贵州晴隆锑矿区土壤中锑的形态分布和地球化学模型

以贵州晴隆锑矿区某冶炼厂及周边地区土壤为对象研究了锑的形态分布特征.结果发现,冶炼厂土壤中锑污染严重,含量最高达31265 mg·kg-1,但在下游土壤中随距离增加,锑浓度迅速下降到100 mg·kg-1 以内.XRD和XPS结果显示土壤中主要含锑化合物为锑酸钙(Ca2Sb2O7)、锑酸钾(K3Sb5O14)以及氧化锑(Sb2O5),锑以五价形态存在.连续提取形态分析表明除残渣态外,厂区附近污染土壤中碳酸盐和金属氧化物的共沉淀态是锑的主要宿主相,而下游土壤中吸附态比例显著升高,说明在迁移过程中土壤中锑的活性增加.构建了以水合铁氧化物和针铁矿作为锑主要活性表面的土壤中锑地球化学多表面形态模型(MSM),当采用1 mol·L-1 Na2HPO4提取的锑作为总有效态锑输入值时,该模型可很好地预测不同性质和污染程度的土壤中锑的溶出效应(RMSE=0.29),说明该模型可为准确评估锑冶炼厂周边污染土壤中锑生态毒性和迁移淋溶风险提供有潜力的工具和方法.     

微(纳米)塑料对海洋渔业水域中重要饵料藻类的生态风险评估研究

微(纳米)塑料(micro(nano)plastics, MNPs)污染已成为水环境中的热点问题,特别是对于有“海洋牧场”之称的海洋渔业水域,由于陆源性塑料垃圾排放、塑料渔具的大量使用以及海上航运等原因,MNPs污染日益严重。饵料藻类作为渔业水域中重要的初级生产者,是维持生态系统稳定的第一道防线,也是污染物在水生食物链中传递的起点,并且响应污染物的毒性效应较为敏感。上述特征使饵料藻类成为开展渔业水域中污染物生态风险评估的理想生物。为评估MNPs对渔业水域中重要饵料藻类的生态风险,本研究通过文献检索分析了其中4门9科12种常见饵料藻类的毒理学研究数据。进一步利用GraphPad Prism 8.0软件计算MNPs对上述饵料藻类的半数有效浓度(median effect concentration, EC₅₀),并运用Rurrlioz软件绘制物种敏感性分布(species sensitivity distribution, SSD)曲线。通过SSD曲线预测了不同环境浓度MNPs对饵料藻类的潜在影响比例(potential affected fractions, PAF),继而对全球13处渔业水域MNPs的生态风险进行评估。结果发现墨西哥湾MNPs的PAF值超过50%;另有7处渔业水域MNPs的PAF值介于5%和20%之间。基于上述结果并考虑到当前海洋塑料垃圾数量有可能被低估,本研究认为未来需要加强对渔业水域中MNPs生态风险的关注。同时,本研究还揭示了当前研究的局限性并对未来渔业水域中MNPs污染的生态风险评估研究提出了几点建议。     

湖水中磷形态的生物有效性

本文采用化学分析将湖水中的磷划分为七种形态:总磷(TP)、总反应磷(TRP).总溶解磷(TSP)、溶解反应磷(SRP)、溶解的水解性磷(SHP)、溶解的光解性磷(UVSRP)以及颗粒磷(PP).为了确定生物有效磷,把湖水灭菌后再接入羊角月芽藻进行试验,研究了湖水中各种磷形态对羊角月芽藻最大生长量的影响.结果表明:当湖水中磷含量大于100μg/l时,藻的最大生长量与大多数磷形态有较好的相关性(n=16,r0.8600),而与溶解反应磷相关性较差(n=16,r=0.7113).也研究了羊角月芽藻对磷形态的摄取过程,初步探讨了磷形态的生物转化.     

某滨海核电厂冷源取水口生物调查及风险分析

近年来由海洋生物入侵造成的滨海核电冷源安全事件频发,为了解某核电厂取水口海域的生物概况,本研究于2022年9月至2023年8月进行了生物调查。共获得海洋生物10类211种,优势种以脊索动物和甲壳动物为主,5月、7月下旬至8月上旬出现2个生物量高峰期。风险生物有中国毛虾（Acetes chinensis）、中华假磷虾（Pseudeuphausia sinica）、日本鳀（Engraulis japonicus）、球型侧腕水母（Pleurobrachia globosa）等,并初步分析了日本鳀和中国毛虾在取水口海域激增的原因。本文明确了某核电冷源的生物风险期为4－9月,研究成果将有助于优化核电厂生物灾害的预警和防控工作。     

我国西南湖塘溪流的水化学组成与离子平衡的研究

本文研究了我国重酸雨地区四川，贵州省湖塘溪流的水化学组成及离子平衡关系，结果表明：城郊之间水化学组成存在差异；同时，进行离子平衡衡算时，须对溶解态钙，镁进行校正，否则，会出现阴离子短缺现象，仅由钙，镁及硫酸根和弱酸根组成的简单离子平衡也是大致符合的，但其应用有一定的局限性。     

“The Moral Difference between Intragenic and Transgenic Modification of Plants”

Public policy on the development and use of genetically modified organisms (GMOs) has mainly been concerned with defining proper strategies of risk management. However, surveys and focus group interviews show that although lay people are concerned with risks, they also emphasize that genetic modification is ethically questionable in itself. Many people feel that this technology “tampers with nature” in an unacceptable manner. This is often identified as an objection to the crossing of species borders in producing transgenic organisms. Most scientists reject these opinions as based on insufficient knowledge about biotechnology, the concept of species, and nature in general. Some recent projects of genetic modification aim to accommodate the above mentioned concerns by altering the expression of endogenous genes rather than introducing genes from other species. There can be good scientific reasons for this approach, in addition to strategic reasons related to greater public acceptability. But are there also moral reasons for choosing intragenic rather than transgenic modification? I suggest three interrelated moral reasons for giving priority to intragenic modification. First, we should respect the opinions of lay people even when their view is contrary to scientific consensus; they express an alternative world-view, not scientific ignorance. Second, staying within species borders by strengthening endogenous traits reduces the risks and scientific uncertainty. Third, we should show respect for nature as a complex system of laws and interconnections that we cannot fully control. The main moral reason for intragenic modification, in our view, is the need to respect the “otherness” of nature.     

A Systematic Review of Wild Burro Grazing Effects on Mojave Desert Vegetation,USA

Wild burros (Equus asinus), protected by the 1971 Wild Free-Roaming Horse and Burro Act on some federal lands but exotic animals many ecologists and resource mangers view as damaging to native ecosystems, represent one of the most contentious environmental management problems in American Southwest arid lands. This review synthesizes the scattered literature about burro effects on plant communities of the Mojave Desert, a center of burro management contentions. I classified 24 documents meeting selection criteria for this review into five categories of research: (i) diet analyses directly determining which plant species burros consume, (ii) utilization studies of individual species, (iii) control-impact comparisons, (iv) exclosure studies, and (v) forage analyses examining chemical characteristics of forage plants. Ten diet studies recorded 175 total species that burros consumed. However, these studies and two exclosure studies suggested that burros preferentially eat graminoid and forb groups over shrubs. One study in Death Valley National Park, for example, found that Achnatherum hymenoides (Indian ricegrass) was 11 times more abundant in burro diets than expected based on its availability. Utilization studies revealed that burros also exhibit preferences within the shrub group. Eighty-three percent of reviewed documents were produced in a 12-year period, from 1972 to 1983, with the most recent document produced in 1988. Because burros remain abundant on many federal lands and grazing may interact with other management concerns (e.g., desert wildfires fueled by exotic grasses), rejuvenating grazing research to better understand both past and present burro effects could help guide revegetation and grazing management scenarios.     

Associations between stream valley geomorphology and riparian vegetation as a basis for landscape analysis in the eastern Sierra Nevada,California, USA

Ten streams in the eastern Sierra Nevada, California, were classified into six geomorphic valley types and sampled to determine environmental and riparian vegetation conditions. The geomorphic valley types were relatively uniform geologically and hydrologically, collectively representing the range of stream environments in the region. There were significant associations between the geomorphic valley types and riparian community composition. These geomorphic-vegetation units are landscape elements which comprise the riparian ecosystems in the region. They differ in their ecological charactersitics and sensitivity to management. The system of landscape elements can be used to classify streams for the purposes of resource inventory, detailed ecological studies, and impact prediction.