The concentrations of heavy metals (HMs) in plants served to indicate the metal contamination status of the site, and also revealed the abilities of various plant species to take up and accumulate ...them from the soil dressed with sewage sludge. A study to comprehend the mobility and transport of HMs from soil and soil amended with untreated sewage sludge to different newly breaded varieties of wheat (Anmol, TJ-83, Abadgar and Mehran-89) in Pakistan. A pot-culture experiment was conducted to study the transfer of HMs to wheat grains, grown in soil (control) and soil amended with sewage sludge (test samples). The total and ethylenediaminetetraaceticacid (EDTA)-extractable HMs in agricultural soil and soil amended with domestic sewage sludge (SDWS) and wheat grains were analysed by flame atomic absorption spectrometer/electrothermal atomic absorption spectrometer, prior to microwave-assisted wet acid digestion method. The edible part of wheat plants (grains) from test samples presented high concentration of all HMs understudy (mg
kg
−1). Significant correlations were found between metals in exchangeable fractions of soil and SDWS, with total metals in control and test samples of wheat grains.
The bio-concentration factors of all HMs were high in grains of two wheat varieties, TJ-83 and Mehran-89, as compared to other varieties, Anmol and Abadgar grown in the same agricultural plots.
The current study was conducted to evaluate the arsenic (As) and fluoride (F
−
) concentrations in growing media (stored rainwater and soil), of district Tharparkar, Pakistan. The ...bioaccumulation/transportation of As and F from growing media to different types of vegetables (wild cucumis, Indian squish and cluster bean) was evaluated. Total concentrations of As and F
−
in stored rainwater samples were observed up to 585 μg/L and 32.4 mg/L, respectively, exceeding many folds higher than WHO provisional guideline values. The As and F
−
contents in soil samples of nine agricultural sites were found in the range of 121–254 mg/kg and 115–478 mg/kg, respectively. The highest contents of As and F
−
were observed in wild cucumis as compared to Indian squish and cluster bean (
p
< 0.05), grown in the same agricultural field. The bioaccumulation factors of As and F
−
were to be > 4.00, indicating the high rate of transportation of As and F
−
from growing media to vegetables. A significant positive correlation of As and F
−
in vegetables with their concentrations in soil and water was observed (
r
> 0.60 with
p
< 0.05). The risk assessment elucidated that the population of different age group consuming local vegetables and drinking water contaminated with As and F
−
may have adverse health effects.
Graphical Abstract
A fast microwave assisted extraction procedure was developed and optimized for their eventual exploitation in the three-stage sequential extraction procedure proposed by modified BCR protocol (the ...community Bureau of Reference now the European Union “Measurement and Testing Programme”). The effects of the microwave treatment on the extraction of Cd, Cr, Cu, Ni, Pb and Zn from untreated sewage sludge collected from Hyderabad city (Pakistan) were compared with those obtained from sequential BCR extraction procedure. In sequential BCR method, each extraction step takes 16
h, where as with the use of compromised microwave conditions, extraction steps could be completed in about 120
s, for each step, respectively. Extractable Cd, Cr, Pb and Ni obtained by both comparable methodologies were measured by electrothermal atomic absorption spectrometry (ETAAS), while for Cu and Zn flame atomic absorption spectrometry (FAAS) was used. The validations of both extraction techniques were compared by the analysis of certified reference material of soil amended with sewage sludge (BCR 483). The results of the partitioning study of untreated waste water sewage sludge, indicate that more easily mobilized forms (step 1) were predominant for Cd, Ni and Zn (28.3, 28.4 and 43.7%), in contrast, the largest amount of Cd and Pb (66.4 and 72.8%) was associated with the iron/manganese oxide while Cr and Ni (71.2 and 38.7%) in organic matter/sulphide fractions. The overall metal recoveries in steps 1–3 (excluding residual step) were 95.3–104% of those obtained with the sequential BCR protocol. The accuracy of the proposed microwave extraction method (expressed as %R.S.D.) was lower than 10% for all metals.
The toxic metals in coal have different modes of occurrence required their frequent assessment by accurate and time‐saving chemical fractionation schemes. In the current study, the conventional ...sequential extraction BCR (SE‐BCR) method applied to recognize the chemical fraction of lead (Pb) in coal samples of recently developed Thar coalfield. The SE‐BCR scheme modified with a time‐saving single‐step extraction (SSE) method assisted with ultrasound energy and conventional shaking devices under the same operating conditions applied for the original SE‐BCR scheme. The conventional single‐step extraction (CSS) and ultrasonic‐assisted extractions (USE) methods efficiently reduced the time expected to separate all fractions by the SE‐BCR method in 51 h to 22 and 2 h, respectively. The validity of both single‐step extraction (SSE and USE) and SE‐BCR methods were confirmed by applying certified reference material (CRM) of sediment (BCR‐701) followed by the standard addition method. The Pb observed to be highest in the organic fraction (28.9–35.2%) and lowest in the acid‐soluble fractions (1.39–2.61%) of coal samples at both blocks (X and XI) of Thar coalfield.
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•The drawbacks of traditional CPE problems are overcome by dual-cloud point extraction.•The effects of the surfactant on the analysis and separation of analytes are eliminated.•The ...developed d-CPE was applied to evaluate Cu in serum samples of viral hepatitis patients.•The hepatitis patients of B, C and D have high levels of Cu in serum than patients have A and E virus.
An efficient, innovative preconcentration method, dual-cloud point extraction (d-CPE) has been developed for the extraction and preconcentration of copper (Cu2+) in serum samples of different viral hepatitis patients prior to couple with flame atomic absorption spectrometry (FAAS). The d-CPE procedure was based on forming complexes of elemental ions with complexing reagent 1-(2-pyridylazo)-2-naphthol (PAN), and subsequent entrapping the complexes in nonionic surfactant (Triton X-114). Then the surfactant rich phase containing the metal complexes was treated with aqueous nitric acid solution, and metal ions were back extracted into the aqueous phase, as second cloud point extraction stage, and finally determined by flame atomic absorption spectrometry using conventional nebulization. The multivariate strategy was applied to estimate the optimum values of experimental variables for the recovery of Cu2+ using d-CPE. In optimum experimental conditions, the limit of detection and the enrichment factor were 0.046μgL−1 and 78, respectively. The validity and accuracy of proposed method were checked by analysis of Cu2+ in certified sample of serum (CRM) by d-CPE and conventional CPE procedure on same CRM. The proposed method was successfully applied to the determination of Cu2+ in serum samples of different viral hepatitis patients and healthy controls.
In present study a biomass derived from the stem of
Acacia nilotica has been investigated to remove As ions from surface water samples of different origins (lake, canal and river). The effects of ...various parameters viz. pH, biosorbent dosage, contact time and temperature on the biosorption processes were systematically studied. Experimental data were modeled by Langmuir, Freundlich and Dubinin–Radushkevich (D–R) isotherms. It was observed that As biosorption best fitted to the Langmuir and Freundlich isotherms. The mean sorption energy (
E) calculated from D–R model, indicated physico-chemical biosorption. Study of thermodynamic parameters revealed the endothermic, spontaneous and feasible nature of biosorption process. The pseudo-second-order rate equation described better the kinetics of As biosorption with good correlation coefficients than pseudo-first-order equation. The biomass of
A. nilotica was found to be effective for the removal of As with 95% sorption efficiency at a concentration of <200
μg/L of As solution, and thus uptake capacity is 50.8
mg As/g of biomass. The
A. nilotica biomass could be used as a low-cost biosorbent for As ion removal.
In the current study, mercury (Hg) and physicochemical parameters have been evaluated in aquifer water at different depths of Thar coal field. The water samples were collected from first aquifer (AQ
...1
), second aquifer (AQ
2
), and third aquifer (AQ
3
) at three depths, 50–60, 100–120, and 200–250 m, respectively. The results of aquifer water of three depths were interpreted by using different multivariate statistical techniques. Validation of desired method was checked by spiking standard addition method in studied aquifer water samples. The content of Hg in aquifer water samples was measured by cold vapor atomic absorption spectrometer (CV-AAS). These determined values illustrate that the levels of Hg were higher than WHO recommended values for drinking water. All physicochemical parameters were higher than WHO permissible limits for drinking water except pH and SO
4
2−
in aquifer water. The positive correlation of Hg with other metals in aquifer water samples of AQ
1
, AQ
2
, and AQ
3
of Thar coalfield except HCO
3
−
was observed which might be caused by geochemical minerals. The interpretation of determined values by the cluster technique point out the variations within the water quality parameter as well as sampling location of studied field. The aquifer water AQ
2
was more contaminated with Hg as compared to AQ
1
and AQ
3
; it may be due to leaching of Hg from coal zone. The concentration of Hg in aquifer water obtained from different depths was found in the following decreasing order: AQ
2
< AQ
1
< AQ
3
.
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The extraction efficiency of metals is improved by modified cloud point extraction (m-CPE) as compared to conventional approach (c⿿CPE).The preconcentration and enhancement factors ...obtained by m-CPE were 25⿿56% increased as compared to c-CPE.The elimination of surfactant effects via aqueous media, proposed by m-CPE, boosts up the selectivity of method.The analytes in aqueous media is well-matched with the conditions of atomic absorption spectrometry.
A new method based on modification of cloud point extraction for simultaneous enrichment of cadmium, lead and copper in water and fish muscle samples was proposed. The extraction efficiency by modified cloud point extraction (m-CPE) was compared with conventional cloud point extraction (c-CPE) method. The procedure for both CPE methods was comprised of formation of metal complexes with a hydrophobic chelating agent, dithizone, followed by entrapment of the chelates in a nonionic surfactant, Triton X-114. For c-CPE, the surfactant rich phase was treated with ethanolic solution of nitric acid and analyzed by flame atomic absorption spectrometer (FAAS). Whereas for m-CPE, aqueous nitric acid was used to back extract the metal ions from the surfactant rich phase and finally determined. The efficiency of the methods was tested by analyzing certified reference material and standard addition to a real sample. All the experimental parameters were optimized. At optimized experimental conditions, preconcentration and enhancement factors were 62.5 and 78.0 to 83.0 respectively for m-CPE, 25.0 and 56.0% higher than that of c-CPE. This improvement might be due to elimination of the effects of surfactant on the signal of analytes by FAAS. The developed method of m-CPE was applied successfully for analysis of the selected heavy metals in water and muscle tissues samples of fish of different lakes in Sindh, Pakistan.
Sequential extraction procedure proposed by the European Standards, Measurements and Testing (SM&T) Program, formerly the Community Bureau of Reference (BCR), has been applied for the heavy metals ...(HMs) partitioning in fresh water lake sediment samples. The results obtained by conventional sequential extraction BCR method (SEB) for Cd, Cu, Cr, Ni, Pb and Zn were compared with those estimated from three alternative single extractions, conventional (CSE), ultrasonic (USE) and microwave assisted (MSE), using identical operating conditions applied in each individual BCR fraction and validated by the CRM BCR 701. Extractable HMs contents obtained by all compared methodologies were measured by atomic absorption spectrometery. With the use of compromised sonication and microwave conditions, steps 1–3 of the sequential extraction (excluding the hydrogen peroxide digestion in step 3) could be completed between 15–30
min using ultrasonic bath, while 60–120
s were required for MSE. The total extractable metal contents obtained by three single extractions ranged from 75.1% to 114.0% except Cr in first step, which was extracted (125.3%) by MSE method as compared to those obtained by SEB procedure. The precision of the proposed BCR single extraction methods (expressed as RSD%) was found in the range of (3.99–9.6%) for all metals.
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•The drawbacks of traditional extraction method are overcome by dispersive ionic liquid extraction.•Direct analysis of Al in biological samples is not precise due to low levels and ...complex matrix.•The developed TIL-DLLME, was applied to evaluate Al in hair of Alzheimer’s patients.•The Alzheimer’s patients have high level of Al in scalp hair than healthy controls.
A green and sensitive temperature controlled dispersive liquid–liquid microextraction (TIL-DLLME) methodology based on the application of ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate, C4mimPF6, as an extractant solvent was proposed for the preconcentration of trace levels of aluminium (Al3+) in scalp hair samples of Alzheimer’s (AD) patients, prior to analyzing by flame atomic absorption spectrometry (FAAS). The Al3+ was complexed with 8-hydrooxyquinoline (oxine) (L1) and 3,5,7,2′-4′ pentahydroxy flavone (morin) (L2) separately and then extracted by IL at temperature (50±2.0°C). Some effective factors that influence the TIL-DLLME efficiency such as pH, ligands concentrations, volume of IL, ionic strength, and incubation time were investigated and optimized by multivariate analysis. In the optimum experimental conditions, the limit of detection (3s) and enhancement factor were 0.56μgL−1, 0.64μgL−1 and 85, 73 for both ligands, respectively. The relative standard deviation (RSD) for six replicate determinations of 100μgL−1 Al3+ complexed with oxine and morin were found to be 3.88% and 4.74%, respectively. The developed method was validated by the analysis of certified reference material of human hair (NCSZC81002).and applied satisfactorily to the determination of Al3+ in acid digested scalp hair samples of AD patients and healthy controls. The resulted data shows significant higher level in scalp hair samples of AD male patients with related to referents of same age and socioeconomic status.
