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This study evaluated the novel application of a mineral-rich biochar derived from a spent Agaricus bisporus substrate (SAS). Biochars with various pyrolysis temperatures (350&ndash, 750 &deg, C) were used to remove Cu(II), Zn(II), and Cd(II) from aqueous solutions. The adsorption characteristics and removal mechanisms of the biochars were investigated. The adsorption kinetics and isotherm data were fitted well by pseudo-second-order and Freundlich models. The Langmuir maximum removal capacity (Qmax) values of Cu(II), Zn(II), and Cd(II) were ordered as SAS750 &gt, SAS350 &gt, SAS550, and the Qmax values of SAS750 were 68.1, 55.2, and 64.8 mg&middot, g&minus, 1, respectively. Overall, the removal mechanisms of biochar at a low production temperature (350 &deg, C) to Cu(II), Zn(II), and Cd(II) were mainly via ion exchange (54.0, 56.0, and 43.0%), and at a moderate production temperature (550 &deg, C), removal mechanisms were mainly via coordination with &pi, electrons (38.3, 45.9, and 55.0%), while mineral precipitation (65.2, 44.4, and 76.3%, respectively) was the dominant mechanism at a high produced temperature (750 &deg, C). The variation of the mutual effect of minerals and heavy metals was the predominant factor in the sorption mechanism of mineral precipitation and ion exchange. The results demonstrated that spent Agaricus bisporus substrate biochar is a potential candidate for the efficient removal of heavy metals, which provides a utilization route for spent mushroom substrates.

This study aims to establish a simple and efficient method for the mass culture of bdelloid rotifers, which is the basis for the application of bdelloid rotifers as biological manipulators to improve wastewater biological treatment performance. A common bdelloid rotifer, Habrotrocha sp., in a wastewater biological treatment system was selected as the culture target. Rotifers fed on flour could reproduce faster than those fed traditional food such as Chlorella vulgaris or mixed bacteria. As a rotifer food, flour has the advantages of simple preparation, effortless preservation, and low cost compared to live Chlorella vulgaris or mixed bacteria, so it is more suitable for the mass culture of rotifers. The optimal rotifer culture conditions using flour as food were also studied. According to the experimental results, the recommended rotifer culture conditions are a flour particle size of 1 µm, a flour concentration of 6 × 106 cell/mL, a temperature of 28°C, a pH level of 6.5 and salinity of 100–500 mg/L. In addition, the sludge volume index in the sequencing batch reactor (SBR) with the addition of cultured rotifers was 59.9 mL/g at the end of operation and decreased by 18.2% compared to SBR without rotifer, which indicates that the cultured rotifers still retained the function of helping to improve sludge settling. This function may be related to the rotifer’s role in inhibiting bacteria from producing loosely bound extracellular polymeric substances in the SBR.

Phytoremediation is a kind of efficient strategy for remediating soils polluted with heavy metals. The aim of this study was to investigate the influence of spent mushroom substrate (SMS) on the phytoremediation potential of Ricinus communis in Cd- and Zn-polluted soil. We treated the soil with SMS before growing plants and analyzed the contents, distribution of heavy metals, and response of plants after growth. SMS increased the contents of Cd (5%-13%) and Zn (16%-20%) in the cell wall. This finding suggested that high amounts of Cd and Zn were absorbed and bonded to the cell wall through metabolism adaption and formed stable compounds, which reduced the damage of the heavy metal to cells. SMS also decreased the levels of superoxide dismutase, peroxidase, and catalase by 9.5%-27.7%, 8.8%-30.0% and 8.5%-28.1%, respectively. Treatment of SMS alleviated the toxicity of heavy metal in plants and increased the extracted amounts of Zn and Cd by 101%-227% and 51%-189%, respectively. Hence, SMS treatment could reduce the toxicity of heavy metals to plants and strengthen the phytoremediation potential.

Crop co-planting is widely used in agriculture because it can increase total crop yields through increased resource use efficiency, and phytoremediation is based on the contaminant remediation system in plants. This study focused on the phytoextractive effects of co-planting Ricinus communis and/or legumes in Cd- and Zn-contaminated soil. A Cd- and Zn-contaminated factory relocation site in Shanghai was selected for the experiment, and according to the results of a potential ecological risk assessment of heavy metals, the study area was divided into 3 levels of pollution: slight, moderate, and high. The results showed that the presence of Medicago sativa can significantly increase the height and biomass of R. communis, and there was a greater impact on the chlorophyll content of R. communis at higher pollution levels. Differences in pollution levels could significantly change the oil content of R. communis plants, but M. sativa can alleviate the impact of heavy metals. The presence of M. sativa increased the cumulative amount of cadmium and zinc in R. communis by 1.14 and 2.19 times, respectively. In short, co-planting R. communis and legumes remediated contaminated soil and may be one practical phytoremediation pathway for heavy metal-contaminated soil in the future.

During the process of treating and recycling Municipal Solid Waste Incinerators (MSWIs) fly ash, polychlorinated dibenzo-p-dioxins (PCDD/Fs) and polychlorinated dibenzofurans (dl-PCBs) in fly ash may potentially mobilize in the atmosphere and be widely distributed in the environment because of the inevitable re-suspension. Thus, this work presents the distributions of PCDD/Fs and dl-PCBs in inhalable coarse particles (Dp10-2.5 (particle diameter in μm)), fine particles (Dp

Cd and Zn pollution was observed to often occur simultaneously in soils. However, previous studies focused on single heavy metal instead of Cd and Zn combined pollution. Castor (Ricinus communis) is considered to have great potential for contaminated soil remediation. The resistance of castor seedlings to heavy metals and the mechanism behind it remain unknown. In this study, the tolerance and accumulation ability of castor seedlings to Cd and Zn were investigated, and the accumulation mechanism involving the subcellular distribution in different tissues was further explored. The results on biomass and chlorophyll revealed that castor seedlings have good tolerance to the pollution with 0–5 mg/kg Cd and 380 mg/kg Zn, while not to the heavy pollution with 25 mg/kg Cd and 380 mg/kg Zn. The maximum accumulation concentrations of Cd and Zn, 175.3 mg Cd/kg and 386.8 mg/kg Zn, appeared in castor seedling root instead of stem and leaf, indicating that root played a significant part in accumulating Zn and Cd. The relative low dosage of Cd (0–5 mg/kg) promoted the accumulation of Zn in the subcellular component, while high dosage (25 mg/kg) inhibited the accumulation of Zn. In subcellular accumulation and distribution of castor seedlings, Cd (27.1%–69.4%) and Zn (39.6%–66.6%) in the cell wall was the highest. With the increase of Cd addition, the accumulation of Cd increased in cell wall while decreased in organelle and soluble fraction. Hydroxyl, amino, amides and carboxyl functional groups on cell wall might provided the main binding sites for Cd and Zn.

Mercury (Hg) in municipal solid waste incineration fly ash attracts much attention for its potential risk in environment and human health. In this work, Hg in fly ashes collected from 15 cities over China was surveyed in terms of speciation, leaching behavior and health risk assessment. In general, total Hg (HgT) concentration was 1–24 mg kg −1 , where fly ash in esten cities had higher HgT concentration. After systemic research, several conclusions were obtained: (1) the amount of strongly-complexed Hg was 65–94% of HgT, which was consistent with the sequential inspection result, indicating that Hg predominantly bonded to Fe oxide or Hg(I); (2) the Hg leaching test together with principal component analysis (PCA) showed that leaching level of Hg was lower than 0.2 mg/L of the USEPA regulatory limitation. This suggests that the dominating strongly-complexed Hg in HgT could probably not be leached out; (3) moreover, the health risk assessment of fly ash for workers was performed according to the main exposure pathway inhalation of mercury vapor and resuspended particles. As a result, the total non-carcinogenic risk values (HQ total ) of Hg ranged from 0.02 to 0.75, far from the “safe” threshold of 1. Therefore, our results provide the further understanding of Hg contamination level in fly ash, which is important to the fly ash management in China.

Colloid-facilitated transport of metals is widely observed while manure is used for the improvement of contaminated soil. Details on the mechanism of colloid-associated metal transport are still lacking. This work investigated the nature of water-dispersible colloids (WDC) from different organic manures, differentiated the significance of clay and organic colloids in the metal transport, and finally provided direct and quantitative evidence for the importance of WDC in the colloid-facilitated transport of metals. Column experiments were conducted to assess the overall significance of WDC from effective microbial inoculated manure (EM) and leaf mulch (LM) for metal transport in alkali-contaminated soil. The properties of organic colloids such as hydrophilicity, aromaticity, and functional characteristics were analyzed by DAX-8 resin column, specific UV absorbance, and Fourier-transform infrared spectroscopy, respectively. Colloid identification and metal species determination were conducted using a combination of X-ray absorption near-edge structure, X-ray fluorescence spectroscopy, and transmission electron microscopy coupled with energy-dispersive X-ray analysis. Approximately 100 % of Pb, 69 % of Zn, and 38 % of Cu in the colloidal particles came from soil clay in the presence of EM colloids, while more than 80 % of Pb, Zn, and Cu in the LM colloids. Combined with the quantities of colloidal metals, it revealed that clay release was inhibited in the former and enhanced in the latter. The quantities of Cu and Zn associated with the EM colloids were much higher than that with the LM colloids. The contrary result was observed for Pb. LM colloids increased the quantities of organically associated Pb significantly. Clay-associated metal transfer was influenced by the nature of WDC. Microbial manure colloids inhibited the clay-associated transfer of metals in the soils probably due to the presence of polysaccharide and microbially derived extracellular proteins. Leaf mulch colloids, with more hydrophobicity and aromaticity, enhanced the clay-facilitated transfer of metals in the soils.

Heavy metal contamination of soil may pose risks to human health and ecosystem environment. Phytoremediation is a low-cost and ecologically sustainable way to remediate heavy metal contaminated soils. As most of the heavy metal accumulator plants are low biomass producers, we selected maize as our experimental phytoremediation plant, which can both produce large useful biomass and remediate heavy metal contaminated soils. The effect of humic acid and bacterial manure on heavy metal accumulation in different organs of maize was studied in this paper, in order to investigate whether the fertilizer application has an effect on phytoremediation efficiency. The results showed that Cu, Pb and Zn contents in the organs of maize generally followed the order root>stem≈leaf>grain. Application of humic acid and bacterial manure improved the contents of Cu, Zn and Pb in different organs compared with those without fertilizer application. Maize with humic acid application generally had higher contents of Cu, Zn and Pb in the organs than that with bacterial manure application. This study indicated that fertilizer application was possibly one of the efficient ways to enhance the efficiency of soil phytoremediation.

Phytoremediation is a low cost and eco-friendly emerging technology for treatment of contaminated soils with the use of green plants. In this study, the accumulation potential to heavy metals by two biofuel crops (maize and sunflower) and two metal accumulator plants (Elsholtzia splendens (ES), Tagetes patula L. (TP)) was studied with pot culture filled with a heavy metal contaminated soil, in order to compare their suitability for phytoremediation of contaminated soils. Sunflower showed the highest accumulation level for Cu (150 ug/pot) and Zn (10893 ug/pot) in the shoot part compared to other three plants. Maize showed a similar accumulation level for Cu (104 ug/pot) and Zn (7454 ug/pot) to TP, but a much higher level than ES. TP showed noticeable accumulation levels for Pb (196 ug/pot) and Cd (637 ug/pot). ES generally had the lowest accumulation capacity for Cu (38.5 ug/pot), Zn (2784 ug/pot), Pb (35.4 ug/pot) and Cd (18.2 ug/pot). Therefore, the two biofuel plants had higher or similar phytoremediation potential of heavy metals compared to the two accumulator plants. This study provided useful data for considering biofuel plants as potential economic crops for phytoremediation.

Stormwater draining from impervious surfaces in urban areas often contains readily soluble salts in runoff, which contribute dramatically to the degradation of aquatic ecosystem. The concentrations of potassium (K), cadmium (Ca), sodium (Na), magnesium (Mg), chloride (Cl) and sulfate (SO42-) in stormwater runoff in the urban areas of Shenyang city were measured in 4 rainfall events during July 2009 to June 2010. The results showed that there was an obvious increasing of salt ions concentrations in stormwater runoff samples, especially Na and Cl. It is also found that readily soluble salts ions in stormwater runoff peaked at the first storm event after winter. This study demonstrated that the applied deicing salts in winter significantly contributed to the increasing concentrations of K, Ca, Na, Mg, Cl, and SO42- in urban stormwater runoff. It is evident that the application of deicing salts in cold regions of China every year has had adverse impacts on the aquatic ecology through stormwater runoff.

Photocatalytic degradation of methyl orange by TiO2–SiO2–NiFe2O4 suspensions was investigated. Adsorption studies revealed photocatalytic degradation occurred mainly on the surface of the TiO2–SiO2–NiFe2O4. The disappearance of the compound followed the zero-order kinetics according to the Langmuir–Hinshelwood model and the rate constant was 0.0035 mg L−1 min−1. The rate constant depended on the amount of photocatalyst, initial pH, and the presence of additional scavengers. •OH radicals and h+ had important roles in the photocatalytic degradation of methyl orange by TiO2–SiO2–NiFe2O4.

TiO2/graphene composite photocatalysts have been prepared by a simple liquid phase deposition method using titanium tetrafluoride and electron beam (EB) irradiation-pretreated graphene as the raw materials. The products were characterized by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, and thermogravimetric analysis. The effects of varying the synthesis parameters such as graphene content, concentration of titanium tetrafluoride solution and irradiation dose were investigated. It was found that the preparation conditions had a significant effect on the structure and properties of the final products. The irradiated graphene was covered with petal-like anatase TiO2 nanoparticles, which were more uniform and smaller in size than those in products synthesized without EB irradiation-pretreated graphene. The photocatalytic activities of the products were evaluated using the photocatalytic degradation of methyl orange as a probe reaction. The results showed that the products synthesized using EB irradiation-pretreated graphene exhibited higher photocatalytic activities than those using graphene without EB irradiation pretreatment.

Heavy metal pollution of soils has become a major concern in China as a consequence of rapid urbanization and industrialization in recent years. However, the evaluation on soil heavy metal pollution in Shenyang, the largest heavy industrial base city in China, has not yet been conducted. In this study, accumulation, chemical speciation, and vertical distribution Cu, Zn, Pb and Cd in soils were studied and pollution condition was assessed in Tiexi Industrial District of Shenyang, the largest and oldest industrial zone in Northeastern China. The results showed that in topsoil, the average concentration of total Cu, Zn, Pb, and Cd was 209.06, 599.92, 470.19 and 8.59 mg kg−1, respectively, much higher than the national threshold limit. The values of pollution index and integrated pollution index showed that the pollution level was Cd > Cu > Zn > Pb, and Cd, Cu and Zn belong to heavy pollution level. The residual, Fe and Mn oxide-bound, and organic-bound species accounted for about 90%, while carbonate-bound and exchangeable species accounted for about 10%. This study indicates that the soils in the industrial zone were widely and extremely polluted by multi-heavy metals as a result of long-term industrial activities.

Ricinus communis L. is a bioenergetic crop with high-biomass production and tolerance to cadmium (Cd) and lead (Pb), thus, the plant is a candidate crop for phytoremediation. Pot experiments were performed to study the effects of citric acid in enhancing phytoextraction of Cd/Pb by Ricinus communis L. Citric acid increased Cd and Pb contents in plant shoots in all treatments by about 78% and 18-45%, respectively, at the dosage of 10 mM kg(-1) soil without affecting aboveground biomass production. Addition of citric acid reduced CEC, weakened soil adsorption of heavy metals and activated Cd and Pb in soil solutions. The acid-exchangeable fraction (BCR-1) of Pb remained lower than 7% and significantly increased with citric acid amendment. Respective increases in soil evaluation index induces by 14% and 19% under the Cd1Pb50 and Cd1Pb250 treatments upon addition of citric acid resulted in soil quality improvement. Ricinus communis L. has great potential in citric acid-assisted phytoextraction for Cd and Pb remediation.

In this study, a field investigation combined with a laboratory column leaching experiment were carried out to assess the effects of de-icing salts application on the heavy metal mobilization in roadside soils in an old and large industrial zone in Northeastern China. In the field investigation, 41 roadside soils were collected from the industrial zone, and the results showed a strong rise in deicing salts related concentrations of Na (352–513 mg/kg) and Cl (577–2,353 mg/kg) and high values of Cd (1.2–7.6 mg/kg) and Pb (28.7–101.6 mg/kg). The most serious contaminated roadside soil was used for column leaching experiment alternately with de-icing salts solution and deionized water to simulate the runoff of de-icing salts into roadside soils followed by snowmelt or rainwater. The results showed that an extensive mobilization of Cd (20.90 % of the total Cd in the soil) occurred in the salt leachate, and a high correlation with Cl were found, indicating that Cl complexes are important for the mobilization. Conversely, only 2.34 % of the total amount of Pb in the soil was leached, confirming the usual hypotheses about the high immobility of Pb in soils. However, it was found that high Pb concentration coincided with peaks in Fe and TOC concentrations, and the proportion of Pb in the >0.45 µm phase was much low, which implied an extensive Pb mobilization with small-sized colloids.

Oil-degrading strains were domesticated and enriched using the medium recycling method. Then the microorganisms were used in bioremediation of oil-contaminated soil from Daqing Oilfield, China. The laboratory study showed that the addition of enhanced microorganism and medium can make the oil degrading efficiency reach to more than 90% after 150 days degradation. The activity of the predominant microorganism could be measured by the test of TTC- dehydrogenase, which reached the maximum value at day 30 and then declined with the drop of oil content. The GC-MS analysis of the oil-contaminated soil showed that the most components in oil were among C10-C36. From the gas chromatograph analysis of the carbon chains during the degradation, every oil composition was degraded obviously after 150 days and the molecule chains longer than 28 C nearly disappeared. The field study in Daqing Oilfield was affected by air temperature and after 300 days treatment, 80-93% of degrading efficiency was obtained.

With Carassius auratus, one of the main economic fish species in Eastern China as test material, this paper studied the hydroxyl radical generation and oxidative stress in its liver under the effect of 2,4,6-trichlorophenol (2,4,6-TCP). Different doses of 2,4,6-TCP were injected intraperitoneally into the fishes, and the Electron paramagnetic resonance (EPR) spectra of hepatic free radicals, activities of superoxide dismutase (SOD), catalase (CAT) and glutathione-s-transferase (GST), levels of reduced glutathione (GSH) and oxidized glutathione (GSSG), and malondialdehyde (MDA) contents were determined 24 h after injection. The results showed that under the effects of 2,4,6-TCP, the generation of free radical that was considered to be hydroxyl radical increased significantly, the activities of antioxidant enzymes decreased, with CAT most strongly affected and followed by SOD and GST, the GSH level decreased significantly while GSSG level had little difference, resulting in a decreased GSH/GSSG ratio, and the MDA content increased significantly. All the test parameters showed that C. auratus was subjected to oxidative stress and damage when exposed to 2,4,6-TCP.