Thus, autumn samples were the only ones with high concentrations of As, compared to the four reference stations. This is due to leaching of bare soil by the first stormy rains of autumn. In winter and spring samples, the concentrations of tracers Mn, Zn, Cu, Pb, Cd and Cr were relatively high compared to those of the reference stations. Summer sample concentrations were most comparable with the reference stations, probably due to the scarcity of rainfall and runoff in this season.Editor Z.W. Kundzewicz Associate editor E. Gargouri

Spatial variability of heavy metal concentrations in vineyard soils on Malayer Plains (Iran)

ABSTRACTAccumulation of trace elements in arable soils is an important global hazard worldwide. Human activities, such as agriculture, are a continuous source of risk for heavy metal pollution that seriously disturbs the soil environment. In the present study, topsoil (0–20 cm) samples from vineyard soils in Malayer (Iran) were collected and analyzed for heavy metals, including Cu, Pb, and Zn by HR-CS FAAS. Compared with their levels in the earth's crust, these metals exhibited low concentrations. Variations in these metals were studied and geostatistics techniques were applied to generate spatial distribution maps. Empirical semivariograms can be simulated for the three heavy metals by spherical and linear models. The results of the statistical analyses (significant correlations among these metals) and their similar spatial distribution patterns indicate that Cu, Pb, and Zn probably derive from the same origin as their soil parent materials because of low levels of metals in vineyard soils. However, the high concentrations found in eastern-southern regions were probably created by anthropogenic influences, particularly application of manure and fertilizer.

Heavy Metals in Agricultural Soils of Central Ethiopia: The Contribution of Land Use Types and Organic Sources to Their Variability

In the present study, about 94% of the arable land had a phosphorus deficiency (available P < 10 mg&#183kg&#451). To compensate for this deficiency, high amounts of phosphorous fertilization were applied to soils to get better crop yield. In the past two decades, soil organic matter has sharply declined from 34.8 g/kg in late 1980s’ to 12.0 g/kg in 2010. The soil has moderate to high cation exchanging capacity (CEC) in the range of 45 - 58 Meq/100 gm. The low soil organic carbon, high CEC and high phosphorus fertilization could lead to poor heavy metal availability to plants. Nevertheless, DTPA extractable concentrations were 40.5 mg/kg for copper, 35.5 mg/kg for iron, 134 mg/kg for manganese, 2.1 mg/kg for nickel, 2.6 mg/kg for lead and 53.5 mg/kg for zinc. All the available micronutrients seem to be adequate for plant growth. In terms of toxicity, the values of Cu, Fe, Mn, Zn, Ni and Pb found in the present investigation were lower than those of above critical value set by the international guidelines and other researchers. Variations in heavy metal content in the soil were attributed due to differences in land use types and disparity in organic sources amongst the plant and animal composites. For better crop productivity, more organic matter should be added to the soils. The traditional nutrient cycling practices, such as manure application, allow crop residue to decay on fields, fallowing and rotational cropping has to be followed to rehabilitate the soil and buildup both macro-and micro-nutrients to their natural level.

Heavy metal enrichments in the Changjiang (Yangtze River) catchment and on the inner shelf of the East China Sea over the last 150 years

Compositions of heavy metals including Cu, Zn, Cr and Pb in three sediment cores recovered from the lower basin of the Changjiang (Yangtze River) and the inner shelf mud of the East China Sea were analyzed by traditional X-ray florescence (XRF) and XRF Core Scanner. This study aims to investigate the accumulation of heavy metals in the fluvial sediments and to decipher the influence of anthropogenic activities within the large catchment over the last 150years. The data suggest that the heavy metals, especially Pb and Zn, show obvious enrichments in concentrations since 1950s, and the small and consistent variations of heavy metal concentrations before 1950s can represent geochemical background values. After removing the grain size effect on elemental concentrations, we infer that the sources of heavy metals predominantly come from natural weathering detritus, while human contamination has increased over the last half century. The calculations of both enrichment factor and geoaccumulation index, however, indicate that the pollution of these heavy metals in the fluvial and shelf environments is not significant. The rapid increase in human activities and fast socioeconomic development in the Changjiang catchment and East China over the last five decades accounts for the enrichments of heavy metals in the river and marine sediments. The inner shelf of the East China Sea, as the major sink of the Changjiang-derived fine sediments, provides a high-resolution sediment archive for tracing the anthropogenic impacts on the catchment.

Correction: Song, J.; Yang, X.; Zhang, J.; Long, Y.; Zhang, Y.; Zhang, T. Assessing the Variability of Heavy Metal Concentrations in Liquid-Solid Two-Phase and Related Environmental Risks in the Weihe River of Shaanxi Province, China. Int. J. Environ. Res. Public Health 2015, 12, 8243-8262.

The authors wish to make the following corrections to this paper [1]. [...]

Prevalence and proliferation of antibiotic resistance genes in two municipal wastewater treatment plants

The propagation of antibiotic resistance genes (ARGs) is an emerging health concern worldwide. Thus, it is important to understand and mitigate their occurrence in different systems. In this study, 30 ARGs that confer resistance to tetracyclines, sulfonamides, quinolones or macrolides were detected in two activated sludge wastewater treatment plants (WWTPs) in northern China. Bacteria harboring ARGs persisted through all treatment units, and survived disinfection by chlorination in greater percentages than total Bacteria (assessed by 16S rRNA genes). Although the absolute abundances of ARGs were reduced from the raw influent to the effluent by 89.0%–99.8%, considerable ARG levels [(1.0 ± 0.2) × 103 to (9.5 ± 1.8) × 105 copies/mL)] were found in WWTP effluent samples. ARGs were concentrated in the waste sludge (through settling of bacteria and sludge dewatering) at (1.5 ± 2.3) × 109 to (2.2 ± 2.8) × 1011 copies/g dry weight. Twelve ARGs (tetA, tetB, tetE, tetG, tetH, tetS, tetT, tetX, sul1, sul2, qnrB, ermC) were discharged through the dewatered sludge and plant effluent at higher rates than influent values, indicating overall proliferation of resistant bacteria. Significant antibiotic concentrations (2%–50% of raw influent concentrations) remained throughout all treatment units. This apparently contributed selective pressure for ARG replication since the relative abundance of resistant bacteria (assessed by ARG/16S rRNA gene ratios) was significantly correlated to the corresponding effluent antibiotic concentrations. Similarly, the concentrations of various heavy metals (which induce a similar bacterial resistance mechanism as antibiotics – efflux pumps) were also correlated to the enrichment of some ARGs. Thus, curtailing the release of antibiotics and heavy metals to sewage systems (or enhancing their removal in pre-treatment units) may alleviate their selective pressure and mitigate ARG proliferation in WWTPs.

The Assessment Of Sediment Contamination Level In The Lampung Bay, Indonesia: Heavy Metal Perspective

The potency and utilization of Lampung Bay has been recognized for their socio-economical and ecological values. However, heavy use of this Bay may alter the abundance of hazardous chemical like heavy metals. The aims of this study were to determine the concentration of Cd, Cu, Pb and Zn in the sediment and to assess Lampung Bay water condition. The observation of heavy metal content in sediment of Lampung Bay was conducted at 13 stations in March 2008. Analysis of heavy metals in sediment was conducted using three kinds of acid: HNO3, HCl and H2O2 while measurement was carried out by Atomic Absorption Spectrophotometer. The result indicated a variation of heavy metal concentration in sediment and that concentrations of Cd, Cu, Pb and Zn in sediment were 0.08 mg/kg dry weight, 22.99 mg/kg dry weight, 24.75 mg/kg dry weight and 118.48 mg/kg dry weight, respectively. Factors influenced heavy metal concentration in sediment in this study including the distance between sampling location and anthropogenic activities and the sediment fraction SQG-Q index indicated that 7 stations have SQG-Q ≤ 0.1 whereas other 6 stations have 0.1≤ SQG-Q &lt;1, meaning that more than half sampling stations are in uncontaminated state.

Assessing the Variability of Heavy Metal Concentrations in Liquid-Solid Two-Phase and Related Environmental Risks in the Weihe River of Shaanxi Province, China

Accurate estimation of the variability of heavy metals in river water and the hyporheic zone is crucial for pollution control and environmental management. The biotoxicities and potential ecological risks of heavy metals (Cu, Zn, Pb, Cd) in a solid-liquid two-phase system were estimated using the Geo-accumulation Index, Potential Ecological Risk Assessment and Quality Standard Index methods in the Weihe River of Shaanxi Province, China. Water and sediment samples were collected from five study sites during spring, summer and winter, 2013. The dominant species in the streambed sediments were chironomids and flutter earthworm, whose bioturbation mainly ranged from 0 to 20 cm. The concentrations of heavy metals in surface water and pore water varied obviously in spring and summer. The degrees of concentration of Cu and Cd in spring and summer were higher than the U.S. water quality Criteria Maximum Concentrations. Furthermore, the biotoxicities of Pb and Zn demonstrated season-spatial variations. The concentrations of Cu, Zn, Pb and Cd in spring and winter were significantly higher than those in summer, and the pollution levels also varied obviously in different layers of the sediments. Moreover, the pollution level of Cd was the most serious, as estimated by all three assessment methods.

Spatial pattern and distribution regularity of soil environmental quality in East China

Random numbers of heavy metal (Cd, As, and Pb) concentrations were created by Monte Carlo simulation of 16 representative sites in five soil zones from published papers for subsequent research. Ordinary kriging and significant analyses were used in a dataset of the 16 areas. Concentration of heavy metals in topsoil was found to be mainly influenced by zonality, non-zonality, and anthropogenic inputs. Nevertheless, human-induced correlations among heavy metals could not be detected on a regional spatial scale. Soil zone and landform were found to be representations of zonality and non-zonality, respectively. It was found that in east China, heavy metals accumulated in the south, especially the southwest, and were not uniform in each soil zone, indicating that zonality was not the unique influencing factor of soil environment quality. Both soil zone and landform may be responsible for heavy metal concentrations. An analysis of variance, coefficients of divergence analysis, was applied to assess the effects of soil zone and landforms on the variation of heavy metal concentrations in the study region. The influence of soil zone and landform was relatively homogeneous in areas of the north; while in the south, landform played a dominating role. Therefore, soil environment quality formed mainly under the effect of landform. This was mainly due to the fact that landform in fluences other natural environment elements including climate, further impacting the division of soil zone.

Textural and geochemical characteristics of marine sediments in the SW Gulf of Mexico: implications for source and seasonal change.

Two oceanographic cruises were taken during the winter (SAV I, November and December 2007) and summer (SAV II, July and August 2008) across the mouth of the Papaloapan River in the Gulf of Mexico. Surficial sediment samples were collected from shallow (16-30m), intermediate (30 to 80m), and deeper areas (≥300m). Shallow water sediments are coarser, better-sorted, and primarily composed of sands during the winter, while those found in the summer are finer. At depths greater than 30m, sediments are primarily fine-grained no matter the season. Major element analysis from shallow areas indicates higher SiO2 concentrations during the windy season with negative correlation against Al2O3 during both seasons, following the respective abundances of sand and muds. High organic carbon content was observed in shallow areas during the summer. Trace metals V, Ni, Cu, Zn, Pb, Li, Cr, Co, and Ba were evaluated. The first six metals showed higher average concentration in the deeper areas, although the highest values at some individual sampling sites for Cr, Co, Cu, and Ba were observed in the coastal area. Factor and cluster analysis were used to explain the sediment distribution pattern and the factors that determine the sediment characteristics within the study area. In shallow areas, four clusters were observed during the winter and five during the summer. The geochemical characteristics of the samples in each cluster suggest association with fluvial sediment input, textural characteristics, heavy minerals, and Cu and Ba concentration. To evaluate the variations in heavy metal concentration, metal enrichment factors (EFs) were calculated. Enrichment in V, Cr, Co, Zn, Ba, and Pb was detected at certain sites, whereas Cu behaved differently. The distribution of Cu enrichment suggests that it may be of natural origin, associated with the lithology of the volcanic continental area. The minor enrichment observed for other elements may be associated with river discharge. According to sediment quality guidelines, trace metal concentrations of Cu, Pb, and Zn present occasional risks to aquatic organisms.

Determination of toxic heavy metal levels in commonly consumed species of shrimp and shellfish using ICP-MS/OES

Toxic metal concentrations, including lead (Pb), cadmium (Cd), aluminum (Al), mercury (Hg), and arsenic (As) in edible tissues of different species of shrimp and shellfish consumed in South Korea were analyzed. Analysis was performed using inductively coupled plasma (ICP)-MS) for Pb, Cd and As, ICP-optical emission spectrometry (OES) for Al, and a direct mercury analyzer for Hg. Methods used were validated. Limited variation in heavy metal concentrations between shrimp and shellfish were observed. Al and As concentrations were highest while Hg was lowest. Heavy metal levels found in edible tissues of shellfish and shrimp were below international and local maximum permissible levels for human consumption. The methods used were accurate and reproducible for use in determination of toxic heavy metal levels in seafoods.

Metal Accumulation Profile in Roadside Soils, Grass and Caesalpinia Plant Leaves: Bioindicators

Heavy metals are important environmental pollutants and their toxicity in human, plants and animals have been received much more attention. A study was conducted to investigate the heavy metal pollution of roadside soil, grass and Caesalpinia species of Bagalkot city (India). The highest levels of metal concentration of Pb, Cu, Cd, Mn, Zn, Cr and Ni were found in the samples from very traffic congestion. The soil samples at a depth (0-20 cm) grass leaves and Caesalpinia leaves were taken from different sampling sites viz; S1, S2, S3, S4 and S5 on state high way with high traffic roads passing through Bagalkot (India) were determined by Atomic Absorption Spectrophotometer. Results showed that soil and both grass and Caesalpinia contained elevated levels of the metal. It was found that the primary source of the contamination occurs mainly by the vehicular exhausts. The increased circulation of the toxic metals in soils, grass and Caesalpinia may result in the inevitable build up of such xenobiotics in the food chain. The variation in heavy metal concentration is due to the changes in traffic density and anthropogenic activities. Thus, it is concluded that grass, Caesalpinia and soil samples were used as bioindicators of metal pollution in roadside.

Assessment of Trace Metals Concentration in Tree Barks as Indicator of Atmospheric Pollution within Ibadan City, South-West, Nigeria.

Tree bark species were randomly collected from 65 sites having different anthropogenic activities, such as industrial, high traffic commercial, residential high and residential low traffic volume areas of Ibadan City, Nigeria. Levels of Cd, Cu, Pb, Zn, Co, and Cr of the dry-ashed bark samples were determined by AAS. The mean metal concentrations (mg kg−1) in samples from industrial zone were found as Pb: 3.67 ± 1.97, Cd: 0.10 ± 0.07, Zn: 30.96 ± 32.05, Cu: 7.29 ± 5.17, Co: 0.91 ± 0.58, and Cr: 2.61 ± 1.84. The trend of mean trace metal concentrations at high traffic commercial zone follows the order: Zn > Pb > Cu > Cr > Co > Cd. Residential high traffic and low traffic zones revealed the same trend as Cd < Co < Cr < Pb < Cu < Zn. Relatively strong positive correlation between the heavy metals at ρ < 0.05, such as Zn versus Cu (r = 0.79) and Co versus Cu (r = 0.77), was observed. The results of the study suggest that tree bark samples could potentially serve as bioindicators for Cu, Pb, Zn, Cr, and possibly Co and Cd. Furthermore, interspecies variation of heavy metal concentrations in plants barks is recommended.

Assessment of Heavy Metal Concentration in Hand Dug Well Water from Selected Land Uses in Wukari Town, Wukari, Taraba State, Nigeria

Hand dug well water remains the major source of domestic (drinking) water in the city of Wukari. This study was aimed at the assessment of heavy metal concentration in hand dug well water from four land uses of abattoir (A), waste dump site (B), residential (C) and commercial (D) in Wukari Town, Wukari, Taraba State. There are about 76 hand dug wells in the study area and for the purpose of this study. Yamane (1967) sample size technique was adopted. Based on this, 95% confidence level and an error limit of 5% were adopted. Thus, four (4) samples A, B, C and D of hand dug well water purposively drawn from the study area used sterilized bottles. The heavy metals tested for in the water samples include: zinc (Zn), copper (Cu), manganese (Mn), iron (Fe), potassium (K), phosphate, and chromium. The results of the analyses were compared with the NSDWQ*MPL and FEPA (2001) standards. The results shows that the concentration of magnesium and manganese in hand dug well water samples A, B, C and D had higher concentrations than the maximum permissible limits of NSDWQ*MPL and FEPA (2001) standards and the concentration of zinc, copper, iron, potassium, phosphate and chromium in hand dug well water sample A, B, C and D was at different compliance level with NSDWQ*MPL and FEPA (2001) standards. ANOVA (F-ratio) statistics at P_0.05 for variation in heavy metal concentration in hand dug well water from land uses A, B, C and D were insignificant. For now, it can be concluded that hand dug well water in Wukari Town is fit for domestic use, but that efforts should be made to reduce the magnesium and manganese concentration by having control on the anthropogenic factors that lead to such high concentration levels or else, soon this source of water may become unfit for domestic use. It was recommended that aggressive public awareness and enlightenment on possible impacts of hand dug well water pollution from human activities should be embarked upon by relevant agencies.

Bioindication of the Area of Heavy Metal Deposition for Point Sources of Pollution

When assessing the environmental situation in territories, where industrial plants or combined heat and power stations (CHPs) are situated, a special interest is paid to determining the size of the area of heavy metal (HM) deposition, due to their high toxicity and ability to accumulate in human body. Over the last decade, the estimation of air heavy metal content widely implements the method of moss biomonitoring. This work analyses a three-year amount of moss growth. Sampling was carried out in the northeastern direction from CHP-5 (Novosibirsk, Russia) in accordance with the wind rose at distance varying from 1 to 5 km. The study includes preparation and analysis of 38 samples of moss by neutron activation method. The work is based on the measurement of the concentration of various heavy metals and frequency of wind occurrence in seven main directions.

Variation and correlation of content and leachability of hazardous metals in MSW molten slag.

To increase the amount of accessible municipal solid waste molten slag (MSWS) for its use in aggregates such as sand, MSWS must be deemed environmentally safe. Municipal solid waste (MSW) is a heterogeneous waste source used in MSWS and varies in chemical composition. Due to its nature, there is great concern about hazardous metal contamination among users of MSWS. In this study, MSWS samples were obtained weekly for 1year from a typical incineration ash melting facility for municipal solid waste in Japan. Variation in heavy metal contents and the leachability of MSWS were investigated using two content analysis methods and two leaching tests, respectively. There is a weak correlation between metal content and concentration, and the leachability of metals in slag could not be reduced by decreasing its metal content. No measured values of hazardous metal concentration and metal content exceed the regulation levels stipulated in Japanese Industrial Standards A5031 and A5032, respectively, thereby demonstrating that the slag can be safely utilized as road and concrete aggregates. However, metal concentrations varied widely and differed by greater than 1 order of magnitude and Pb concentrations of several MSWS samples approach the regulation level. Therefore, frequent monitoring of lead leachability of MSWS and storing MSWS for several weeks to obtain a high quality that is more homogeneous in chemical composition are demanded. This study provides fundamental information for controlling the quality of MSWS and the contributing factors for achieving a safe slag recycling system.

Natural and anthropogenic influences on heavy metals in airborne particles over the Korean Peninsula.

Six monitoring stations were selected to characterize the variations in airborne concentrations of heavy metals in South Korea between 1999 and 2012. Three stations represented higher concentrations, and three represented lower concentrations. The heavy metals monitored at these stations include cadmium, chromium, copper, iron (Fe), lead, manganese (Mn), and nickel. During the study period, concentrations of heavy metals at many stations, including those around the Seoul metropolitan area, showed a decreasing trend. However, concentrations of Mn and Fe that are primarily of crustal origin increased at four of the six stations. Some stations were significantly affected by emissions from the local industrial complex (IC), and heavy metal concentrations at those stations were relatively high even in summer. Many heavy metal concentrations were higher in spring than in winter, but wintertime concentrations of Cr and Pb were higher at the stations representing lower concentrations due to the dominant influence of combustion emissions. At stations less affected by emissions from the IC, concentrations of Fe and Mn that are predominantly crustal in origin were higher in spring, when Asian dust (AD) events are most frequent. Although Mn concentrations were also high at stations within the steelmaking IC during AD periods, they were much higher during non-AD periods due to local emissions. Variations in heavy metal concentrations, which are heavily influenced by emissions from the IC, warrant individual analysis because their emission characteristics differ from those of typical cases.

Spatial and temporal variation of lead, cadmium, and zinc in feathers of great tit and blue tit nestlings in Central Poland.

In this study, we examined heavy-metal concentrations in feathers of nestling great tits Parus major and blue tits Cyanistes caeruleus at two different sites (urban parkland vs. deciduous forest) located in the Łódź agglomeration in relation to interyear variation. We found that tit species did not differ significantly in lead and cadmium concentrations. Zinc concentration was significantly higher in blue tits. We also found that lead and cadmium levels in blue tit nestlings and the level of lead in great tit nestlings were higher in the parkland site than in the woodland site. We explain habitat variation in heavy-metal concentrations in feathers of nestlings by different levels of contamination at study sites. For both tit species, significant variation in heavy-metal amounts accumulated by nestlings was found between years with the lowest value in a year with the lowest value of rainfall. We suggest that the interyear variation may be accounted for by differences in rainfall, thus influencing quantities of trace elements bioavailable in the environment.