南通市人为源大气氨排放清单及特征

根据收集的南通市各类人为氨排放源的活动水平数据,采用合理的估算方法和排放因子,估算了2009年南通市的人为源大气氨排放量。结果表明,2009年南通市人为源大气氨排放量为60.02 kt,其中,畜禽源和氮肥使用是两个最大排放源,氨排放量分别为31.54 kt和23.43 kt,分别占南通市大气氨排放总量的52.5%和39.0%。畜禽源中生猪是NH3排放最大贡献源,占畜禽源排放总量的46.4%,其次是家禽,其贡献率为36.4%。南通市氨平均排放强度为6.59 t.km-2.a-1。     

珠江三角洲人为氨源排放清单及特征

根据收集的珠江三角洲(珠三角)人为氨源的活动水平数据,采用合理的估算方法和排放因子,建立了该地区2006年人为氨源分类别和分城市的排放清单.结果表明:①2006年珠三角地区人为氨源NH3排放总量约为194.8kt;②农业源是珠江三角洲地区人为氨源的主要排放贡献源,其中畜禽源排放的NH3占总排放量的62.1%,其次是氮肥施用源,其贡献率为21.7%;③畜禽源中肉鸡是NH3排放最大贡献源,占畜禽源NH3排放总量的43.4%,其次是肉猪,其贡献率为32.1%;④广州是珠三角地区2006年人为氨源排放量最大的城市,其次是江门,分别占NH3总排放量的23.4%和19.1%,主要的排放源均为畜禽和氮肥施用源.     

西安市人为源大气氨排放清单及特征

根据西安市各类氨排放源活动水平数据,采用合理的估算方法和排放因子,建立了2013年西安市人为源大气氨排放清单.结果表明,2013年西安市人为源大气氨排放量为47.17×10~3t,排放强度为4.57 t·km~(-2);畜禽养殖和氮肥施用是排放贡献最大的两个人为源,氨排放量分别为20.55×10~3t和17.51×10~3t,占排放总量的80.68%;畜禽养殖中,牛和猪是最大的排放源,占畜禽养殖排放总量的75.03%;临潼区是排放量最大行政区,排放量为10.73×10~3t,分担率为23.22%;阎良区的排放强度最大,达到14.75 t·km~(-2).     

长江三角洲地区人为源氨排放清单及分布特征

根据各类氨排放源的活动水平和排放因子,估算了2004年长江三角洲地区16个城市的氨排放量.结果表明,2004年长三角地区氨排放量为460.68kt,其中,氮肥使用和畜牧源是两个最大排放源,氨排放量分别为227.33kt和203.28kt,分别占长江三角洲地区氨排放总量的49.3%和44.1%,氨排放在长三角地区各城市间有较大差异,排放量超过40kt·a-1的城市为南通市、上海市、嘉兴市和泰州市,这4个城市的氨排放总量约占长三角地区氨排放量的42.5%.长江三角洲地区氨平均排放强度为4.20t·km-2·a-1,排放强度超过6t·km-2·a-1的城市为嘉兴市、南通市、泰州市和上海市,其中,嘉兴市的排放强度最大,为10.83 t·km-2·a-1.     

2013～2017年江苏省人为源氨排放清单的建立及特征

根据江苏省各类氨排放源活动水平数据,采用合理的清单测算方法和排放因子,建立了2013～2017年江苏省人为源氨排放清单,对其历年来人为源氨排放量的变化趋势进行分析.利用Arc GIS软件对江苏省人为源氨排放量及排放强度的分布特征进行分析.结果表明,江苏省的氨排放量由2013年的624. 84 kt减少至2017年的562. 47 kt,年均下降率约为2. 6%.农业源一直是江苏省最主要的氨排放源,2017年时占江苏省氨排放总量的82. 4%;蛋鸡是畜禽养殖源中最大的氨排放源,占畜禽源氨排放量的49. 3%. 2017年江苏省氨平均排放强度为5. 3 t·km~(-2),其中盐城市和徐州市是江苏省人为源氨排放量和排放强度最大的两个城市,镇江市的氨排放量和排放强度最小.     

红河州人为源氨排放清单及分布特征

根据收集的红河州各类人为源氨排放活动水平数据和排放因子,建立了2017年红河州人为源氨分类别和县市排放清单。结果表明,2017年红河州人为氨源排放总量为93. 21kt,其中农田生态系统、畜牧养殖业和其它源排放量分别为10. 43kt、71. 18kt和11. 6kt,畜牧养殖业是红河州氨排放的主要来源,占排放总量的73. 37%。弥勒市、建水县和泸西县是红河州氨排放量最大的3个县市,排放量为36. 57kt,排放份额占红河州总排放量的39. 23%,排放量最小的是河口县为0. 85kt,仅占全州的0. 91%。红河州的氨排放强度为3. 0t/km2·a-1,泸西县是氨排放强度最大县市,高达6. 8t/km2·a-1。     

浙江省人为源氨排放清单建立及分布特征

通过收集各类氨排放源的活动水平数据,选取合适的排放因子以及估算方法,建立了2017年浙江省人为源氨排放清单,分析各排放源的排放分摊率以及浙江省各市的排放情况,并利用ArcGIS对浙江省氨排放量和排放强度的空间分布进行分析.结果表明, 2017年浙江省人为源氨排放量为122.00 kt,以农业源排放为主,其中农田生态系统氨排放量最高,达到36.06 kt,并以氮肥施用贡献最大(87.12%);其次是禽畜养殖,占到人为源氨排放总量的29.44%.非农业源中废物处理和人体排放源贡献最大,分别占到非农业源氨排放量的44.07%和28.49%. 2017年杭州市氨排放量最高,占浙江省氨排放总量的17.83%;但嘉兴市的氨排放强度最大,达到3.82 t·km~(-2).从空间分布来看,氨排放量主要集中在浙江省北部和东南部,而浙江省北部和东北部的氨排放强度相对较高.     

四川省2012年人为源氨排放清单及分布特征

根据收集到的各类人为氨源的活动水平数据,采用合理的估算方法和排放因子,建立了四川省2012年人为源氨排放清单,并分析了氨排放的空间分布特征.结果表明:四川省2012年人为源氨排放总量为994.8×103t,排放强度为2.12 t·km-2;畜禽养殖为最主要的排放源,分担率达62.31%,其次为氮肥施用,分担率为23.14%;生猪和牛是畜禽养殖中主要贡献者,共占畜禽排放总量的64%;成都市和达州市为氨排放量较大的城市,均占四川省排放总量的10%;空间分布特征显示排放量较大的网格主要集中在四川省东部,且多来自于城市周边区县.     

广东省人为源氨排放清单及减排潜力研究

根据各类氨排放源活动水平数据,采用排放因子法,建立了2010年广东省人为源氨排放清单,在分析其排放特征的基础上探讨了氨的减排潜力.结果表明:2010年广东省人为源氨排放量为582.9 kt,畜禽和氮肥施用是排放贡献最大的人为源,分别占总排放量的44.2%和40.4%;茂名、湛江和肇庆依次是排放量最大的3个城市,共占广东省总排放量33.0%;在畜禽源中,肉猪排放量最大,占畜禽源排放总量44.4%,其次是肉鸡、母猪和黄牛,分别占16.0%、15.2%和6.5%;畜禽在畜舍、储存管理、农田施肥和放牧4个养殖阶段的氨排放量不同;控制农业源对NH3的减排起关键性作用,茂名、湛江和肇庆是广东省重点控制的3个城市,肉猪、母猪、肉鸡、黄牛和氮肥施用则为重点控制源,主要控制措施包括低氮饲料喂养、畜舍改造、粪便密封、粪肥注施、延长放牧时间和使用尿素替代物.     

贵阳地区氨排放量估算

根据氨的不同排放源和排放因子,对贵阳地区2006年氨排放总量进行了估算。结果表明:贵阳地区氨排放总量为72.6kt,其中99.85%来自人为源排放,仅0.15%为自然源排放;在人为源中主要以家畜排放为主,排放量为27.8kt,占总排放量的38.30%;其次为燃煤排放,排放量为23.4kt,占32.26%。贵阳地区氨的排放强度达9.04t/km2,比中国和国外其他地区高,人均排放量达20.57kg/人,虽然与欧洲人均排放量接近,但比其他地区高很多;贵阳地区氨的排放与日本相似,都是以能源和动物排放为主,与中国和国外其他地区均不同,这可能跟贵阳特殊的地理条件和能源结构有关。     

Evaluation of phytoextracting cadmium and lead by sunflower, ricinus, alfalfa and mustard in hydroponic culture

Soil contaminated with heavy metals cadmium(Cd)and lead(Pb)is hard to be remediated.Phytoremediation may be a feasible method to remove toxic metals from soil,but there are few suitable plants which can hyperaccumulate metals.In this study,Cd and Pb accumulation by four plants including sunflower(Helianthus annuus L.),mustard(Brassica juncea L.),alfalfa(Medicago sativa L.), ricinus(Ricinus communis L.)in hydroponic cultures was compared.Results showed that these plants could phytocxtract heavy metals, the ability of accumulation differed with species,concentrations and categories of heavy metals.Values of BCF(bioconcentration factor)and TF(translocation factor)indicated that four species had dissimilar abilities of phytoextraction and transportation of heavy metals.Changes on the biomass of plants,pH and Eh at different treatments revealed that these four plants had distinct responses to Cd and Pb in cultures.Measurements should be taken to improve the phytoremediation of sites contaminated with heavy metals,such as pH and Eh regulations,and so forth.     

Oxidation of As(Ⅲ) by potassium permanganate

The oxidation of As(Ⅲ) with potassium permanganate was studied under conditions including pH, initial As(Ⅲ) concentration and dosage of Mn(Ⅶ). The results have shown that potassium permanganate was an effective agent for oxidizing of As(Ⅲ) in a wide pH range. The pH value of tested water was not a significant factor affecting the oxidation of As(Ⅲ) by Mn(Ⅶ). Although theoretical redox analyses suggest that Mn(Ⅶ) should have better performance in oxidization of As(Ⅲ) within lower pH ranges, the experimental results show that the oxidation efficiencies of As(Ⅲ) under basic and acidic conditions were similar, which may be due to the adsorption of As(Ⅲ) on the Mn(OH)2 and MnO2 resulting from the oxidation of As(Ⅲ).     

Chlorobenzenes in waterweeds from the Xijiang River （Guangdong section） of the Pearl River

The Xijiang River is the major source of water for about 4.5 millions of urban population and 28.7 millions of rural population. The water quality is very important for the health of the rural population. The concentration and distribution of chlorobenzenes (CBs) in both water and waterweeds collected from 4 stations in the Xijiang River (Gangdong section) of the Pearl River in April and November were determined. The result showed that nearly every congener of CBs was detected. The total contents of CBs (∑CBs) in the river water ranged from 111.1 to 360.0 ng/L in April and from 151.9 to 481.7 ng/L in November, respectively. The pollution level of CBs in the water in April was higher than that in November. The contents of ∑ CBs in waterweeds ranged from 13.53×102 μg/g to 38.27×102μg/g dry weight (dw). There was no significant difference between April and November in waterweeds. The distribution of CBs in roots, caulis, and leaves of Vallisneria spiralis L. showed different patterns. The leaves mainly contained low-molecular-weight CBs(DCBs), whereas the roots accumulated more PCBs and HCBs. The average lgBCFlip (bioconcentration factor) of CBs ranged from 0.64 to 3.57 in the waterweeds. The spatial distribution character of CBs in the Xijiang River was: Fengkai County ＜ Yunan County ＜Yun'an County ＜ Gaoyao County according to the ∑CBs, and the pollution deteriorated from the upstream to the downstream of the Xijiang River. Further analysis demonstrated that the discharge of waste containing CBs may be the main source of CBs pollution in the Xijiang River.     

Degradation of 2,4-dichlorophenol with a novel TiO2/Ti-Fe-graphite felt photoelectrocatalytic oxidation process

Degradation of 2,4-dichlorophenol(2,4-DCP)was studied in a novel three-electrode photoelectrocatalytic(PEC)integrative oxidation process,and the factors influencing the degradation rate,such as applied current,flow speed of O_2,pH,adscititious voltage and initial 2,4-DCP concentration were investigated and optimized.H_2O_2 was produced nearby cathode and Fe~(2 )continuously generated from Fe anode in solution when current and O_2 were applied,so,main reactions,H_2O_2-assisted TiO_2 PEC oxidation and E-Fenton reaction,occurred during degradation of 2,4-DCP in this integrative system.The degradation ratio of 2,4-DCP was 93% in this integrative oxidation process,while it was only 31% in E-Fenton process and 46% in H_2O_2-assisted TiO_2 PEC process.So,it revealed that the degradation of 2,4-DCP was improved greatly by photoelectrical cooperation effect.By the investigation of pH,it showed that this integrative process could work well in a wide pH range from pH 3 to pH 9.     

Effect of copper on the degradation of pesticides cypermethrin and cyhalothrin

The influence of coexisting copper (Cu) ion on the degradation of pesticides pyrethroid cypermethrin and cyhalothrin in soil and photodegradation in water system were studied.Serial concentrations of the pesticides with the addition of copper ion were spiked in the soil and incubated for a regular period of time,the analysis of the extracts from the soil was carried out using gas chromatography (GC).The photodegradation of pyrethroids in water system was conducted under UV irradiation.The effect of Cu~(2 ) on the pesticides degradation was measured with half life (t_(0.5)) of degradation.It was found that a negative correlation between the degradation of the pyrethroid pesticides in soil and Cu addition was observed.But Cu~(2 ) could accelerate photodegradation of the pyrethroids in water.The t_(0.5) for cyhalothrin extended from 6.7 to 6.8 d while for cypermethrin extended from 8.1 to 10.9 d with the presence of copper ion in soil.As for photodegradation,t_(0.5) for cyhalothrin reduced from 173.3 to 115.5 rain and for cypermethrin from 115.5 to 99.0 min.The results suggested that copper influenced the degradation of the pesticides in soil by affecting the activity of microorganisms.However, it had catalyst tendency for photodegradation in water system.The difference for the degradation efficiency of pyrethroid isomers in soil was also observed.Copper could obviously accelerate the degradation of some special isomers.     

Effects of arsenic on seed germination and physiological activities in wheat seedlings

The effects of arsenic(As)were investigated on seed germination,root and shoot length and their biomass and some other factors to elucidate the toxicity of As.The results showed low concentrations of As(O-1 mg/kg)stimulated seed germination and the growth of root and shoot,however,these factors all decreased gradually at high concentrations of As(5-20 mg/kg).The contents Of O2-,MDA,soluble protein and peroxidase(POD)activity all increased with increasing As concentrations.Soluble sugar content,ascorbate peroxidase(APX),and superoxide dismutase(SOD)activities decreased at low concentrations of As,and increased at high concentrations of As.While acetylsalicylic acid(ASA)and chlorophyll contents,catalase(CAT)activity displayed increasing trend when the concentrations of As was lower than 1 mg/kg,and then decreasing trend.By polyacrylamide gel electrophoresis(PAGE).As induced the expression of POD isozymes of wheat seedlings.As induced the expression of CAT isozymes but inhibited the expression of SOD isozymes of wheat seedlings at concentrations lower than 1 mg/kg.However,As inhibited the expression of CAT isozymes but induced the expression of SOD isozymes at concentrations higher than 5 mg/kg.The results indicated As could exert harmfulness in the early development stage of wheat at inappropriate concentrations.     

Bioconcentration kinetics of PCBs in various parts of the lifecycle of the tadpoles Xenopus laevis

Polychlorinated biphenyls （PCBs） in Xenopus laevis have been reported only for a few congeners. Additionally, there is very little information on the ability of Xenopus laevis to bioconcentrate PCBs. To address these issues, the tadpole Xenopus laevis was exposed to Aroclor 1254 mixtures in water at room temperature for 110 d followed by an additional 110 d of nonspiked PCBs in the water for the control group. During the whole process, bioconcentration factors （BCFs） of PCBs ranged from 1180 to 15670. For most PCB congeners, the highest and lowest bioconcentrations of the kinetic curves were found to be remarkably simultaneous, respectively. All 141 PCB congeners under the same experimental conditions had no linear correlation on the lgBCF versus lgKow relationship. The relationship between lgBCFs and lgKow followed a parabolic pattern indicative of selective bioconcentration, suggesting that the kinetic curves of the PCB congeners observed in the lifecycle of the tadpoles may be concentrated due to the amphibian special species and internal metabolism. In contrast, lgBCFs for PCBs were inversely related to lgKow, suggesting that a metabolism of the higher Kow PCB congeners occurred. These results support the author＇s conclusion that the tadpole Xenopus laevis plays major roles in the bioconcentration of PCB congeners, and demonstrated that the exposure kinetic curves of PCB congeners are complex. Besides the amphibian metamorphous development, the lifecycle of the tadpole Xenopus laevis also may be of importance in determining the bioconcentration of PCB congeners.     

Sustainability： A view from the wind-eroded field

This article explores the assessment of sustainability in fields subject to wind erosion. In the first part, simple sustainability audits are examined, as of soil depth and nutrients. Direct measurement of these characteristics has many problems, largely because of huge variability in space and time at all scales. Modelling still has its problems, but it may be possible to overcome many of them soon. It is true that wind erosion preferentially removes soil nutrients, but there are imponderables even here. The nutrient balance in many of these soils includes considerable input from dust. In West Africa, it has been shown that the amounts of calcium and potassium that are added in dust are sufficient to fertilize dispersed crops. In mildly acidic sandy soils, such as those found on the widespread palaeo- aeolian deposits, much of the phosphorus is fixed and unavailable to plants by the time it is removed by wind erosion, so that erosion has no added downside. Most of the nutrients carried by dust have been shown to travel close to the ground （even when they are attached to dust-sized particles）, and so are trapped in nearby fallow strips, and are thus not lost to the farming system. Second, the sustalnabillty of a whole semi-arid farming system is explored. Wind erosion in semi-arid areas （like China, the Sahel and Norflawestern Europe） generally takes place on aeolian deposits of the recent geological past. Most of these soils are deep enough to withstand centuries of wind erosion before they are totally lost to production, and some of these soils have greater fertility at greater depth （so that wind erosion may even improve the soil）. Finally some remarks are made about environmental change in relation to sustainability.     

Amplification of plasmid DNA bound on soil colloidal particles and clay minerals by the polymerase chain reaction

Polymerase chain reaction(PCR)was used to amplify a 600-base pair(bp)sequence of plasmid pGEX-2T DNA bound on soil colloidal particles from Brown soil(Alfisol)and Red soil(Ultisol),and three different minerals(goethite,kaolinite,montmorillonite). DNA bound on soil colloids,kaolinite,and montmorillonite was not amplified when the complexes were used directly but amplification occurred when the soil colloid or kaolinite-DNA complex was diluted,10- and 20-fold.The montmorillonite-DNA complex required at least 100-fold dilution before amplification could be detected.DNA bound on goethile was amplified irrespective of whether the complex was used directly,or diluted 10- and 20-fold.The amplification of mineral-bound plasmid DNA by PCR is,therefore,markedly influenced by the type and concentration of minerals used.This information is of fundamental importance to soil molecular microbial ecology with particular reference to monitoring the fate of genetically engineered microorganisms and their recombinant DNA in soil environments.     

Arsenic uptake and transport of Pteris vittata L. as influenced by phosphate and inorganic arsenic species under sand cu｜ture

In order to understand the similarity or difference of inorganic As species uptake and transport related to phosphorus in As-hyperaccumulator, uptake and transport of arsenate (As(Ⅴ)) and arsenite (As(Ⅲ)) were studied using Pteris vittata L. under sand culture. Higher concentrations of phosphate were found to inhibit accumulation of arsenate and arsenite in the fronds of P. vittata. The reduction in As accumulation was greater in old fronds than in young fronds, and relatively weak in root and rhizome. Moderate increases, from 0.05 to 0.3 mmol/L, in phosphate reduced uptake of As(Ⅲ) more than As(Ⅴ), while the reverse was observed at high concentrations of phosphate (≥ 1.0 mmol/L). Phosphate apparently reduced As transport and the proportion of As accumulated in fronds of P. vittata when As was supplied as As(Ⅴ). It may in part be due to competition between phosphorus and As(Ⅴ) during transport. In contrast, phosphate had a much smaller effect on As transport when the As was supplied as As(Ⅲ). Therefore, the results from present experiments indicates that a higher concentration of phosphate suppressed As accumulation and transport in P. vittata, especially in the fronds, when exposure to As(Ⅴ); but the suppression of phosphate to As transport in the root or rhizome may be insignificant when P. vittata when exposure to As(Ⅲ) under sand culture conditions. The finding will help to understand the interaction of P and As during their uptake process in P. vittata.