Heavy metal pollution and human health risk assessment at mercury smelting sites in Wanshan district of Guizhou Province,China

The Wanshan district of Guizhou Province has a long history of mercury mining and smelting. Previous studies have been carried out on heavy metal (HM) pollution in the soil around Wanshan (such as in urban and farmland areas), but these studies have not been conducted at mercury smelting sites. In this study, the distribution characteristics of As, Be, Cd, Cr, Cu, Hg, Ni, Sb, Pb and Zn and their sources in the shallow stratum (<10 m) of the mercury smelting site in the Wanshan district were analyzed. Human health risks were evaluated using deterministic risk assessment (DRA) and probabilistic risk assessment (PRA) models. The contribution rates of different HM sources to human health risks were also calculated. The maximum HM concentration in mercury smelting site soil occured in the shallow soil (0–1 m), and the concentration sequences were as follows: 358.51 mg kg⁻¹ (Hg) > 248.6 mg kg⁻¹ (Zn) > 67.42 mg kg⁻¹ (As) > 59.04 mg kg⁻¹ (Ni) > 57.56 mg kg⁻¹ (Pb) > 49.59 mg kg⁻¹ (Cr) > 46.65 mg kg⁻¹ (Sb) > 15.65 mg kg⁻¹ (Cu) > 2.02 mg kg⁻¹ (Be) > 0.78 mg kg⁻¹ (Cd). The variable coefficients (CVs) were 1.64 (As), 0.67 (Be), 3.15 (Cd), 1.89 (Cr), 0.95 (Cu), 3.08 (Hg), 0.79 (Ni), 1.41 (Sb), 0.68 (Pb) and 1.13 (Zn), respectively. The HM concentrations in deep soils (9 m) still exceed the local background values, suggesting that heavy metals in shallow soil have migrated downward in the site. Three pollution sources identified with the shallow soil (0–1 m) HMs using the positive matrix factorization (PMF) model, were mercury smelting and coal combustion mixed sources (As, Hg and Zn), parent material sources (Ni, Cu, Cr, Cd and Sb) and wastewater discharge sources (Cu and Pb), respectively. DRA indicated that oral ingestion was the main pathway affecting the carcinogenic risk (CR) and hazard quotient (HQ) of heavy metals. The total-CR of twenty-five sampling points is between 1.219 × 10⁻⁶ and 3.446 × 10⁻⁴, and the total-HQ is between 0.37 and 43.56. PRA results indicated that DRA will underestimate the health risk of all populations in Guizhou Province, especially female, and BW_a is the most influential variable for the PRA results. Smelting and coal combustion mixed sources contributed the most CR (99.29%) and with an HQ of 89.38% were the major sources of pollution affecting human health.

The DRA model was used to analyze the human health risk contribute of different HMs sources in the mercury smelting site, and the PRA model was used to verify.     

Total and bioaccessible heavy metals in cabbage from major producing cities in Southwest China: health risk assessment and cytotoxicity

Green leafy vegetables are economical and nutritious, but they may be contaminated with heavy metals. In this study, we assessed the total and bioaccessible concentrations of As, Cd, Pb and Cr in a popular vegetable cabbage (Brassica oleracea) from four major producing cities in Yunnan, Southwest China. With the mean concentrations of As, Cd, Pb and Cr being 0.24, 0.20, 0.32 and 1.28 mg kg⁻¹, the As, Cd and Pb concentrations were within the limits of 0.2–0.5 mg kg⁻¹ based on Chinese National Standards and the WHO/FAO, but Cr concentration was 2.6-times greater than the limit of 0.5 mg kg⁻¹. Based on an in vitro bioaccessibility assay of the Solubility Bioaccessibility Research Consortium (SBRC), As bioaccessibility was the lowest at 11% while those of Cd, Pb and Cr were much greater at 68–87%. The estimated daily intake (EDI) of metals through cabbage ingestion was similar for children and adults. Among the four metals, only Cr''s EDI at 2.29–1.87 exceeded 1 based on total and bioaccessible concentrations. The high Cr concentration at 1.28 mg kg⁻¹ coupled with its high bioaccessibility at 67.5% makes Cr of concern in cabbage. However, human gastrointestinal cells exposed to the gastric digesta with high bioaccessible heavy metals and risky EDI, showed no obvious cytotoxicity, indicating that existing models based on total or bioaccessible heavy metals may overestimate their human health risk. Taken together, to accurately assess the human health risk of heavy metals in cabbage, both total/bioaccessible concentrations and the gastrointestinal cell responses should be considered.

We analyzed the total and bioaccessible concentrations of heavy metals in a popular vegetable cabbage (Brassica oleracea) from producing cities in Yunnan, Southwest China and assessed their health risk based on both bioaccessibility and cytotoxicity.     

Three-dimensional mesoporous calcium carbonate–silica frameworks thermally activated from porous fossil bryophyte: adsorption studies for heavy metal uptake

In this paper, three-dimensional mesoporous calcium carbonate–silica frameworks have been created from the straw tufa (ST) originating from porous fossil bryophyte by a thermal activation technique. A batch of adsorption kinetic and thermodynamic experiments were used to investigate the adsorption capacity of Cd(ii) onto the samples. The ST after thermal activation has shown a significant ability for the uptake of heavy metals. It exhibited maximum adsorption capacities of 12.76 mg g⁻¹, 14.09 mg g⁻¹, 17.00 mg g⁻¹, and 33.81 mg g⁻¹ for Cd(ii) at the activation temperature of 300, 450, 600 and 750 °C, respectively. Through competitive adsorption for Cd(ii)and Pb(ii), the ST thermally activated at 750 °C exhibited maximum equilibrium adsorption capacities of 24.65 mg g⁻¹, 25.91 mg g⁻¹, and 30.94 mg g⁻¹ for Cd(ii) uptake at 298.1 K, 308.1 K and 318.1 K, respectively, whereas it exhibited values of 91.59 mg g⁻¹, 101.32 mg g⁻¹, and 112.19 mg g⁻¹ for Pb(ii) removal. The adsorption capacities of Cd(ii) and Pb(ii) both decrease with the addition of the other heavy metal cations, indicating that the adsorption is hindered by the competitive adsorption and the adsorption active sites on the mineral surface are readily exchangeable. The adsorption of Cd(ii) and Pb(ii) followed the pseudo-second order kinetics model well. In addition, the Langmuir model could accurately describe the adsorption isotherms. Based on the results of characterization with TEM, XRD and XPS, the adsorption mechanisms could be primarily explained as formation of Cd(OH)₂ and CdCO₃ as well as Cd(HCO₃)₂ precipitation on the surface of ST. These characteristics of ion-exchange and the adsorptive property for ST modified allow it to be widely used in artificial wetland landfill and environmental protection.

Three-dimensional mesoporous calcium carbonate–silica frameworks have been created and have shown excellent adsorption capacities for Cd(ii) and Pb(ii).     

Arbuscular mycorrhizal inoculation increases molybdenum accumulation but decreases molybdenum toxicity in maize plants grown in polluted soil

Molybdenum (Mo) is an important micronutrient required by both plants and microorganisms, but may become toxic when presents in excess concentration. However, Mo toxicity in soil-plant systems as influenced by arbuscular mycorrhizal (AM) fungi (AMF) still remains unknown. Here, a pot culture experiment was conducted to study the effects of inoculation with Claroideoglomus etunicatum BEG 168 on the growth and Mo content of maize plants growing in soil supplemented with different levels (0, 1000, 2000, and 4000 mg kg⁻¹) of Mo. Results show that the added Mo had no significant effects on AM colonization rate, which ranged from 77% to 92%. Mo addition decreased plant dry weights and leaf pigment contents, as well as nutrient uptake of P, N, Fe, Mg and Cu in shoots and roots, and in most cases, the highest level (4000 mg kg⁻¹) showed the most inhibitory effects. Overall, AM inoculation enhanced plant growth, mineral nutrient uptake, leaf pigment contents and photosynthetic rate under all Mo addition levels. Mo concentrations in plants without Mo addition ranged from 13.1 to 40.1 mg kg⁻¹ in roots, and from 42.8 to 58.4 mg kg⁻¹ in shoots. Addition of Mo increased Mo concentrations in both shoots and roots of all the plants, but showed no significant dose-dependent effects. In non-inoculated plants receiving Mo addition, Mo concentrations were not lower than 400 mg kg⁻¹ in shoots and higher than 1300 mg kg⁻¹ in roots respectively. AM inoculation further enhanced Mo concentrations in shoots and roots, but decreased shoot/root Mo ratio at 2000 and 4000 mg kg⁻¹ Mo addition levels. In AM inoculation treatments, soil pH exhibited a decreasing trend with increasing Mo addition level. In conclusion, excess Mo caused toxicity in maize plants, while AM fungus C. etunicatum BEG 168 was tolerant to the added Mo, and could alleviate the Mo-induced phytotoxicity by improving plants'' mineral nutrition, leaf pigment contents and photosynthetic properties, and by mediating Mo partitioning in plants and soil pH. Our present results suggest a specific protection mechanism exists in AM plants against excess Mo, and their promising potential in ecological restoration and phytoremediation of Mo-polluted sites.

Arbuscular mycorrhizal inoculation increases Mo accumulation but decreases Mo phytotoxicity in maize plants grown in polluted soil.     

Soil Nutrient Status and Leaf Nutrient Norms in Oil Palm (<Emphasis Type="Italic">Elaeis guineensis</Emphasis> Jacq.) Plantations Grown on Southern Plateau of India

Oil palm is a heavy feeder of nutrients and requires balanced and adequate supply of nutrients for optimum growth and yield. Information regarding soil nutrient status and leaf nutrient concentration is very much required for proper fertilizer application. Therefore, a survey was conducted for assessment of soil nutrient status and leaf nutrient concentration in 42 oil palm (Elaeis guineensis Jacq) plantations in the state of Karnataka, situated in southern plateau of India. In surface soil layers, soil acidity (pH), electrical conductivity (EC) and organic carbon (OC) content ranged from 4.91 to 8.74, 0.10 to 2.54 dS m^?1 and 1.17 to 28.9 g kg^?1 respectively. The values of available potassium (K) (NH₄OAc–K), phosphorus (P) (Olsen-P) and exchangeable calcium (Ca) (Exch. Ca) varied from 31.2 to 386 mg kg^?1, 7.69 to 242 mg kg^?1 and 156 to 1273 mg kg^?1 respectively. The concentration of exchangeable magnesium (Mg) (Exch. Mg), available sulphur (S) (CaCl2-S) and hot water soluble boron (B) (HWB) ranged from 52.8 to 307 mg kg^?1, 2.25 to 73.5 mg kg^?1 and 2.29 to 16.0 mg kg^?1 respectively. Diagnosis and recommendation integrated system (DRIS) norms were established for different nutrient expressions and it was used to compute DRIS indices. As per DRIS indices, the order of requirement of nutrients in the region was found to be K > P > nitrogen (N) > B > Mg. Optimum leaf nutrient ranges varied from 2.24 to 2.97 %, 0.08 to 0.14 % and 0.78 to 0.91 % for N, P and K respectively, from 0.74 to 1.53 %, 0.25 to 0.98 % and 0.72 to 1.09 % for Ca, Mg and S respectively and from 5.71 to 31.0 mg kg^?1, 7.42 to 12.9 mg kg^?1, 33.6 to 58.6 mg kg^?1, 82.5 to 681 mg kg^?1 and 82.8 to 936 mg kg^?1 for B, copper (Cu), zinc (Zn), manganese (Mn) and iron (Fe) respectively. On the basis of DRIS derived sufficiency ranges, 57, 24, 62, 3, 3, 9, 7, 5, and 26 % leaf samples were having less than optimum concentration of N, P, K. Ca, Mg, S, B, Cu and Mn respectively. The optimum ranges developed can be used as a guide for routine diagnostic and advisory purpose for balanced utilization of fertilizers.     

CO2–C evolution rate in an incubation study with straw input to soil managed by different tillage systems

A laboratory incubation experiment was conducted to assess the impact of straw input on CO₂–C emissions. After the winter wheat (Triticum aestivum L.) growing season, soil samples were collected from the 0–20 cm soil layer. The experiment was conducted on a brown loam soil, classified as a Udoll according to the U. S. soil taxonomy. Treatment levels consisted of three tillage practices: sub-soiling (ST), no-till (NT) and the conventional tillage (CT), two straw management (with and without input of straw), three temperature (25, 30 and 35 °C), and three moisture regimes (55%, 65% and 75% of field moisture capacity or FMC). The results showed that the rate of straw decomposition was the highest in the soil under NT management. The relationship between rate of cumulative CO₂–C and straw decomposition was significant under NT (R² = 0.52). The soil CO₂–C release under incubation was significantly higher with than without the input of straw (R² = 0.95). Furthermore, soil respiration increased with increases in incubation temperature and FMC. At 75% FMC, the rate of CO₂–C release increased by 21.9 mg kg⁻¹ d⁻¹ at 30 °C and 32.0 mg kg⁻¹ d⁻¹ at 35 °C compared with that at 25 °C. At 35 °C, the rate of CO₂–C release increased by 43.6 mg kg⁻¹ d⁻¹ at 65% FMC and 51.2 mg kg⁻¹ d⁻¹ at 75% FMC incubation than that of at 55% FMC under ST. The degree of control on the CO₂–C evolution rate during the pre-incubation period and with higher incubation temperature and FMC was better for the soil from NT than that from CT and ST, and better yet for the soil from ST than that from CT.

A laboratory incubation experiment was conducted to assess the impact of straw input on CO₂–C emissions.     

Differential Effects of Insulin on Splanchnic and Peripheral Glucose Disposal after an Intravenous Glucose Load in Man

The present study was designed to investigate the mechanisms by which insulin regulates the disposal of an intravenous glucose load in man. A combined tracer-hepatic vein catheter technique was used to quantitate directly the components of net splanchnic glucose balance (NSGB), i.e., splanchnic glucose uptake and hepatic glucose output, and peripheral (extrasplanchnic) glucose uptake. Four different protocols were performed: (a) intravenous infusion of glucose alone (6.5 mg kg⁻¹ min⁻¹) for 90 min (control group); (b) glucose plus somatostatin (0.6 mg/h) and glucagon (0.8 ng kg⁻¹ min⁻¹; (c) glucose plus somatostatin, glucagon, and insulin (0.15 mU kg⁻¹ min⁻¹); and (d) glucose plus somatostatin, glucagon, and insulin (0.4 m U kg⁻¹ min⁻¹). In groups 2-4, arterial blood glucose was raised to comparable levels to those of controls (170 mg/dl) by a variable glucose infusion. In the control group, plasma insulin levels reached 40 μU/ml at 90 min. NSGB switched from a net output of 1.71±0.13 to a net uptake of 1.5-1.6 mg kg⁻¹ min⁻¹ due to a 90-95% suppression of hepatic glucose output (P < 0.01) and a 105-130% elevation of splanchnic glucose uptake (from 0.78±0.13 to 1.6-1.8 mg kg⁻¹ min⁻¹; P < 0.01). Peripheral glucose uptake rose by 150-160% (P < 0.01). In group 2, plasma insulin fell to <5 μU/ml. Net splanchnic glucose output initially rose twofold but later returned to basal values. This response was entirely accounted for by similar changes in hepatic glucose output since splanchnic glucose uptake remained totally unchanged in spite of hyperglycemia. In contrast, peripheral glucose uptake rose consistently by 100% (P < 0.01) despite insulin deficiency. In an additional group of experiments, glucose metabolism by the forearm muscle tissue was quantitated during identical conditions to those of group 2 (hyperglycemia plus insulin deficiency). Both the arterial-deep venous blood glucose difference and forearm glucose uptake increased markedly by 300-400% (P < 0.05 - <0.01). In group 3, plasma insulin was maintained at near-basal, peripheral levels (12-14 μU/ml). Hepatic glucose output decreased slightly by 35-40% (P < 0.05) while splanchnic glucose uptake remained unchanged. Consequently, the net glucose overproduction seen in group 2 was totally prevented although NSGB still remained as a net output. In group 4, peripheral insulin levels were similar to those of the control group (35-40 μU/ml). The suppression of hepatic glucose output was more pronounced (60-65%) and splanchnic glucose uptake rose consistently by 65% (P < 0.01). Consequently, NSGB did not remain as a net output but eventually switched to a small uptake (0.3 mg kg⁻¹ min⁻¹). Peripheral glucose uptake rose to the same extent as in controls.     

Determination and distribution of pesticides and antibiotics in agricultural soils from northern China

Different types of soil samples from a typical farmland in northern China were collected and evaluated for the presence of the pesticides and antibiotics. 47 pesticides were extracted with a quick, easy, cheap, effective, rugged, and safe (QuEChERS) preparation method and cleanup with 50 mg C₁₈, while 10 antibiotics were extracted with methanol/EDTA–McIlvaine buffer solution (v/v = 1/1), then both of them were analyzed with high performance liquid chromatography-tandem mass spectrometer (HPLC-MS/MS). Total concentrations of the 47 pesticides in the soil samples ranged from not detectable (ND) to 3.8 mg kg⁻¹. The soil exhibited relatively high ecological risk for atrazine, chlorpyrifos, tebuconazole, difenoconazole, pymetrozine, and thiamethoxam, as over 1.0% of the sample concentrations exceeded 0.1 mg kg⁻¹. The residual levels of the 10 antibiotics were relatively low (ND-951.0 μg kg⁻¹). Tetracyclines exhibited a high detection rate (20.9%), with 2.8% of the soil samples exhibiting tetracyclines concentrations exceeding 100 μg kg⁻¹, implying high ecological risk. The 4 sulfonamides and 2 macrolides analyzed showed detection rates below 0.8%. Spatial changes in the distribution of pesticides and antibiotics appear to be related to land use patterns, particularly orchards and vegetable plots. The over-standard rate of pesticides and antibiotics in orchards was greater than that of vegetable plots, and grain fields had the lowest over-standard rate. These data were helpful to figure out the pollution of these pesticides and antibiotics, and provided valuable information for soil quality assessment and risk assessment.

Different types of soil samples from a typical farmland in northern China were collected and evaluated for the presence of the pesticides and antibiotics.     

Molecular docking analysis and anti-hyperglycaemic activity of Synacinn™ in streptozotocin-induced rats

Synacinn™ is a standardized polyherbal supplement formulated from Cinnamomum zeylanicum Blume, Curcuma zanthorrhiza Roxb., Syzygium polyanthum (Wight) Walp., Orthosiphon stamineus Benth. and Andrographis paniculata (Burm.f.) Nees. It is designed for the synergistic treatment of diabetes mellitus and its complications. Although the beneficial effects are yet to be verified scientifically, it is traditionally used to improve general health in patients with diabetes. This study aimed to evaluate the anti-hyperglycemic effects of Synacinn™ in a streptozotocin-induced type 1 diabetes rat model. Initially, Synacinn™ was used for in vivo acute oral toxicity tests and 14 day repeated dose toxicity tests to determine the toxicity levels. An efficacy study of Synacinn™ was carried out via the oral administration of 10, 50, 100, 250, and 250 (b.i.d.) mg kg⁻¹ doses to streptozotocin-induced diabetic rats. After 28 days, blood serum was collected to measure the fasting blood glucose, triglyceride, cholesterol, alanine aminotransferase, alkaline phosphatase, creatinine, and uric acid levels. The liver, kidney, and pancreas structures were histopathologically analyzed. In silico binding interaction studies of five phytochemicals in Synacinn™ identified via HPLC with glucokinase were performed using molecular docking analysis. The results showed that although no mortality was observed during the acute oral toxicity tests, notable damage to the liver and kidney occurred during the 14 day repeated dose testing at Synacinn™ levels of 600 mg kg⁻¹ and 2000 mg kg⁻¹. Treatment with 250 mg kg⁻¹ (b.i.d.) Synacinn™ of the streptozotocin-induced type 1 diabetic rats significantly (p < 0.05) improved the fasting blood glucose (59%), triglyceride (58%), cholesterol (47%), alanine aminotransferase (60%), alkaline phosphatase (90%), and creatinine (32%) levels. Synacinn™ also improved the relative weights of liver (35%), kidney (36%), and pancreatic (36%) tissue. Histological analysis showed improvements in the conditions of the central vein of the liver, the kidney Bowman''s capsule and glomerulus, and the pancreatic islets of Langerhans. HPLC analysis of a standardized extract identified five active phytochemicals: andrographolide (17.36 mg g⁻¹), gallic acid (11.5 mg g⁻¹), curcumin (2.75 mg g⁻¹), catechin (3.9 mg g⁻¹), and rosmarinic acid (5.54 mg g⁻¹). Molecular docking studies with glucokinase showed that andrographolide yields the highest binding energy (−12.1 kcal mol⁻¹), followed by catechin (−10.2 kcal mol⁻¹), rosmarinic acid (−8.6 kcal mol⁻¹), curcumin (−7.8 kcal mol⁻¹), and gallic acid (−5.6 kcal mol⁻¹). These current findings suggest that Synacinn™ at a dose of 250 mg kg⁻¹ was non-toxic to rats. A twice-daily 250 mg kg⁻¹ dose of Synacinn™ is an effective anti-hyperglycemic agent, lowering blood glucose, triglyceride, and cholesterol levels, and assisting the recovery of organ impairment caused by streptozotocin in type 1 diabetic rats.

Synacinn™, a standardized polyherbal supplement, was shown to improve hyperglycemic conditions and related complications in STZ-induced rats.     

Heavy metal mediated phytotoxic impact on winter wheat: oxidative stress and microbial management of toxicity by Bacillus subtilis BM2

Heavy metals are toxic environmental contaminants, which severely affect microbial composition and functions and, concurrently, crop production. Due to these issues, the present study focussed on the selection of metal tolerant microbes endowed with metal detoxification abilities and their role in the management and remediation of metal contaminated soils. The metal tolerant bacterium BM2, identified as Bacillus subtilis by 16SrRNA gene sequencing, survived well under metal pressure and tolerated 1600 and 2000 μg mL⁻¹ of Ni and Pb, respectively. The inhibitory impact of metals on wheat increased consistently with a progressive increase in metal concentration. Deposition of Ni and Pb within root and leaf and oxidative stress were validated by SEM, EDX and CLSM. The overall growth parameters of wheat grown under metal stress were improved following B. subtilis BM2 colonization. As an example, B. subtilis with 195 mg Pb kg⁻¹ enhanced the length and dry biomass of shoots by 14% and 23%, respectively, over the control. Also, strain BM2 improved the grain yield significantly by 49% at 870 mg Ni kg⁻¹ and by 50% at 585 mg Pb kg⁻¹ compared to uninoculated plants. Moreover, B. subtilis BM2 relieved the metal stress on wheat and caused a significant drop in proline and malondialdehyde content and the activities of antioxidant enzymes, like catalase (CAT), superoxide dismutase (SOD) and glutathione reductase (GR). This study, therefore, provided solutions to the metal toxicity problems faced by winter wheat and clearly suggests that the metal detoxification potential of B. subtilis BM2 could be greatly useful in the management of metal polluted soils.

The bacterial management of heavy metal toxicity to durum wheat under a metal stressed environment was demonstrated.     

Analysis of 17 elements in cow,goat, buffalo,yak, and camel milk by inductively coupled plasma mass spectrometry (ICP-MS)

We analyzed the concentrations of 17 elements including arsenic (As), lead (Pb), cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni), zinc (Zn), strontium (Sr), tin (Sn), aluminum (Al), potassium (K), calcium (Ca), magnesium (Mg), iron (Fe), manganese (Mn), sodium (Na), and selenium (Se) in cow, goat, buffalo, yak, and camel milk in China using inductively coupled plasma mass spectrometry. The concentrations of the elements varied and depended on the milk type. K, Ca, Na, and Mg were the most abundant elements. Fe and Zn concentrations ranged from 1 to 6 μg g⁻¹, while Cu, Al, and Mn concentrations ranged from 0.1 to 1 μg g⁻¹. Trace elements, especially toxic trace elements, were present at very low concentrations; however, Pb concentrations in cow milk reached the MRLs established by the Codex Alimentarius Commission. Data were analyzed by chemometrics to evaluate the correlations between elements in the milk samples. PCA and factor analysis highlighted the relationship between element distribution and milk type. The LDA model correctly identified most milk types. Element analysis combined with chemometrics can be used to distinguish milk types.

17 elements in cow, goat, buffalo, yak, and camel milk were determined by ICP-MS; element analysis combined with chemometrics can be used to distinguish milk types.     

Hydrogels derived from galactoglucomannan hemicellulose with inorganic contaminant removal properties

The adsorption of Cu(ii), Cd(ii), and Pb(ii) ions onto hydrogels derived from modified galactoglucomannan (GGM) hemicellulose was studied. GGM hemicellulose was modified with methacrylate groups (GGM-MA) to incorporate vinyl groups into the polymeric structure, which reacted later with synthetic monomers such as 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS). The results show that all the synthesized hydrogels were capable of adsorbing contaminating ions with high adsorption efficiency during short periods of time. Furthermore, an increase in the content of GGM-MA generated a hydrogel (H3) with a similar ion adsorption property to the other hydrogels but with a lesser degree of swelling. The H3 hydrogel had an adsorption capacity of 60.0 mg g⁻¹ Cd(ii), 78.9 mg g⁻¹ Cu(ii), and 174.9 mg g⁻¹ Pb(ii) at 25 °C. This result shows that modified GGM hemicelluloses can be employed as renewable adsorbents to remove Cu(ii), Cd(ii), and Pb(ii) ions from aqueous solutions.

The adsorption of Cu(ii), Cd(ii), and Pb(ii) ions onto hydrogels derived from modified galactoglucomannan (GGM) hemicellulose was studied.     

Effects of activated charcoal-herb extractum complex on the growth performance,immunological indices,intestinal morphology and microflora in weaning piglets

This study was conducted to evaluate the effects of activated charcoal-herb extractum complex (CHC) on the growth performance, immunological indices, intestinal morphology and microflora in weaning piglets to determine the optimal supplemental dose. A total of 216 weaned piglets (Duroc × Landrace × Large White) with an initial body weight of 8.55 ± 1.18 kg were randomly assigned to six treatment groups; each treatment group had six pens, with six pigs per pen. The study period was 28 d. Pigs were fed a corn-soybean meal-based diet supplemented with 500, 1000, 1500 or 2000 mg kg⁻¹ of CHC over two 14-d periods. Two additional diets containing 0 and 1000 mg kg⁻¹ of montmorillonite were set as the negative and positive controls, respectively. Supplementation with 500 mg kg⁻¹ of CHC significantly increased average daily gain compared with the positive and negative controls during phase I and the entire experimental period (P < 0.05). During phase I, 500 and 1000 mg kg⁻¹ of CHC significantly decreased diarrhea incidence compared with the negative control, and increased serum IGF-1 and serum IgM levels compared with the controls (P < 0.05). CHC at 500 mg kg⁻¹ significantly decreased the diarrhea score during the entire experimental period compared with the negative control (P < 0.05). On day 28, supplementation with 500 and 1000 mg kg⁻¹ of CHC increased serum IgG, IL-1β, and duodenum and jejunum secretory IgA compared with the negative control and decreased duodenum and jejunum MDA levels compared with the controls (P < 0.05). Increased duodenum and jejunum villus height and an increased ratio of villus height to crypt depth were observed compared with the negative control and decreased viable counts of E. coli in the cecum were detected compared with the controls (P < 0.05). Collectively, the optimal dose of CHC was found to be 500 to 1000 mg kg⁻¹ in this study.

This study was conducted to evaluate the effects of activated charcoal-herb extractum complex (CHC) on the growth performance, immunological indices, intestinal morphology and microflora in weaning piglets to determine the optimal supplemental dose.     

Sensitive determination of trace Cd(ii) and Pb(ii) in soil by an improved stripping voltammetry method using two different in situ plated bismuth-film electrodes based on a novel electrochemical measurement system

In this study, a simple but effective electrochemical method was developed to minimize the interference from real soil samples and increase the sensitivity of Pb(ii) and Cd(ii) detection by square-wave anodic stripping voltammetry (SWASV) using a novel electrochemical measurement system, which can be used for the on-site determination of trace Cd(ii) and Pb(ii) in real soil samples. The method involved performing SWASV following double deposition and stripping steps at two in situ plated bismuth-film electrodes with drastically different surface properties. Pb(ii) and Cd(ii) were first deposited on an in situ plated bismuth-film graphite carbon paste electrode (Bi/GCPE). When the first deposition was finished, the GCPE was moved to a micro-electrolytic cell to perform the first stripping step. The following measurements were performed with the other deposition and stripping steps using a highly sensitive in situ plated bismuth-film multiwalled carbon nanotube–Nafion composite modified glassy carbon electrode (Bi/MWCNT–Nafion/GCE) as the working electrode. Pb(ii), Cd(ii) and Bi(iii) stripped from the GCPE in the micro-electrolytic cell were partially deposited on the MWCNT–Nafion/GCE, and the stripping current signals were obtained from their oxidation during the second stripping step. Considering the small volume of the micro-electrolytic cell, the concentrations of Cd(ii) and Pb(ii) were drastically higher than those in the bulk solution, and therefore, the detection limits were reduced. Under the optimized conditions, the concentrations in the linear range spanned from 1.0 to 45.0 μg L⁻¹ for both Pb(ii) and Cd(ii), with a detection limit of 0.03 μg L⁻¹ for Pb(ii) and 0.02 μg L⁻¹ for Cd(ii) (S/N = 3). Finally, analyses of real samples were performed to detect trace levels of Pb(ii) and Cd(ii) in soil with satisfactory results.

A double-stripping voltammetry method was designed and developed to improve the sensitivity and anti-interference ability for detection of heavy metals.     

Metal (Cd,Cr, Ni,Pb) removal from environmentally relevant waters using polyvinylpyrrolidone-coated magnetite nanoparticles

Water pollution is a major global challenge given the increasing growth in industry and human population, and certain metals can be highly toxic and contribute to this significantly. In this study, polyvinylpyrrolidone-coated magnetic nanoparticles (PVP–Fe₃O₄ NPs) were used to remove metals (Cd, Cr, Ni, and Pb) from synthetic soft water and sea water in the presence and absence of fulvic acid. Nanoparticle (NP) suspensions were added to water media at a range of metal concentrations (0.1–100 mg L⁻¹). Removal at different time points (1.5, 3, 6, 12, 24 hours) was also evaluated. Results showed that 167 mg L⁻¹ PVP–Fe₃O₄ NPs could remove nearly 100% of four metals at 0.1 mg L⁻¹ and more than 80% at 1 mg L⁻¹. The removal decreased as the initial metal concentration increased, although essentially 100% of the Pb was removed under all conditions. The kinetic adsorption fitted well to the pseudo-second-order model and in general, the majority of metal adsorption occurred within the first 1.5 hours. These NPs are a reliable method to remove metals under a wide range of environmentally relevant conditions. Our previous research showed the NPs effectively removed oil from waters, so these NPs offer the possibility of combined in situ remediation of oil and metals.

PVP–Fe₃O₄ NPs synthesized with no organic solvents, low toxicity reactants and low temperature/energy requirements could remove Cd, Cr, Ni, Pb efficiently in the different synthetic water media under environmentally relevant conditions.     

Application of hydrotalcite in soil immobilization of iodate (IO3−)

Radioactive iodine is quite mobile in soil and poses threats to human health and the ecosystem. Many materials, including layered double hydroxides (LDH), have been synthesized to successfully capture iodine from aqueous environments. However, limited information is available on the application of LDH in soil to immobilize iodine species. In the present study, the feasibility of using Mg–Al–NO₃ LDH for retention of soil iodate (IO₃⁻) in both batch and column systems was analyzed. The 2 : 1 Mg–Al–NO₃ LDH exhibited the greatest removal efficiency of IO₃⁻ from aqueous solution, compared with 3 : 1 and 4 : 1 Mg–Al–NO₃ LDH. The Mg₂–Al–NO₃ LDH demonstrated a strong affinity for IO₃⁻, with a high sorption capacity of 149 528 mg kg⁻¹ and a Freundlich affinity constant K_F of 21 380 L kg⁻¹. The addition of Mg₂–Al–NO₃ LDH in soil resulted in significant retention of IO₃⁻ in both the batch and column experiments. The affinity parameter K_F of soil with the addition of 1.33% Mg₂–Al–NO₃ LDH was 136 L kg⁻¹, which was 28.6 times higher than soil without LDH added. Moreover, the eluted iodate percentage was only 12.9% in the soil column with the 1.33% Mg₂–Al–NO₃ LDH addition, whereas almost 43.5% iodate was washed out in the soil column without LDH addition. The results suggested that Mg₂–Al–NO₃ LDH could effectively immobilize iodate in soil without obvious interference.

Addition of Mg₂–Al–NO₃ LDH at a very low dosage significantly retarded iodate in soil.     

The effect of beta-sitosterol and its derivatives on depression by the modification of 5-HT,DA and GABA-ergic systems in mice

Beta-sitosterol belongs to the group of phytosterols, which are active trace components existing in natural plants, known as the “key of life”, and have a steroid nucleus structure similar to cholesterol. Due to the insolubility issue of beta-sitosterol, most pharmacological studies and clinical applications are limited. Therefore, the modification of beta-sitosterol into its derivatives to enhance its pharmacologic activity is viable. In this study, 4 kinds of new beta-sitosterol derivative were obtained by an esterification reaction with beta-sitosterol, organic acids, EDCI and DMAP in dichloromethane. The chemical structures were defined by IR and NMR. Beta-sitosterol and its derivatives were used to carry out antidepressant research in the tail suspension test (TST) and the forced swimming test (FST) in mice. Additionally, the roles of different parts of the central nervous system (CNS) in the antidepressant-like effect of Sit-S, which is one of the beta-sitosterol derivatives, were also investigated. The results showed that the derivatives exhibited a stronger antidepressant activity than beta-sitosterol. Among the derivatives, administration of Sit-S (4 mg kg⁻¹) gave the lowest immobility time in the TST, demonstrating that Sit-S exhibited the strongest antidepressant-like activity. The study into the roles of different parts of the CNS in the antidepressant-like effect of Sit-S showed that agomelatine (40 mg kg⁻¹), haloperidol (0.2 mg kg⁻¹) and bicuculline (4 mg kg⁻¹) reversed the antidepressant effect of Sit-S (4 mg kg⁻¹). This study confirmed the conclusions that beta-sitosterol derivatives broaden the pharmacological effects of beta-sitosterol, Sit-S (4 mg kg⁻¹) exhibits antidepressant-like effects, and this antidepressant-like effect on male adult mice is mediated by the 5-HT, DA and GABA-ergic systems.

Beta-sitosterol and its derivatives exhibit antidepressant-like activity mediated by the modification of 5-HT, DA and GABA-ergic systems.     

Effect of different forms of N fertilizers on the hyperaccumulator Solanum nigrum L. and maize in intercropping mode under Cd stress

In the present study, we investigated the effects of different forms of nitrogen fertilizers on the hyperaccumulator Solanum nigrum L. and maize in intercropping mode under cadmium (Cd) stress and explored the physiological response mechanism. This research lays the foundation for the appropriate use of nitrogen (N) fertilizer, reduced costs of ecological restoration, and phytoremediation of environmental pollution by using this intercropping system. The main greenhouse pot experiment was conducted using 1.92 mg kg⁻¹ Cd-contaminated soil. NH₄⁺–N fertilizer and NO₃⁻–N fertilizer treatments were performed along with no nitrogen fertilizer treatment as the control. The results indicate that intercropping could decrease the Cd uptake of maize compared with maize monocropping, but the biomass of maize would decrease under the intercropping mode. The application of N fertilizer to the maize–S. nigrum intercropping system could increase the total biomass of maize and S. nigrum. Compared with the NO₃⁻–N fertilizer treatment, the Cd content of stem, leaf and grain tissues of S. nigrum significantly increased by 9.43%, 22.2%, and 8.33%, respectively, under the NH₄⁺–N fertilizer treatment. The bioconcentration and translocation factors of S. nigrum significantly increased by 11.1% and 15.3%. Moreover, the Cd content of stem, leaf, and grain tissues of maize decreased by 26.5%, 21.2%, and 21.4%, respectively. The bioconcentration and translocation factors of maize significantly decreased by 38.8% and 46.7%. The application of N fertilizers promoted the accumulation of Cd in maize roots, while Cd content decreased in maize shoots. Compared with NO₃⁻–N fertilizer, NH₄⁺–N fertilizer can improve Cd accumulation in various S. nigrum tissues under intercropping, which could reduce Cd accumulation in maize under intercropping. Therefore, the application of NH₄⁺–N fertilizer is recommended for satisfactory bioremediation when using the Cd-hyperaccumulator S. nigrum and for supporting the safe production of maize in Cd-contaminated soil, thus enabling the goal of simultaneous agricultural production and remediation.

In the present study, we investigated the effects of different forms of nitrogen fertilizers on the hyperaccumulator Solanum nigrum L. and maize in intercropping mode under cadmium (Cd) stress and explored the physiological response mechanism.     

Micranthanosides I and II,two novel 1,10-secograyanane diterpenoids and their antinociceptive analogues from the leaves and twigs of Rhododendron micranthum

Micranthanosides I and II (1–2), two diterpenoid glucosides featuring a new 1,10-secograyanane skeleton, thirteen new diterpenoid glycosides (3–15), and 21 known analogues were obtained from the ethanol extract of the leaves and twigs of Rhododendron micranthum. Micranthanoside XII (12) represent the first example of 3,5-epoxy-4,5-seco-ent-kaurane diterpenoid. The structures of these compounds were determined by spectroscopic data analysis and quantum chemical calculations. To clarify the chemical basis and provide reference for rational use of this medicinal plant, the antinociceptive and the anti-inflammatory activities of the compounds were tested. In the acetic acid-induced writhing test, compounds 17 and 19 showed significant antinociceptive activity at a dose of 3 mg kg⁻¹ and compounds 2, 6 and 32 showed significant antinociceptive activity at a dose of 10 mg kg⁻¹. Toxic reactions such as nausea and convulsion were observed when 17, 19, 29, and 31 at a dose of 10 mg kg⁻¹ or 30 and 33 at a dose of 1 mg kg⁻¹ were administered. The anti-inflammatory activities of the isolated compounds were evaluated by measuring the inhibitory effects of LPS-induced NO production in BV2 cells. At 10 μM, micranthanoside IX (9) and rhodomicranoside F (26) showed moderate anti-inflammatory activities with inhibition rates of 56.31% and 72.43%, respectively.

Two unusual diterpenoids with a new 1,10-secograyanane skeleton and thirteen new analogues from the leaves and twigs of Rhododendron micranthum were obtained.     

Weathering treatment coupled with nano-silica filling to promote the engineering property of municipal solid waste incinerator bottom ash

A new approach including weathering treatment and nano-silica filling was employed to promote the engineering properties of municipal solid waste incinerator (MSWI) bottom ash. X-ray diffraction (XRD), scanning electron microscopy (SEM) and electron dispersive spectroscopy (EDS) was used to characterize the mineralogical and morphological changes due to the treatment. Changes of chemical stability, compressive strength and heavy metal leaching of MSWI bottom ash were also explored. After the weathering treatment, the content of organic matter decreased from 2.70% to 1.07%, while the carbonates increased from 0.70% to 2.05%. The nano-silica treatment filled the intrinsic and neo-formed micropores and coated the surface of MSWI bottom ash. Due to this process, the chemical stability was promoted. The compressive strength increased from 4.83 to 5.32 MPa. The leaching of Cu, Zn, Pb, Cr and Cd sharply decreased from 250.05 to 89.97 mg L⁻¹, 1080.45 to 173.14 mg L⁻¹, 1.25 to 0.70 mg L⁻¹, 72.58 to 12.96 mg L⁻¹ and 0.94 to 0.30 mg L⁻¹, respectively. The results suggested that the weathering treatment coupled with nano-silica filling could greatly promote the engineering properties of MSWI bottom ash, which is beneficial with respect to the reuse of MSWI bottom ash as the building material.

A new approach including weathering treatment and nano-silica filling was employed to promote the engineering properties of municipal solid waste incinerator (MSWI) bottom ash.