Prediction of the solubility of zinc, copper, nickel, cadmium, and lead in metal-contaminated soils

Risk assessment of metal-contaminated soil depends on how precisely one can predict the solubility of metals in soils. Responses of plants and soil organisms to metal toxicity are explained by the variation in free metal ion activity in soil pore water. This study was undertaken to predict the free ion activity of Zn, Cu, Ni, Cd, and Pb in metal-contaminated soil as a function of pH, soil organic carbon, and extractable metal content. For this purpose, 21 surface soil samples (0–15 cm) were collected from agricultural lands of various locations receiving sewage sludge and industrial effluents for a long period. One soil sample was also collected from agricultural land which has been under intensive cropping and receiving irrigation through tube well water. Soil samples were varied widely in respect of physicochemical properties including metal content. Total Zn, Cu, Ni, Cd, and Pb in experimental soils were 2,015?±?3,373, 236?±?286, 103?±?192, 29.8?±?6.04, and 141?±?270 mg kg^?1, respectively. Free metal ion activity, viz., pZn²⁺, pCu²⁺, pNi²⁺, pCd²⁺, and pPb²⁺, as estimated by the Baker soil test was 9.37?±?1.89, 13.1?±?1.96, 12.8?±?1.89, 11.9?±?2.00, and 11.6?±?1.52, respectively. Free metal ion activity was predicted by pH-dependent Freundlich equation (solubility model) as a function of pH, organic carbon, and extractable metal. Results indicate that solubility model as a function of pH, Walkley–Black carbon (WBC), and ethylenediaminetetraacetic acid (EDTA)-extractable metals could explain the variation in pZn²⁺, pCu²⁺, pNi²⁺, pCd²⁺, and pPb²⁺ to the extent of 59, 56, 46, 52, and 51 %, respectively. Predictability of the solubility model based on pH, KMnO₄-oxidizable carbon, and diethylenetriaminepentaacetic acid-extractable or CaCl₂-extractable metal was inferior compared to that based on EDTA-extractable metals and WBC.     

A nanosilver-based spectrophotometric method for determination of malachite green in surface water samples

A new spectrophotometric method is reported for the determination of nanomolar level of malachite green in surface water samples. The method is based on the catalytic effect of silver nanoparticles on the oxidation of malachite green by hexacyanoferrate (III) in acetate–acetic acid medium. The absorbance is measured at 610 nm with the fixed-time method. Under the optimum conditions, the linear range was 8.0?×?10^?9–2.0?×?10^?7?mol?L^?1 malachite green with a correlation coefficient of 0.996. The limit of detection (S/N?=?3) was 2.0?×?10^?9?mol?L^?1. Relative standard deviation for ten replicate determinations of 1.0?×?10^?8?mol?L^?1 malachite green was 1.86 %. The method is featured with good accuracy and reproducibility for malachite green determination in surface water samples without any pre-concentration and separation step.     

Environmental assessment of 2-mercaptobenzimidazole based on the surface plasmon resonance band of gold nanoparticles

A colorimetric assay method is described for the environmental detection of 2-mercaptobenzimidazole (MBI) using surface plasmon resonance of gold nanoparticles (AuNPs). Stable and dispersed AuNPs with intensified plasmon resonance were prepared in situ using a simple, rapid, and eco-friendly procedure by applying ascorbic acid as a reducer and cetyltrimethylammonium bromide as a stabilizer. The presence of MBI has a strong effect on the plasmon absorbance of AuNPs, which was employed for the detection of MBI. The calibration curve was linear in the range of 1.0?×?10^?6–5.5?×?10^?5 mol/L of MBI; the detection limit was 8.4?×?10^?7 mol/L. The relative standard deviations for eight replicate measurements of 3.0?×?10^?6 and 5?×?10^?5 mol/L MBI were 3.9 and 1.4 %, respectively. The method was successfully applied to the determination of MBI in tap, river, sea, and heat exchanger cooling water samples.     

Assessment of physico-chemical qualities and heavy metal concentrations of Umgeni and Umdloti Rivers in Durban,South Africa

We assessed the effects of seasonal dynamics on the physico-chemical qualities and heavy metals concentrations of the Umgeni and Umdloti Rivers in Durban, South Africa. Water samples were taken from nine different sampling points and analysed for the following parameters; temperature, pH, turbidity, electrical conductivity (EC), biological oxygen demand (BOD₅), chemical oxygen demand (COD), phosphate (PO₄ ^2?), nitrate (NO₃ ^2?), ammonium (NH₄ ⁺), sulphate (SO₄ ^2?), lead (Pb²⁺), mercury (Hg²⁺), cadmium (Cd²⁺), aluminium (Al³⁺), and copper (Cu²⁺) using standard methods. The data showed variations it terms of the seasonal fluctuations and sampling regime as follows: temperature 12–26.5 °C; pH 5.96–8.45; turbidity 0.53–18.8 NTU; EC 15.8–5180 mS m^?1; BOD₅ 0.60–7.32 mg L^?1; COD 10.5–72.9 mg L^?1; PO₄ ^2??<?500–2,460 μg L^?1; NO₃ ^2? <0.05–4.21 mg L^?1; NH₄ ⁺?<?0.5–1.22 mg L^?1; SO₄ ^2? 3.90–2,762 mg L^?1; Pb²⁺ 0.023–0.135 mg L^?1; Hg²⁺ 0.0122–0.1231 mg L^?1 Cd²⁺ 0.068–0.416 mg L^?1; Al³⁺ 0.037–1.875 mg L^?1, and Cu²⁺0.006–0.144 mg L^?1. The concentrations of most of the investigated parameters exceeded the recommended limit of the South African Guidelines and World Health Organization tolerance limits for freshwater quality. We conclude that these water bodies are potentially hazardous to public health and this highlights the need for implementation of improved management strategies of these river catchments for continued sustainability.     

Simultaneous quantification of Bi(III) and U(VI) in environmental water samples with a complicated matrix containing organic compounds

Trace amounts of bismuth(III) and uranium(VI) can be simultaneously determined in a single scan by adsorptive cathodic stripping voltammetry in the presence of cupferron as a complexing agent. Optimal conditions were found to be: 0.1 mol?L^?1 acetate buffer (pH 5.3), 5?×?10^?5?mol?L^?1 cupferron, accumulation potential of ?0.25 V, and accumulation time of 30 s. The linear range of Bi(III) and U(VI) was observed over the concentration range from 2?×?10^?9 to 2?×?10^?7?mol?L^?1 and from 1?×?10^?8 to 5?×?10^?7?mol?L^?1, respectively. The influence of the main components of real water samples such as foreign ions and organic substances (surface active substances, humic substances) was precisely investigated. The method was applied to the simultaneous measurements of bismuth and uranium in natural water samples.     

cDNA sequence encoding metallothionein protein from Aegiceras corniculatum and its gene expression induced by Pb2+ and Cd2+ stresses

Constructing various green wetland examples for mangrove wetland systems is a useful way to use natural power to remediate the polluted wetlands at intertidal zones. Metallothioneins (MT) are involved in heavy metal tolerance, homeostasis, and detoxification of intracellular metal ions in plants. In order to understand the mechanism of heavy metal uptake in Aegiceras corniculatum, we isolated its metallothionein gene and studied the MT gene expression in response to heavy metals contamination. Here, we report the isolation and characterization of MT2 genes from young stem tissues of A. corniculatum growing in the cadmium (Cd) and lead (Pb) polluted wetlands of Quanzhou Bay, southeast of China. The obtained cDNA sequence of MT is 512 bp in length, and it has an open reading frame encoding 79 amino acid residues with a molecular weight of 7.92 kDa and the theoretical isoelectric point of 4.55. The amino acids include 14 cysteine residues and 14 glycine residues. It is a non-transmembrane hydrophilic protein. Sequence and homology analysis showed the MT protein sequence shared more than 60 % homology with other plant type 2 MT-like protein genes. The results suggested that the expression level of MT gene of A. corniculatum young stems induced by a certain range concentration of Cd²⁺ and Pb²⁺ stresses (0.2 mmol L^?1 Pb²⁺, 1 mmol L^?1 Pb²⁺, 0.2 mmol L^?1 Pb²⁺, and 40 μmmol L^?1 Cd²⁺; 1 mmol L^?1 Pb²⁺ and 40 μmol L^?1 Cd²⁺) compared with control might show an adaptive protection. The expression levels of MT gene at 20 h stress treatment were higher than those at 480 h stress treatment. The expression levels of MT gene with 0.2 mmol L^?1 Pb²⁺ stress treatment were higher than those with 0.2 mmol L^?1 Pb²⁺ and 40 μmol L^?1 Cd²⁺ stress treatment, and the MT gene expression levels with 1 mmol L^?1 Pb²⁺ treatment were higher than those with 1 mmol L^?1 Pb²⁺ and 40 μmol L^?1 Cd²⁺ treatment. There exists an antagonistic action between Pb²⁺ and Cd²⁺ in the MT metabolization of A. corniculatum.     

Spatial and temporal variability of metals in inter-tidal beach sediment of Mumbai, India

Nine metals were monitored in the beach sediment in Mumbai from May 2011 to March 2012 to evaluate the spatial and temporal distributions. The average heavy metal concentrations exhibited the following order: Fe > Mn > Cr > Co > Ni > Pb > Zn > Cu > Cd for the four sampling sites. The mean concentrations (± SD) of Fe, Mn, Cr, Co, Ni, Pb, Zn, Cu and Cd were estimated to be 31.15?±?10.02 g kg^?1, 535.04?±?76.42, 151.98?±?97.90, 92.76?±?14.18, 67.52?±?11.32, 59.57?±?15.19, 54.65?±?15.01, 32.24?±?8.07 and 18.75?±?1.76 mg kg^?1, respectively. The results indicated that the sediments were polluted with Cd, Cr, Co and Pb due to high anthropogenic influences. Spatial variation of metals revealed that most of the metals were high in Dadar beach and low in Aksa beach. Cd was the highest contaminant metal studied with a mean contamination factor of 93.75. The pollution load indices of the studied beaches ranged from 1.63 (Aksa) to 1.91 (Dadar) and indicated that the beach sediments were polluted with heavy metals. The heavy metal contents increased in relation to monsoon, and most of the heavy metals showed significantly high concentrations in November during the post-monsoon. The statistical analysis revealed significant effect of study site on all the metals studied. Further, there was a significant difference on metal accumulation on bimonthly basis in relation to weather pattern in Mumbai beaches.     

Effect of citric acid on metals mobility in pruning wastes and biosolids compost and metals uptake in <Emphasis Type="Italic">Atriplex halimus</Emphasis> and <Emphasis Type="Italic">Rosmarinus officinalis</Emphasis>

To assess metal mobility in pruning waste and biosolids compost (pH?6.9 and total concentration of metals in milligram per kilogram of Cd 1.9, Cu 132, Fe 8,513, Mn 192, Pb 81, and Zn 313), shrubs species Atriplex halimus and Rosmarinus officinalis were transplanted in this substrate and irrigated with citric acid (4 g?L^?1, pH?2.9) and nutrient solution daily for 60 days. Citric acid significantly increased the concentrations of soluble Mn and Fe in the nutrient substrate solution measured by suction probes, while other metals did not vary in concentration (Cu and Zn) or were not observed at detectable levels (Cd and Pb). In plants, citric acid significantly increased the concentrations of Cu (2.7?±?0.1–3.3?±?0.1 mg?kg^?1), Fe (49.2?±?5.2–76.8?±?6.8 mg?kg^?1), and Mn (7.2?±?1.1–11.4?±?0.7 mg?kg^?1) in leaves of R. officinalis, whereas the concentration of only Mn (25.4?±?0.3–42.2?±?2.9 mg?kg^?1) was increased in A. halimus. Increasing Fe and Mn solubility by citric acid addition indicates the possibility of using it to improve plant nutrition. The mobility of metals in this substrate was influenced for the concentration of the metal, the degree of humification of organic matter and its high Fe content.     

Heavy metal concentration in deepwater rose shrimp species (Parapenaeus longirostris,Lucas, 1846) collected from the Marmara Sea Coast in Tekirdağ

Zn, Cd, Cr, Hg, As (total), Cu, Pb, and Ni levels of the deepwater rose shrimp (Parapenaeus longirostris, Lucas 1846), which were collected from the Tekirda? coast of the Marmara Sea, were evaluated. The Marmara Sea is the recipient of discharges from both land-based sources and the Black Sea Bosphorus stream. There are large numbers of anthropogenic activities in the coastal region of the northern Marmara Sea that include urban effluent, discharges from touristic resorts, agricultural runoff, fishing, and transportation. Heavy metal contamination of water resources may cause critical health problems for the people living around these water bodies. In deepwater rose shrimp (P. longirostris), the highest concentration level detected for Zn was 22.4?±?24.4 mg/kg in winter 2012, Cd 0.106?±?0.01 mg/kg in summer 2012, Cr 0.77?±?0.05 mg/kg in winter 2012, Hg 0.18?±?0.04 mg/kg in summer 2011, As 9.93?±?1.4 mg/kg in spring 2012, Cu 25.48?±?0.3 mg/kg in winter 2012, Pb 2.12?±?0.8 mg/kg in spring, and Ni 19.25?±?7.1 mg/kg in spring. The values of heavy metal analysis were compared to both the Turkish Food Codex (TFC) limits and international standards for human consumption. The Pb, As, and Cu levels were found to be higher than the maximum allowable limits.     

Determination of hydrazine hydrate based on electrochemiluminescence of Ru(bpy) 3 2+

Considering of the basic properties and also the two nitrogen atoms in the structure, hydrazine hydrate was employed to be an amine additive candidate, to build a Ru(bpy) ₃ ²⁺ /hydrazine electrochemiluminescence (ECL) system, and ECL of Ru(bpy) ₃ ²⁺ has been employed for the determination of hydrazine hydrate in the paper. The result demonstrated that the logarithmic ECL increasing (ΔECL?=?ECL_{after addition of hydrazine}???ECL_{before addition of hydrazine}) versus the logarithmic concentration of hydrazine hydrate is linear over a concentration range of 1.0?×?10^?9 to 1.0?×?10^?5?mol/L, on both glassy carbon and Pt electrodes in a pH 9 phosphate buffer. The hydrazine hydrate detection limit was down to 1.0?×?10^?9?mol/L, comparatively lower than other detection methods. To check its applicability, the proposed method was applied to the determination of hydrazine hydrate added into a tap water sample with good reproducibility and stability. All these provide a possibility to develop a novel ECL detection method for hydrazine in water.     

Accumulation of heavy metals in Spinacia oleracea irrigated with paper mill effluent and sewage

The present study on heavy metal contamination in soil and their accumulation in edible part (leaves) and roots of Spinacia oleracea (Spinach) on irrigation with paper mill effluent (PME)/sewage revealed that there was significant increase in the nickel (Ni, +227.17 %) content of the soil irrigated with PME, whereas in the soil irrigated with sewage chromium (Cr, +274.84 %), iron (Fe, +149.56 %), and cadmium (Cd, +133.39 %), contents were increased appreciably. The value of enrichment factor (EF) for Ni (3.27) indicated moderate enrichment in PME-irrigated soil. The EF of Fe, zinc (Zn), Cd, and Cr were <2 in PME effluent-irrigated soil which showed deficiency of minimal enrichment. In sewage irrigated soil, EF value for Cr, Fe, and Cd indicated moderate enrichment, while the values for Zn and Ni indicated deficiency of minimal enrichment. Among various metallic concentrations, the maximum concentration of Fe was observed in leaves (400.12?±?11.47 mg/kg) and root (301.41?±?13.14 mg/kg) of S. oleracea after irrigation with PME, whereas the maximum concentrations of Fe was found in leaves (400.49?±?5.97 mg/kg) and root (363.94?±?11.37 mg/kg) of S. oleracea after irrigation with sewage for 60 days. The bioaccumulation factor value was found maximum for Cd (2.23) in the plants irrigated with PME while that of Fe (0.90) in the plants irrigated with sewage. The undiluted use of PME/sewage for irrigation increased the concentration of Cr, Cd, Zn, Ni, and Fe metals which were accumulated in S. oleracea, posing a potential threat to human health from this practice of irrigation.     

Biological endpoints, enzyme activities, and blood cell parameters in two anuran tadpole species in rice agroecosystems of mid-eastern Argentina

Different biological variables of tadpoles, including survival, development and growth rates, and biomarkers [cholinesterases, glutathione-S-transferases (GST), and blood cell morphology] were evaluated in two anuran species, Scinax squalirostris (Hylidae) and Leptodactylus mystacinus (Leptodactylidae), using in situ experimental chambers in a rice field (RF) sprayed with insecticide Lambda-cyhalothrin (LTC) by aircraft in Santa Fe Province, Argentina. We found a significant decrease in body weight (0.62?±?0.04 g) of L. mystacinus and an increased development rate of S. squalirostris in individuals from RF (41?±?1; Gosner) with respect to individuals from the reference site (RS: 0.93?±?0.04 g and 37?±?0; respectively). In S. squalirostris, individuals from RF mean values of butyrylcholinesterase activities decreased at 48 (4.09?±?0.32 nmol min^-1 mg^-1 of TP) and 96 h (3.74?±?0.20 nmol min^-1 mg^-1 of TP), whereas inhibition of acetylcholinesterase was observed at 96 h (47.44?±?2.78 nmol min^-1 mg^-1 of TP). In L. mystacinus from RF, an induction of acetylcholinesterase activity was observed at 96 h (36.01?±?1.09 nmol min^-1 mg^-1 of TP). Glutathione-S-transferase levels varied between species, being higher in L. mystacinus individuals but lower in S. squalirostris from RF at 48 (272.29 ±11.78 and 71.87?±?1.70 nmol min^-1 mg^-1 of TP; respectively) and 96 h (279.25?±?13.06 and 57.62?±?4.58 nmol min^-1 mg^-1 of TP, respectively). Blood cell parameters revealed a lower number of mitotic cells (MC: 0.36?±?0.31%o for S. squalirostris and 0.08?±?0.05 %o for L. mystacinus) and higher number of eosinophils (E: 3.45?±?1.75 %o for S. squalirostris and 7.64?±?0.98 %o for L. mystacinus) in individuals from the RF than in individuals from the RS (MC: 2.55?±?0.74 %o for S. squalirostris and 1.87?±?0.72%o for L. mystacinus; and E: 0.13?±?0.09 for S. squalirostris and 3.20?±?0.80 for L. mystacinus). Overall, our results demonstrate the existence of apparent differences in sensitivity between species in a series of sublethal responses to short-term exposure in RF after the application of Lambda-cyhalothrin. We suggest that the integral use of biological endpoints (development and growth) together with biomarkers (cholinesterase, GST, and blood cell parameters) may be a promising integral procedure for investigating pesticide exposure in wild frog populations.     

Heavy metals in the habitat and throughout the food chain of the Neotropical otter, Lontra longicaudis, in protected Mexican wetlands

Top predators like the Neotropical otter, Lontra longicaudis annectens, are usually considered good bioindicators of habitat quality. In this study, we evaluated heavy metal contamination (Hg_tot, Pb, Cd) in the riverine habitat, prey (crustaceans and fish), and otter feces in two Ramsar wetlands with contrasting upstream contamination discharges: Río Blanco and Río Caño Grande in Veracruz, Mexico, during the dry, the wet, and the nortes seasons. Most comparisons revealed no differences between sites while seasonal differences were repeatedly detected for all of the compartments. Higher concentrations of Pb during the dry season and of Cd during the wet season in otter feces mirrored differences detected in the most seasonally consumed prey. Compared with fecal methylmercury values reported for the European otter (0.25–0.75 mg kg^?1) in unprotected areas, the Hg_tot levels that we measured were lower (0.02–0.17 mg kg^?1). However, Pb (117.87 mg kg^?1) and Cd (9.14 mg kg^?1) concentrations were higher (Pb, 38.15 mg kg^?1 and Cd, 4.72 mg kg^?1) in the two Ramsar wetlands. Protected areas may shelter species, but those with water-linked diets may suffer the effect of chemicals used upstream.     

Some selected heavy metal concentrations in water,sediment, and oysters in the Er-Ren estuary,Taiwan: chemical fractions and the implications for biomonitoring

Studies of heavy metal contamination and ecological risk in estuaries are an important emerging area of environmental science. However, there have been few detailed studies of heavy metal contamination that concern the spatial variation of heavy metal levels in water, sediment, and oyster tissue. Because of the effective uptake of heavy metals, cultured oysters are a cheap and effective subject for study. This study, conducts an experiment in the Er-Ren river to examine the biological uptake of heavy metals in farmed, cultured oysters. The distribution of copper, zinc, lead, cadmium, and arsenic concentrations in water, sediment, and oysters from the Er-Ren river is also evaluated. By sequential extraction of the sediments, the following order of mobilities is found for heavy metals Pb?>?Cd?>?As?>?Zn?>?Cu. The highest percentages of heavy metals are found in the residual phase. The mean uptake rates for young oysters are 7.24 mg kg^?1 day^?1 for Cu and 94.52 mg kg^?1 day^?1 for Zn, but that for adult oyster is 10.79 mg kg^?1 day^?1 for Cu and 137.24 mg kg^?1 day^?1 for Zn. With good policies and management, the establishment of cultured oyster frames in these contaminated tributaries and near shore environments is a potential method for removing Cu and Zn and protecting the coast.     

Hazard assessment of metals in invasive fish species of the Yamuna River,India in relation to bioaccumulation factor and exposure concentration for human health implications

Monitoring of heavy metals was conducted in the Yamuna River considering bioaccumulation factor, exposure concentration, and human health implications which showed contamination levels of copper (Cu), lead (Pb), nickel (Ni), and chromium (Cr) and their dispersion patterns along the river. Largest concentration of Pb in river water was 392 μg L^?1; Cu was 392 μg L^?1 at the extreme downstream, Allahabad and Ni was 146 μg L^?1 at midstream, Agra. Largest concentration of Cu was 617 μg kg^?1, Ni 1,621 μg kg^?1 at midstream while Pb was 1,214 μg kg^?1 at Allahabad in surface sediment. The bioconcentration of Cu, Pb, Ni, and Cr was observed where the largest accumulation of Pb was 2.29 μg kg^?1 in Oreochromis niloticus and 1.55 μg kg^?1 in Cyprinus carpio invaded at Allahabad while largest concentration of Ni was 174 μg kg^?1 in O. niloticus and 124 μg kg^?1 in C. carpio in the midstream of the river. The calculated values of hazard index (HI) for Pb was found more than one which indicated human health concern. Carcinogenic risk value for Ni was again high i.e., 17.02?×?10^?4 which was larger than all other metals studied. The results of this study indicated bioconcentration in fish due to their exposures to heavy metals from different routes which had human health risk implications. Thus, regular environmental monitoring of heavy metal contamination in fish is advocated for assessing food safety since health risk may be associated with the consumption of fish contaminated through exposure to a degraded environment.     

Vehicular stress a cause for heavy metal accumulation and change in physico-chemical characteristics of road side soils in Pahalgam

In an effort to determine vehicular impact on soil quality, soil samples were collected from three different zones (Pahalgam, Batakote, and Chandanwari) in Pahalgam forest ecosystem. Results showed that a significant decrease in moisture content, organic carbon, available nitrogen, and potassium was observed in nearby road side soils. However, pH was observed to be on neutral side and available phosphorus recorded high concentration. The concentration of heavy metals Pb²⁺, Cu²⁺, Zn²⁺, Ni²⁺, and Cd²⁺ estimated was also significantly high. Furthermore, concentration of Pb²⁺ at high vehicular load subzones was observed to be highest (1.168 mg/Kg) followed by Zn²⁺ (0.896 mg/Kg), Ni²⁺ (0.649 mg/Kg), Cu²⁺ (0.415 mg/Kg), and Cd²⁺ (0.079 mg/Kg). An inter-zone analysis revealed that the concentration of the heavy metals (Pb²⁺?>?Ni²⁺?>?Cd²⁺) was observed to follow the trend, Z-I?>?Z-II?>?Z-III. Variation along the temporal gradient and the impact on soil qualities were notably higher in summer. Vehicular pollution to a great extent impacts physico-chemical characteristics and more interestingly adds substantial concentration of heavy metals in soils.     

Distributions, sources, and ecological risks of DDT-related contaminants in water, suspended particulate matter, and sediments from Haihe Plain, Northern China

The residual levels of dichlorodiphenyltrichloroethane (DDT) and its metabolites (DDXs, including p,p′-DDT, DDD, and DDE) in water, suspended particulate matter (SPM), and sediments from major rivers, lakes, and reservoirs in Haihe Plain were measured with a gas chromatograph equipped with a ⁶³Ni microelectron capture detector. In the fall of 2004, the contents of the total DDXs in the water and SPM were 0.29?±?0.69 ng L^?1 and 423.13?±?577.85 ng g^?1 dry wt., respectively. In the spring of 2005, the total DDXs were 0.36?±?0.91 ng L^?1 for water and 35.93?±?62.65 ng g^?1 dry wt. for SPM. The average concentration of DDXs for sediments was 7.10?±?7.57 ng g^?1 dry wt. during the two seasons. The Eastern-Hebei-Province Coastland River System was the most polluted, which was mainly attributable to the extensive use of DDT pesticide and dicofol in that system. Recent DDT inputs still occur in some regions, as indicated by DDT/(DDD + DDE) > 1 at 29–36 % of the sites for water and 55–61 % of the sites for SPM. The potential ecological risks of DDT in the water were assessed using a species sensitivity distribution model. Only shrimp and crabs were found to have potentially affected fraction values of 1.63?×?10^?3 to 2.27?×?10^?4, with probabilities beyond the hazardous concentration for 5 % of species (HC5) values of 1.90–2.56 %, suggesting only slight risks. DDXs in the sediments of some sites were also of potential risk to benthic organism based on consensus-based sediment quality guidelines.     

Cloud point extraction–atomic absorption spectrometry for pre-concentration and determination of cadmium in cigarette samples

A new complexing agent, 2-((2-((1H-benzo[d]imidazole-2yl)methoxy)phenoxy)methyl)-1H-benzo[d]imidazole (BIMPI), was used in cloud point extraction and applied for selective pre-concentration of trace amounts of cadmium in cigarette samples. Cadmium was complexed with BIMPI in a buffer solution (pH?=?10) using Triton X-114 as surfactant and quantitatively extracted into a small volume of the surfactant-rich phase after centrifugation. Under optimized conditions (pH?=?10.0, 0.8?×?10^?4?mol?L^?1 BIMPI and 0.08 % (w/v) Triton X-114), calibration graph was linear in the range of 34.0–1,670.0 μg?L^?1. The proposed method was applied to the determination of Cd in various cigarette (tobacco) samples which gave satisfactory results.     

The levels and composition of persistent organic pollutants in alluvial agriculture soils affected by flooding

The concentrations and composition of persistent organic pollutants (POPs) were determined in alluvial soils subjected to heavy flooding in a rural region of Poland. Soil samples (n?=?30) were collected from the upper soil layer from a 70-km² area. Chemical determinations included basic physicochemical properties and the contents of polychlorinated biphenyls (PCBs), hexachlorocyclohexanes (HCHs), dichlorodiphenyltrichloroethanes (DDTs) and polycyclic aromatic hydrocarbons (PAHs, 16 compounds). The median concentrations of Σ7PCB (PCB28?+?PCB52?+?PCB101?+?PCB118?+?PCB138?+?PCB153?+?PCB180), Σ3HCH (α-HCH?+?β-HCH?+?γ-HCH) and Σ3pp′(DDT?+?DDE?+?DDD) were 1.60?±?1.03, 0.22?±?0.13 and 25.18?±?82.70 μg kg^?1, respectively. The median concentrations of the most abundant PAHs, phenanthrene, fluoranthene, pyrene, benzo[b]fluoranthene and benzo[a]pyrene were 50?±?37, 38?±?27, 29?±?30, 45?±?36 and 24?±?22 μg kg^?1, respectively. Compared with elsewhere in the world, the overall level of contamination with POPs was low and similar to the levels in agricultural soils from neighbouring countries, except for benzo[a]pyrene and DDT. There was no evidence that flooding affected the levels of POPs in the studied soils. The patterns observed for PAHs and PCBs indicate that atmospheric deposition is the most important long-term source of these contaminants. DDTs were the dominant organochlorine pesticides (up to 99 %), and the contribution of the parent pp′ isomer was up to 50 % of the ΣDDT, which indicates the advantage of aged contamination. A high pp′DDE/pp′DDD ratio suggests the prevalence of aerobic transformations of parent DDT. Dominance of the γ isomer in the HCHs implies historical use of lindane in the area. The effect of soil properties on the POP concentrations was rather weak, although statistically significant links with the content of the <0.02-mm fraction, C_total or N_total were observed for some individual compounds in the PCB group.     

The high potential of Pelargonium roseum plant for phytoremediation of heavy metals

The major objective of this investigation was to evaluate the potential of scented geraniums, Pelargonium roseum, to uptake and accumulate heavy metals nickel (Ni), cadmium (Cd), or lead (Pb). For this, plants were grown in an artificial soil system and exposed to a range of metal concentrations over a 14-day treatment period. Then, metals from the entire biomass were extracted. The results showed that scented geranium plants accumulated in excess of 20,055 mg of Ni kg^?1 dry weight (DW) of root and 10,889 mg of Ni kg^?1 DW of shoot, and in excess of 86,566 mg of Pb kg^?1 DW for roots and 4,416 mg of Pb kg^?1 DW for shoots within 14 days. Also, the uptake and accumulation of cadmium in roots of scented geranium plants increased with the exposure at low (250, 500 mg?L^?1) and medium level (750 mg?L^?1) followed by a decline at the highest level (1,000 mg?L^?1). The highest accumulation in roots (31,267 mg?kg^?1 DW) was observed in 750 mg?L^?1 cadmium treatment. In the shoots of scented geraniums, the highest amount of metal accumulation (1,957 mg?kg^?1 DW) was detected at 750 and 1,000 mg?L^?1 of cadmium in the culture solution. Finally, since the high concentrations of Ni or Pb accumulated in shoots of scented geranium has far exceeded 0.1 % DW and for Cd has far exceeded 0.01 % DW, P. roseum is a new hyperaccumulator species for these metals and can be used in phytoremediation industry.