浊漳河山西省潞城市境内段河流生态健康评价研究

浊漳河山西省潞城市境内干流段及南源段河道生态环境目前最突出的问题在于水质恶化、水量减少以及生物多样性衰退。本文从水质、水量、生物状况三个要素出发,通过建立浊漳河潞城市境内河段的水生态健康评价体系,对浊漳南源及干流段进行了生态健康诊断。结果显示,浊漳干流段生态健康总指数36.74,呈生态病态状;南源段生态健康总指数60.03,呈基本健康状态。据此,浊漳河潞城境内段目前的核心问题是生态恢复问题,应当针对其存在的问题选择适当的生态修复模式,采取相应的生态环境管理方法,把生态系统的恢复和重建作为其流域治理的最终目标。     

Origin and distribution of trace elements in high-elevation precipitation in southern China

Introduction

During a 2009 investigation of the transport and deposition of trace elements in southern China, 37 event-based precipitation samples were collected at an observatory on Mount Heng, China (1,269?m asl).

Methods

Concentrations of trace elements were analyzed using inductively coupled plasma?Cmass spectrometry and the wet deposition fluxes were established. A combination of techniques including enrichment factor analysis, principal component analysis, and back trajectory models were used to identify pollutant sources.

Results

Trace element concentrations at Mount Heng were among the highest with respect to measured values reported elsewhere. All elements were of non-marine origin. The elements Pb, As, Cu, Se, and Cd were anthropogenic, while Fe, Cr, V, Ba, Mn, and Ni were of mixed crustal/anthropogenic origin. The crustal and anthropogenic contributions of trace elements were 12.8 % (0.9?~?17.4 %) and 87.2 % (82.6?~?99.1 %), with the maximum crustal fraction being 17.4 % for Fe. Coal combustion, soil and road dust, metallurgical processes, and industrial activities contributed to the element composition.

Conclusions

Summit precipitation events were primarily distant in origin. Medium- to long-range transport of trace elements from the Yangtze River Delta and northern China played an important role in wet deposition at Mount Heng, while air masses from south or southeast of the station were generally low in trace element concentrations.     

山地城市暴雨径流污染特性及控制对策

为了解山城重庆的暴雨径流污染特性,充实国内仍然薄弱的基础资料,对4种用地类型的4场暴雨进行了监测,测试指标包括TSS、COD、TP、TN和NH3-N。结果表明,对于坡度2.5%的交通干道和坡度30%的校园人行道,从污染物浓度降幅的角度考虑初期径流的控制量应分别为2～3 mm和1.8 mm。随降雨时间的延长,路面污染物浓度迅速降低,坡度越大,降低速率越快。对于平均浓度,校园屋顶和草坪的各污染物浓度均达到地表水环境质量Ⅴ类标准(总氮和氨氮除外)。交通干道和校园人行道的总磷平均浓度也满足地表水环境质量Ⅴ类标准,但2种下垫面的COD、TN和氨氮平均浓度分别超出地表水环境质量Ⅴ类标准的2～8倍、1.9～3.1倍和1.9～4.3倍。对于交通干道,场次降雨径流的总氮、总磷和氨氮平均浓度与初期浓度的比值和污染物浓度20 min降幅接近(分别为0.5～0.53和50%～55%)接近,而COD和TSS平均浓度与初期浓度的比值和污染物浓度20 min降幅相近(分别为0.35～0.37和78%～84%)。对于校园人行道,污染物浓度20 min降幅均达到90%以上(90%～96%),场次降雨径流的总氮、总磷、氨氮、COD和TSS的平均浓度与初期浓度的比值接近(0.3～0.4)。研究结果为山地城市暴雨径流的污染控制提供了参考。     

微波诱导AC/Cu、AC/Fe催化非均相Fenton 反应催化降解垃圾渗滤液

采用活性炭载体负载Cu、Fe为催化剂,在微波诱导作用下,对垃圾渗滤液污染物进行降解。实验结果表明,活性炭负载金属前经适当浓度硝酸浸泡处理后,催化剂对COD去除率提高可超过15%,过高硝酸盐浓度对COD去除有不利影响;催化剂对COD去除率随Cu、Fe金属负载量增加呈先增加后降低的趋势,催化剂对Cu、Fe的最佳负载量分别为质量百分比2.11%和1.12%。对于AC-Cu体系,在初始pH=3,H2O2投加量为4.98×103mg/L,催化剂用量为5.0×103mg/L,420 W功率下微波辐射10 min时,垃圾渗滤液COD去除率可达到84.13%;对于AC-Fe体系,当H2O2投加量为0.33×103mg/L,催化剂AC-Fe用量为2.0×104mg/L,420 W功率下微波作用10 min时,垃圾渗滤液COD去除率为60.16%。分析2种催化剂对COD去除差异的原因,可能是催化剂AC-Cu表面单分子分布的阈值比AC-Fe高。降解液的pH值对AC-Cu体系、AC-Fe体系COD去除影响存在拐点,最高COD去除率点对应的降解液pH值为3。微波辐射功率较低时,体系COD去除率随辐射功率增加而增加;辐射功率较高时,高温下垃圾渗滤液中有机硫化物分解成小分子硫化物,对催化剂活性存在一定抑制作用。     

接地极的土壤腐蚀

接地极是接地装置的主要组成部分,接地极埋设在土壤中,用于泄流,保障电网和电气设备的安全运行。近年来,接地极的腐蚀损坏造成的事故屡有发生,接地极的土壤腐蚀引起了普遍的重视,防止接地极腐蚀已成为一个重要的研究课题。本文介绍了目前我国电网和电气设备接地极的选材,接地极土壤腐蚀的特点,并对接地极防腐蚀方法做了简单总结。     

污泥热解残渣制备聚合氯化铝的实验研究＊

含铝污泥热解或焚烧残渣制备聚合氯化铝的研究,有利于实现污水处理过程投加的铝盐絮凝药剂的回收与高效循环利用,减少污染物排放和资源消耗。针对辽河油田欢三联稠油污水处理污泥的热解残渣具有较高铝含量的特点,开展采用盐酸进行铝溶出及制备聚合氯化铝的实验研究。结果表明:焙烧温度为700～750℃,焙烧时间控制在1h即可。将经过焙烧活化的残渣在常温下进行酸溶,酸溶时间为2～5h,选用25%～30%盐酸,氧化铝与盐酸的摩尔比为1∶1.0～1∶1.2为宜。将溶出的铝溶液制备聚合氯化铝,在常温下采用CaO粉末来调节pH值为3.5,聚合反应时间为1d,即可得聚合氯化铝溶液。     

嗜盐菌在油田含盐采出废水处理中的应用

嗜盐菌具有独特的细胞结构、生理功能和代谢产物,能够在高盐环境下正常生存和生长,适宜于偏碱性的环境,因而能有效应用于含盐污染物的治理。结合油田含盐采出废水的特点,介绍了嗜盐菌的特点、嗜盐机制等,及嗜盐菌在含盐采出废水和其它有机污染物处理中的作用,为油田含盐采出废水的处理提供理论基础和技术依据,并为更大范围地推广嗜盐菌在油田含盐采出废水处理中的应用提供技术参考。     

Impact of anthropogenic emissions and open biomass burning on regional carbonaceous aerosols in South China

Carbonaceous aerosols were studied at three background sites in south and southwest China. Hok Tsui in Hong Kong had the highest concentrations of carbonaceous aerosols (OC = 8.7 ± 4.5 μg/m³, EC = 2.5 ± 1.9 μg/m³) among the three sites, and Jianfeng Mountains in Hainan Island (OC = 5.8 ± 2.6 μg/m³, EC = 0.8 ± 0.4 μg/m³) and Tengchong mountain over the east edge of the Tibetan Plateau (OC = 4.8 ± 4.0 μg/m³, EC = 0.5 ± 0.4 μg/m³) showed similar concentration levels. Distinct seasonal patterns with higher concentrations during the winter, and lower concentrations during the summertime were observed, which may be caused by the changes of the regional emissions, and monsoon effects. The industrial and vehicular emissions in East, Southeast and South China, and the regional open biomass burning in the Indo-Myanmar region of Asia were probably the two major potential sources for carbonaceous matters in this region.     

以红薯浸泡液为碳源的生物反硝化

为选择低碳氮比污水生物脱氮中合适的碳源,以搅拌罐浸泡淀粉类物质释放碳源,在确定利用红薯浸泡液为碳源后,以浸没式生物滤池为反应器进行生物反硝化实验。实验结果表明:20 g红薯置于2 L自来水中,采用250 r/m in的搅拌速度,搅拌频率为每搅拌3 h停1 h,2 d后得到的浸泡液COD浓度平均为5 921 mg/L,最高可超过7 000 mg/L;将此红薯浸泡液和污水以1∶50的流量比例,采用分别投加的方式进入反应器,污水中总氮、硝酸盐氮、亚硝酸盐氮及氨氮的平均去除率分别为88.6%、91.6%、88.2%和54.8%,出水COD平均在30 mg/L以下;在红薯浸泡液COD浓度为5 700 mg/L左右时,进水中亚硝酸盐氮浓度与硝酸盐氮浓度比为3∶2时总氮去除率为95.3%,当该比例为2∶3时总氮去除率为88.2%。研究表明,红薯浸泡液是一种经济合适的碳源,采用红薯浸泡液作为低碳氮比污水生物处理中反硝化的碳源是可行的。     

SO2 inhalation causes synaptic injury in rat hippocampus via its derivatives in vivo

SO₂ remains a common air pollutant, almost half of the world’s population uses coal and biomass fuels for domestic energy. Limited evidence suggests that exposure to SO₂ may be associated with neurotoxicity and increased risk of hospitalization and mortality of many brain disorders. However, our understanding of the mechanisms by which SO₂ causes harmful insults on neurons remains elusive. To explore the molecular mechanism of SO₂-induced neurotoxic effects in hippocampal neurons, we evaluated the synaptic plasticity in rat hippocampus after exposure to SO₂ at various concentrations (3.5 and 7 mg m⁻³, 6 h d⁻¹, for 90 d) in vivo, and in primary cultured hippocampal neurons (DIV7 and DIV14) after the treatment of SO₂ derivatives in vitro. The results showed that SYP, PSD-95, NR-2B, p-ERK1/2 and p-CREB were consistently inhibited by SO₂/SO₂ derivatives in more mature hippocampal neurons in vivo and in vitro, while the effects were opposite in young hippocampal neurons. Our results indicated that in young neurons, SO₂ exposure produced neuronal insult is similar to ischemic injury; while in more mature neurons, SO₂ exposure induced synaptic dysfunctions might participate in cognitive impairment. The results implied that SO₂ inhalation could cause different neuronal injury during brain development, and suggested that the molecular mechanisms might be involved in the changes of synaptic plasticity.