The identification of readily bioavailable pollutants in lake shkodra/skadar using semipermeable membrane devices (SPMDs), bioassays and chemical analysis

GOAL, SCOPE AND BACKGROUND: Lake Shkodra/Skadar is the largest lake in the Balkans region and located on the border between Albania to the south and Montenegro to the north. Because of the wide range of endemic, rare or endangered plant and animal species it supports, Lake Shkodra/Skadar and its extensive associated wetlands are internationally recognised as a site of significance and importance (Ramsar site). In recent years, social and economic changes in both Albania and Montenegro have lead to unprecedented levels of urban and industrial effluent entering the lake. Of particular concern is the increasing input of toxic hydrophobic organic pollutants (HOPs) into the lake and the degree to which these compounds are available for uptake by aquatic biota. Semipermeable membrane devices (SPMDs) have been shown to sample the readily bioavailable fraction (dissolved phase) of waterborne HOPs and in doing so provide relevant data for exposure assessment. The aim of the current study was to use SPMD-based sampling in conjunction with appropriate bioassays and chemical analysis to identify readily bioavailable HOPs in the lake. METHODS: SPMDs were constructed and deployed at three sites in the Albanian sector and three sites in the Montenegrin sector of Lake Skadar/Shkodra for 21 days. Following the dialytic recovery of target analytes and size exclusion chromatographic clean-up, aliquots of SPMD samples were subjected to GC-MS scan analysis for major components, GC-MS SIM analysis for 16 priority pollutant polycyclic aromatic hydrocarbons (PP-PAHs) and assayed for EROD-inducing, estrogenic and mutagenic potential using rainbow trout liver cells (RTL-W1), the yeast estrogen screen (YES) and the Ames Test, respectively. RESULTS AND DISCUSSION: A total of 39 compounds were tentatively identified in SPMD samples from the six sampling sites. Alkylated PAHs were the most abundant and ubiquitous compounds present along with various sterols and sterol derivatives. Numerous other compounds remain unidentified. 15 of the 16 targeted PP-PAHs were present in samples from one or more of the sampling sites indicating these compounds are both readily bioavailable and widely distributed in Lake Shkodra/Skadar. Total PP-PAH concentrations ranged between 3991 ng/SPMD and 10695 ng/SPMD. Bioassays carried out on SPMD samples revealed significant EROD-inducing and estrogenic potential at five of the six sampling sites indicating toxicologically relevant compounds are readily available for uptake by resident aquatic biota. EROD-inducing potential was positively correlated with targeted PP-PAH concentration (r2 = 0.74). However, comparison of bioassay- and analytically-derived toxicity equivalents revealed targeted PP-PAHs were responsible for less than 0.06% of the total EROD-inducing potential. CONCLUSIONS AND OUTLOOK: The combination of SPMD-based sampling with appropriate bioassays and chemical analysis provided an effective tool for the identification of environmentally relevant waterborne pollutants in Lake Shkodra/Skadar. Our results show that toxicologically relevant HOPs including EROD-inducing and potentially estrogenic compounds are widely distributed in the lake and readily available for uptake by aquatic biota. Our results also suggest that alkylated PAHs rather than parent compounds may be of greater toxicological relevance in the lake. As anthropogenic influences continue to increase, SPMD-based sampling is expected to play a central role in future research concerned with the identification, monitoring and assessment of the risk posed by HOPs to Lake Shkodra/Skadar's aquatic biota.     

酵母菌处理高浓度色拉油加工废水研究

从含油土壤中筛选出适用于色拉油加工废水的酵母菌菌群,并用摇瓶试验研究了该菌群对未经预处理的高浓度含油色拉油加工废水的降解效果．采用酵母菌菌群处理总有机碳（ Ｔ Ｏ Ｃ） 含量为ρ Ｔ Ｏ Ｃ＝ ２ ５００ ｍｇ Ｌ－ １ 的色拉油加工废水,２４ ｈ 内可以去掉８５ ．２ ％ 的 Ｔ Ｏ Ｃ．酵母菌菌群在酸性条件下（ｐ Ｈ３ 左右） 表现出更好的处理效率,反应温度升高时 Ｔ Ｏ Ｃ 去除率有降低的趋势．结果表明,高浓度含油色拉油废水可以直接用酵母菌法进行处理     

湍流环形通道热泳脱除可吸入颗粒物技术研究

湍流中PM 2.5粒子的热泳沉积是国际上研究热门课题.但目前单纯热泳沉积效率也不过20%左右.依据热泳基本原理,设计了一种新型湍流方环形双壁冷却式通道.计算表明,该类型通道比一般单管通道有着较高的可吸入颗粒物脱除效率.同时,利用湍流的沉积效率,加上热泳沉积效率,可以达到较高的总泳沉积效率.通过结构设计,可以提高可吸入颗粒物的脱除效率,是值得进一步探索的新路子.     

温度对生物除磷系统微生物种群关系及动力学的影响

以西安市第三污水处理厂的氧化沟工艺为对象,利用荧光原位杂交技术（FISH）,研究了温度对强化生物除磷系统（EBPR）除磷性能及微生物种群关系的影响。结果表明：当水温低于20 ℃时,厌氧释磷速率和乙酸吸收速率随着温度上升逐渐增加,聚磷菌（PAOs）占总细菌（EUB）的比例也逐渐增加;当水温在20~25 ℃之间,厌氧释磷速率达到最大值,为10.86 mg P·（g VSS·h）-1,乙酸吸收速率随温度升高持续增加,PAOs占EUB的比例也达到最大值,为6.65%;当水温高于25 ℃时,厌氧释磷速率随温度的升高而下降,而乙酸吸收速率则继续增加,聚糖菌（GAOs）的数量已经超过PAOs而成为优势菌,导致处理效果下降。通过对实验数据的统计,得出活性污泥厌氧乙酸吸收速率的温度系数为1.018。     

Application of fluorescent in situ hybridization for ‘de novo’ anomalies in prenatal diagnosis

Fluorescent in situ Hybridization (FISH) was carried out for three cases of abnormal karyotypes in prenatal studies. Two concerned de novo structural anomalies and the third a marker chromosome. The origin of the extra material could be defined in all three cases, which gives a better insight into the relationship between genotype and phenotype and makes more adequate genetic counselling possible.     

Numerical simulation of stratified turbulent two phase flow in aquatic environment

Ｉｎｅｓｔｕａｒｙ,ｄｅｎｓｉｔｙｓｔｒａｔｉｆｉｅｄｆｌｏｗｅｘｉｔｓｗｉｄｅｌｙｂｅｃａｕｓｅｆｒｅｓｈｗａｔｅｒｊｏｉｎｓｉｎｔｏｓｅａｗａｔｅｒａｎｄｔｈｅｄｅｎｓｉｔｙｏｆｆｒｅｓｈｗａｔｅｒｉｓｄｉｆｆｅｒｅｎｔｆｒｏｍｔｈａｔｏｆｓｅａ?..     

1种钝化剂对3种水稻生长影响及降镉效果的研究

为了考察钝化剂对不同程度污染土壤及不同水稻品种的适应性,采用盆栽试验研究了2种程度镉污染农田土壤(轻度污染土壤和重度污染土壤)中钝化剂的修复效果以及3个品种水稻对镉的吸收。结果表明:添加钝化剂后,2种污染程度土壤的pH值在不同时期均显著提高(轻度污染土壤pH值提高了0. 18～0. 73,重度污染土壤pH值提高了0. 42～0. 71),土壤中pH值与土壤有效态Cd呈负相关性(轻度污染土壤的pH值与土壤有效态Cd相关系数为0. 77;重度污染土壤的pH值与土壤有效态Cd的相关系数为0. 91)。2种程度镉污染土壤分蘖期和成熟期的有效态Cd在施加钝化剂后明显降低(轻度污染土壤有效态Cd在分蘖期的最大降幅为30. 69%,在成熟期的最大降幅为25. 69%;重度污染土壤有效态Cd在分蘖期的最大降幅为6%,在成熟期的最大降幅为7. 5%)。糙米总Cd在施加钝化剂后也明显降低(轻度污染土壤的糙米总Cd降低幅度为59. 46%～66. 67%,重度污染土壤的糙米总Cd降低幅度为18. 71%～57. 60%)。施加钝化剂对水稻株高、叶绿素、有效穗、生物量及产量无显著性差异。此外,3个水稻品种的糙米Cd富集系数有一定的差异,2种污染程度土壤中水稻生长有差异。因此,钝化剂对3种水稻品种均具有降镉效果,且对3种水稻生长无负面影响。钝化剂对水稻生长轻度镉污染土壤的修复效果优于重度污染土壤的修复效果,施用钝化剂能使轻度污染土壤中糙米总Cd达标,不能使重度污染土壤中糙米总Cd达标;轻度污染土壤中水稻生长效果明显优于重度污染土壤中水稻生长。     

UASB-A/O工艺处理垃圾渗滤液短程生物脱氮的实现

应用缺氧/厌氧UASB-A/O组合工艺处理高氮晚期渗滤液,在获得稳定有机物和氮同步去除的前提下,考察了如何实现并维持A/O系统内稳定短程硝化的途径.结果表明:在单一UASB反应器内,同时发生了缺氧反硝化和厌氧产甲烷的反应,有机物和NOx--N去除速率分别为5.3,1.1kg/(m3×d).12~30.6℃时,经过54d的运行, A/O反应器实现短程硝化 (亚硝态氮积累率>50%),此后亚硝态氮积累率迅速上升,70d后,亚硝态氮积累率稳定在90%以上.在A/O反应器内,游离氨和游离亚硝酸协同作用是实现并维持稳定短程硝化的决定因素.此外,以pH值作为A/O硝化反应进行的过程控制参数,可准确把握硝化终点,避免过度曝气破坏短程硝化,为氨氧化菌的生长创造有利条件,有效抑制亚硝酸盐氧化菌的生长并逐渐从系统中淘洗出去,实现了硝化菌种群的优化,荧光原位杂交技术检测也证明这一点.     

Adaptive introgression as a resource for management and genetic conservation in a changing climate

Current rates of climate change require organisms to respond through migration, phenotypic plasticity, or genetic changes via adaptation. We focused on questions regarding species’ and populations’ ability to respond to climate change through adaptation. Specifically, the role adaptive introgression, movement of genetic material from the genome of 1 species into the genome of another through repeated interbreeding, may play in increasing species’ ability to respond to a changing climate. Such interspecific gene flow may mediate extinction risk or consequences of limited adaptive potential that result from standing genetic variation and mutation alone, enabling a quicker demographic recovery in response to changing environments. Despite the near dismissal of the potential benefits of hybridization by conservation practitioners, we examined a number of case studies across different taxa that suggest gene flow between sympatric or parapatric sister species or within species that exhibit strong ecotypic differentiation may represent an underutilized management option to conserve evolutionary potential in a changing environment. This will be particularly true where advanced‐generation hybrids exhibit adaptive traits outside the parental phenotypic range, a phenomenon known as transgressive segregation. The ideas presented in this essay are meant to provoke discussion regarding how we maintain evolutionary potential, the conservation value of natural hybrid zones, and consideration of their important role in adaptation to climate.     

Determination of biodegradation potential by two culture-independent methods in PAH-contaminated soils

Biodegradation potentials of polycyclic aromatic hydrocarbons (PAHs) were determined with soil samples collected from various depths of a PAH-contaminated site and of a site nearby where PAHs were not found. Putative dioxygenase genes were amplified by a primer set specific for initial dioxygenases and identified by web-based database homology search. They were further categorized into several groups of which four dioxygenases were selected as probes for DNA hybridization. The hybridization signals according to the presence of putative dioxygenases were positively related to the extent of PAH contamination. However, the signal intensities varied depending on the probes hybridized and moreover were not consistent with PAH biodegradation activities determined by CO2 evolution. Despite widely accepted advantages of molecular biodegradation assessment, our data clearly present the variations of assessment results depending on the genetic information used and suggest that the methodology may tend to underestimate the real biodegradation capacity of a site probably due to the limited dioxygenase database available at the moment. Therefore, the molecular assessment of biodegradation potential should involve a very careful primer and probe design and an extensive microbiological examination of a site of interest to accurately delineate the biodegradation potential of the site.