拟柱孢藻毒素生态毒性的研究进展和展望

随着全球变暖的加剧,拉氏拟柱胞藻(Cylindrospermopsis raciborskii)表现出从热带和亚热带地区向温带地区迁移和扩张的趋势。拟柱孢藻过度繁殖引发的主要生态环境问题是其有毒次级代谢产物——拟柱孢藻毒素(cylindrospermopsin,CYN)的大量产生。这种蓝藻毒素水溶性很高,可长时间停留在水体中,对动植物和人类健康造成威胁。近年来,国际上对CYN的研究越来越多,研究范围也日趋广泛,而国内的相关研究却很少。本文根据现有的研究结果,介绍了CYN的分子结构和理化特性;总结了CYN可能对水生生物、土壤作物和人类健康造成的影响和危害,并对相应的致毒机理进行了归纳总结;最后对未来的研究内容和方向进行了展望。     

Illicit drugs as new environmental pollutants: cyto-genotoxic effects of cocaine on the biological model Dreissena polymorpha

The increase in global consumption of illicit drugs has produced not only social and medical problems but also a potential new environmental danger. Indeed, it has been established that drugs consumed by humans end up in surface waters, after being carried through the sewage system. Although many studies to measure concentrations of several drugs of abuse in freshwater worldwide have been conducted, no data have been available to evaluate their potentially harmful effects on non-target organisms until now. The present study represents the first attempt to investigate the cyto-genotoxic effects of cocaine, one of the primary drugs consumed in Western Countries, in the biological model Dreissena polymorpha by the use of a biomarker battery. We performed the following tests on Zebra mussel hemocytes: the single cell gel electrophoresis (SCGE) assay, the apoptosis frequency evaluation and the micronucleus assay (MN test) for the evaluation of genotoxicity and the lysosomal membranes stability test (neutral red retention assay; NRRA) to identify the cocaine cytotoxicity. We exposed the molluscs for 96 h to three different nominal concentrations in water (40 ng L⁻¹; 220 ng L⁻¹; and 10 μg L⁻¹).Cocaine caused significant (p < 0.05) primary DNA damage in this short-term experiment, but it also caused a clear increase in micronucleated cells and a marked rise in apoptosis, which was evident in samples from even the lowest environmental cocaine concentration. Because cocaine decreased the stability of lysosomal membranes, we also highlighted its cytotoxicity and the possible implications of oxidative stress for the observed genotoxic effects.     

厌氧—交替O/A的序批式膜生物反应器脱氮除磷性能比较

提出一种高效脱氮除磷的新工艺,即厌氧-交替O/A的序批式膜生物反应器.在HRT为8.4 h、交替O/A时间为10min/10 min时,系统氨氮、总氮、总磷的平均去除率分别达到99.57%、89.92%、93.26%.典型周期试验证明.频繁的O/A环境更利于系统高效脱氮除磷,且O/A交替越频繁,系统中反硝化聚磷菌(DPAO)占聚磷菌(PAO)的比例(即缺氧吸磷速率与好氧吸磷速率的比值)越大.当交替O/A时间为10 min/10 min时.系统中DPAO占PAO的比例为70.87%,比交替O/A时间为30 min/30 min时提高了66%.     

Sediment Quality Assessment in the Gulf of Gdańsk (Baltic Sea) Using Complementary Lines of Evidence

Sediments from Polish coastal environments were classified by a quality assessment approach that took into account trace metal and organic micropollutant concentrations, grain-size distribution, and organic carbon content. Generally, no benthic organisms were found at sites where sediments were classified as heavily polluted. However, areas characterized by a moderate contamination showed a variable composition of the benthic community and changing bioaccumulation patterns; therefore, no single species found in the Gulf of Gdańsk could be considered representative of the whole benthic environment. Although sediment monitoring must be considered a suitable tool to detect hot-spot pollution areas in coastal and inland waters, it should be complemented by bioaccumulation measurements to evaluate the actual risk posed by contaminants to benthic organisms. This “biological information” allows a better appreciation of the real benthic infaunal community exposure to chemicals and can usefully complement the existing sediment quality guidelines.     

The case for regulating intragenic GMOs

This paper discusses the ethical and regulatory issues raised by “intragenics” – organisms that have been genetically modified using gene technologies, but that do not contain DNA from another species. Considering the rapid development of knowledge about gene regulation and genomics, we anticipate rapid advances in intragenic methods. Of regulatory systems developed to govern genetically modified organisms (GMOs) in North America, Europe, Australia, and New Zealand, the Australian system stands out in explicitly excluding intragenics from regulation. European systems are also under pressure to exclude intragenics from regulation. We evaluate recent arguments that intragenics are safer and more morally acceptable than transgenic organisms, and more acceptable to the public, which might be thought to justify a lower standard of regulation. We argue that the exemption of intragenics from regulation is not justified, and that there may be significant environmental risks associated with them. We conclude that intragenics should be subject to the same standard of regulation as other GMOs.     

低碳源条件下改良双污泥系统脱氮除磷优化研究

在低碳源废水条件下,通过对改良后的双污泥处理工艺与传统厌氧-好氧-缺氧工艺效果进行比较分析,探究解决城市生活污水碳源不足的方法.实验组反应器为改良型双污泥系统,即在原双污泥系统缺氧段增加两个阶段的微曝气(曝气量0.5 L·min~(-1)),对照组反应器为多级厌氧-好氧-缺氧SBR.结果表明,进水COD、氨氮、SOP浓度分别为200、35、10 mg·L-1时,实验组比对照组脱氮除磷效果好(去除率分别为:TN 94.8%与60.9%;TP 96.5%与75%),出水SOP浓度0.35 mg·L-1,NH+4-N浓度0.50 mg·L-1,TN浓度1.82 mg·L-1,完全满足《城镇污水处理厂污染物排放标准》(GB 18918-2002)一级A标准.采用优化后的工艺,单位碳源(以COD计)可实现的最大的氮、磷的去除量分别为0.17 g·g-1和0.048 g·g-1,可以最大程度地解决当前城市废水碳源浓度较低的问题.     

粤港澳大湾区土壤污染问题计量及可视化分析

土壤污染问题已经成为粤港澳大湾区迈向国际一流湾区的桎梏,对标纽约、旧金山和东京三大世界一流湾区可以为应对大湾区土壤环境压力提供方向指引.以Web of Science核心数据库中相关文献为研究对象,运用文献共被引分析、关键词共现分析和关键词突现检测的文献计量定量分析方法,对世界三大湾区土壤污染领域的研究现状进行了分析.结果表明,目前世界湾区土壤污染的研究主题主要集中在土壤污染物来源、空间分布、修复处理研究,以及土壤污染的生物可利用度、对海洋生物的不利影响、海洋生物指标在土壤污染评估的作用;土壤污染物研究的热点集中在重金属污染和有机污染上,海洋生物关联研究则对土壤污染的毒性、引发的生物性畸变和生物标志物讨论较多.通过对比国内外湾区土壤污染研究状况,发现我国湾区土壤污染研究相比世界三大湾区起步较晚,且现有国内文献成果的研究区域和主题分布不均衡,特别是在湾区土壤污染的海洋生物关联研究方面热度较低.因此,开展粤港澳大湾区海陆一体化研究、扩展考察领域至土壤污染的相关海洋生物研究,对完善我国粤港澳大湾区土壤污染研究、应对大湾区土壤环境问题至关重要.     

间歇曝气连续流反应器同步硝化反硝化除磷

采用连续流反应器处理生活污水,保持厌氧段格室为3格,将缺氧段格室从2格减少至0格,好氧段格室由5格逐渐增加至7格,Run1时对好氧段格室采用连续曝气,Run2～Run4时采用间歇曝气.曝/停比分别为:40 min/20 min、40 min/30min、40 min/40 min,硝化液回流比从150%逐渐减少至0%. Run4时,平均进水COD、NH+4-N、TN、PO_4~(3-)-P浓度分别为259. 34、60. 26、64. 42、6. 10 mg·L-1,出水COD、NH+4-N、TN、PO_4~(3-)-P分别为26. 40、1. 03、5. 84、0. 30 mg·L-1.反应器对氮素的去除量从Run1时的192. 30 mg·h-1逐渐增加至Run4时的244. 00 mg·h-1,相应地去除率从65. 40%逐渐增大至95. 30%;从Run1～Run4,反硝化聚磷菌和聚磷菌的活性分别从36. 05%和38. 20%增大至140. 50%和133. 40%;通过间歇曝气在连续流反应器中实现了同步硝化反硝化除磷脱氮,为污水处理厂提标改造提供参考.     

O2、NO-3、NO-2为电子受体的生物除磷比较

通过平行运行3个分别以O₂、NO^-₃、NO^-₂为电子受体的SBR除磷系统,探讨了反硝化除磷区别于好氧除磷的工艺特征及其内在微生物竞争机制.NO^-₂不会对经驯化后反硝化聚磷菌（DPAO）的缺氧吸磷产生直接抑制作用,但其作为反硝化除磷电子受体的效能远低于NO^-₃;具备利用NO^-₃而缺乏NO^-₂反硝化酶系的DPAO（DPAO₅）流失及聚糖菌（GAO）增殖是根本原因.而NO^-₃是一种高效电子受体,其反硝化除磷效能与以O₂为受体的好氧除磷系统相当,两者在除磷计量学和功能菌群构成上十分接近.作为聚磷菌（PAO）的竞争者,GAO在3个研究系统中均大量存在.基于对不同电子受体的利用能力,PAO包含P_O、P_N、P_n、P_Nn、P_ON、P_ONn等6个种类.P_ON和P_ONn等兼性PAO是生物除磷的主体,其在污泥中比例越高,系统的除磷负荷也越大,即SBR_o＞SBR_n5＞SBR_n3.     

不同污泥龄(SRT)对SNEDPR系统脱氮除磷影响

为了解不同污泥龄(SRT)对同步硝化内源反硝化除磷(SNEDPR)系统脱氮除磷性能的影响,采用4组延时厌氧(180min)/低氧(溶解氧0.5~1.0 mg·L~(-1))运行的SBR反应器,以实际城市污水为处理对象,考察不同的SRT(5、10、15、25 d)条件下系统的脱氮除磷性能及其污泥性状的变化情况.结果表明,当SRT≥10 d时,短SRT有利于提高PAOs的竞争优势;在SRT为15 d和10 d时,系统除磷性能均较高,尤其是当SRT=10 d时,PPAOs,An平均为68.4%,PRA和PUA分别高达31.9mg·L~(-1)和34.3 mg·L~(-1).在SRT为15 d和10 d时,系统的硝化性能不受SRT变化的影响,且在SRT=15 d时,系统具有最高的脱氮性能,TN去除率和SNED率分别平均为89.6%和71.8%.在SRT≥10 d时,系统的COD去除性能不受SRT的变化影响,去除率达78%以上;但SRT=5 d时,由于系统生物量的流失使得系统对C、N、P的去除性能均较差,SNED率和PO3-4-P去除率分别低至5.7%和0.5%.此外,在SRT=15 d时,系统污泥沉降性能最好,SV和SVI分别为20%和64 mL·g~(-1),且污泥浓度随着SRT的延长而升高;长SRT(25 d)下系统抗冲击负荷能力较强,但污泥的沉降性能变差.