湖南毛竹笋及产地土壤重金属与健康风险研究

为了解湖南毛竹产区竹笋及产地土壤重金属的状况，保障竹笋质量安全，选择炎陵、湘乡、耒阳3个县市，共采集毛竹笋样品及对应产地的土壤样品各80份，分析土壤样品中重金属Cd、Hg、As、Pb、Cr、Cu含量和毛竹笋样品中相应重金属含量，探讨土壤重金属含量与原产地毛竹笋中重金属含量之间的相关性，并对毛竹笋中重金属进行健康风险评价。参照标准GB 15618-2018，对土壤重金属进行单因子污染指数、综合污染指数评价，其次对竹笋中检出的重金属进行致癌和非致癌污染物健康风险评价。结果表明，毛竹笋产地土壤样品中Cd、As、Pb均有不同程度的超标现象，合格率分别为67.5%、96.2%、77.5%，3个地区综合污染指数分别为1.183、1.219、1.475，表明毛竹笋产地土壤均有不同程度污染。毛竹笋样品中除Hg未检出外，Cd、As、Pb、Cr 4种重金属均有检出，合格率为98.8%。毛竹笋中各重金属元素含量与对应产地土壤各重金属元素含量相关性系数较低，其中仅炎陵毛竹笋重金属As含量与对应产地土壤的As含量呈极显著(P<0.01)正相关，相关系数为0.606。毛竹笋中检出的Cd、As、Pb、Cr 4种重金属总目标危险系数分别为0.377、0.277、0.118。Cd致癌风险分别为7.30×10^-6、8.45×10^-6、1.33×10^-5。综合得出，可食部分毛竹笋对重金属积累较少，且毛竹笋与产地土壤对应重金属元素含量无相关性，通过食用毛竹笋摄入重金属的总目标危险系数低于USEPA推荐的最大可接受水平，不会对暴露人群健康造成危害，Cd致癌风险在可接受范围内。     

Effectiveness of measures aiming to stabilize urban gullies in tropical cities: Results from field surveys across D.R. Congo

Urban gullies are a rapidly growing concern in many tropical cities of the Global South. Various measures are already implemented for their stabilization. However, an overview of these measures and their overall effectiveness is currently lacking. We aim at addressing this gap by documenting existing initiatives to stabilize urban gullies in D.R. Congo and assessing their overall effectiveness. To this end we conducted extensive field campaigns in Kinshasa, Kikwit and Bukavu and combined our terrain observations with data on gully expansion rates (derived from series of satellite imagery). In total, we characterized present and past stabilization initiatives for 398 urban gullies. For 69 of these gullies, the effect of a specific measure on gully expansion rates could be estimated. Results show that for the large majority of gullies, various measures have been implemented. Yet, these are mainly ad-hoc measures installed by the affected population. More structural measures based on larger engineering works were observed for only 20–30% of gullies. The huge efforts invested in the installation of measures strongly contrast with their overall low impact. Among all strategies, only the deviation of runoff resulted in significantly lower expansion rates after installation. The numerous initiatives that rely on the sparse means available seem to have limited effects. This does not imply, however, that they are completely ineffective and should be abandoned. Based on our findings, we formulate recommendations for further research on how to effectively prevent and stabilize urban gullies, taking into account the difficult environmental and socio-economic context.     

利用MCI指数和Gumbel-Copula函数评估新疆干旱灾害危险性

干旱是新疆地区的主要气象灾害之一，其危险性评估对该地区防旱抗旱工作具有重要的指导意义。该研究基于新疆106个气象站1961—2019年逐日观测数据计算气象干旱综合指数（meteorological drought composite index，MCI），根据游程理论识别干旱过程，采用Gumbel-Copula函数建立干旱历时和烈度的联合分布并计算干旱重现期；选取干旱频次、历时和烈度作为危险性评估因子，采用随机森林算法计算权重并得到新疆干旱灾害危险性结果。结果表明：1961—2019年间新疆共出现了47次干旱过程，其中短历时、低烈度（干旱烈度≤50且干旱历时≤60d）干旱过程多发，长历时、高烈度（干旱烈度≥200且干旱历时≥180d）重现期较长。长历时和高烈度倾向于同时发生，但随着干旱历时和烈度的增加，长历时和高烈度干旱过程发生概率较低。新疆地区干旱灾害危险性空间分布上呈现“中间低，南北高”的特点，天山山脉地区干旱重现期长于其他地区，危险性低，天山北坡的干旱过程发生频率低、持续时间短、强度小，危险性较低；南疆大部分地区的干旱过程发生频率较低，但持续时间长、强度大、危险性较高。而北疆大部分地区干旱发生频率高，但持续时间不长，强度不高，但塔城地区西北部和阿勒泰地区危险性较高。因此南北地区对干旱灾害应对应有所不同。在全球变暖背景下，新疆各地区用水矛盾进一步加剧，各地应结合实际，统筹提高水资源高效配置合理利用水平，合理开发水资源，降低干旱灾害的风险。     

燕麦抗倒伏性研究进展

饲草燕麦是我国重要的优质饲草。倒伏是限制燕麦饲草高产、稳产和优质的主要原因之一。本文系统整理、分析了国内外相关文献，综述了倒伏对燕麦生产的影响。倒伏会降低燕麦营养物质积累量、籽粒产量、燕麦草饲用价值和贮藏品质。影响燕麦倒伏的因素主要包括燕麦形态特征、茎秆力学特性、木质素代谢等内在因素，以及自然条件、栽培措施等外界因素。目前评价燕麦倒伏性能的方法主要有田间观察法、人工模拟法、模型综合评价法等。通过关键性状筛选、品种培育及高产栽培措施优化等途径提高燕麦抗倒伏性能。     

某电镀搬迁场地土壤重金属污染健康风险评估

采用《污染场地风险评估技术导则》中的评估方法,运用HERA软件对广州某电镀搬迁场地土壤中的重金属污染物进行人体健康风险评估。结果表明:①该场地土壤中铬(Cr6+)和镍的致癌风险指数分别为1.92×10–6、2.31×10–6,均超过其评估标准值1×10–6,表明其对人类有较高的致癌风险。②该场地土壤中铬(Cr3+)、镍、铜、银的非致癌危害熵分别为16.7、20.8、4.68、1.48,均高于其基准值1,表明该场地土壤中的铬(Cr3+)和镍有较高的非致癌危害,铜和银具有一定的非致癌危害。③根据评估结果,提出了加强治理防护工作、根据目标污染物含量和位置分布确定修复重点区域、防治污染物扩散等管理、修复与治理该场地的建议。