Application of rotating cylinder method for ecotoxicological evaluation of antifouling paints

The environmental impact of two biocide-free antifouling paints, fluoropolymer and silicone types, painted on a test cylinder was assessed using a battery of ecotoxicity test and chemical analyses for organic micro-pollutants such as perfluoroalkyl substances (PFAS). A biocide paint containing zinc pyrithione (ZnPT₂) and cuprous oxide was assessed as a positive control. A standardized laboratory rotating-cylinder method using each test cylinder with artificial seawater was performed for 45 days. After 1?h rotation, the leaked seawater was subjected for bioassay and chemical analyses twice weekly. The seawater extracts from the biocide paint showed adverse effects on bacteria, algae, and crustaceans, but those from the biocide-free paints did not. The leakage seawater from biocide-free paints, after 7-day continuous rotation, contained the same concentration levels of PFAS as blank seawater used to conduct the tests. Thus, no significant toxicities of the biocide-free paints were found under the conditions of this study. Simultaneous analysis of ZnPT₂ and copper pyrithione (CuPT₂) was developed using an HPLC with a polymeric resin column, showing that ZnPT₂ was converted to CuPT₂ by trans-chelation in the leakage seawater from the positive control paint. The experimental results using a laboratory rotating-cylinder method demonstrated that biocide-free paints did not markedly affect three species tested and no PFAS was detected. In contrast, biocide paint was significantly toxic to test species and toxicity of the extract on bacteria was partly responsible for CuPT₂ produced in leakage seawater. Thus, a laboratory rotating-cylinder method may be applied for ecotoxicological assessment of antifouling paints.     

Roe and red deer as bioindicators of heavy metals contamination in north-western Poland

The present paper examines the degree of environmental contamination in areas covered by the Natura 2000 programme, located in north-western Poland, with selected heavy metals based on their concentration in target organs of roe and red deer. Lead, cadmium, copper, iron, and zinc concentrations were determined by inductively coupled plasma–atomic emission spectrometry. Residues of lead and cadmium were found in most of the analysed samples of roe and red deer organs The concentration of cadmium in the organs of the animals studied was much higher than that of lead. The median for Pb in liver and kidneys was 0.055 and 0.092 μg/g dry weight (d.w.) in roe deer, and 0.067 and 0.081 μg/g d.w. in red deer, respectively. The median for liver and kidney cadmium was 0.770 and 6.139 μg/g d.w. in roe deer, and 0.422 and 6.365 μg/g d.w. in red deer, respectively. Our study has demonstrated that this area is laden with lead and cadmium. This is evidenced by the fact that maximum permissible levels of these elements in the organs of red and roe deer, which were used as bioindicators of environmental contamination, were exceeded.     

离子交换膜应用于光/电/化学协同催化反应器

在光/电/化学协同催化反应器中,以离子交换膜代替盐桥连通阴、阳两室,以30 mg/L的甲基红溶液为目标降解物,考察了不同连通方式、初始pH和阴极电位对反应的影响. 结果表明:甲基红在阳离子膜型反应器中的表观反应速率常数明显高于盐桥型及阴离子交换膜型反应器,这是由于阳离子交换膜可以及时有效地将阳极室中产生的H+转移至阴极室中参与阴极反应. 甲基红在阳离子膜型反应器中的去除率随溶液初始pH的增高而降低,随阴极电位的增加先增大后减小,最佳反应条件为pH=2.0～3.0,阴极电位(-E_c)=0.6 V.      

灵菌红素对有害藻类的除藻活性研究

研究了沙雷氏菌的天然产物灵菌红素对引起海洋赤潮和淡水水华的有害藻类的除藻活性和光解性质.结果表明,5.0μg/mL灵菌红素能够在24h内将新月菱形藻、中肋骨条藻、水华鱼腥藻和微小平列藻培养液中的藻类全部杀死,除藻活性高达100%.5.0μg/mL灵菌红素在30000lx光强下36h完全分解,不会给自然环境带来二次污染.     

加压溶氧光催化反应器降解活性艳红X-3B

探讨了加压溶氧条件对活性艳红X-3B的降解与脱色的作用,考察了加压条件下pH值,TiO2投加量及温度等对活性艳红X-3B降解的影响.结果表明,加压条件与常压条件下变化趋势基本一致.加压充氧有助于活性艳红X-3B的降解与脱色,加压充N2对反应基本没有作用,说明增加活度不是关键因素,加压使溶液中溶解氧增加是导致活性艳红X-3B降解与脱色的主要原因.光催化降解过程,发色基团最易被打碎,60min内降解效果显著,而萘环和苯环降解效果不十分明显.CODCr的降解与色度的褪除成正相关,脱色率越高,COD的降解率也越高.     

高效絮凝剂制备的前期浸取研究

我国油田多采用絮凝剂处理含油污水。为得到高效、廉价的絮凝剂,使用赤泥最优化制备聚合氯化铝铁。通过化学分析法和X射线衍射分析,得出赤泥中铝﹑铁元素含量。正交实验结果表明:影响Fe溶出的因素由强到弱依次为盐酸用量系数﹑反应温度﹑目数和反应时间,最佳浸出条件为目数80～120、液固比5.5、反应温度95℃、反应时间3.5h。     

亚热带土壤氮素反硝化过程中N2O的排放和还原

将采集于江西鹰潭的45个发育于不同成土母质和不同利用方式的土壤样本,在密闭、淹水、充N2的严格厌氧条件下进行了28d的培养试验(30℃),在培育过程中,定期测定NO3--N(加入量为200mg·kg-1)含量和培养瓶上部空间N2O的含量变化.实验结果表明,N2O含量(N)随培养时间t的变化可用方程N=A×(1-exp(-k1 t))-B×exp(k2 t)拟合(A表示培养过程中N2O总排放量;B为常数;k1和k2分别为N2O排放速率常数和还原速率常数,拟合值和实测值之间回归方程的决定系数R2=0.84±0.11).不同土壤之间培养期间N2O总排放量(A)的变异可以用培养7d内被反硝化的NO3--N量和N2O排放率(A值与28d内被反硝化的NO3--N总量的百分比)进行解释(R2=0.829,p＜0.01).被反硝化的NO3--N量则主要受土壤有机碳含量或有机氮矿化量控制,N2O排放率则随k2的增大而呈指数下降(p＜0.01).由此可见,在该实验条件下,还原N2O能力强的土壤,在相同量的NO3--N被反硝化的情形下,排放的N2O可能较少.但影响k2值的主要因素还有待进一步研究.     

长期有机物循环对红壤稻田养分及水稻生长的影响

通过长期有机物循环的定位试验,研究了长期有机物循环利用对红壤稻田养分供应及水稻生长发育的影响,目的是了解长期有机物循环利用后土壤养分含量变化、水稻生长特性及两者的相关性。结果表明有机物循环明显提高了土壤有机质含量,并使土壤养分维持在一个相对较高的水平上。有机物循环处理的土壤有机质,全N、全P和全K及其有效部分的平均含量分别比无循环处理提高了445％、347％、175％、94％,特别是碱解N,速效P和速效K含量提高显著,有机物循环处理比无循环处理提高达469％、452％和347％。有机物循环利用提高了水稻分蘖数和叶面积指数,使水稻群体的透光率减少。有机物循环处理平均单叶净光合速率比无循环处理高68％,蒸腾作用比无循环处理高50％,最终表现为干物质积累量及稻谷产量的增加。对长期有机物循环利用后的红壤稻田养分指标与水稻生长指标进行逐步回归分析后发现,土壤中速效P及有机质含量的增加是促进水稻生长的主要因素.     

Flow and transport characteristics at an Epinephelus guttatus (red hind grouper) spawning aggregation site in St. Thomas (US Virgin Islands)

This study characterizes the flow field at a spawning site located at the shelf break of a Caribbean island for the Epinephelus guttatus (red hind grouper) in relation to this species spawning events. In order to understand the oceanographic dynamics targeted by the fishes, current measurements were profiled throughout the water column for almost a year at the spawning site. The characteristics of the flow field and its evolution after spawning were investigated by using a numerical ocean model that resolved the observed tide and simulated the island scale flow where passive, neutrally buoyant virtual particles were released for 10 days to trace the flow pathways.Observed currents during the spawning period revealed that the flow was vertically sheared, to the south and weakest at the bottom, and to the west or east at the surface. The tidal analysis revealed that the flow at the time of spawning was directed across and on-shelf, although weaker close to the bottom. The model showed that the initial on-shelf transport was counteracted by the bottom flow directed to the shelf break, where virtual particles were entrained by the downwelling flow. A significant percent of particles resided less than two hundred meters deep, in the vicinity of the chlorophyll maximum and returned to the shelf break, close to the release location within 8-10 days. This journey was largely controlled by the timing between downwelling at the spawning site and upwelling further east at the shelf break, which was driven by the coupling between wind and tide induced vertical movements at the shelf break and deeper. The release location, vertical rotation of its flow field, and its transport properties were shown to be relatively resilient to the passage of transient sub-mesoscale eddies as well as to acute mesoscale flow reversals, suggesting that physical retention is maximized in the area surrounding the spawning site.     

模拟海平面上升和氮负荷增加对河口感潮沼泽湿地CO2垂直交换的影响

海平面上升和氮负荷增加是入海河流河口面临的两个主要全球性环境问题.揭示河口潮滩沼泽湿地CO₂垂直通量对二者及交互作用的响应,对于科学评估全球变化背景下的河口潮滩沼泽湿地生态系统蓝碳功能具有重要的科学意义.本研究以闽江河口鳝鱼滩中潮滩短叶茳芏湿地为研究对象,在野外原位实施模拟海平面上升、氮负荷增加及二者交互作用的实验处理近1年后,在2019年冬季各月的大潮日白天涨潮前、平潮期及落潮后3个阶段,运用透明静态箱（或遮光布遮光）+Li-6800光合作用仪对短叶茳芏湿地生态系统净CO₂交换（NEE）和生态系统呼吸（ER）进行测定.结果发现,与对照处理相比,冬季尺度3种处理下短叶茳芏湿地生态系统NEE均显著增加;模拟海平面上升影响下短叶茳芏湿地生态系统ER无显著变化;氮负荷增加及二者交互作用下,短叶茳芏湿地ER均显著增加.模拟海平面上升、氮负荷增加及二者交互作用情景下,短叶茳芏湿地生态系统总初级生产力（GPP）均明显增加.研究表明,在未考虑甲烷排放的情景下,即使在冬季,海平面上升、氮负荷增加及二者交互作用将可能增加亚热带河口潮滩半咸水沼泽湿地的碳汇功能.