桂畔海河底泥氨氮释放动力学模型

针对桂畔海河水体中氨氮季节性变化较大的特点,在分析底泥构成的基础上,探讨底泥中氨氮的分布特性及其释放对桂畔海河水质的影响,分别考察温度、溶解氧和扰动强度在冬季期间对氨氮异常增加的影响,并以试验为基础构建底泥氨氮释放动力学模型,为后续治理桂畔海河底泥污染提供了参考依据。     

顺德桂畔海水系河涌清淤与底泥处理技术

顺德桂畔海水系河涌分布广、环境复杂、污染底泥数量大、污染物成分多样,如何治理面临巨大的挑战。通过合理选择清淤及运输方式,应用带式压滤机脱水+稳定固化工艺对污染底泥进行分类处理,处理后泥饼用于生态筑堤等措施,实现了污染底泥的"减量化、稳定化、无害化、资源化"。在运行与监管系统的协助下,确保了泥饼含水率稳定在60%以下,重金属指标满足生态筑堤要求。该套施工工艺的成功运用,缩短了施工工期,具有良好的经济和环境效益。     

佛山水道底泥的污染物释放动态模拟

为定量评价底泥对上覆水水质的影响，给河道底泥整治工程方案的选择提供参考，采用佛山水道的污染底泥以COD、NH3-N和TP为研究对象，进行了污染物释放的动态模拟，并根据试验结果用平均值法计算了底泥污染物的释放量。结果表明，污染程度较高的底泥对上覆水中NH3-N、COD和TP浓度的贡献依次为0．65、4．25和0．067mg／L，分别占Ⅳ类水质标准值的43．3％、14．2％和22．3％。这说明在外源污染被控制后，如果没有采取有效措施抑制底泥污染物的释放，很难使佛山水道的水质达到Ⅳ类标准。     

城市景观水体底泥氮磷释放研究

以城市景观水体的底泥为研究对象,研究了底泥中氮磷的释放规律,以及p H和温度对底泥氮磷释放的影响,结果表明,总氮和总磷的浓度随时间而增加,在前期增加较快;p H值对氮磷也有明显的影响;在较高的温度下促进底泥向水体中释放氮和磷。     

潮汕地区虾类养殖水体水质及底泥特性分析

通过研究潮州市饶平县钱东镇沈厝村的南美白对虾不同养殖年限塘体,在2017年养殖过程中水体及底泥p H值、氨氮、溶解氧、亚硝酸盐、磷酸盐、有机质等的情况,分析了水体水质及底泥条件在养殖过程中的变化,以及监测指标对养殖生态环境和养殖收益的影响,为当地养殖户改进养殖方式、提高收益提供决策的参考。     

PAC絮凝沉积藻量对水-底泥系统营养盐释放的影响

聚合氯化铝(PAC)絮凝除藻对降低水体藻密度效果显著,但絮凝形成的沉积藻量对水-底泥系统营养盐释放的影响鲜有报道。通过监测不同量的絮凝藻沉积于一定量的底泥表面时上覆水水质和底泥组成的变化,探究使用PAC絮凝除藻时沉积藻量对水体水质及底泥内源释放的影响。结果表明,沉积藻会显著增加底泥中的氮向上覆水释放,当泥与藻的干质量之比为167. 2、83. 6和41. 8时,反应器上覆水中NH₄⁺-N浓度均值分别为控制反应器(CK)的2. 86、2. 42和1. 43倍,对应TN浓度均值分别为CK的2. 06、1. 66和1. 09倍。此外,沉积藻会促进泥水界面处的反硝化过程,促进效果与沉积藻量呈负相关。然而,沉积藻对于控制底泥磷释放具有积极作用,试验期间CK上覆水中TP和PO₄^3--P浓度均值分别为0. 35和0. 22 mg/L,而覆有沉积藻的所有反应器中TP和PO₄^3--P浓度均值分别都低于0. 05和0. 03 mg/L,且沉积藻量越大,对应的磷浓度越低。     

南四湖表层底泥有机质及氮磷分布特征

为进一步诊断南四湖的重大水环境问题,分别于2006、2007、2010和2011年4次对南四湖水质与底质进行布点监测.根据4次监测数据,通过数理统计和综合比较的分析方法对南四湖表层底泥进行了有机质及氮磷的空间分布特性及其与上覆湖水相关性研究.结果表明,南四湖湖区表层底泥有机质、总氮(TN)和总磷(TP)呈现北高南低的分布特征,这与水质的空间分布特征相一致,其中TP分布均一化明显;南四湖上覆湖水氮磷浓度与其对应表层底泥氮磷含量没有明显关联性,说明南四湖水体污染仍以外源污染为主;2011年监测的入湖河口表层底泥有机质、TN和TP含量的平均值低于湖区平均值,说明南四湖湖区表层底泥对有机质、TN和TP的富集作用比较明显.     

水溶液电导率与三峡库区底泥氮磷释放关系研究

通过对三峡库区底泥总氮、总磷（TN、TP）释放特性研究,分析了水溶液电导率对底泥TN、TP释放的影响及其原因,得出了水溶液的电导率在257～2012μs／cm范围内,对底泥TN、TP释放的影响曲线。同时说明了三峡库区底泥TN、TP对库区水质存在的危险性,为三峡库区富营养化治理提供参考。     

Distribution and modelling of rare earth elements in Chinese river sediments

Fifty-nine sediment samples were collected from the major rivers of China and analysed using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). The background rare earth element (REE) concentrations (μg/g) of these samples were: Sc, 11.1 (1.3–23.1); Y, 13.7 (3.3–24.8); La, 30.8 (7.6–57.2); Ce, 64.4 (16.5–122.6); Pr, 7.3 (1.6–14.4); Nd, 27.8 (5.6–58.5); Sm, 5.74 (1.1–11); Eu, 0.98 (0.05–1.7); Gd, 8.9 (1.6–16.8); Tb, 0.62 (0.12–1.2); Dy, 3.0 (0.53–5.0); Ho, 0.55 (0.09–1.00); Er, 1.4 (0.26–2.4); Tm, 0.19 (0.06–0.4); Yb, 1.0 (0.22–2.9); Lu, 0.16 (0.05–0.42). The total REE concentration (ΣREE), light-REE concentration (LREE) and heavy-REE concentration (HREE) were 44.5–315.8, 38.1–264.6 and 6.36–51.2 μg/g, respectively. The ratio of LREE to HREE ranged from 3.7 to 7.7. The average ratio was approx. 5.1 and did not show much variation with location. Total and individual element concentrations were normally distributed. The variation in the average REE concentration was not greater than 25 μg/g. A high degree of correlation was found between the REEs. Factor analysis indicated that REE concentrations in sediments were mainly described by two factors and the loading of the first two factors could be described by: Y = 1 − X². Factor score plots were employed to distinguish between samples of natural and anthropogenic origin. Based on the inter-correlation determined between REEs in sediment samples, a model was developed to predict REE concentrations.     

低温条件下微生物对沉积物氮释放的影响研究

通过室内静态模拟实验,研究了沉积物中氮的释放特性。将反应器密封后自然达到厌氧状态,温度与水库底部相近（7～8℃）,进行未灭菌和灭菌两个系列对比试验,连续监测两个系列装置中NO3^-N、NO^2-N、NH4^＋-N、TN、DO和pH的变化,并对试验前后沉积物中的总氮含量进行测定。结果表明,未灭菌装置沉积物中总氮减少量明显多于灭菌装置,而上覆水中可监测总氮少于灭菌装置,说明在厌氧条件下氮元素会在微生物作用下从沉积物中释放出来,并通过反硝化和厌氧氨氧化等作用以气态形式释放出水体。试验前后对底泥表面的硝化、亚硝化、反硝化和氨化细菌的数量通过计数进行了比较,发现厌氧后反硝化细菌和氨化细菌明显增多,说明厌氧过程中对氮释放起主要作用的是反硝化细菌和氨化细菌。     

Seawater induced release and transformation of organic and inorganic phosphorus from river sediments

This paper reports an investigation of the release of organic and inorganic phosphorus from a riverine sediment subjected to salinity conditions typical of estuarine mixing. Freshwater sediment was mixed with filtered river water in a thermostatted reactor, and allowed to equilibrate under aerobic conditions for 3 days. Salinity was then increased in a stepwise manner by addition of filtered low-nutrient seawater over a period of 4 days. A control experiment was performed in a second reactor by substituting ultrapure water for seawater. Using a flow injection analysis method for measurement of filterable reactive phosphorous (FRP, the so-called inorganic fraction) and filterable organic phosphorous (FOP), it was found that rapid releases of both FOP and FRP occurred at salinities of >/=10 per thousand. Over the 4-day experimental period, sediment release increased the filterable P concentration by approx. 50 microgL(-1), and of this, nearly half was initially present as FOP, which subsequently underwent rapid mineralisation to FRP. The observed behaviour may be explained by a combination of salinity induced plasmolysis of sediment bacteria and ion exchange by suspended sediment particles.     

Inorganic nitrogen release kinetics and exchangeable inorganic nitrogen of the sediments from shallow lakes in the middle and lower reaches of the Yangtze River region

Inorganic nitrogen (IN) release kinetics and exchangeable inorganic nitrogen (EIN) of the sediments from shallow lakes in the middle and lower reaches of the Yangtze River region were investigated. The results showed that the EIN contents of the studied sediments ranged from 131 to 274 mg/kg. With the increase of the total nitrogen (TN) contents, their EIN also significantly increased. Their ratios of EIN to TN ranged from 5 to 17%, and with the increase of their TN contents, their ratios decreased. The relative contribution of NH₄⁺‐N and NO₃^‐N to EIN ranged from 83 and 11% to 89 and 17%, respectively. The curves of the NO₃^‐N release kinetics of the studied sediments were not completely consistent with those of IN and NH₄⁺‐N. The amounts of the IN released from sediments not only relate to their EIN contents, but also to other N fractions.     

再生水中氨氮和总氮的相关性分析研究

通过检测某再生水厂生活出水中的氨氮和总氮含量,分析了氨氮和总氮含量之间的相关性.结果表明,再生水中氨氮和总氮两个监测因子之间的相关关系为：秋季最好,R为0.992 5;冬季其次,R为0.934 6;最后是春季和夏季,R分别为0.777 0和0.725 7.氨氮和总氮含量之间的比例系数为0.010～0.310,波动较大,根据各不同季节氨氮和总氮的比例系数K季均值,可以得到氨氮和总氮含量的比例系数K年均值为0.078.     

Enzyme activity and kinetics in substrate-amended river sediments

Methods to assay amylase, cellulase and urease activity in diverse river sediments are resported. Enzyme activity was low in non-amended sediments, but increased markedly when the appropriate substrate was added, paralleling both athropogenic and natural amendment. Linear relationships between enzyme activity, length of incubation, sample size and substrate concentration were established. Sediment enzyme activity generally obeyed Michaelis-Menten kinetics, but of the three enzymes, urease gave least significant correlation coefficients when the data for substrate concentration versus activity was applied to the Eadie-Hofstee transformation of the Michaelis-Menten equation. K_m and V_max for amylase, cellulase and urease in sediments are reported.     

A bacterial methylmercury-mineralizing activity in river sediments

A bacterial activity involving mineralization of methylmercury was found in bottom sediments of the river Sambre (Belgium), in a zone highly polluted with inorganic mercury. The possibility, shown by other authors and ourselves, that biological production of toxic methylmercury compounds occurs in such a medium gives a great ecological significance to this finding.Some properties of this mineralizing activity were studied at the community level in the laboratory.The mineralizing capacity of the community can be increased in response to increased concentrations of methylmercury, probably by means of the selection of methylmercury-resistant bacterial species, among which the organisms responsible for the transformation constitute only a part.Because of this adaptation, it is suggested that some equilibrium can be reached between the degradation of methylmercury and its addition to, or its production in, mineral mercury polluted environments.     

Anthropogenic organic contaminants in sediments of the Lippe river, Germany

Sediment samples of the Lippe river (Germany) taken between August 1999 and March 2001 were investigated by GC-MS-analyses. These analyses were performed as non-target-screening approaches in order to identify a wide range of anthropogenic organic contaminants. Unknown contaminants like 3,6-dichlorocarbazole and bis(4-octylphenyl)amine as well as anthropogenic molecular marker compounds were selected for quantification. The obtained qualitative and quantitative analytical results were interpreted in order to visualize the anthropogenic contamination of the Lippe river including spatial distribution, input effects and time dependent occurrence. Anthropogenic molecular markers derived from municipal sources like polycyclic musks, 4-oxoisophorone and methyltriclosan as well as from agricultural sources (hexachlorobenzene) were gathered. In addition molecular markers derived from effluents of three different industrial branches, e.g. halogenated organics, tetrachlorobenzyltoluenes and tetrabutyltin, were identified. While municipal and agricultural contaminations were ubiquitous and diffusive, industrial emission sources were spatially isolated. Specific seasonal trends of distribution patterns were not observed.     

Sorption-desorption behavior of triazine and phenylurea herbicides in Kishon river sediments

Sorption and desorption hysteresis of widely applied triazine and phenylurea herbicides were studied for river sediments. Organic carbon normalized sorption coefficient (K_OC) values for all herbicides were significantly higher for the sediment from the downstream region of the river vs. the upstream sediment. On the basis of the measured K_OC values, the triazine herbicides can be arranged in the following order: terbutryn>terbuthylazine>ametryn>atrazine. Among the phenylurea herbicides, chlorotoluron exhibited higher sorption than isoproturon (K_OC values of 137 vs. 60 and 228 vs. 125 L/kg for the upstream and downstream sediments, respectively). Moreover, chlorotoluron exhibited lower desorption potential as compared with isoproturon (apparent hysteresis index values were 0.2–0.3 for chlorotoluron vs. 0.6–0.9 for isoproturon, measured with the upstream sediment). High sorption affinity of chlorotoluron to the sediments is probably due to stronger H-bonding interactions of the herbicide molecules with the sorbents. For both phenylurea herbicides, desorption hysteresis increased with decrease in sorbed amount. This behavior was opposite to the hysteresis trend observed for the triazines. The Cl-triazines (atrazine and terbuthylazine) exhibited higher desorption hysteresis than the S-triazines (ametryn and terbutryn). Therefore, the apparent hysteresis index values calculated for the Cl-triazines were lower than the values of S-triazines (about 0.4 and 0.7, respectively). Based on the relative strength of H-bonding interactions of Cl- and S-triazines with formate anion and on the desorption hysteresis data we suggest a gradient-derived hole-filling sorption mechanism for the triazine herbicides with the river sediments.