Biochar-mediated regulation of greenhouse gas emission and toxicity reduction in bioremediation of organophosphorus pesticide-contaminated soils

Organophosphorus pesticides(OPPs) are a set of toxic persistent organic pollutants(POPs) present in the environment. Recently, biochar-mediated bioremediation has exhibited many advantages over conventional methods for the remediation of pesticide-contaminated soil. In the present study, biochar and nitrogen fertilizer(NH_4NO_3)were employed to remediate OPP-contaminated soil and the greenhouse gas(GHG) emission during 90 days of incubation was investigated. After thermal desorption treatment, the content of organophosphorus pesticides reduced from 175.61 μg·kg^(-1) to 62.68 μg·kg^(-1). The addition of NH_4NO_3 in the following bioremediation led to larger reduction(34.35%) of the pesticide concentration than that of biochar(31.90%) for the contaminated soils with thermal desorption treatment, while the simultaneous addition of biochar and NH_4NO_3 led to the largest reduction of pesticide concentration(11.07%) for the soil without thermal desorption treatment. The addition of biochar and NH_4NO_3 only slightly increased the emission rate of GHGs from the soil without thermal treatment,but remarkably increased the emission rate of GHGs from the soil after thermal treatment. In most cases, the addition of NH_4NO_3 is more effective than biochar to promote the degradation of pesticide, but also exhibited higher GHG emission. The microbial community analysis suggests that the enhanced degradation of pesticide is mainly owing to the increased activity of microorganism.

Toxic effects of crude-oil-contaminated soil in aquatic environment on Carassius auratus and their hepatic antioxidant defense system

Under the indoor simulant conditions, toxic effects of crude-oil-contaminated soil which was put into aquatic environment on the young fishes Carassius auratus and their hepatic antioxidant system after a 20-d exposure were investigated. Results showed that the relationship between the mortality of C. auratus and the exposed doses could be divided into 3 phases： fishes exposed to the low dose groups （0.5-5.0 g/L） were dead due to the ingestion of crude-oil-contaminated soils in aquatic environment; at the medium dose groups （5.0-25.0 g/L） fishes were dead due to the penetration of toxic substances; at the high dose groups （25.0-50.0 g/L） fishes were dead due to environmental stress. The highest mortality and death speed were found in the 1.0 g/L dose group, and the death speed was sharply increased in the 50.0 g/L dose group in the late phase of exposure. The activities of superoxide dismutase （SOD）, catalase （CAT） and glutathione S-transferase （GST） and the content of malaondialdehyde （MDA） in the hepatic tissues of C. auratus were induced significantly. The activity of SOD was increased and then decreased. It was significantly inhibited in the 50.0 g/L dose group. The activity of CAT was highly induced, and restored to a level which is little more than the control when the exposed doses exceeded 10.0 g/L. The activity of GST was the most sensitive, it was significantly induced in all dose groups, and the highest elevation was up to 6 times in the 0.5 g/L dose group comparing with the control. The MDA content was significantly elevated in the 50.0 g/L dose group, and the changes of the MDA content were opposite with the changes of GST activity.

Horizontal distribution and levels of heavy metals in the biggest snowstorm in a century in Shenyang,China

The horizontal distribution and levels of heavy metals in the biggest snowstorm in Shenyang since 1904 were investigated by analyzing 4 metals (As,Cd,Pb,and Cu) in a series of ultraclean samples collected from 17 sites distributed in different regions of the Shenyang area,China.The results showed that the concentrations of all the 4 heavy metals in snow from the industrial regions were high,up to 7.3 (As),2.2 (Cd),850.0 (Pb),and 0.197-20.2 (Cu)μg/kg,respectively.In the suburb,in contrast,their concentration...

Culture techniques and growth characteristics of Dinophysis acuminata and its prey

The dinoflagellate Dinophysis acuminata Claparede & Lachmann is a toxic alga that causes diarrhetic shellfish poisoning.No Dinophysis species were maintained in culture for a long period of time until 2006 when Park successfully established D.acuminata in culture using a three-step feeding protocol in which the cryptophyte,Geminigera cryophila,is fed to Myrionecta rubra(=Mesodinium rubrum),a ciliate that is in turn fed to D.acuminata.In this paper,we present the details of culturing D.acuminata from the Northeastern United States.The protocols described herein can be adopted for laboratory studies of this species.The effects of temperature on the growth and ingestion rates of D.acuminata were also examined.The results show that D.acuminata growth rate was 0.23 /d at 10°C and 0.11 /d at 4°C when fed M.rubra prey.The maximum prey ingestion rate was 2.80 Dinophysis cell/d at 10°C,although the rate decreased slightly at 4°C.In overall,temperature showed a greater influence on growth rate of D.acuminata than on the ingestion rate under the study conditions,and the quantity of available food was also an important regulator to D.acuminata growth.

Conversion relationships between environmental quality criteria of water/air and soil

The conversion study on the environmental quality criteria between water/air and soil is the need to carry out research on soil-environmental quality standards in an all-round way, and also the demand for solving emerging problems in this field using the system dynamic and the overall view. Carrying out this study is of practical significance and theoretical values in the face of formulation and revision of soil-environmental quality standards in China. Firstly, the theoretical basis and relative models of soil-water and soil-air systems were expounded, respectively. And on this basis, a preliminary conceptual model about the conversion was constructed. After that, the current worldwide environmental quality criteria/standards for soil, water and air media were introduced based on their types, concerned pollutants and hierarchical classification, and their variation were also analyzed briefly. Particularlly, the key points for the conversion of environmental quality criteria between soil and water and/or between soil and air were discussed, respectively, while combined with the relative researching results. Finally, this conversion study was commented and prospected.

Vertical response of microbial community and degrading genes to petroleum hydrocarbon contamination in saline alkaline soil

A column microcosm was conducted by amending crude oil into Dagang Oilfield soil to simulate the bioremediation process. The dynamic change of microbial communities and metabolic genes in vertical depth soil from 0 to 80 cm were characterized to evaluate the petroleum degradation potential of indigenous microorganism. The influence of environmental variables on the microbial responds to petroleum contamination were analyzed. Degradation extent of 42.45% of n-alkanes(C8–C40) and 34.61% of 16ΣPAH were reached after 22 weeks. Relative abundance of alkB, nah, and phe gene showed about 10-fold increment in different depth of soil layers. Result of HTS profiles demonstrated that Pseudomonas, Marinobacter and Lactococcus were the major petroleum-degrading bacteria in0–30 and 30–60 cm depth of soils. Fusarium and Aspergillus were the dominant oil-degrading fungi in the 0–60 cm depth of soils. In 60–80 cm deep soil, anaerobic bacteria such as Bacteroidetes, Lactococcus, and Alcanivorax played important roles in petroleum degradation.Redundancy analysis(RDA) and correlation analysis demonstrated that petroleum hydrocarbons(PHs) as well as soil salinity, clay content, and anaerobic conditions were the dominant effect factors on microbial community compositions in 0–30, 30–60, and 60–80 cm depth of soils, respectively.

Graphitic carbon nitride/biochar composite synthesized by a facile ball-milling method for the adsorption and photocatalytic degradation of enrofloxacin

In order to enhance the removal performance of graphitic carbon nitride(g-C_(3)N_(4)) on organic pollutant, a simultaneous process of adsorption and photocatalysis was achieved via the compounding of biochar and g-C_(3)N_(4). In this study, g-C_(3)N_(4) was obtained by a condensation reaction of melamine at 550 °C. Then the g-C_(3)N_(4)/biochar composites were synthesized by ball milling biochar and g-C_(3)N_(4) together, which was considered as a simple, economical, and green strategy. The characterization of resulting g-C_(3)N_(4)/biochar suggested that biochar and g-C_(3)N_(4) achieved effective linkage. The adsorption and photocatalytic performance of the composites were evaluated with enrofloxacin(EFA) as a model pollutant. The result showed that all the g-C_(3)N_(4)/biochar composites displayed higher adsorption and photocatalytic performance to EFA than that of pure g-C_(3)N_(4). The 50% g-C_(3)N_(4)/biochar performed best and removed 45.2% and 81.1% of EFA(10 mg/L) under darkness and light with a dosage of 1 mg/mL, while g-C_(3)N_(4) were 19.0% and 27.3%, respectively. Besides, 50% g-C_(3)N_(4)/biochar showed the highest total organic carbon(TOC) removal efficiency(65.9%). Radical trapping experiments suggested that superoxide radical( ·O_(2)^(-)) and hole(h~+) were the main active species in the photocatalytic process. After 4 cycles, the composite still exhibited activity for catalytic removal of EFA.

Treatment and remediation of a wastewater lagoon using microelectrolysis and modified DAT/IAT methods

To examine treatment and remediation of a wastewater lagoon with poor biodegradability, a typical wastewater lagoon in Tianjin, China, was treated and remedied using microelectrolysis and modified demand aeration tank （DAT）/intermittent aeration tank （IAT） methods. After pretreatment by microelectrolysis, the removal efficiency of chemical oxygen demand （COD） was up to 64.6% and the ratio of BOC/COD in the effluent increased from 0.013 to 0.609. The removal rates of CODcr and NH4＋-N were affected by sludge backflow rate, mixed liquor suspended solids （MLSS）, and hydraulic retention time （HRT） in the modified DAT/IAT reactor. The highest removal rates of CODcr and NH4＋-N were up to 78.9% and 62.6%, respectively, when the sludge backflow rate was 38.0 mL/min, the total HRT was 8.0 hr and MLSS was 4088.0 mg/L. In this case, some protozoa and metazoa were observed in activated sludge and biofilm carriers. Most of chrominance was removed by microelectrolysis treatment, while the modified DAT/IAT methods were more effective for CODcr and NH4＋-N removal.

Joint effects of Penta-BDE and heavy metals on Daphnia magna survival,its antioxidant enzyme activities and lipid peroxidation

The joint toxicity of Penta-BDE(Pe-BDE)and heavy metals including cadmium and copper on Daphnia magna(D.magna)was evaluated on the basis of determining the 48 h survival,antioxidative enzyme responses,and lipid peroxidation.The response was classified as additive,greater than additive,or less than additive by comparing the measured“toxic units,TU”with one.Based on the survival of D.magna,less-than-additive interactions were found in most of mixtures treatments.This may be attributed to the different toxicity mechanism between Pe-BDE and metals.Cu and Cd played a greater role in toxicity than what Pe-BDE did.As for the superoxide dismutase(SOD)and catalase(CAT)activity,most response was less than additive.For the glutathione S-transferases(GST)activity,most of the greater-thanadditive responses were found in the Cu plus Pe-BDE treatments,but the additive responses occurred in Cd plus Pe-BDE treatments and binary metal treatments.For lipid peroxide levels,which were measured as malondialdehyde(MDA)levels,less-than-additive response occurred in the 50%Cd plus 50%Cu and ternary mixture treatments.Results suggested that Pe-BDE,Cd,and Cu could induce different patterns of antioxidant enzyme responses,such as antioxidant/prooxidant responses,depending on their capability to produce reactive oxygen species and antioxidant enzymes to detoxify them.

The effect of capping with natural and modified zeolites on the release of phosphorus and organic contaminants from river sediment

A microcosm system that included river sediment,water and different zeolite capping materials(natural zeolite,surfactant-modified zeolite(SMZ),or aluminum modified zeolite(AMZ))was designed to study the effect of capping on the release of phosphorus and three organic pollutants(phenol,pyridine,and pyrene)from the sediment to the overlying water over the course of three month.For the same amount of the three capping materials,the efficiency of phosphorus inactivation was in the order of SMZ>AMZ>natural zeolite.The inactivation of phosphorus was mainly caused by the covering effect,co-precipitation and adsorption by the capping materials.The different zeolites gave different results for the release of phenol,pyridine,and pyrene from the sediment.When natural zeolite was used as the capping material,there was no effect on the release of pyrene and pyridine,whereas capping the sediment with SMZ or AMZ inhibited the release of pyrene and pyridine but to different extents.However,for controlling the release of phenol from the sediment,aluminum modified zeolite was the most efficient material,whereas no effects were observed when natural zeolite or SMZ were used.The different capabilities of the zeolite materials for controlling the release of different organic pollutants are related to the differences in the electrical properties of these pollutants.

Single and joint effects of HHCB and cadmium on zebrafish （Danio rerio） in feculent water containing bedloads

As an important type of emerging pollutants, ecological toxicity and risk of artificial musks are increasingly concerned. Thus, single and joint toxic effects of 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8- hexamethylcyclopenta-gamma-2-benzopyran （HHCB） as one of the most widely applied artificial musks and cadmium （Cd） as an toxic metal on zebrafish （Danio rerio） were investigated by the exposure of zebrafish to various concentrations of HHCB or/and Cd in feculent water containing bedloads. The results indicated that the joint effect of HHCB and Cd changed during different exposure times within 120 h. The index of the antioxidant enzyme system including superoxide dismutase （SOD） and perox- idase （POD）, and malondialdehyde （MDA） were sensitive and induced in the zebrafish stressed by Cd, and content of soluble protein （SP） was sensitive to HHCB and could be used as a biomarker for HHCB. Joint effects on antioxidant enzymes depended more on the effect of single Cd in the first one or two days. However, in the rest exposure days, the effect of HHCB began to dominate in the joint effect during the exposure process.

Integration of Chemical Methods and Biomarkers for Assessment of Chlorimuron-Ethyl Bioavailability in Soil

Bioavailability is a critical factor for assessing the environmental risk of organic pollutants in soil. In this study, extractions with 3 different solvents, including 2 aqueous solutions, calcium chloride(CaCl_2) and a phosphate buffer solution(PBS), and a mixture of aqueous solution and organic solvent, a PBS-methanol(8:2,volume/volume) mixture(PBS-M), were performed to assess the bioavailability of chlorimuron-ethyl in soil in comparison to a battery of toxicity tests in wheat seedlings. The results indicated that the peroxidase(POD) activity in wheat leaves after 7 d of exposure was one of the sensitive biomarkers of chlorimuron-ethyl in soil.The extractability of chlorimuron-ethyl by all the 3 solvents decreased with exposure time, and the rate of decrease of the PBS-M extraction between 1 and 7 d of exposure was substantially higher than those of the aqueous solution extractions. Chlorimuron-ethyl gradually changed from a water-soluble form into a soil organic matter(SOM)-bound form in the soil. The PBS extraction correlated best with the POD activity in the leaves after 7 d of exposure.

Soil bacterial communities respond differently to graphene oxide and reduced graphene oxide after 90 days of exposure

Graphene-based nanomaterials(GBNs)are likely to be entering the soil environment in increasing amounts via consumer products.However,the disturbance of bacterial communities and their associated ecological functions by GBNs remains elusive.We performed a soil incubation experiment with the addition of graphene oxide(GO)and reduced graphene oxide(RGO).The Illumina sequencing technique was used to investigate changes in bacterial communities,and the functional groups of the communities were analyzed using the functional annotation of prokaryotic taxa database.After 90 days of exposure,RGO induced a lower bacterial richness than GO.However,GO induced larger changes in community composition and functions than RGO.After exposure to GBNs,some of the functional groups associated with organic matter degradation and biogeochemical cycling of nitrogen and sulfur decreased.However,the functional group associated with aromatic compound degradation increased,possibly because GBNs contain rich aromatic hydrocarbon structures,which are tolerated by this functional group.

Degradation of some typical pharmaceuticals and personal care products with copper-plating iron doped Cu_2O under visible light irradiation

A mixture of five commonly used pharmaceuticals and personal care products （PPCPs） was degraded using a new combined catalyst under visible light irradiation. Scanning electron microscopy and X-ray diffraction analysis revealed that the combined catalyst was composed of copper-plating iron doped Cu2O （FeCu/Cu2O）. Compared with the Fe/C inner micro-circuit, the electric currents flowing between Cu and Fe increase the speed of anodic Fe dissolution. Moreover, due to the photochemical properties, Cu2O can accelerate the PPCPs degradation processes under the irradiation of visible light. In addition, shaking increased the dissolved oxygen concentration in the solution, which not only preconditioned the photo-catalysis reaction, but also set the stage for Fe reduction. According to the experimental results, we propose the possible reaction mechanism of the reaction.

High pyrolysis temperature biochar reduced the transport of petroleum degradation bacteria Corynebacterium variabile HRJ4 in porous media

Biochar has been widely applied for the remediation of petroleum-contaminated soil.However,the effect of biochar on the transport of petroleum degradation bacteria has not been studied.A typical Gram-positive petroleum degradation bacteria-Corynebacterium variabile HRJ4 was used to study the effect of different biochars on bacterial transport and retention.Results indicated that the addition of biochar in sand was effective for reducing the transport of bacteria and poplar sawdust biochar(PSBC)had a stronger hinder effect than corn straw biochar(CSBC).The hindrance was more evident with pyrolysis temperature of biochar raised from 300℃ to 600℃,which was attributed to the increase of specific surface area(309 times).The hindrance effect also enhanced with higher application rate of biochar.Furthermore,the reduction of HRJ4 transport was more obvious in higher(25 mmol/L)concentration of Na Cl solution owing to electrostatic attraction enhancement.The adsorption of biochar to HRJ4 was defined to contribute to the hindrance of HRJ4 transport mainly.Combining the influence of feedstocks and pyrolysis temperature on HRJ4 transport,it suggested that specific surface area had the greatest effect on HRJ4 transport,and pore-filling,electrostatic force also contributed to HRJ4 retained in quartz sand column.At last,phenol transportation experiment indicated that the restriction of biochar on HRJ4 enhanced the phenol removal rate in the column.This study provides a theoretical basis for the interaction of biochar and bacteria,which is vital for the remediation of oil-contaminated soil and groundwater in the field.

Modeling effects of a tidal barrage on water quality indicator distribution in the Severn Estuary

在这研究，强调集中了于越过 Severn 河口估计一个堰坝的潜在的水疗院环境的影响，与被开发并且适用于估计在河口以内的水动力学，沉积运输和排泄物的指示物有机体分发上的建议 Severn 堰坝的影响的河口的一个数字模型一起。结果证明 Severn 堰坝有潜力在一个高度有活力的河口减少潮汐的水流。这导致推迟的沉积集中的减小，它接着与沉积运输过程有关高度影响是的细菌的运输过程。

A novel bioremediation strategy for petroleum hydrocarbon pollutants using salt tolerant Corynebacterium variabile HRJ4 and biochar

The present work aimed to develop a novel strategy to bioremediate the petroleum hydrocarbon contaminants in the environment.Salt tolerant bacterium was isolated from Dagang oilfield,China and identified as Corynebacterium variabile HRJ4 based on 16 S r RNA gene sequence analysis.The bacterium had a high salt tolerant capability and biochar was developed as carrier for the bacterium.The bacteria with biochar were most effective in degradation of n-alkanes（C16,C18,C19,C26,C28） and polycyclic aromatic hydrocarbons（NAP,PYR） mixture.The result demonstrated that immobilization of C.variabile HRJ4 with biochar showed higher degradation of total petroleum hydrocarbons（THPs） up to 78.9%after 7-day of incubation as compared to the free leaving bacteria.The approach of this study will be helpful in clean-up of petroleum-contamination in the environments through bioremediation process using eco-friendly and cost effective materials like biochar.

选择性降解污染物和资源化的电芬顿水处理技术

Since Brillas et al.[1]first proposed electro-Fenton(EF)technology as one of the advanced oxidation processes(AOPs)in 1996,there has been a great deal of development and progress in this research area in electrode materials preparation,catalysts development,reactor design,and process coupling with other technology[2].Owing to the advantages of efficient performance,low cost,and easy operation,EF has become one of the most promising water/wastewater treatment technologies.The judicious selection of electrode materials is crucial in the electrochemical remediation of pollutants.