蒽醌染料及其中间体絮凝菌的特性

本文研究所分离到的真菌ＮＸ１对蒽醌染料ＫＮＲ及其中间体溴氨酸的作用,并考察营养条件、体系ＰＨ等对ＮＸ１的生长及絮凝作用的影响,结果表明,ＮＺ１及溴氨酸有很好的絮絮凝效果,对ＰＨ的适应范围广,最佳碳、氮源分别为蔗粮主尿素。     

生物炭改良盐碱地研究与应用进展

盐碱地作为21世纪严重威胁粮食产量的农田问题土壤之一,分布广泛,具有极大的开发潜力.生物炭作为高效的新型土壤改良剂,在缓解土壤酸碱障碍、土壤污染治理、碳封存和肥料缓释等方面发挥了重要作用,有力地推动了盐碱地农业的可持续发展.近年来,关于生物炭改良盐碱地的研究和应用备受关注.但由于生物炭来源、结构和组分的复杂性和非均质性,其对盐碱地的改良效果存在极大的不确定,也缺乏关键机制的系统总结和深度探讨,这限制了生物炭技术在盐碱地改良中的进一步推广和应用.通过综合分析生物炭对盐碱地土壤理化性质、养分有效性和生物特征的影响,归纳总结生物炭和改性生物炭对盐碱地的改良效果及其提质增效作用,阐明生物炭在盐碱地改良中存在的可能机制,并对未来研究方向进行了展望,可为进一步研发绿色高效精准的盐碱地生物炭改良技术及其推广应用提供参考.     

污水处理厂计算机仿真模拟研究

将上海市某城市污水处理厂的生产运行数据进行了计算机模拟,并将模拟结果中的COD及TSS、TN、NH3-N等组分的浓度与实测数据进行了比较。通过对模型参数进行修正和调整,仅改变ASM1数学模型中的4个参数,即取得了较好的预测效果。同时对城市污水处理厂进一步运用数学模型的可行性进行了讨论。     

EFFECT OF A POINT SOURCE INPUT ON STREAM NUTRIENT RETENTION1

ABSTRACT: We examined the effect of a point source (PS) input on water chemistry and nutrient retention in Spavinaw Creek, Arkansas, during summer baseflows in 1998 and 1999. The nutrient uptake length (S_w) concept was used to quantify the impact of nutrient inputs in the receiving stream. We used an artificial injection upstream of the PS inputs to estimate background S and used the natural decline in nutrient concentrations below the PS to estimate the net nutrient uptake length (S_net). S_w for soluble reactive phosphorus (SRP) in the upstream reference section was O.75 km, but S_net ranged from 9.0 to 31 km for SRP and 3.1 to 12 km for NO₃‐N in the reach below the PS. S_net‐SRP was significantly correlated with discharge whereas S_net‐NO₃‐N was correlated with the amount of NO₃‐N enrichment from the PS. In order to examine specific mechanisms of P retention, loosely exchangeable P and P Sorption Index (PSI) of stream sediments were measured. Sediments exhibited little natural P buffering capacity (low PSI) above the PS, but P loading from the PS further reduced PSI. Loosely exchangeable P in the sediments also increased three fold below the PS, indicating sediments removed some water column P. The physical process of flow and sediment sorption apparently regulated P retention in Spavinaw Creek, whereas the level of N enrichment and possibly biotic uptake and denitrification influenced N retention. Regardless of the mechanism, Spavinaw Creek demonstrated little ability to retain PS‐added nutrients because net nutrient uptake lengths were in the km range.     

PREDICTABILITY OF SURFACE WATER POLLUTION LOADING IN PENNSYLVANIA USING WATERSHED‐BASED LANDSCAPE MEASUREMENTS1

ABSTRACT: We formally evaluated the relationship between landscape characteristics and surface water quality in the state of Pennsylvania (USA) by regressing two different types of pollutant responses on landscape variables that were measured for whole watersheds. One response was the monthly exported mass of nitrogen estimated from field measurements, while the other response was a GIS‐modeled pollution potential index. Regression models were built by the stepwise selection protocol, choosing an optimal set of landscape predictors. After factoring out the effect of physiography, the dominant predictors were the proportion of “annual herbaceous” land and “total herbaceous” land for the nitrogen loading and pollution potential index, respectively. The strength of these single predictors is encouraging because the marginal land cover proportions are the simplest landscape measurements to obtain once a land cover map is in hand; however, the optimal set of predictors also included several measurements of spatial pattern. Thus, for watersheds at this general hierarchical scale, gross landscape pattern may be an important influence on instream pollution loading. Overall, there is strong evidence that using landscape measurements alone, obtained solely from remotely sensed data, can explain most of the water quality variability (R²= approx. 0.75) within these watersheds.     

WATER QUALITY CHARACTERISTICS OF AGRICULTURAL PUMPAGE IN THE UPPER ST. JOHNS RIVER,FLORIDA1

Several large agricultural pumps, located in the upper St. Johns River Basin, Florida, and representative of the numerous pumps operating in the basin, were monitored during the spring and summer of 1982. These pumps have rated capacities ranging from 36 to 334 ft³/s and drain various quantities of improved pasture, row crop, and citrus land uses. The combined total pumping capacity of the pumps in this study is approximately equal to the average flow at US 192, near Melbourne (691 cfs). Results indicate high nutrient and suspended solids loading to the river, but the relative magnitude of each parameter varies with pump site and date. The row crop/Mary A pump (267 ft³/s capacity) exhibited the poorest water quality of the sampled pumps and appeared to have the greatest pollutional potential. The average suspended solids loading rate from the Mary A pump was high (37,900 Kg/day). The average total nitrogen (TN) and total phosphorus (TP) discharge concentrations at this pump were also high, with values of 3.96 mg/L and 0.79 mg/L, respectively. As expected, nutrient loading rates reflected discharge rates, to a large degree. Average TN loading rates for the pumping stations varied from 86 to 1935 Kg/day while TP loading ranged from 7 to 390 Kg/day. Nutrients from pumping are contributing factors to the increasing aquatic plant growth and algal blooms in the area. Poor quality discharge water, as well as rapid rises in water level from the cumulative discharges resulting in dead marsh vegetation and accompanying oxygen sags, have been suggested as causative factors for fish kills in the area.     

The Importance of Leaching from Litter Collected in Litterfall Traps

Litterfall (LF) is usually collected by means of opentraps. However, this litter will be subject toleaching by the throughfall which passes through theaccumulated litter in the traps. The nutrients lostduring this leaching are not taken into account in thecalculation of LF nutrient fluxes. We report theresults from a 2-month (August–September) studycarried out in 8 northern coniferous forest stands toassess the possible importance of leaching from litterin LF traps. Compared to throughfall (TF), thelitterfall leachate (LFL_gross), which includes athroughfall component, had significantly (p < 0.05)higher concentrations and fluxes of Ca, Mg, Na and S.The average net LFL (i.e., LFL_net = LFL_gross-TF) fluxes were 21 (Ca), 7 (Mg), 57 (K), 10 (Na), 10 (N), and 19 (S) mg m^-2 mo^-1. LFL_net accounted for 42%, 37% and 50% of the LFL_gross flux, and for 91%, 51% and 49% of the total litterfall flux (i.e.,LF + LFL_net) of Na, S and K, respectively. ForCa, Mg and N, the LFL_net flux accounted for 64%,58% and 29% of the LFL_gross flux, and for< 14% of the total litterfall flux. Compared to TF,LF was the dominant return pathway for Ca, Mg and N tothe forest floor regardless of whether LFL_net wasincluded or not. However, for K and S, takingLFL_net into account determined whether TF or LFwas the dominant pathway. TF remained the dominantpathway for Na even when LFL_net was included.     

1951—2017年滇池流域极端降水变化及湖体水质响应

极端降水是流域水文水质变化的重要驱动事件.本研究使用RclimDex、随机森林回归和Mann-Kendall等方法分析了滇池流域多年极端降水指标变化特征及其对滇池湖体水质的影响,评估了不同极端降水指标、经济社会指标、人为氮磷输入量、调水量等驱动因子对滇池TP、TN浓度的重要性.结果表明：近67年间,滇池流域的总降水量没有显著变化,极端降水的频次及强度显著降低,但由于极端降水对流域总降水量的贡献较大,流域面临的极端降水风险较大.近20年来,滇池湖体TP、TN浓度呈显著降低趋势,水质显著好转,但极端降水将持续影响滇池水质,并且,在人为氮磷输入与极端降水变化的双重作用下,滇池水质持续好转的压力较大.     

石油烃在非均质包气带中的吸附作用及迁移规律

为深入分析强非均质性污染场地中石油烃的运移规律,探究石油烃类污染物在场地中的吸附、迁移及其影响因素,选取潮白河上游为典型研究区,受冲洪积扇条件控制,区域内包气带非均质性强,地下水埋深较大.采集污染场地包气带介质样品,分别装填原状土（0~20 mm）、细颗粒（< 2 mm）和粗颗粒（>4 mm）3种介质迁移柱,通过土柱淋滤试验表征石油烃在典型介质中的迁移特性;通过静态吸附试验和微生物降解试验识别石油烃迁移过程的关键影响因素,揭示多要素作用条件下的石油烃迁移规律.结果表明:原状土、细颗粒和粗颗粒这3种介质迁移柱出水中石油烃浓度均呈先下降、后波动上升、最终趋于稳定的趋势.3种介质对石油烃的吸附过程均呈现快吸附和慢吸附两个阶段,快吸附阶段发生在试验0~15 h内,完成了吸附的70%~80%;慢吸附阶段持续时间较长,吸附总量缓慢增加.固液比、温度和pH等要素对3种介质石油烃吸附性能的影响相对较小.微生物降解是慢吸附阶段石油烃浓度呈波动上升的主要原因,且在整个石油烃垂向迁移过程中,吸附作用对石油烃去除的贡献率为80%,微生物降解的贡献率为20%.研究显示,相对于微生物作用而言,强非均匀介质在石油烃类污染场地的污染物吸附和迁移过程中起关键控制作用.      

水华过程水质参数与浮游植物定量关系的研究——以太湖梅梁湾为例

考虑到太湖水华暴发过程中水质参数（如营养盐或水体理化参数）对浮游植物增殖的滞后效应,利用有滞后变量参与的格兰杰因果关系检验和向量自回归模型,分析了太湖梅梁湾湖区2000年~2012年的监测数据,探讨了湖泊水质参数对于水华暴发的影响和定量关系.结果发现,表征浮游植物生物量的叶绿素a（Chl-a）浓度与总磷（TP）、氮磷比（N/P）、水温（WT）之间存在长期的均衡关系,格兰杰因果关系模型和向量自回归模型（VAR）的结果显示,水体中TP浓度、N/P和WT是Chl-a含量变化的格兰杰原因,上述结果提供了湖泊水质参数与蓝藻生物量的定量关系,在其他水质参数保持不变的情况下,约1%湖泊TP含量、N/P和水温的变化分别造成0.97%、0.078%和0.55%的浮游植物生物量的变化.本研究为水华暴发研究过程中水质参数的定量化影响提供一个新颖的视角,考虑了时间滞后变量的时间序列分析方法也可以加深对水华暴发过程的理解.