Temperature dependence of Henry's law constants of metolachlor and diazinon

A dynamic system based on the water/air equilibrium at the interface within the length of a microporous tube has been used to determine experimentally the Henry's law constants (HLC) of two pesticides: metolachlor and diazinon. The measurements were conducted over the temperature range 283-301 K. At 293 K, HLCs values are (42.6+/-2.8) x 10(3) (in units of M atm(-1)) for metolachlor and (3.0+/-0.3)x10(3) for diazinon. The obtained data were used to derive the following Arrhenius expressions: HLC=(3.0+/-0.4) x 10(-11) exp((10,200+/-1,000)/T) for metolachlor and (7.2+/-0.5) x 10(-15) exp((11,900+/-700)/T) for diazinon. At a cumulus cloud temperature of 283 K, the fractions of metolachlor and diazinon in the atmospheric aqueous phase are about 57% and 11% respectively. In order to evaluate the impact of a cloud on the atmospheric chemistry of both studied pesticides, we compare also their atmospheric lifetimes under clear sky (tau(gas)), and cloudy conditions (tau(multiphase)). The calculated multiphase lifetimes (in units of hours) are significantly lower than those in gas phase at a cumulus temperature of 283 K (in parentheses): metolachlor, 0.4 (2.9); diazinon, 1.9 (5.0).     

Oyster Contamination with Human Noroviruses Impacted by Urban Drainage and Seasonal Flooding in Vietnam

This study investigated the level of norovirus contamination in oysters collected at a lagoon receiving urban drainage from Hue City for 17 months (August 2015–December 2016). We also investigated the genetic diversity of norovirus GI and GII in oyster and wastewater samples by using pyrosequencing to evaluate the effect of urban drainage on norovirus contamination of oysters. A total of 34 oyster samples were collected at two sampling sites (stations A and B) in a lagoon. Norovirus GI was more frequently detected than GII (positive rate 79 vs. 41%). Maximum concentrations of GI and GII were 2.4 × 10⁵ and 2.3 × 10⁴ copies/g, respectively. Co-contamination with GI and GII was observed in 35% of samples. Norovirus GII concentration was higher at station A in the flood season than in the dry season (P = 0.04, Wilcoxon signed-rank test). Six genotypes (GI.2, GI.3, GI.5, GII.2, GII.3, and GII.4) were identified in both wastewater and oyster samples, and genetically similar or identical sequences were obtained from the two types of samples. These observations suggest that urban drainage and seasonal flooding contribute to norovirus contamination of oysters in the study area.     

生物炭施用量对紫色水稻土温室气体排放的影响

为探究生物炭施用量对紫色水稻土温室气体排放的影响,通过盆栽试验,采用静态暗箱/气相色谱法,研究了不施肥对照(CK)、常规施肥(NPK)、10 t·hm-2生物炭+NPK(LBC)、20 t·hm-2生物炭+NPK(MBC)、40 t·hm~(-2)生物炭+NPK(HBC)这5种处理下温室气体的排放规律.结果表明:(1)生物炭施用显著降低了土壤CH_4排放通量,其排放通量大小顺序为:NPKCKLBCMBCHBC,各处理CH_4排放通量均呈单峰型曲线,峰值主要集中在水稻的生长后期,整个观测期CH_4的排放通量在-0.05~47.34 mg·( m~2·h)~(-1)之间;各处理CO_2排放通量变化较复杂,介于32.95~1 350.88mg·( m~2·h)~(-1)之间,除LBC和MBC处理呈双峰型曲线外,其余处理均呈单峰型,不同生物炭施用量处理均延后了CO_2排放通量峰值出现的时间;N_2O的排放通量在-309.39~895.48μg·( m~2·h)~(-1)之间,除LBC处理呈双峰型曲线变化外,其余处理均呈单峰型曲线;(2)与空白对照处理相比,生物炭处理均可显著降低CH_4的累积排放量,而促进了CO_2和N_2O累积排放量,CH_4、CO_2和N_2O的平均累积排放量从大到小分别为CKLBCMBCHBC处理、LBCMBCHBCCK处理和HBCMBC≈LBCCK处理;与常规施肥处理相比,不同施用量生物炭添加均可显著降低CH_4和CO_2的排放,且生物炭添加量越多,对CH_4和CO_2排放的减缓作用越明显,但是对N_2O排放的抑制作用尚不明显;(3)在100 a时间尺度上各生物炭处理可显著降低温室气体的综合增温潜势,表明生物炭配施化肥是一种有效的减排措施.     

菌渣还田量对紫色水稻土净温室气体排放的影响

中国是食用菌生产大国,每年食用菌菌渣产出量较大,为探明菌渣还田量对紫色水稻土净温室气体排放的影响,于2017年3~9月,通过盆栽试验,采用静态暗箱/气相色谱法,研究了不施肥(CK)、常规施肥(NPK)、9 t·hm~(-2)菌渣+NPK(LM)、18 t·hm~(-2)菌渣+NPK(MM)、36 t·hm~(-2)菌渣+NPK(HM)这5种处理稻田土壤温室气体的排放规律,并采用土壤碳库法对农田系统净温室气体排放(NGHGE)进行评价.结果表明:(1)土壤温室气体(包括CH_4、CO_2、N_2O)排放随着菌渣还田量的增加而增加,CH_4排放量顺序为:HMMMLM≈NPKCK;HM处理显著增加了CH_4的排放通量(P0.01),其他处理差异并不显著(P0.05),CH_4排放通量LM处理呈双峰型曲线,MM处理呈多峰型,HM处理呈现非常明显的单峰型曲线;CO_2累积排放量大小依次为:MMNPK≈LMHMCK,CO_2排放通量曲线LM处理呈单峰型、MM处理呈双峰型、HM处理呈现多峰型;NPK处理N_2O累积排放量显著高于其他处理,N_2O排放通量曲线NPK处理呈双峰型、LM和MM处理呈现多峰型,HM呈单峰型变化;(2)LM处理土壤固碳能力较低,NPK、MM与HM处理土壤固碳能力均较高;MM处理土壤固碳能力显著高于其他处理(P0.01),比纯施化肥处理提高了59.2%,比LM和HM处理提高了87.79%和65.65%;与土壤固碳能力相反,LM处理植物固碳能力最高,比NPK和MM处理提高了16.1%~22.2%,约为CK处理和HM处理的2.1倍;(3)MM处理整个水稻生产期NGHGE值最小,为-490.29 kg·hm~(-2),表现为温室气体的"汇",18 t·hm~(-2)菌渣还田是紫色水稻土净温室气体排放最优的还田方式.     

邯郸市黑碳气溶胶浓度变化及影响因素分析

根据2013年3月—2017年2月邯郸市河北工程大学站点的黑碳气溶胶、PM2.5、大气污染物的小时浓度数据及常规气象数据,对邯郸市黑碳浓度的时间变化特征及影响因素进行分析.结果表明,4年来邯郸市黑碳浓度呈逐年下降的趋势:与2013年相比,2014—2016年黑碳气溶胶浓度分别下降了5%、16%、24%;邯郸市黑碳气溶胶浓度的季节变化趋势基本一致且季节变化特征明显,冬季黑碳气溶胶浓度最高,秋季次之,春夏两季最低,其中,冬季平均浓度分别是春、夏、秋季的2.07、2.77、1.49倍;其日变化呈单峰单谷状,且4个季节的日变化趋势相同,峰值均出现在6:00—8:00,谷值均出现在14:00—15:00.黑碳与PM2.5的相关系数r为0.860,相关性显著,说明黑碳气溶胶和PM2.5的来源大部分是一致的;风速和风向对黑碳气溶胶浓度也有影响,黑碳气溶胶浓度随风速增加而降低;4个季节高频风向为南-西南方向,且该风向下黑碳气溶胶浓度均较高,冬季南-西南风向下的黑碳浓度最高;应用后向轨迹对研究时段内4段重污染期间的气流轨迹进行模拟发现,邯郸市黑碳气溶胶浓度较高的主要原因是本地源排放和近距离传输,远距离传输贡献较小.     

生物炭的制备及其镁改性对污染物的吸附行为研究

以小麦和玉米秸秆为原料,于不同温度下制备了生物炭样品,并采用氯化镁(MgCl_2)、乙酸镁(Mg(CH_3COO)_2)和硝酸镁(Mg(NO_3)_2)对秸秆及其生物炭进行改性.通过分析各生物炭产率、pH、元素分析、比表面积、CEC、XRD及FT-IR,探究了生物炭理化性质的变化规律.各样品对氨氮、Pb(Ⅱ)及乙草胺的吸附试验结果表明:小麦秸秆经Mg(CH_3COO)_2改性后得到的生物炭的饱和吸附量最大;对3种吸附质的吸附过程均符合准二级吸附动力学方程;低浓度下吸附过程均可自发进行,对氨氮的吸附符合Langmuir模型且以离子交换作用为主,对Pb(Ⅱ)的吸附符合Freundlich模型且以离子交换作用为主,对乙草胺的吸附符合Langmuir模型且以分配、氢键和π-π电子受体供体作用为主.     

Development and Evaluation of a Multiplexed Real-Time TaqMan RT-PCR Assay with a Sample Process Control for Detection of F-specific RNA Coliphage Genogroups I and IV

There are increasing concerns of zoonotic transmission of some animal enteric viruses, such as calicivirus, hepatitis E virus, and rotavirus, which are closely related to human pathogenic strains. Most enteric viruses are detected by molecular techniques because they cannot be cultured. Surrogates such as F-RNA coliphages are cultivable but few molecular methods exist. Individual real-time TaqMan RT-PCR assays for the replicase gene of F-RNA coliphage genogroups I and IV were developed and multiplexed with a real-time TaqMan RT-PCR assay for feline calicivirus as a sample process control for the simultaneous detection and enumeration of genogroup I and IV F-RNA coliphages. Genogroup IV were successfully detected with the multiplexed assay in 80% of fecal samples that contained F-RNA coliphage levels ≥3.2 log plaque forming units (pfu). F-RNA coliphage were at or below the limit of detection in most fecal samples when levels were ≤4 log pfu/g.     

石油炼制业污染防治与清洁生产

石油炼制业是国民经济的支柱行业,直接关系到整个国民经济的发展,它不仅提供各种石油产品,同时也为石油化工、化纤、化肥等工业提供原料。同时,石油炼制业也是污染物排放大户,在生产过程中产生大量废水、废气、固体废物,对人体健康和环境造成了一定潜在的影响。石油产品和中间产品多为易燃、易爆、有毒、有害的化学物质,在生产、储运和使用过程中,会对大气、水域、湖泊、土壤、环境造成危害,必须采取有效的方法加以预防和治理。而实施清洁生产可以有效的帮助石油炼制业节能资源、减少排污。     

徐州市环境监测网络建设现状及发展探讨

从环境质量监测、污染源监测、应急监测、生态监测和监测信息等方面对徐州市环境监测网络建设的现状进行分析及未来徐州市环境监测网络的发展探讨.