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1.
The analysis of heavy metals is very important for assessing the feasibility of the agricultural utilization for the municipal
sludge. In this paper, a four-step sequential extraction method was applied to extract heavy metals (Cu, Zn, Mn, Cr, and Ni)
in municipal sludges from seven individual wastewater treatment plants located in Jilin and Heilongjiang Province, China,
for estimating the mobility and bioavailability of the metal ions in the agricultural application. The total concentrations
of heavy metals and their chemical fractions after the sequential extraction were determined. Principal component analysis
(PCA) was applied to analyze the relations of heavy metals fractions in the municipal sludges. Experimental results indicated
that the total concentrations of Cu, Zn, Cr, and Ni in all sludge samples were below the threshold values set out by the Chinese
legislation (GB18918-2002). Specially, Zn had a high bioavailability and mobility, Cu and Cr had potential bioavailability,
while Mn mainly existed in the residual fraction of municipal sludge. On the other hand, Ni had different mobility in different
municipal sludge. PCA results were confirmed by the environmental behavior of heavy metals. 相似文献
2.
Contado C Blo G Conato C Dondi F Beckett R 《Journal of environmental monitoring : JEM》2003,5(6):845-851
A review of the different methodologies employed to fractionate and characterize riverine suspended particulate matter is presented. The importance of size-based metal speciation is underlined and the possibility of studying it by the Sedimentation Field Flow Fractionation (SdFFF) technique is illustrated. The studies on the metal load in river Suspended Particulate Matter (SPM) performed over the last ten years are critically reviewed focusing on the different methods employed to collect, concentrate and size-fractionate samples. The fact that there is no homogeneity in methods and data collection in this field is underlined. Among the different fractionation techniques, Field Flow Fractionation (FFF) methodologies have proved to be a good approach to study the role of SPM in metal load and transport. The possibility of studying size-based metal speciation using the SdFFF technique is presented and the importance of metal speciation in rivers is underlined. 相似文献
3.
An analysis of the geochemical distribution of selected trace metals among various geochemical phases of the sediments in the Tees estuary was carried out using a sequential extraction technique and Differential Stripping Voltammetry. The sediments of the estuary are mainly organic rich clay silts and metal concentrations exceed those in the water column. Speciation results show that contamination of the estuary is mainly from anthropogenic sources. Pb and Zn are associated with the reducible, residual and oxidisable fractions. The speciation pattern of Cd was similar to those of lead and zinc. However there were also some exchangeable and bound to carbonate fractions although these were less significant. Cu is largely associated with the oxidisable and residual fractions, with insignificant bound to carbonate, exchangeable and reducible fractions. The most bioavailable forms of the metals are the free inorganic ions. Total metal concentrations in the estuary display a downward trend since the 1970s. 相似文献
4.
Heavy metal mobility, bioavailability and toxicity depends largely on the chemical form of metals and ultimately determines potential for environmental pollution. For this reason, determining the chemical form of heavy metals and metalloids, immobilized in sludges by biological mediated sulfate reduction, is important to evaluate their mobility and bioavailability. A modified Tessier sequential extraction procedure (SEP), complemented with acid volatile sulfide (AVS) and simultaneous extracted metals (SEM) measurements, were applied to determine the partitioning of five heavy metals (defined as Fe, Ni, Zn and Cu, and the metalloid As) in anoxic solid-phase material (ASM) from an anaerobic, sulfate reducing bioreactor into six operationally defined fractions. These fractions were water soluble, exchangeable, bound to carbonates (acid soluble), bound to Fe-Mn oxides (reducible), bound to organic matter and sulfides (oxidizable) and residual. It was found that the distribution of Fe, Ni, Zn, Cu and As in ASM was strongly influenced by its association with the above solid fractions. The fraction corresponding to organic matter and sulfides appeared to be the most important scavenging phases of As, Fe, Ni, Zn and Cu in ASM (59.8-86.7%). This result was supported by AVS and SEM (Sigma Zn, Ni and Cu) measurements, which indicated that the heavy metals existed overwhelmingly as sulfides in the organic matter and sulfide fraction. A substantial amount of Fe and Ni at 16.4 and 20.1%, respectively, were also present in the carbonate fraction, while an appreciable portion of As (18.3%) and Zn (19.4%) was bound to Fe-Mn oxides. A significant amount of heavy metals was also associated with the residual fraction, ranging from 2.1% for Zn to 18.8% for As. Based on the average total extractable heavy metal (TEHM) values, the concentration of heavy metals in the ASM was in the order of Cu > Ni > Zn > Fe > As. If the mobility and bioavailability of heavy metals are assumed to be related to their solubility and chemical forms, and that they decrease with each successive extraction step, then the apparent mobility and bioavailability of these five heavy metals in ASM increase in the order of Cu < As < Ni < Fe < Zn. The SEM/AVS ratio was less than one in eight replicate ASM samples, indicating that the ASM was non-toxic with regards to having a low probability of bioavailable metals in the pore water. 相似文献
5.
Concentration of heavy metals (Cd, Ni, Zn, Fe, Cu, Mn, Pb, Cr, Hg and As) in the waters of River Yamuna and in the soil of
agricultural fields along its course in Delhi are reported from 13 sites, spread through the Delhi stretch of Yamuna, starting
from the Wazirabad barrage till the Okhla barrage. Varying concentration of heavy metals was found. Peaks were observed in
samples collected downstream of Wazirabad and Okhla barrage, indicating the anthropogenic nature of the contamination. The
Wazirabad section of the river receives wastewater from Najafgarh and its supplementary drains, whereas the Shahdara drain
releases its pollution load upstream of the Okhla barrage. Average heavy metal concentration at different locations in the
river water varied in the order of Fe>Cr>Mn>Zn>Pb>Cu>Ni>Hg>As>Cd. The river basin soil shows higher level of contamination
with lesser variation than the water samples among sampling locations, thereby suggesting deposition over long periods of
time through the processes of adsorption and absorption. The average heavy metal concentration at different locations in soil
varied in the order of Fe>Mn>Zn>Cr>Pb>Ni>Hg>Cu>As>Cd. 相似文献
6.
Chaudhari PR Gupta R Gajghate DG Wate SR 《Environmental monitoring and assessment》2012,184(4):2487-2496
Heavy metals released from different sources in urban environment get adsorbed on respirable particulate matter less than
10 μm in size (PM10) and are important from public health point of view causing morbidity and mortality. Therefore, the ambient air quality monitoring
was carried out to study the temporal and special pattern in the distribution of PM10 and associated heavy metal content in the atmosphere of Nagpur, Maharashtra State, India during 2001 as well as in 2006.
PM10 fraction was observed to exceed the stipulated standards in both years. It was also observed that minimum range of PM10 was observed to be increased in 2006 indicating increase in human activity during nighttime also. Six heavy metals were analyzed
and were observed to occur in the order Zn > Fe > Pb > Ni > Cd > Cr in 2006, similar to the trend in other metro cities in
India. Lead and Nickel were observed to be within the stipulated standards. Poor correlation coefficient (R
2) between lead and PM10 indicated that automobile exhaust is not the source of metals to air pollution. Commercial and industrial activity as well
as geological composition may be the potential sources of heavy metal pollution. Total load of heavy metals was found to
be increased in 2006 with prominent increase in zinc, lead, and nickel in the environment. Public health impacts of heavy
metals as well as certain preventive measures to mitigate the impact of heavy metals on public health are also summarized. 相似文献
7.
Omar Celis-Hernández Leticia Rosales-Hoz Arturo Carranza-Edwards 《Environmental monitoring and assessment》2013,185(11):8891-8907
The south west coastal zone in the Gulf of Mexico is an area with great industrial and agricultural development, which experiences intensive prospecting and extraction of hydrocarbons. After running through industrial, agricultural, and urban areas, waters from both the Jamapa River and La Antigua River arrive here. The rivers’ discharge areas of influence were estimated considering the textural and chemical composition of the supplied sediments. The main factors that determine sediment distribution were mineralogy, heavy minerals, carbonates, and anthropic contributions. The presence of metals in excess was evaluated using various pollution indicators, such as the enrichment factor, contamination factor, modified contamination factor, and geo-accumulation indexes. Data from different used contamination indexes show metal enrichments in As, Cu, Zn, Co, Cr, and V in La Antigua; As, Cu, and Cr in Jamapa; and As, Zn, and Pb in the Continental slope area. The adverse effects of metals on aquatic organisms were assessed using sediment quality guidelines that show Ni, As, Cu, and Cr may produce adverse effects on coastal areas. There was no evidence of contamination associated to the oil industry. 相似文献
8.
Venkatesha Raju K Somashekar RK Prakash KL 《Environmental monitoring and assessment》2012,184(1):361-373
The purpose of this research work was to appraise extent of heavy metals in sediment and the degree to which its quality tainted
seasonally and spatially in river Cauvery. In this study, heavy metals such as Fe, Zn, Ni, Mn, Pb, Cu, Co, Cd and Cr were
analysed in sediments. Results were compared with sediment quality guidelines from various derived criteria. Twenty-five sampling
points were selected based on geographical proximity of agricultural fields and industrial discharges; river-tributary confluence
points; settlements located along the river bank; ritual and recreational activities. Sampling was done for the period of
3 years (2007 to 2009). Digestion of the samples was done by microwave-assisted digestion technique. Analysis was carried
out using flame furnace atomic absorption spectrophotometer, and results are expressed in micrograms per gram. The mean concentration
of Fe (11144 μg/g) followed by Mn (1763.3 μg/g), Zn (93.1 μg/g), Cr (389 μg/g), Ni (27.7 μg/g), Cu (11.2 μg/g), Pb (4.3 μg/g),
Co (1.9 μg/g) and Cd (1.3 μg/g) remained within the levels of sediment quality guidelines. Multivariate statistical techniques
such as principal component analysis and cluster analysis (CA) were employed to better comprehend the controlling factors
of sediment quality and spatial homogeneity among the stations. The sediment geo-accumulation index (Igeo) showed maximum value of Cd (2.69) and least value of Mn (−1.44). The geo-accumulation class (Igeo class) was in the sequence as follows: Cd>Zn>Pb>Cr>Cu>Co>Ni>Fe>Mn. Negative total geo-accumulation indices (Itot) revealed that mean concentration of heavy metals in the river bed sediment are lower than their respective shale values.
The statistical analysis of inter-metallic relationship revealed the high degree of correlation among the metals indicated
their identical behaviour during transport. This study concludes that insignificant geo-accumulation with metals except Cd
(moderate contamination), Pb and Zn (slight contamination) principally in downstream stretch may perhaps deteriorate the sediment
quality due to intensification anthropogenic influences. It also proves that extent of existing metal concentrations in sediments
of river Cauvery in Karnataka not exceeded the toxic limit, and there is no peril to the aquatic life. 相似文献
9.
Yutao Wang Qiu Qiu Guorong Xin Zhongyi Yang Jing Zheng Zhihong Ye Shaoshan Li 《Environmental monitoring and assessment》2013,185(7):5775-5787
Concentrations of six heavy metals (Cu, Ni, Zn, Cd, Cr, and Pb) in sediments and fine roots, thick roots, branches, and leaves of six mangrove plant species collected from the Futian mangrove forest, South China were measured. The results show that both the sediments and plants in Futian mangrove ecosystem are moderately contaminated by heavy metals, with the main contaminants being Zn and Cu. All investigated metals showed very similar distribution patterns in the sediments, implying that they had the same anthropogenic source(s). High accumulations of the heavy metals were observed in the root tissues, especially the fine roots, and much lower concentrations in the other organs. This indicates that the roots strongly immobilize the heavy metals and (hence) that mangrove plants possess mechanisms that limit the upward transport of heavy metals and exclude them from sensitive tissues. The growth performance of propagules and 6-month-old seedlings of Bruguiera gymnorhiza in the presence of contaminating Cu and Cd was also examined. The results show that this plant is not sufficiently sensitive to heavy metals after its propagule stage for its regeneration and growth to be significantly affected by heavy metal contamination in the Futian mangrove ecosystem. However, older mangrove seedlings appeared to be more metal-tolerant than the younger seedlings due to their more efficient exclusion mechanism. Thus, the effects of metal contamination on young seedlings should be assessed when evaluating the risks posed by heavy metals in an ecosystem. 相似文献
10.
11.
Binggan Wei Fengqing Jiang Xuemei Li Shuyong Mu 《Environmental monitoring and assessment》2010,160(1-4):33-45
A total of 169 samples of road dust collected in the city of Urumqi, capital of the Xinjiang Uygur Autonomous Region in northwest China, were analyzed by method of inductively coupled plasma-mass spectrometry for 10 elements (i.e., Cd, Cr, Cu, Ni, Pb, Mn, Be, Co, Zn, and U). The possible sources of metals are identified with multivariate analysis such as correlation analysis, principal component analysis, and cluster analysis. Besides, enrichment factors are used to quantitatively evaluate the influences of human activities on heavy metal concentrations. Moreover, the potential ecological risk index is applied to evaluating the ecological risk of heavy metal pollutants. The results indicate that: (1) the concentrations of the heavy metals involved were much higher in urban areas than the background values, except those of Co and U. Mn, U, and Co are mainly of natural origin; Cu, Pb, Zn, and Cr are mainly of traffic sources and are partly of industrial sources; Ni and Be are mainly the results of industrial activities, such as machine shops, firepower plants, tire and rubber factories, cement factories, and textile mills and are partly of the traffic sources; (2) with high “toxic-response” factor and high concentration, Cd has more serious influences on the environment than other heavy metals. Therefore, commercial and industrial areas are usually characterized by higher potential ecological risk when compared with residential areas and new developing urban areas. The results of this study could be helpful for the management of environment in industrial areas. 相似文献
12.
Dorra Gargouri Chafai Azri Mohamed Moncef Serbaji Younes Jedoui Mabrouk Montacer 《Environmental monitoring and assessment》2011,175(1-4):519-530
Sixty-seven surface marine sediment samples in the <63 ?? m fraction collected from the coast of Sfax (Tunisia) were analyzed by inductively coupled plasma-atomic emission spectrometry for seven heavy metals (Pb, Ni, Cu, Cr, Zn, Cd, and Fe). Metal concentrations were compared with natural values, marine sediment quality standards, and also with other results concerning sediments from several Mediterranean coasts. The study of their spatial distributions refined by complementary approaches including principal component analysis, enrichment factors, and geoaccumulation index showed a significant impact of multiple anthropogenic sources. These included industrial sources and municipal discharges of the urban Sfax and also non-controlled discharges in rural zones close to the coastline. Moderate pollution of sediments, especially by Pb, Zn, and Ni, was shown to exist in localized sites. Besides, it was shown that other sites, slightly to highly enriched in terms of Cu, Cr, and Cd, are characterized by a quality of sediments varying from unpolluted to moderately polluted. 相似文献
13.
James M. Skeaff Yves Thibault David J. Hardy 《Environmental monitoring and assessment》2011,177(1-4):165-192
Base metal smelters may be a source of particulates containing metals of environmental concern released to the atmosphere. Knowledge of the quantitative chemical speciation of particulate releases from base metal smelters will be of value in smelter emission fingerprinting, site-specific risk assessments, predictions of the behaviour of smelter stack particulates released to the environment and in resolving liability issues related to current and historic releases. Accordingly, we have developed an innovative approach comprising bulk chemical analysis, a leaching procedure, X-ray diffraction analysis and scanning electron microscopy/electron probe microanalysis characterisation in a step-wise apportioning procedure to derive the quantitative speciation of particulate samples from the stacks of three copper smelters designated as A, B and C. For the A smelter stack particulates, the major calculated percentages were 29 CuSO4, 20 ZnSO4.H2O, 13 (Cu0.94Zn0.06)2(AsO4)(OH), 11 PbSO4 and four As2O3. For the B smelter stack particulates, the primary calculated percentages were 20 ZnSO4.H2O, 20 PbSO4, 12 CuSO4 and nine As2O3. Finally, we calculated that the C smelter stack particulates mostly comprised 34 ZnSO4.H2O, 19 (Cu0.84Zn0.16)(AsO3OH), 11 PbSO4, 10 As2O3 and nine Zn3(AsO4)2. Between 56% and 67% by weight of the smelter stack particulates, including the As, was soluble in water. For these and other operations, the data and approach may be useful in estimating metals partitioning among water, soil and sediment, as well as predictions of the effects of the stack particulates released to the environment. 相似文献
14.
Different sources of pollution in Karasu Creek were investigated to obtain the water quality and ratio of contamination in
this region. To achieve the main objectives of the present study, water samples were collected from Karasu Creek, starting
from flow pattern at the upstream site of Akkaya Dam to the end of the dam, crossing the place where the Creek drains into.
Dissolved oxygen, electrical conductivity, temperature and maximum/minimum pH were measured systematically for 12 months in
the stations, where the water samples were collected. Chemical analyses of the water samples were carried out by using Cadas
50 S brand UV spectrometer to find out the Pb, Fe, Cu, Zn, Ni, Cr, Cd, S, F and Cn concentrations. These concentration were
determined in μg/lt as 80–850; 180–4,920; 10–6,100; 440–25,530; 130–2,400; 120–280; 20–150; 214,250–1,113,580; 1,560–4,270
and 40–690, respectively. To determine metal levels of the water samples, multivariate analyses (element coefficient correlation,
coefficient correlation dendrogram, hierarchical cluster analysis dendrogram, model summary and ANOVA) were used. The analyses
yielded highly accurate results. There were positive correlations between some elements and their possible sources were the
same. The stations which resembled each other along the creek were divided into three groups. The water quality of the creek
was low and had toxic qualities. Eutrophication developed in Akkaya Dam along the creek. The source of pollution was thought
to be industrial and residential wastes. Absolute (0–100 m), short distance (100–500 m) and medium distance (500–2,000 m)
conservation areas should be determined in pollution areas along Karasu Creek and they should be improved. 相似文献
15.
Mehrdad Cheraghi Bahareh Lorestani Hajar Merrikhpour Nasim Rouniasi 《Environmental monitoring and assessment》2013,185(2):1825-1831
The long-term application of phosphate fertilizers on vegetable production fields has raised concerns about the potential health risks of heavy metal contamination of crops grown on contaminated soils in the Hamadan province, western Iran. This study found that long-term fertilizer use led to a growing accumulation of heavy metals in soils. High concentrations of elemental As, Cd, Cr, Cu, Pb, and Zn were found in potatoes sampled from overused phosphate-fertilized soils, which increased the daily intake of metals in food. However, the ingestion of potatoes from soils affected by phosphate fertilizers posed a low health risk when compared with the health risk index of <1 for heavy metals. Nevertheless, heavy metal concentrations should be periodically monitored in vegetables grown in these soils. It would also be beneficial to implement effective remediation technologies to minimize possible impacts on human health. 相似文献
16.
Liu H Chen LP Ai YW Yang X Yu YH Zuo YB Fu GY 《Environmental monitoring and assessment》2009,152(1-4):25-33
Heavy metal concentration in soil was investigated at three sites with different topography (cut slope, flat and embankment) within the vicinity of Chengdu-Kunming railway in Sichuan, China. Surface soil was sampled at certain distances from the track at each site and was analyzed for Cu, Mn, Pb, Zn, Cd by atomic absorption spectrometry. Cu, Cd and Zn concentrations in some soil exceeded the thresholds for non-polluted soil following the soil quality standard set by the State Environmental Protection Agency of China. Compared to local background values, the highest enrichment factor values of Cu, Mn, Zn and Cd were 2.7, 3.4, 3.7 and 7.7, respectively, indicating a moderate or significant enrichment of these metals in soil closest to the railway. Pb showed little accumulation with the EF values generally nearer 1 at the chosen sites. Topography profile was found to influence metal levels and distribution in soil alongside railway. At the cut slope site, Mn, Zn, Cd showed the highest concentrations and the smallest dispersion distance of 2 m, while Cu showed further dispersion distance of 25 m due to a main Cu emission source, the head-over traction cable, being located higher than any other metal emission source (wheels and tracks). Heavy metal concentrations decreased conversely as compared to distance from the track, peak values occurring at locations closest to the tracks, whilst embankment site soil Cd concentrations peaked at distances of 25 m. Significant correlation was found amongst Mn, Cu, Zn and Cd, which indicates that these metals have the same anthropogenic origin there. Organic matter content had no significant correlation to the elements Mn, Cu and Zn, which implies relatively high mobility to those metals. 相似文献
17.
Taghinia Hejabi A Basavarajappa HT Karbassi AR Monavari SM 《Environmental monitoring and assessment》2011,180(1-4):1-13
Critical to habitat management is the understanding of not only the location of animal food resources, but also the timing of their availability. Grizzly bear (Ursus arctos) diets, for example, shift seasonally as different vegetation species enter key phenological phases. In this paper, we describe the use of a network of seven ground-based digital camera systems to monitor understorey and overstorey vegetation within species-specific regions of interest. Established across an elevation gradient in western Alberta, Canada, the cameras collected true-colour (RGB) images daily from 13 April 2009 to 27 October 2009. Fourth-order polynomials were fit to an RGB-derived index, which was then compared to field-based observations of phenological phases. Using linear regression to statistically relate the camera and field data, results indicated that 61% (r (2)?= 0.61, df = 1, F?= 14.3, p?= 0.0043) of the variance observed in the field phenological phase data is captured by the cameras for the start of the growing season and 72% (r (2)?= 0.72, df = 1, F?= 23.09, p?= 0.0009) of the variance in length of growing season. Based on the linear regression models, the mean absolute differences in residuals between predicted and observed start of growing season and length of growing season were 4 and 6?days, respectively. This work extends upon previous research by demonstrating that specific understorey and overstorey species can be targeted for phenological monitoring in a forested environment, using readily available digital camera technology and RGB-based vegetation indices. 相似文献
18.
Fawzy MA Badr Nel-S El-Khatib A Abo-El-Kassem A 《Environmental monitoring and assessment》2012,184(3):1753-1771
The concentrations of Cd, Cu, Pb, and Zn in sediments, water, and different plant organs of six aquatic vascular plant species,
Ceratophyllum demersum L. Echinochloa pyramidalis (Lam.) Hitchc. & Chase; Eichhornia crassipes (Mart.) Solms-Laub; Myriophyllum spicatum L.; Phragmites australis (Cav.) Trin. ex Steud; and Typha domingensis (Pers.) Poir. ex Steud, growing naturally in the Nile system (Sohag Governorate), were investigated. The aim was to define
which species and which plant organs exhibit the greatest accumulation and evaluate whether these species could be usefully
employed in biomonitoring and phytoremediation programs. The recorded metals in water samples were above the standard levels
of both US Environmental Protection Agency and Egyptian Environmental Affairs Agency except for Pb. The concentrations of
heavy metals in water, sediments, and plants possess the same trend: Zn > Cu > Pb > Cd which reflects the biomonitoring potentialities
of the investigated plant species. Generally, the variation of heavy element concentrations in water and sediments in relation
to site and season, as assessed by two-way repeated measured ANOVA, was significant (p < 0.05). However, insignificant variations were observed in the concentrations of Pb and Cd in sediments in relation to season
and of Cu and Zn in relation to site. Results also showed that the selectivity of the heavy elements for the investigated
plants varied significantly (p < 0.05) with species variation. The accumulation capability of the investigated species could be arranged according to this
pattern: C. demersum > E. crassipes > M. spicatum > E. pyramidalis > T. domingensis > P. australis. On the basis of the element concentrations, roots of all the studied species contain higher concentrations of Cu and Zn
than shoots while leaves usually acquire the highest concentrations of Pb. Cd concentrations among different plant organs
are comparable except in M. spicatum where the highest Cd concentrations were recorded in the leaves. Our results also demonstrated that all the studied species
can accumulate more than 1,450-fold the concentration of the investigated heavy elements in water rendering them of interest
for use in phytoremediation studies of polluted waters. Given the absence of systematic water quality monitoring, heavy elements
in plants, rather than sediments, provide a cost-effective means for assessing heavy element accumulation in aquatic systems
during plant organ lifespan. 相似文献
19.
Heavy metal binding fractions in the sediments of the Godavari estuary,East Coast of India 总被引:1,自引:0,他引:1
Sequential chemical extraction was used to study the operationally determined chemical forms of five heavy metals (Pb, Cu,
Zn, Co and Ni) and their spatial distribution in the sediments. The binding behaviour of heavy metals associating with Fe–Mn
oxides showed a good correlation towards Cu, Zn and Co, but moderate linear dependence with Ni and Pb. Among the five metals,
correlation between Fe–Mn oxide bound Cu and Fe–Mn oxides (r = 0.95) is highest. The coefficient of determination (r
2) in organically bound heavy metals versus organic matter (OM) ranges from 0.772 to 0.952, which indicates a good linear dependence.
The OM fraction in the sediments is more accessible to heavy metals and is the major ligand available for complexation. In
particular, Zn and Cu are preferentially bound to OM. In general, Zn co-precipitation with carbonates is the dominant chemical
form when Fe–Mn oxide and OM are less abundant. In this study, however, carbonates were less abundant, hence Zn bound to carbonates
was less pronounced. Based on the results, even if the excessive binding sites are contained in the sediments, competition
of various complexation reactions between sediment phases and heavy metals could dominate metal association. 相似文献
20.
Heavy metal pollution is an increasing environmental problem in Chinese regions undergoing rapid economic and industrial development, such as the Pearl River Delta (PRD), southern China. We determined heavy metal concentrations in surface soils from the PRD. The soils were polluted with heavy metals, as defined by the Chinese soil quality standard grade II criteria. The degree of pollution decreased in the order Cd?>?Cu?>?Ni?>?Zn?>?As?>?Cr?>?Hg?>?Pb. The degree of heavy metal pollution by land use decreased in the order waste treatment plants (WP)?>?urban land (UL)?>?manufacturing industries (MI)?>?agricultural land (AL)?>?woodland (WL)?>?water sources (WS). Pollution with some of the metals, including Cd, Cu, Ni, and Zn, was attributed to the recent rapid development of the electronics and electroplating industries. Cd, Hg, and Pb (especially Cd) pose high potential ecological risks in all of the zones studied. The soils posing significantly high and high potential ecological risks from Cd covered 73.3 % of UL, 50 % of MI and WP land, and 48.5 % of AL. The potential ecological risks from heavy metals by land use decreased in the order UL?>?MI?>?AL?>?WP?>?WL?>?WS. The control of Cd, Hg, and Pb should be prioritized in the PRD, and emissions in wastewater, residue, and gas discharges from the electronics and electroplating industry should be decreased urgently. The use of chemical fertilizers and pesticides should also be decreased. 相似文献