进出口工业化学品风险管理与风险评估进展

我国是世界化学品生产和贸易的大国。大量化学品的生产和进出口贸易给我国化学品风险管理和风险评估带来了巨大挑战。在借鉴发达国家和经济组织对化学品风险管理经验和评估技术的基础上,我国在近年来也逐步开展了化学品的管理和控制,以应对当前日益突出的化学品环境安全和健康安全事故。本文从我国化学品管理与国外化学品风险管理之间的对比出发,在梳理化学品管理政策发展的过程中,重点就我国环境保护部门对有毒和进口化学品、新化学物质和废弃危险化学品以及质检部门对进出口工业化学品的管理和控制措施,以及化学品的评估技术进行了综述。通过与发达国家就化学品风险管理与评估技术的对比,指出我国目前化学品管理和评估的不足与欠缺,并提出一些可行的应对措施与办法,为完善我国化学品风险管理和评估提供一定的参考。     

日粮中铜胁迫对吉富罗非鱼幼鱼抗氧化、脂质过氧化及肝脏组织结构的影响

吉富罗非鱼是我国南方沿海地区水产养殖中的主要经济鱼类之一,但近年来,随着我国城镇化和工业化进程的推进,罗非鱼养殖面临着前所未有的铜富集的挑战。为探明日粮中铜胁迫对吉富罗非鱼幼鱼抗氧化系统和肝脏组织结构的影响,将1 080条罗非鱼幼鱼暴露于6个浓度梯度(0、3、30、300、1 000、3 000 mg·kg-1)的高铜日粮中,通过60 d的暴露试验,实时测定罗非鱼血清与肝脏抗氧化能力,监测肝脏病理变化。结果表明,在本试验条件下,罗非鱼幼鱼血清和肝脏中MDA的含量随日粮中铜含量的增加和胁迫时间的延长显著升高,而SOD、GSH-PX和Cu Zn-SOD的活性表现出先升高后降低的趋势;各组间肝脏表现出不同程度的病变,主要是浊肿变性和脂肪变性,且第Ⅲ、Ⅳ、Ⅴ组肝脏病变严重。综上,日粮中铜胁迫对吉富罗非鱼幼鱼的抗氧化机能有较明显的抑制作用,长时间的暴露能严重损伤其肝脏的组织结构,因此,建议吉富罗非鱼幼鱼日粮中铜的实际含量应控制在42.36 mg·kg-1以下。     

固定化多酚氧化酶对水中苯酚和氯酚的去除

以壳聚糖/蒙脱土插层复合物为载体,吸附法制备固定化多酚氧化酶,并以此催化氧化去除水中的苯酚、4-氯苯酚和2,4-二氯苯酚.考察了固定化多酚氧化酶的制备条件,对酚类化合物的催化氧化条件、动力学特性以及固定化酶的重复使用性能.结果表明,固定化多酚氧化酶的最佳制备条件为p H 5.0,酶与载体质量比20 mg·g-1,固定化6 h,所得固定化酶的载酶量为12.12 mg·g-1,每克单位载体酶活为12.76×103U·g-1.固定化多酚氧化酶对酚类化合物的最佳去除条件为:苯酚溶液p H 7.0,温度30℃;4-氯苯酚溶液p H 5.0,温度20℃;2,4-二氯苯酚溶液p H 5.0,温度30℃.在最佳反应条件下,酶与底物质量比为20 mg·mg-1时,固定化多酚氧化酶对苯酚、4-氯苯酚和2,4-二氯苯酚溶液去除率分别为63.6%、85.8%和87.8%.苯酚、4-氯苯酚和2,4-二氯苯酚的米氏常数Km值依次减小,最大反应速率Vmax依次增大,表明固定化酶对2,4-二氯苯酚的亲和力最强,催化速度最快.固定化酶循环使用6次(24 h)后对苯酚、4-氯苯酚和2,4-二氯苯酚的去除率分别为15.7%、24.2%和27.8%.     

Look before you leap - individual variation in social vigilance shapes socio-spatial group properties in an agent-based model

Next to predator detection, primate vigilance also serves to keep track of relevant conspecifics. The degree of vigilance towards group members often reflects the dominance rank of an individual: subordinates pay attention to dominants. Although it has been suggested that subordinates' vigilance may result in spatial centrality of dominants, this has not been addressed in either empirical or modeling studies. Using agent-based models, we determined how social vigilance affects socio-spatial properties of primate groups. A basic model without social vigilance, where individuals avoid potential aggressors (avoidance model), was contrasted with two models that each additionally included a different type of social vigilance: a) monitoring a specific potential aggressor to remain informed on its whereabouts (monitoring model) or b) scanning the whole group to detect potential aggressors (scanning model). Adding monitoring or scanning behavior to the avoidance model reinforced spatial centrality of dominants, a pattern often observed in primates, and resulted in more spread out groups. Moreover, variation in scanning tendency alone was already sufficient to generate spatial centrality of dominants: frequently scanning subordinates could move further away from the group center than dominants, before losing sight of group members. In the monitoring model, two mechanisms caused decreased encounter frequencies among subordinates: a) increased inter-individual distances, and b) frequent monitoring of central dominants. In the scanning model, encounters among subordinates decreased due to increased inter-individual distances. This agent-based model study provides a clear indication that individual variation in social vigilance may be an important structuring feature of primate social groups.     

Seasonal variations of monoterpene emissions from Pinus densiflora in East Asia

The emission rates and compositions of monoterpene from Pinus densiflora were investigated in the Gumsung (GM) and Worak (WM) mountains. The standard emission rates (ERs: ERs is the monoterpene emission rate at standard temperature, 30 degrees C) from P. densiflora ranged from 0.817 to 1.704 (mugC/gdw-h). The ERs and beta-values of total monoterpene were measured at the two study sites (GM and WM). In the spring and summer, the ERs were the highest, while relatively low values (<0.058mugC/gdw-h) were measured in the autumn and winter. In GM and WM sites the beta-value obtained for the different seasons ranged from 0.047 to 0.179, with an average of 0.09. The major monoterpene compounds from P. densiflora were alpha-pinene, myrcene, beta-phellandrene, d-limonene and alpha-terpinene. The fractional compositions of individual monoterpene compounds were significantly different between the two test sites in the summer and winter. The ERs of the older group (31-40 years) were higher than those in the younger group (21-30 years). However, the monoterpene compositions were similar between the two age groups.