生态系统健康理论在流域水环境管理中应用研究的意义、难点和关键技术——代“流域水环境管理战略研究”专栏序言

系统总结了国际河流水环境管理的发展趋势,对国际上基于河流健康的水环境管理体系与关键技术进行了分析.针对我国河流生态环境的问题与管理现状,在借鉴国外管理经验和方法的基础上,以全国环境管理关键技术研究为契机,阐述了生态系统健康理论在我国流域水环境管理中应用的意义、用途和关键技术.     

长江流域鲤鱼和鲟鱼的模型建立与剂量率估算研究

针对长江流域两种典型淡水鱼类-鲤鱼和鲟鱼,通过实验对两种鱼类各部分的浓集性质进行了研究,并建立了相关的的简化解剖学模型(区分了不同组织和器官部分)和外照射环境模型;用蒙特卡罗方法模拟源器官和环境水体对靶器官的能量沉积,采用某厂址水体数据以及实验得到的鱼类不同部位的浓集系数,估算了上述两种鱼类在该环境中所受到的内外照射剂量率,并与ERICA方法进行了比较分析.     

Eutrophication and algal blooms in channel type reservoirs: A novel enclosure experiment by changing light intensity

To explore eutrophication and algal bloom mechanisms in channel type reservoirs, a novel enclosure experiment was conducted by changing light intensity (LI) in the Daning River of the Three Gorges Reservoir (TGR). Square enclosures (side 5.0 m) were covered on the surface with shading materials of different thickness, and with their bases open to the river. Changes and characteristics of the main eutrophication factors under the same water quality and hydrodynamic conditions but different LI were evaluated. All experimental water samples were neutral and alkalescent, with high nitrogen and phosphate concentrations, low potassium permanganate index, stable water quality, and different LI. At the same water depth, LI decreased with increasing shade material, while dissolved oxygen and water temperature were both stable. The growth peak of phytoplankton was with light of 345-4390 lux underwater or 558-7450 lux above the water surface, and water temperature of 25.6-26.5℃. Algae were observed in all water samples, accounting for 6 phylum and 57 species, with algal density changing frequently. The results showed that significantly strong or weak light was unfavorable for phytoplankton growth and the function together with suitable temperature and LI and ample sunshine encouraged algal blooms under the same water quality and hydrodynamic conditions. Correlation analysis indicated that algae reduced gradually lengthwise along water depth in the same enclosure while pH became high. The power exponent relationship between chlorophyll a (Chl-a) and LI was found by curve fitting, that is Chl-a = K(LI)ⁿ.     

环渤海典型海域潮间带沉积物中重金属分布特征及污染评价

对环渤海11个采样点潮间带沉积物中重金属含量进行了测定,结果表明:Cu、Cr、Zn、As、Cd、Pb的平均含量分别为14.92,31.73,73.68,11.34,0.448,21.94 mg · kg^-1.与国内典型的河口和海湾比较,Cu、Cr、Zn、As处于相对较低水平,Cd、Pb处于中等水平.重金属表现出相似的空间变化规律,即高值区集中在辽东湾,次高值区在渤海湾,低值区位于莱州湾.相关性分析表明:Cr、Cu、Zn、Cd、Pb可能具有相似的输入源,As的主要来源可能与其它几种金属不同.地累积指数法评价结果显示:Cr、Cu、Zn、As属于清洁级别,Pb处于轻度污染水平,Cd处于偏中度污染.重金属元素污染程度排序为Cd>Pb>Zn>Cu>As>Cr.潜在生态危害指数法评价结果表明:重金属对渤海典型海域生态风险构成的危害程度排序为Cd>Pb>As>Cu>Zn>Cr.Cr、Cu、Zn、As、Pb均为低生态危害等级,Cd以中等生态危害等级为主,局部海域出现强、很强、极强生态危害等级.     

基于营养盐分布特征的长江口附近海域分区研究

基于长江口海域2005年夏季、秋季和2006年春季三期调查数据,对盐度、无机氮、活性磷酸盐、活性硅酸盐、悬浮物和溶解氧浓度进行了聚类分析,并依据聚类结果对长江口附近海域进行分区.结果表明,长江口海域可分为4个区域.受陆地径流和海洋环流的影响,4个分区的范围随着季节略有变化.各区域水体的水文、化学特征和控制因素各不相同.一区是淡水控制区,受淡水影响表现出低盐、中沙、高营养盐、氮磷比远高于Redfield比值等特征;二区处于悬沙锋控制区域,最突出的特征是悬浮物含量高.悬沙锋内外含沙量相差3倍以上;三区在羽状锋控制范围,具有明显的盐度水平梯度,表层盐度和底层盐度差异较大;四区处于长江冲淡水外缘,受外海陆架水控制,盐度较高.     

多方法研究呼伦湖表层沉积物有机质的赋存特征及来源

湖泊沉积物有机质是全球碳循环的重要组成部分之一.寒旱区湖泊由于地理位置和气候条件的特殊性,其沉积物有机质的赋存和迁移转化特征更容易受到气候变化的影响.以我国寒旱区典型代表湖泊——呼伦湖为例,采用连续提取法、C/N（碳氮比值）、δ13C（碳稳定同位素）、三维荧光光谱技术对呼伦湖表层沉积物有机质的含量和组分的时空分布特征、污染来源及稳定性进行了研究.结果表明:①2018年10月（秋季）、2019年3月（冬季）、2019年5月（春季）、2019年7月（夏季）,呼伦湖表层沉积物中w（TOC）的平均值分别为（25.05±9.73）（26.92±11.60）（24.68±10.19）（24.36±10.01）g/kg,呈冬季高、夏季低,由西北部向东南部递减的时空分布趋势.②w（WEOM）（WEOM为水提态有机质）、w（FA）（FA为富里酸）、w（HA）（HA为胡敏酸）和w（HM）（HM为胡敏素）的年均值分别为（0.63±0.33）（2.31±1.26）（3.42±1.49）（19.21±7.83）g/kg,w（WEOM）:w（FA）:w（HA）:w（HM）为1.0:3.7:5.5:30.7,其中HM为有机质的优势组分.③WEOM包括类富里酸组分C1,类腐殖酸组分C2和C3,以及类色氨酸组分C4共4个荧光组分,其中,类腐殖质组分（C1+C2+C3）贡献了总荧光强度的79.2%,为优势荧光组分.④沉积物有机质主要来自于陆源,陆源有机质的平均贡献率在80%左右.⑤沉积物PQ值（胡敏酸占腐殖酸的比例）和WEOM的HIX（腐殖化指数）年均值分别为0.55和6.39,表明现阶段呼伦湖表层沉积物有机质腐殖化程度较高且相对稳定.研究显示:呼伦湖表层沉积物有机质含量较高,表现出季节和空间分布差异性;有机质主要来自陆源,以类腐殖质为主,具有腐殖化程度高和相对稳定的特点.      

呼伦湖水体悬浮颗粒物中有机质的赋存特征及来源解析

SPOM（suspended particulate organic matter,悬浮颗粒物中的有机质）是地表水体中有机质的重要组分之一,在全球碳循环和水体富营养化过程中发挥着重要作用.采用连续提取法、δ13C（碳稳定同位素）、三维荧光光谱和平行因子分析技术对呼伦湖夏季SPOM的含量、组分、荧光特性、污染来源及生物有效性进行系统研究.结果表明:①SPOM（以碳质量计）在14.4~31.5 g/kg之间,其中HM（提取残渣）为SPOM的主要组分,占SPOM总量的61.2%.②SPOM中WEOM（水提态有机质）含有类富里酸组分（C1）、类腐殖酸组分（C2）和类色氨酸组分（C3）3个荧光组分,类腐殖质组分（C1+C2）和类蛋白质组分（C3）对总荧光强度的贡献分别为70.4%和29.6%.③SPOM的C/N〔总有机碳（TOC）浓度与总氮（TN）浓度的比值〕和δ13C的值分别在7.53~15.2和-27.2‰~-26.1‰之间.利用C/N和δ13C端元混合模型计算陆源对SPOM的平均贡献率分别为67.2%和68.9%,结果相近.④WEOM的HIX值在4.09~7.40之间,腐殖化程度较高,生物可利用性较差.研究显示,呼伦湖中SPOM以难降解的腐殖质组分为主,腐殖化程度较强,生物可利用性较低,但随着温度升高,预估自生源SPOM的贡献将增大,可能导致其生物可利用性升高,需引起足够的重视.      

岷江干旱河谷典型地段整地造林效果评估

长期以来通过整地造林去恢复重建植被已在横断山区干旱河谷广为采用,然而这样的实践是否能有效提高植被覆盖率并改善土壤水源涵养能力仍不清楚.选择岷江干旱河谷3个典型地段,调查了多年(7～16 a)后整地造林地上植被覆盖、土壤物理性质以及目的造林树种岷江柏(Cupressus chengiana S.Y. Hu)的保存、生长与结实状况,以评价干旱河谷乡土树种造林成效及造林后的生态效果.结果表明:(1)岷江柏在栽植多年后仍有大量死亡,保存率明显下降,造林16 a后仅为38%;(2)不同年代栽植的岷江柏在造林后2～6 a即开始旱现直径年生长量下降趋势;(3)造林带内乡土植被总盖度、灌木盖度、草本盖度、地衣苔藓盖度均低于保留带,因此等高线水平沟整地造林措施未能有效促进乡土植被发育;(4)造林带土壤水分物理性质也不如保留带,整地造林也没有有效改善土壤水源涵养能力.综合分析发现,整地造林多年后岷汀柏造林不仅没有达到岷江干旱河谷预期的生态恢复重建效果,甚至有加剧生态退化的趋势.因此认为:(1)规模化整地造林并不是有效的干旱河谷生态恢复和保护措施;(2)尽管岷江柏是乡土树种,但并不是干旱河谷植被恢复的适宜种.图3表3参29     

Distribution,sources, and risk assessment of polycyclic aromatic hydrocarbons (PAHs) in surface water in industrial affected areas of the Three Gorges Reservoir,China

Water samples were collected from wastewater treatment plant (WWTP), drain water (DW), major tributaries (MT), and main course of the Yangtze River (MY) in areas of three industrial parks (IPs) in Chongqing city in the Three Gorges Reservoir (TGR). Sixteen EPA priority polycyclic aromatic hydrocarbon (PAH) pollutants were quantified to identify the effects of industrial activities on water quality of the TGR. The results showed that 11 individual PAHs were quantified and 5 PAHs (naphthalene (Nap), acenaphthylene (Acy), benzo[k]fluoranthene (BkF), indeno[1,2,3-cd]pyrene (InP), and benzo[g,h,i]perylene (BgP)) were under detection limits in all of the water samples. Three-ring and four-ring PAHs were the most detected PAHs. Concentrations of individual PAHs were in the range of not detected (nd) to 24.3 ng/L. Total PAH concentrations for each site ranged from nd to 42.9 ng/L and were lower compared to those in other studies. The mean PAH concentrations for sites WWTP, DW, MT, and MY showed as follows: DW (25.9 ng/L) > MY (15.5 ng/L) > MT (14.0 ng/L) > WWTP (9.3 ng/L), and DW contains the highest PAH concentrations. Source identification ratios showed that petroleum and combustion of biomass coal and petroleum were the main sources of PAHs. The results of potential ecosystem risk assessment indicated that, although PAH concentrations in MT and MY are likely harmless to ecosystem, contaminations of PAHs in DW were listed as middle levels and some management strategies and remediation actions, like strengthen clean production processes and banning illegal sewage discharging activities, etc., should be taken to lighten the ecosystem risk caused by PAHs especially risks caused by water discharging drains.