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1.
J Environ Manage ; 283: 112004, 2021 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-33529931

RESUMEN

Acid mine waters (AMWs), generated in the processing of polymetallic sulphides, contain copper and zinc as the main valuable transition metal ions, which are typically removed by liming, due to their great environmental impact. In this context, this work proposes the integration of selective precipitation (SP) and ion-exchange (IX) processes for the separation and recovery of both valuable metals to encourage on-site and off-site management options promoting valorisation routes. Thus, the main objectives of this work were (i) the selective removal of Fe(III) and Al(III), using NaOH under pH control (pH < 5) to avoid the precipitation of Cu(II) and Zn(II) and (ii) the evaluation of a solvent-impregnated resin (Lewatit VP OC 1026, named VP1026) and a cation IX resin (Lewatit TP 207, named TP207) for the sequential extraction of both metal ions from AMW (batch and column experiments). Results indicated that the metallic pollution load was mostly removed during the SP process of Fe(III) (>99%) and Al(III) (>90%) as hydroxylsulphates (e.g., schwertmannite and basaluminite). The metal extraction profiles were determined for both metals from pH 1 to pH 5 by batch experiments, and indicated that the best extraction of Zn(II) was obtained using VP1026, being higher than 96% (pH = 2.6-2.8), whereas TP207 extraction performance was optimal for Cu(II) extraction (>99%) at pH = 3-4. Moreover, in dynamic experiments using a fixed-bed configuration, it was possible to separate and concentrate Zn(II) (concentration factor = 10) and Cu(II) (concentration factor = 40) using VP1026 and TP207, respectively. Overall, the integration of SP and IX processes showed a great potential in the separation and recovery of valuable metals from mine waters to promote a circular economy, based on the management proposal for non-ferrous metallurgical industries. The recovered Zn-rich and Cu-rich sulphuric concentrated streams were theoretically evaluated for further on-site or off-site re-use treatments (e.g., electrowinning, precipitation, crystallization).


Asunto(s)
Compuestos Férricos , Metales Pesados , Cobre/análisis , Concentración de Iones de Hidrógeno , Intercambio Iónico , Metales Pesados/análisis , Minería , Zinc/análisis
2.
J Environ Manage ; 284: 111996, 2021 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-33535125

RESUMEN

The development of efficient strategies for the removal of heavy metal ions from aqueous solutions is rapidly demanded as these contaminants are very toxic and carcinogenic and show detrimental effects on the living creatures. The main focus of the current study is on the preparation and assessment of electrospun adsorptive nanofiber membranes for the removal of toxic Ni(II) and Cu(II) from wastewater in the ultrafiltration process. Hydrothermally synthesized titanate nanotubes (TNT) was modified with thiol functional groups and then directly incorporated to the polyvinyl chloride nanofiber matrices via electrospinning process to fabricate an adsorptive membrane. The as-prepared electrospun nanofiber membranes and the nanoadsorbents were characterized with respect to the physiochemical properties, surface structure and morphology, applying XPS, FTIR, FESEM, EDX and TEM analysis and then, the membranes were evaluated in terms of the removal of the heavy metal ions in a continuous ultrafiltration mode. In adsorptive filtration of the metal ions, the effective factors including nanoadsorbents loading (0.5-1.5 wt%), initial metal ion concentration (60-150 mg/L), feed temperature (~25 °C-45 °C), presence of competing ion and reusability were investigated in the UF system where the membranes containing 1.5 wt% thiol-modified TNT and virgin TNT adsorbents demonstrated excellent removal efficiency compared to the other membranes. The Cu(II) and Ni(II) removal efficiency of the membrane containing 1.5 wt% functionalized TNT was 90% and 86.7%, respectively which was the highest ones. As was expected and due to the uniform dispersion and less aggregation of the modified TNT adsorbents on the large surface area of the electrospun nanofibers, more adsorption capacity of the nanoparticles can be exploited. Moreover, the strong affinity of the thiol functional groups toward the metal cations, these membranes removed metal contaminants more efficiently. Besides, the Cu(II) removal efficiency of the fabricated membranes didn't show any drastic changes in the presence of the competing ions. Furthermore, acceptable performance was achieved for the prepared membranes even after four adsorption/regeneration cycles in the continuous UF experiments, demonstrating the feasibility and effectiveness of the prepared adsorptive nanofiber membranes for the removal of heavy metal ions.


Asunto(s)
Metales Pesados , Nanofibras , Nanotubos , Trinitrotolueno , Contaminantes Químicos del Agua , Purificación del Agua , Adsorción , Iones , Cloruro de Polivinilo , Compuestos de Sulfhidrilo , Contaminantes Químicos del Agua/análisis
3.
Environ Monit Assess ; 193(3): 141, 2021 Feb 23.
Artículo en Inglés | MEDLINE | ID: mdl-33620553

RESUMEN

The water pollution index (PIj), degree of contamination (Cd), heavy metal pollution index (HPI), and statistical analyses were used to assess seawater pollution and identify the possible sources of heavy metals from the Red Sea-Gulf of Aqaba coastline, northwest Saudi Arabia. Concentrations of Cr, Sb, Co, Ni, Cu, Zn, Cd, As, Fe, Mn, Hg, and Pb were analyzed and interpreted in 33 surface seawaters samples. The mean heavy metals of seawater were in the following order: Zn (5.51 µg/l) > Ni (2.45) > As (2.43) > Cu (2.34) > Mn (2.20) > Fe (1.81) > Pb (1.31) > Sb (0.64) > Co (0.31) > Cr (0.26) > Cd (0.05) > Hg (0.008). The spatial distribution of heavy metals showed high levels in some individual samples, especially nearby the residential cities, may be due to anthropogenic sources. PIj and Cd indicated light and low pollution for the seawater samples, respectively, while HPI indicated low pollution for 10 samples and medium pollution for the rest ones. The lack of significant correlations between metal pairs (except Cu and As) indicated different sources of pollution. Pollution indices, principal component analysis, and Pearson's correlation coefficient reveal that the quality of seawater in the Red Sea-Gulf of Aqaba coastline is mainly controlled by geogenic processes with minor anthropogenic input.


Asunto(s)
Metales Pesados , Contaminantes Químicos del Agua , Ciudades , Monitoreo del Ambiente , Sedimentos Geológicos , Océano Índico , Metales Pesados/análisis , Medición de Riesgo , Arabia Saudita , Agua de Mar , Contaminantes Químicos del Agua/análisis
4.
Environ Monit Assess ; 193(3): 136, 2021 Feb 18.
Artículo en Inglés | MEDLINE | ID: mdl-33599829

RESUMEN

Ajali River near some beverage industries was assessed. Eleven physicochemical parameters and six heavy metals (copper, zinc, iron, cadmium, chromium, and lead) were analyzed on water and sediment collected from different locations near three beverage industries. Standard methods were used to determine the physicochemical parameters while heavy metals were determined with atomic absorption spectrophotometer. The health risk assessment of the water samples were estimated by calculating the hazard quotient (HQ), total hazard index (THI), and the probability cancer risk (PCR) of the heavy metals. Results showed that the concentrations of some heavy metal and physicochemical properties were slightly impaired compared to permissible standards. However, cadmium in water (0.56-11.34 mg/L) and sediments (2.81-481.40 mg/kg) samples were above the recommended limit, indicating possible cadmium pollution in the study area. The water quality index values showed that some of the sampled locations had poor (53.43-134.90%) water quality. The risk assessment of the water samples revealed that HQ for Cu, Zn, Fe, and Cr were of no probable risk (HQ < 1) while Cd (HQ = 173-438) were of probable risk. THI of the water samples showed probable risk (THI > 1) resulting from the high percentage contribution of Cd (94.13 to 99.95%). The probability carcinogenic risk assessment for adults (Cd-7.14 × 10-2, Cr-1.43 × 10-4) and children (Cd-1.66 × 10-1 and Cr-3.34 × 10-4) were significantly harmful. Even though the presence of these industries could encourage more economic activities in the area, there is need for the relevant agencies to enforce effective treatment and proper management of wastes especially cadmium, to safeguard this water source for the rural dwellers.


Asunto(s)
Metales Pesados , Contaminantes Químicos del Agua , Adulto , Bebidas , Niño , Monitoreo del Ambiente , Sedimentos Geológicos , Humanos , Metales Pesados/análisis , Nigeria , Medición de Riesgo , Ríos , Contaminantes Químicos del Agua/análisis
5.
Water Sci Technol ; 83(3): 595-609, 2021 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-33600364

RESUMEN

Dewatering of sludge is a key problem that must be solved in the sewage sludge disposal industry. In this study, a series of process optimization tests were conducted to learn how to improve sludge treatment. The optimum process of sludge leaching treatment was studied in a specially designed 100-L reactor system. Four factors were investigated and nine batches of bioleaching tests were run at three levels of these factors. Orthogonal experiments showed that the effect of sludge return ratio and aeration rate on the sludge moisture content was significant and hydraulic retention time (HRT) had a clear effect, but nutrient types had a reduced effect on the moisture content of sludge. The primary and secondary order of each factor is reflux ratio > aeration rate > HRT > nutrient type. Under the optimal process, three batches of sludge were processed and the moisture content of the filter press cake was reduced to less than 60%, the organic matter content reduced to below 5%, and the concentration of heavy metals (Cu, Zn, Pb, and Cr) was much lower than the agricultural standard limit, which is suitable for landscaping, composting, and incineration power generation and other resource applications.


Asunto(s)
Metales Pesados , Aguas del Alcantarillado , Polisorbatos , Tiosulfatos
6.
Waste Manag ; 123: 69-79, 2021 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-33571831

RESUMEN

Although pyrolysis is a promising way for treating animal manure, the application is restricted with some limitations of biochar. To improve the quality of biochar derived from swine manure and enhance the immobilization of heavy metals (Cu and Zn) in it, swine manure was mixed with four types of Ca-based additives (CaO, CaCO3, Ca(OH)2, and Ca(H2PO4)2) prior to pyrolysis at 300-700 °C. The thermogravimetric characteristics of swine manure were obviously influenced The addition of CaO, CaCO3, and Ca(OH)2 during the whole decomposition process. Furthermore, with the addition of CaO and Ca(OH)2, the emission of CO2 and CO was substantially decreased at 200-500 °C, whereas the formation of CO, H2, CO2, and CH4 was drastically increased at 600-800 °C. The biochar produced with CaO addition had the highest pH, surface area and carbon content. Moreover, by addition of Ca-based additives, except for Ca(H2PO4)2, the transformation of labile Cu and Zn to the stable fraction was promoted, and the leachability and environmental risk of them were simultaneously reduced. In contrast, CaO and Ca(OH)2 were more favorable for the immobilization of Cu and Zn than CaCO3. Our study indicated that the catalytic pyrolysis using CaO was an effective and valuable method of animal manure treatment.


Asunto(s)
Estiércol , Metales Pesados , Animales , Calcio , Carbón Orgánico , Porcinos
7.
Waste Manag ; 123: 80-87, 2021 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-33571832

RESUMEN

Enriched in phosphorus, sewage sludge ash has been extensively studied and applied as a secondary source for phosphorus recovery. Wet extraction, especially acid washing, is one of the most feasible methods to recover phosphorus from the ash due to its ease of operation, high efficiency and low cost. However, the management of the resultant acid residue was seldom addressed. In this study, special focus was paid to the reuse and recycling of the acid residue by an alkaline activation method. Its adsorption performance towards four different heavy metals in aqueous solutions was evaluated by batch and fixed-bed column adsorption experiments. The obtained material showed a high BET specific area (98.29 m2/g) and a total pore volume (0.114 cm3/g), and effectively removed Cd(II), Cu(II), Pb(II) and Zn(II) from aqueous solutions with the maximum adsorption capacity of around 26.8, 22.2, 53.3 and 13.5 mg/g respectively. It could be loaded in a fixed-bed column to continuously remove heavy metals especially for Pb(II). The proposed method to recycle the acid residue makes the wet extraction methods designing to recover phosphorus from incinerated sewage sludge complete without the generation of waste, which contributes to circular economy and a sustainable future.


Asunto(s)
Metales Pesados , Aguas del Alcantarillado , Adsorción , Fósforo , Reciclaje
8.
J Environ Qual ; 50(1): 264-277, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-33616977

RESUMEN

Thermal treatment by pyrolysis has been proposed as a sustainable alternative to enable the agricultural use of sewage sludge. The solid product obtained via pyrolysis of sewage sludge is called sewage sludge biochar and presents several advantages for its use as a fertilizer or soil conditioner. However, there are concerns about the accumulation and dynamics of trace elements in soil amended with sewage sludge biochar over the years. This study examined the effect of sewage sludge biochar, under field conditions for 5 yr, on the accumulation and availability of trace elements in a tropical soil. For this, 15 t ha-1 of sewage sludge biochar produced at 300 and 500 °C were applied in the first two growing seasons. Application was interrupted from the third to the fifth seasons to assess the residual effect of sewage sludge biochar in the soil. The total and available trace element concentrations were determined. The total contents of trace elements showed the following variation in the soil over the 5 yr (mg kg-1): Cd (16.8-20.0), Co (19.5-21.5), Cr (98.2-125.7), Cu (8.1-17.1), Mn (62.9-85.7), Ni (20.3-35.0), Pb (27.0-52.4), and Zn (20.3-35.8). There was no change in the availability of Cd, Cr, Ni, and Pb over the years. Additionally, a residual effect of the sewage sludge biochar was the increase in availability of trace elements that are considered essential (Cu, Mn, and Zn) and beneficial elements (Co) for plants. Therefore, in relation to contamination by trace elements, the pyrolysis of sewage sludge of domestic origin proved to be an adequate strategy to enable the safe use of this residue in tropical agriculture.


Asunto(s)
Metales Pesados , Contaminantes del Suelo , Oligoelementos , Carbón Orgánico , Metales Pesados/análisis , Aguas del Alcantarillado , Suelo , Contaminantes del Suelo/análisis
9.
Environ Monit Assess ; 193(3): 140, 2021 Feb 22.
Artículo en Inglés | MEDLINE | ID: mdl-33619671

RESUMEN

The study investigated the contents of selected heavy metals in top soils and sub-soils around the vicinity of artisanal gold mining site in Minna, Niger state, using standard procedures. Digestion was done using HNO3-H2O2-HCl and heavy metal content using atomic absorption spectrometer. The results obtained showed some extent of contamination with mean values of 2.87 ± 0.17mg kg-1, 286.21 ± 0.20mg kg-1, 15,375.46 ± 0.52mg kg-1, 2233.60 ± 0.46mg kg-1, and 131.71 ± 0.15mg kg-1 for Cd, Zn, Fe, Mn, and Pb, respectively. The surrounding environment (50 m away from the gold mining site) also showed significant contamination with mean values of 2.77 ± 0.17mg kg-1, 295.27 ± 0.20mg kg-1, 11,523.64 ± 0.25mg kg-1, 1956.50 ± 0.54mg kg-1, and 74.63 ± 0.15mg kg-1 for Cd, Zn, Fe, Mn, and Pb, respectively. The values obtained were significantly higher when compared with those from the control soil samples. With the exception of Pb and Mn, the values of the other metals investigated were all below the WHO permissible limit. The trend of contamination with respect to contamination factor was in the order: Zn > Fe > Pb > Mn > Cd. The high contents of Pb and Mn in this area therefore show the need for more studies and immediate intervention measures.


Asunto(s)
Metales Pesados , Contaminantes del Suelo , China , Monitoreo del Ambiente , Peróxido de Hidrógeno , Metales Pesados/análisis , Niger , Medición de Riesgo , Suelo , Contaminantes del Suelo/análisis
10.
Environ Monit Assess ; 193(3): 109, 2021 Feb 03.
Artículo en Inglés | MEDLINE | ID: mdl-33537887

RESUMEN

Several commercial test kits such as Microtox, LUMIStox, ToxAlert, Aboatox, and ToxScreen have been widely used for toxicity screening. Though this time saving assays offer excellent sensitivity, cost-effectiveness, and accuracy, these commercial assays are limited in terms of real-time monitoring in Indian coastal environment due to warmer temperatures. This necessitates the need to develop a rapid and accurate assay that can be effectively employed for real time monitoring with respect to heavy metals in the Indian coastal waters. With this objective, the present study was conducted by isolating an indigenous luminescent bacterium from the light organs of chordates Gazza minuta which showed higher luminescence in a wide range of temperatures. The isolate could grow well in the temperature of 30 ± 2 °C and withstand temperature up to 35 ± 2 °C. The isolated bacterium was identified as Photobacterium leiognathi GoMGm1 based on 16S rDNA and luxA gene sequences. The suitable growing medium was optimized using central composite rotational design (CCRD) method to obtain optimal growth and luminescence. The optimized medium exemplified the maximal growth and luminescence of P. leiognathi at OD600 nm of 5.78 ± 0.12 and RLU of 12.49 ± 0.43. The isolate was used to assess the toxicity of several heavy metals. The IC50 values of 0.0051, 1.13, 1.37, 3.1, and 6.68 mg L-1 were observed for the Hg, Cr, Cu, Ni, and Zn, respectively, after 15 min of exposure. Results obtained from principal component analysis (PCA) displayed the present assay's compatibility with other luminescent bacterial assay and commercial Microtox™ assay. Thus, it would the right candidate as an early detection system for heavy metals in aquatic bodies in tropical countries. Schematic representation of the present study.


Asunto(s)
Mercurio , Metales Pesados , Animales , Monitoreo del Ambiente , Mediciones Luminiscentes , Metales Pesados/análisis , Metales Pesados/toxicidad , Photobacterium
11.
Wei Sheng Yan Jiu ; 50(1): 79-85, 2021 Jan.
Artículo en Chino | MEDLINE | ID: mdl-33517966

RESUMEN

OBJECTIVE: To detect the concentrations of ten metals and metalloid elements in the atmospheric PM_(2. 5) in Chengguan district and Xigu district of Lanzhou City from 2015 to 2018, and analyze the pollutant concentration and its change trend. METHODS: From 2015 to 2018, 662 samples of PM_(2. 5) were collected from Chengguan district and Xigu district of Lanzhou City. The concentrations of 10 kinds of metals and metalloid elements such as lead(Pb), arsenic(As), mercury(Hg), cadmium(Cd), chromium(Cr), antimony(Sb), manganese(Mn), nickel(Ni), selenium(Se), beryllium(Be) were detected, and the change trends of different monitoring points, years, seasons and months were analyzed. RESULTS: There was a significant difference in lead content between Chengguan District and Xigu District(χ~2=4. 80, P<0. 05), the median of Pb content in Chengguan and Xigu District was 45. 30 and 37. 20 ng/m~3, which was higher than that in Xigu District; the difference of Mn content in the two districts was statistically significant(χ~2=21. 28, P<0. 05), the median in two District was 32. 04 and 23. 37 ng/m~3, which was higher than that in Xigu District; the median of Be content in the two districts was statistically significant(χ~2=11. 57, P<0. 05), and the median of Be content in two districts was 0. 05 and 0. 07 ng/m~3, Xigu Distric was higher than Chengguan, there was no significant difference in other seven elements(P>0. 05). From 2015 to 2018, the element content of PM_(2. 5) in Chengguan District decreased by 47. 66% compared with 2015; Xigu District in 2018 decreased by 43. 79% compared with 2015; the higher element Pb, Mn and As in Chengguan District decreased by 52. 93%, 47. 00% and 49. 37% compared with 2015; in Xigu District, the content in 2018 decreased by 46. 87%, 47. 49% and 41. 98%compared with 2015, the contents of the remaining seven elements decreased in 2018 compared with those in 2015. There was no statistical significance(P>0. 05) in different seasons except for the difference of Ni content(P<0. 05), and the content of other elements showed a significant seasonal change: winter>spring>autumn> summer. The trend of monthly concentration change in the two regions was basically the same, the concentrations of Sb, As, Pb, Mn, Cd, Ni, Se, Hg and Cr were higher in November and February of next year. In Chengguan District and Xigu District, Ni content was higher in July and August, respectively;and Hg in Xigu District was higher in June, and Be was higher in less months, especially in February, October and December. CONCLUSION: From 2015 to 2018, the levels of 10 metals and metalloids element pollutants in PM_(2. 5) samples from Chengguan District and Xigu District of Lanzhou City showed a decreasing trend year by year, and had obvious seasonal changes.


Asunto(s)
Mercurio , Metaloides , Metales Pesados , Ciudades , Monitoreo del Ambiente , Metales/análisis , Metales Pesados/análisis
12.
Environ Monit Assess ; 193(2): 104, 2021 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-33521861

RESUMEN

Unplanned industrialization and improper management of wastes and gases into open surfaces are affecting the agricultural lands causing heavy metal pollution. This study monitored a suburban industrial zone located beside the Dhaka Export Processing Zone (DEPZ) at the Dhaka district in Bangladesh. We studied the heavy metal (Fe, Mn, Cr, Cu, Ni, Co, Zn, Pb, and Cd) concentration in the agricultural soils, plants, and in the atmospheric particulate matter (PM). The soils were found moderately contaminated with Fe, Cu, Ni, Co, and Zn and less contamination with Mn, Cr, Pb, and Cd. The enrichment factor (EF) and pollution load index (PLI) concluded a moderate level of soil pollution in this region. Besides, the plant samples showed an excess level of Cr and a similar level of Cu, Ni, Co, Zn, Pb, and Cd compared with the levels of industrial polluted sites of Bangladesh. The atmospheric PM analysis showed the presence of Fe, Mn, Cu, Ni, Zn, and Pb metals. The EF showed the anthropogenic origin of Mn and Ni in the atmospheric PM. The statistical correlation (r < 0.0001) of soil and plant heavy metals showed the possibility of transfer of metals from soil to plant which will cause the increase of pollution intensity. Overall, this agricultural region became an intermediate pollution zone. This study will help the decision-maker become conscious of heavy metal pollution in the suburban regions to monitor agricultural lands from anthropogenic pollution.


Asunto(s)
Metales Pesados , Contaminantes del Suelo , Bangladesh , Monitoreo del Ambiente , Contaminación Ambiental , Metales Pesados/análisis , Material Particulado , Medición de Riesgo , Suelo , Contaminantes del Suelo/análisis
13.
Sci Total Environ ; 765: 142789, 2021 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-33572033

RESUMEN

Evaluation of trace metal pollution in an environmentally complex context may require the use of a suite of indicators. Common reed, Phragmites australis, is a well-known biomonitor of sediment pollution. Here, we show its potential for also assessing air pollution. The plant panicles, holding silky hairs with high surface to volume ratio, are appropriate collectors of atmospheric contaminants, which perform independently from root bioconcentration. We applied the dual value of common reed as an indicator of trace metal pollution to the case of a chlor-alkali plant in the Ebro river bank (Spain). This factory had historically damped waste to the shallow Flix reservoir. Extensive common reed meadows are growing on the top of the waste, in a nearby nature reserve across the reservoir and a meander immediately downriver. Three replicated individuals from a total of 11 sites were sampled, and the trace metal content measured in the main plant compartments (roots, rhizomes, stems, leaves, and panicles). Panicles and roots showed a much larger concentration of trace metals than the other plant compartments. Levels of Hg, Cu, and Ni were markedly higher in panicles at the factory and nearby points of the reserve and lowered at the meander. In contrast, Cd, Zn, and Mn in roots increased from the factory to the meander downriver. We conclude that panicles show recent (less than a year) airborne pollution, whereas roots indicate the long-term transport of pollutants from the waste in the shoreline of the factory to downriver sedimentation hotspots, where they become more bioavailable than in the factory waste. The Hg spatial pattern in panicles agree with air measurements in later years, therefore, confirming the panicles suitability for assessing airborne pollution and, consequently, Phragmites as a potential dual biomonitor of air and sediments.


Asunto(s)
Metales Pesados , Contaminantes Químicos del Agua , Monitoreo del Ambiente , Sedimentos Geológicos , Humanos , Metales Pesados/análisis , Poaceae , Ríos , España , Contaminantes Químicos del Agua/análisis , Humedales
14.
Environ Monit Assess ; 193(3): 133, 2021 Feb 16.
Artículo en Inglés | MEDLINE | ID: mdl-33594524

RESUMEN

In this study, the influence of source area weathering and provenance on the stream sediment geochemistry as well as the environmental impacts of selected potentially toxic trace elements (PTE) were evaluated. Four components derived from the R-mode factor analysis of additive logratio-transformed data pointed to the combined influence of weathering of granitoids, sedimentary rocks and greenstone belts and gold mineralisation on the stream geochemistry. Although 13 PTE were enriched in the majority of the samples, only five elements (As, Cr, Cu, Pb and Ni) were likely to have adverse biological effects. Based on the geochemical maps, the areas susceptible to produce adverse biological effects due to As enrichments are solely drained by the greenstone belts, whereas enrichment of Pb was pronounced in areas of high population densities. The linear regression between enrichment factor (EF) and adverse effect indices (AEI) indicated that in order for Pb to pose threats to the benthic organisms, EF should be 4.5, whereas EF for sediment toxicity are 1 for Cu, Cr and Ni and 2 for As. Consequently, Cu, Cr, Ni, As and, to a lesser degree, Pb pose serious environmental threats to benthic organisms in southwestern Burkina Faso. The stream sediment geochemical data of this study constitute a baseline for assessing future environmental risks.


Asunto(s)
Metales Pesados , Contaminantes Químicos del Agua , Burkina Faso , Monitoreo del Ambiente , Sedimentos Geológicos , Metales Pesados/análisis , Medición de Riesgo , Ríos , Contaminantes Químicos del Agua/análisis
15.
Environ Monit Assess ; 193(3): 134, 2021 Feb 16.
Artículo en Inglés | MEDLINE | ID: mdl-33594544

RESUMEN

Despite the key role that areas close to the rivers Cau and Ngu Huyen Khê (Bac Giang Province, Northern Vietnam) play in the socio-economic development of Vietnam, poor information is available on the level of contaminants and their natural backgrounds in local soils and sediments. To partially fill this gap and to take into account for pressures and impacts on different zones and environment types (river sediments, crop fields, family wells, industrial and urban soils), the samples were collected and analyzed for fifteen trace elements at thirty sites distributed over the province. To overcome the lack of information on natural background and to identify the extent of the deviation from natural conditions, we coupled statistical analysis to contamination indices. The multivariate analysis was used to relate sediment chemical composition with a possible alteration from secondary inputs and to highlight those samples that most deviate from the distribution by category and are potentially more problematic. Geoaccumulation indexes and enrichment factors were calculated to discriminate between natural backgrounds and anthropic sources, SQGs were used for a screening evaluation of environmental risk in the study area. Results showed relatively high concentrations, sometimes exceeding international and national guidelines, and local sources could prevail over geogenic origins. Despite its significant natural contribution all over the study area, As evidenced some cases of anthropogenic contamination, similarly to that observed for Cd, Hg, and Zn. Their high concentrations may be a problem for public health, especially when found in family wells.


Asunto(s)
Metales Pesados , Contaminantes Químicos del Agua , Monitoreo del Ambiente , Sedimentos Geológicos , Metales Pesados/análisis , Ríos , Suelo , Vietnam , Contaminantes Químicos del Agua/análisis
16.
Environ Monit Assess ; 193(3): 122, 2021 Feb 13.
Artículo en Inglés | MEDLINE | ID: mdl-33580837

RESUMEN

As a historic gold mining area, the City of Benoni has numerous water bodies close to major tailings dams and mine dumps. Here we assess spatial patterns in the sediment geochemistry of five dams and four natural pans within a 5-km radius of the core mining area to determine the degree of contamination7 by mining-associated pollutants. XRF analysis was used with a geoaccumulation index to assess the degree of contamination above background levels. Prevailing winds blow from the north and north-west with less dominant winds from the east. Sediment concentrations of As, Cu, Pb, Ni and Zn are highly correlated across the region, suggestive of a common source. Except for one pan showing evidence of local industrial pollution, the most contaminated sites are the dams to the west of the mine dumps where concentrations of As, Cu, Pb and Zn increase towards the central mining area, with highest trace metal concentrations in Kleinfontein Dam, adjacent to a reworked mine dump. Sites upwind of the central mining area showed little evidence of mining-related contamination. Trace contaminant concentrations in sediments of these dams are much greater than those found in the nearby Springs-Blesbokspruit wetlands adjacent to more recently active mines. The potential risks to aquatic ecosystems and recreational users of these urban and suburban water bodies from these wind-blown, legacy mining contaminants merit further investigation.


Asunto(s)
Metales Pesados , Contaminantes del Suelo , Oligoelementos , Contaminantes Químicos del Agua , Ecosistema , Monitoreo del Ambiente , Sedimentos Geológicos , Oro , Metales Pesados/análisis , Minería , Contaminantes del Suelo/análisis , Sudáfrica , Contaminantes Químicos del Agua/análisis
17.
Environ Monit Assess ; 193(3): 127, 2021 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-33587193

RESUMEN

According to several reports, the presence of transition metal elements in the atmosphere was associated with adverse health effects. The purpose of this investigation was to analyze the presence of transition metal particles with atomic numbers 22-29 on some medicinal plants (n = 22) from various regions of the Republic of Tajikistan and their content in the atmosphere. Samples (n = 43) of individual plant organs, such as seeds, flowers, leaves, trunks, and plant roots, were examined for their elemental composition using X-ray fluorescence analysis. Selection of particles contained in the atmosphere was carried out for 24 h/3 days by the aspiration method using fiberglass filters GF 10 in an apparatus installed at an altitude of 864 m on the periphery of the capital. For the analysis of plant samples, measurements were carried out on a SPECTROSCAN MAX-G wave-dispersive X-ray fluorescence spectrometer. For samples containing filtered atmosphere elements, a high-resolution PANanalytical Epsilon 5 high-resolution energy-dispersive spectrometer was used. Eight transition elements from the 1st main series of metals with atomic numbers 22-29, such as titanium, vanadium, chromium, manganese, iron, cobalt nickel, and copper, were found in plant organs, as well as in the atmosphere samples. Our results showed that the distribution of metals on plants varied depending on plants and their organs. We did not find any correlation between the region of plant collection and their absorption of metal elements. The distribution of metals varied in various plant organs. In the atmosphere samples, we found all the metals that were found in plants. In conclusion, medicinal plants can adsorb and accumulate some harmful chemical elements in their organs, are involved in the recirculation of these metals, and contribute air pollution.


Asunto(s)
Contaminación del Aire , Metales Pesados , Cobre/análisis , Monitoreo del Ambiente , Metales/análisis , Metales Pesados/análisis , Tayikistán
18.
Environ Monit Assess ; 193(3): 126, 2021 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-33587195

RESUMEN

Ona River is one of the three major rivers draining the city of Ibadan. Groundwater is the major source of drinking water in the metropolis; however, data on quality of shallow aquifers bordering Ona River is relatively scarce. This study aimed to evaluate bacteriological status, heavy metal content, and associated human and ecological health risks in hand-dug wells nearby Ona River. A total of 24 water samples from 12 sampling points were collected for chemical and microbial analyses. Heavy metals and microbial pathogens were analyzed using atomic absorption spectrometry and total plate count methods, respectively. Analyses of microbial and heavy metal (HMs) data showed that shallow hand-dug wells within the vicinity of Ona River were bacteriologically contaminated while most of analyzed heavy metals (except manganese) exceeded the drinking water quality standards. Interpretation of microbial and heavy metal (HMs) data identified predominance of anthropogenic activities as the major source of contamination in drinking water. Further scrutiny of HM data through integrated pollution indices identified two nearby wells (S7 and S8) exceed the safe limits and pose considerable risk to inhabitants. In terms of ecological risk index (ER), cadmium exhibited considerable to very high ER in all collected samples while manganese and zinc showed low ER in all analyzed water samples. Potential of non-carcinogenic risk through ingestion pathway in the study area was identified with the order of contributive ratios by HMs as Cd > Pb > Zn > Fe > Mn. The calculated target hazard quotient (THQ) due to ingested HMs for three human population categories exceeds the safe limit in the order of adult < children < infants. The study revealed the deteriorated state of waterside shallow hand-dug wells that need immediate actions by relevant stakeholders in water management. The study recommends improved hygienic practices, pretreatment of water before use, and most importantly, provision of potable pipe-borne water supply to the residents of the study area.


Asunto(s)
Metales Pesados , Contaminantes Químicos del Agua , Adulto , Niño , Ciudades , Monitoreo del Ambiente , Humanos , Metales Pesados/análisis , Nigeria , Medición de Riesgo , Ríos , Contaminantes Químicos del Agua/análisis
19.
Anal Chem ; 93(4): 1880-1888, 2021 02 02.
Artículo en Inglés | MEDLINE | ID: mdl-33430590

RESUMEN

This Feature summarizes recent works in paper-based potentiometry and voltammetry in heavy metal determination. Interactions of paper substrates with heavy metals, influence on the sensing response, and modification methods applied to paper substrates to improve the performance of recently developed electrochemical sensors are discussed. Since the rekindling of interest in paper-based analytical devices, methodologies and electrode designs for heavy metal determinations are highlighted. Promising aspects of the use of these sensors for samples containing solids and the increased versatility of the use of paper in analytics offers the possibility of increased acceptance of these low-cost platforms.


Asunto(s)
Técnicas Electroquímicas/métodos , Metales Pesados/química , Papel , Técnicas Electroquímicas/economía , Técnicas Electroquímicas/instrumentación , Monitoreo del Ambiente/instrumentación , Monitoreo del Ambiente/métodos
20.
Mar Pollut Bull ; 163: 111954, 2021 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-33440263

RESUMEN

In this study, the characteristics and spatial distribution of heavy metal pollution in the surface sediments of Haizhou Bay, one of the largest bays in China, were investigated. The potential ecological risks posed by seven heavy metals were analyzed by using the Hakanson comprehensive pollution index and geoaccumulation index (Igeo). A correlation matrix map was applied to explore the relationships between the seven heavy metals and environmental elements. The results showed that the contents of heavy metals in the southern area of Haizhou Bay are high, whereas those in the northern area are low. The results of the pollution assessment of heavy metals were largely consistent between the Igeo method and the potential ecological risk index method. The seven heavy metals ranked in descending order of potential ecological risk coefficient as follows: Hg, Cd, As, Pb, Cu, Cr and Zn. The environmental quality assessment showed that Hg is the main heavy metal pollutant in surface sediments in Haizhou Bay, and some stations have reached a high pollution level and should receive more attention.


Asunto(s)
Metales Pesados , Contaminantes Químicos del Agua , Bahías , China , Monitoreo del Ambiente , Sedimentos Geológicos , Metales Pesados/análisis , Medición de Riesgo , Contaminantes Químicos del Agua/análisis
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