郑州市春季大气污染过程VOCs特征、臭氧生成潜势及源解析

利用GC5000在线气相色谱仪于2018年4月15日～5月15日对郑州市城区环境大气挥发性有机物(VOCs)进行监测,开展其污染特征、臭氧生成潜势(OFP)和来源解析研究.结果表明,监测期间,郑州市春季VOCs平均体积分数为40.26×10^-9,非污染日和污染日VOCs平均体积分数分别为35.82×10^-9和44.12×10^-9,污染日相较非污染日增长23%;VOCs物种对OFP的贡献表现为烯烃>芳香烃>烷烃>炔烃;源解析结果显示监测期间郑州市VOCs主要来源是LPG源(66.05%)、机动车源(47.39%)、工业溶剂源(37.51%)、燃烧源(37.80%)和植物排放源(11.25%),且污染日的LPG源和植物排放源的贡献率较非污染日增长22.92%和68.50%.     

华北地区大气细颗粒物(PM2.5)年际变化及其对土地利用/覆被变化的响应

大气细颗粒物(PM_2.5)是大气污染的重要组成成分,对其影响因素进度探讨具有重要的意义.但目前来看,多数的研究都聚焦于PM_2.5与气象要素以及经济因素之间的关系,分析土地利用/覆被变化对PM_2.5影响的研究相对较少,需要进一步的深入探讨.基于PM_2.5空间分布数据及土地利用/覆被数据,对华北地区PM_2.5变化特征及土地利用/覆被变化特征进行了系统分析,并利用地理加权回归、GIS空间分析等手段探讨了PM_2.5变化与土地利用/覆被变化的响应关系,结果表明:①华北地区PM_2.5浓度整体呈现东南高、西北低的空间格局,且18a均保持这一态势没有变化.时间上来看,在2006年达到污染最大值,之后虽有波动但一直居高不下.多数城市PM_2.5浓度超标,整体环境污染形势严峻;②2000～2015年研究区土地利用类型/覆被以耕地、林地和草地为主,土地利用/覆被变化趋势主要表现为耕地的大量减少以及建设用地的持续增加,水域和未利用地面积略...     

郑州市民运会期间大气PM2.5改善效果评估

利用2019年8月5日至9月30日大气污染物和颗粒物组分在线数据,评估郑州市少数民族运动会空气质量管控效果.根据政府管控措施的实施时间,将研究时期分为管控前(8月5～24日)、管控中(8月25日至9月18日)和解除管控后(9月19～30日).相较管控前,管控中PM_2.5平均浓度增加2.3μg·m^-3,解除管控后PM_2.5的浓度增加了11.7μg·m^-3,解除管控后PM_2.5浓度增幅高于管控中,表明管控措施对颗粒物有显著的减排效果.从颗粒物组分来看,研究期间郑州市主要组分依次是有机物、硝酸根、铵根、硫酸根和地壳元素.相比于管控前,管控期间PM_2.5组分中有机物和硝酸根占比分别上升3.9%和0.9%,硫酸根、铵根和地壳元素的占比下降了1.1%、 1.9%和2.2%.利用正定矩阵因子分解法解析颗粒物来源,结果表明二次硫酸、二次硝酸、二次有机气溶胶、机动车源、工艺过程源、扬尘和燃煤是PM_2.5主要来源.管控对一次源中的扬尘、燃煤和工业效果显著...     

德州市夏季臭氧敏感性特征及减排方案

近年来德州市臭氧污染频发, 2018年夏季(6～8月),德州市发生了严重臭氧污染事件,臭氧日最大8 h浓度值超标天数达60 d,超标率65%, 3个月平均值为176μg·m^-3,最高达262μg·m^-3.本研究利用WRF-CAMx耦合的HDDM模块,分析期间德州臭氧敏感性特征及减排方案.结果表明,在空间上,德州市中心城区为VOCs控制区,而郊区为NO_x与VOCs协同控制区.在时间上,VOCs敏感值每日为正值,但dO_3V50在6月(城区18.7μg·m^-3,郊区19.7μg·m^-3)和8月(城区15.3μg·m^-3,郊区16.4μg·m^-3)高于7月(城区13.0μg·m^-3,郊区11.8μg·m^-3),NO_x敏感值城区呈正负交错,郊区大部分为正值,并与VOCs敏感值接近.对于城区减排方案应考虑以仅VOCs...     

长江下游典型滨海地区农业土壤重金属污染特征

为揭示长江下游滨海地区农业土壤重金属污染状况,以滨江临海的南通市为例,网格化布点,采集表层农业土壤样品共计334个,对其重金属Cu、Pb、Cr、As、Hg含量进行了测定分析.结果表明,研究区域表层农业土壤中各重金属含量均已超过其背景值,且以Pb污染最为严重;区域性差异较大,以滨海的如东、海门、启东污染最为严重,且以海门、启东As含量最高;各重金属间相关性不显著,来源途径不止一种.从而提出南通市农业土壤重金属污染的防治应立足于防重于治的方针,着重滨海地区,以Pb、As污染源为主,并对污染土壤进行修复.     

高效液相色谱法测定饮用水中的微囊藻毒素RR和LR

利用高效液相色谱法(HPLC)测定了藻毒素(MC-RR、LR)标准样品,并绘制了标准曲线,藻毒素浓度在0~5mg/L范围内,HPLC峰面积与藻毒素进样量呈线性关系,RR和LR相关系数分别为0·9986和0·9992,表明该方法可靠、灵敏度较高。对毒素的富集方法及分析条件进行了优化,并在藻类高发期的7~10月份,通过固相萃取(SPE)法对T市饮用水中的MCs进行浓缩富集后,用高效液相色谱仪和标准曲线测出MC-RR和MC-LR值。结果显示,T市高藻期饮用水中含有MCs,应引起足够的重视。     

膜、柱串联固相萃取-高效液相色谱法测定水中多环芳烃(PAHs)的研究

建立了用膜-柱串联固相萃取(SPE)技术,甲醇和水作为流动相进行梯度洗脱,紫外和荧光检测器串联的高效液相色谱法(HPLC)分析水中EPA优先监控的16种PAHs的方法.     

Performance of a water hyacinth （Eichhornia crassipes） system in the treatment of wastewater from a duck farm and the effects of using water hyacinth as duck feed

Nowadays, intensive breeding of poultry and livestock of large scale has made the treatment of its waste and wastewater an urgent environmental issue, which motivated this study. A wetland of 688 m2 was constructed on an egg duck farm, and water hyacinth (Eichhornia crassipes) was chosen as an aquatic plant for the wetland and used as food for duck production. The objectives of this study were to test the role of water hyacinth in purifying nutrient-rich wastewater and its effects on the ducks’ feed intake, egg laying performance and egg quality. This paper shows that the constructed wetland removed as much as 64.44% of chemical oxygen demand (COD), 21.78% of total nitrogen (TN) and 23.02% of total phosphorus (TP). Both dissolved oxygen (DO) and the transparency of the wastewater were remarkably improved, with its transparency 2.5 times higher than that of the untreated wastewater. After the ducks were fed with water hyacinth, the average daily feed intake and the egg-laying ratio in the test group were 5.86% and 9.79% higher, respectively, than in the control group; the di erences were both significant at the 0.01 probability level. The egg weight in the test group was 2.36% higher than in the control group (P < 0.05), but the feed conversion ratios were almost the same. The eggshell thickness and strength were among the egg qualities significantly increased in ducks fed with water hyacinth.We concluded that a water hyacinth system was e ective for purifying wastewater from an intensive duck farm during the water hyacinth growing season, as harvested water hyacinth had an excellent performance as duck feed. We also discussed the limitations of the experiment.     

Substrate-induced changes in microbial community-level physiological profiles and their application to discriminate soil microbial communities

The addition of simple substrates could affect the microbial respiration in soils. This substrate-induced respiration is widely used to estimate the soil microbial biomass, but little attention has been paid to its influence on the changes of community-level physiological profiles. In this study, the process of microbial communities responding to the added substrate using sole-carbon-source utilization （BIOLOG） was investigated. BIOLOG is biased toward fast-growing bacteria; this advantage was taken to detect the prompt response of the active microbial communities to the added substrate. Four soil samples from agricultural fields adjacent to heavy metal mines were amended with L-arginine, citric acid, or D-glucose. Substrate amendments could, generally, not only increase the metabolic activity of the microbial communities, but also change the metabolic diverse patterns compared with no-substrate control. By tracking the process, it was found that the variance between substrate-induced treatment and control fluctuated greatly during the incubation course, and the influences of these three substrates were different. In addition, the application of these induced changes to discriminate soil microbial communities was tested. The distance among all samples was greatly increased, which further showed the functional variance among microbial communities in soils. This can be very useful in the discrimination of microbial communities even with high similarity.     

Validation of an agricultural non-point source （AGNPS） pollution model for a catchment in the Jiulong River watershed, China

This study tested and evaluated the agricultural non-point source(AGNPS)model for the Wuchuan catchment, a typical agricultural area in the Jiulong River watershed, Fujian Province. China. The AGNPS model was calibrated and validated for the study area with observed data onten storms. Thedata on eight stormsin 2002 were used for calibration while data on two stormswere used for validation of the model. Considering the lack of water quality data over a long-term series, a novel method, comparing an internal nested catchment with its surrounding catchment, was used to supplement the less long-term series data. Dual calibration and validation of the AGNPS model was obtained by this comparison. The results indicate that the correlation coefficients were 0. 99 and 0. 98 for runoff, 0. 94 and 0. 95 forthe peak runoff rate of the large catchment and the small catchment, respectively, and 0. 76 forthe sediment of the small catchment only. Each pair of correlation coefficients is homogeneous for the same event for the two catchments. With the exception of the sediment yield and particulate phosphorus, the peak nmofr rate and other nutrients were well predicted. Sensitivity analysis showed that the Soil Conservation Service curve number and rainfall quantity were the most sensitive parameters, which resulted in high output variations. Erosivitv and other parameters had little influence on the hydrological and quality outputs.