蒿坪河流域石煤矿区河流铝的白色污染及其成因分析

矿山酸性水及其伴生的重金属污染是含黄铁矿矿山最主要、综合治理难度最大的污染问题。为了查明蒿坪河流域废弃石煤矿开采河流铝的白色污染及成因问题,2021年以来进行了卫星遥感解译、无固定翼无人机航测、样品采集与分析、主要河流断面水质动态监测等工作。结果表明：① 研究区河流普遍存在铝的白色污染,其形成可见3种模式：两条沟道不同酸碱度的河水混合后形成白水带;河道河水自然跌水后在河床形成白色污染物;河水自然演化形成酸性水、酸性磺水与酸性白水。② 河水铝离子污染普遍且超标严重,216件河水中Al离子平均含量为8.6 mg/l,样品超标率65.8%,19条河流断面3次河水中Al离子的平均超标率90.48%。③ 河流中铝来自于石煤矿及其围岩中酸性溶解作用长石的结果,废渣堆底部流水是河流铝的主要污染源。④ 河水中铝离子与pH具有显著的负相关关系,河水酸度愈大,河水中铝离子含量愈高;河水中白色无定形胶凝状物形成后,河水中铝离子含量显著降低。河水pH的升高,是河流白色污染物形成的主要因素。河水中铝的白色污染物具有无定形特点,化学组分复杂,是硫酸根、氢氧根及铝构成的复杂化合物。铝的白色无定形胶凝状物具有吸附河水中重金属离子的能力。研究成果可为研究区铝的污染防治提供重要的理论依据。     

某地陈家沟河水中重金属元素时空变化及影响因素研究

河水重金属污染一直是环境污染防治领域的热点。秦岭某地石煤矿区陈家沟河水中重金属含量严重超标,但重金属来源不明,为污染治理带来困扰。为了查明陈家沟河水中重金属来源和时空变化情况,采集了2期河水、废弃石煤矿硐排水、废渣堆淋溶水等地表水样品,采用污染指数法、主成分分析法和Pearson相关性分析方法,研究河水中重金属污染程度、空间分布,并对河水中重金属来源进行了解析。研究表明,陈家沟源头河水（对照点）重金属含量可以达到地表水的Ⅰ类标准,中游受废弃石煤矿矿硐排水及废渣堆淋溶水的影响,河水中重金属含量显著升高,汇入干流前河水中重金属含量是对照点的3.5～312倍;河水中Cd、Cu、Zn、Ni、Mn等重金属元素同源,均来源于矿硐排水、废渣淋溶水。河水中重金属含量的空间分布与地质体、污染源分布以及河水pH、盐度等因素有关。研究结果可为陈家沟河水重金属污染防治提供科学依据。     

论华北平原的黄河古水系

为合理开发利用地下水及水资料调蓄,通过物探、钻探及室内分析数据,对华北平原埋深２０～３５ｍ的数条ＳＷ－ＮＥ向砂带进行了研究。该砂带具有许多河流相沉积标志,从分布格局、重矿物组合、砂带规模、古生物化石和＾１４Ｃ测年看,该带是末次盛冰期－早全新世形成的黄河古河道带。它切割了末次冰期间冰段棕红色粘土,形成了切割谷。谷内堆积了末次盛冰期－－早全新世砂砾石,后又被中全新世淤泥质粘土掩埋而成为埋藏古河道带。它     

Hydrology of Okarito Lagoon and the inferred effects of selective logging in Okarito Forest

Okarito Lagoon (43° 11′S, 170° 14′E) is a small (20 km²) shore‐parallel, predominantly subtidal estuary, deepest near the landward end, and linked to the sea by two subtidal channels incised through shallow subtidal and intertidal flats which occupy the southern third of the lagoon. Tides at sea vary from 2.1m (spring) to 1.2 m (neap), but in the lagoon the tidal range is constant through the lunar cycle and varies from 0.80 m at the entrance to 0.17 m in the upper lagoon. Tidal water level and flow asymmetries in the subtidal channels are separated by a 1.7 h phase difference. Variations in the net discharge through the inlet result from changing flow cross‐sections rather than from variations in current velocities. Both the tidal‐averaged volume and the tidal compartment of the lagoon vary through the lunar cycle, from maxima at spring tides to minima at neap tides.

Freshwater inflows vary from less than 11 m³.s^‐1 to more than 750 m³.s^‐1. During storms, water level in the lagoon rises rapidly by 2–3 m, then declines to normal over several days. Three water masses, two with salinity and turbidity largely controlled by antecedent rainfall, normally occur in the lagoon. Suspended sediment concentrations in both freshwater inflows and lagoon waters are normally low but increase during floods. Most sediment is supplied by the Waitangi‐taona River or by erosion of tidal channel margins. The lagoon is floored with organic‐rich mud and sandy mud, deposited predominantly from suspension. Surface sediment is consistently muddier than subsurface sediment, probably reflecting an increase in the mud supply since diversion of the Waitangi‐taona River in 1967.

Comparisons of the estimated sediment yield and water inflow effects of the 1967 river diversion with short‐term observations during selective logging suggest that the effects of logging on sediment yield, water balance of the lagoon, and dissolved solids inputs will be small compared with changes caused by diversion of the Waitangi‐taona River.     

Abundance and distribution of pelagic piscivorous fishes in the Columbia River plume during spring/early summer 1998-2003: Relationship to oceanographic conditions, forage fishes, and juvenile salmonids

From 1998 to 2003, we observed large fluctuations in the abundance and distribution of four pelagic predatory (piscivorous) fishes off northern Oregon and southern Washington, USA. Fluctuations in predatory fish species composition and abundance were strongly linked to the date of the spring transition and to ocean temperatures. Predatory fishes, forage fishes, and juvenile salmonids had distinct spatial distributions, with predators distributed primarily offshore and forage fish and salmonids onshore, but this varied depending on ocean conditions. We suggest that predatory and forage fish distributions respond to ocean temperatures, predator/prey interactions, and possibly turbidity. A shift in ocean conditions in 1999 decreased overall predator fish abundance in the Columbia River plume, particularly for Pacific hake. Marine survival of juvenile salmon started to increase in 1999, and forage fish densities increased in 2000, lagging by one year.     

Silting in the Lower Courses of Tidal Sluices in China

Serious sediment deposition often occurs after the construction of tidal sluices in snrall or medium-sized tidal muddy estuaries, so desilting or dredging is needed to meet the demands of flood diseharge, saltwater retaining, and navigation in those areas. In this paper, the problem of sediment deposition induced by construction of tidal sluices is analyzed.Different problems of silting near tidal sluices for different types of estuaries are summed up. at the same time, corresponding methods are given to solve these probleras, and a few successful examples are also given. The idea of comprehensive regulation and utilization of estuaries is put forward, and some proposals for solution of sediment deposition in this kind of estuaries are made.     

广利河口拦门沙运动特性及水力插板断面模型试验研究

通过对广利河口拦门沙运动参数的测试及3种下水力插板上波浪力的试验研究,定量给出了泥沙初动、中动、普动、扬动变化曲线,准确绘制了水力插板波压力分布图,为广利河口拦门沙治理和航道管理提供了科学依据。     

三角洲废弃河道演化过程及受控机制——以黄河刁口废弃河道为例

废弃河道是河流系统的重要组成部分,其沉积记录蕴含了丰富的流域内构造活动、水文特征、海平面波动等环境变化的珍贵记录.然而相比内陆河废弃河道,三角洲废弃河道的演化过程及机制研究尚显不足.1976年黄河人工改道清水沟流路,切断了刁口流路的河流水沙供给,刁口流路逐渐废弃.通过1976—2016年的Landsat遥感影像、黄河水...     

华南不同类型热带风暴驱动下珠江口表层悬沙分布趋势

本文利用1949—2014年的华南热带风暴数据和1960—2014年珠江入海流量等, 统计分析风暴作用期间珠江口的风强迫和珠江入海水沙强迫特征, 结果表明, 热带风暴对珠江口的风强迫和水沙强迫因台风距珠江口的距离、强度等因素的影响有显著差异。依据水沙及风强迫的强度, 将热带风暴对珠江口的影响简单分成四类: 中风中水沙驱动型、中风高水沙驱动型、强风中水沙驱动型及强风高水沙驱动型。利用MODIS (moderate-resolution imaging spectroradiometer)一级数据和已建立的珠江口表层悬沙指数反演模型, 挑选2002—2010年风暴影响期间无云天气的MODIS影像, 反演珠江口悬沙分布, 分析表层悬沙对四种不同来水来沙及风强迫型风暴的响应特征。结果显示, 中风中水沙型风暴驱动下, 珠江口整体含沙量偏低, 其悬沙扩散及时间变化受控于潮流的强弱; 中风高水沙型风暴驱动下, 八大口门特别是磨刀门浅滩、伶仃洋西滩的含沙量高于其他海域, 其高含沙水体向南偏西方向扩散输运; 强风中水沙风暴驱动下, 河口表层悬沙分布及扩散受主导风向的影响, 在强东北风驱动下, 伶仃洋西侧浅滩含沙量因台风浪的掀沙作用高于湾内大部分海域, 高含沙水体向西南侧扩散; 强风高水沙风暴驱动下珠江河口湾含沙量偏高, 水体一片浑浊, 河口悬沙随偏南风驱动下的沿岸流向东侧输运、扩散。     

Trophic Status of the South-Eastern Baltic Sea: A Comparison of Coastal and Open Areas

Primary production, nutrient concentrations, phytoplankton biomass (incl. chlorophyll a) and water transparency (Secchi depth), are important indicators of eutrophication. Earlier basin-wide primary production estimates for the Baltic Sea, a shallow shelf sea, were based mainly on open-sea data, neglecting the fundamentally different conditions in the large river plumes, which might have substantially higher production. Mean values of the period 1993–1997 of nutrient concentrations (phosphate, nitrate, ammonium and silicate), phytoplankton biomass, chlorophyll a (chl a) concentration, turbidity and primary production were calculated in the plumes of the rivers Oder, Vistula and Daugava and Klaipeda Strait as well as the open waters of the Arkona Sea, Bornholm Sea, eastern Gotland Sea and the Gulf of Riga. In the plumes, these values, except for primary production, were significantly higher than in the open waters. N:P ratios in the plumes were >16 (with some exceptions in summer and autumn), indicating potential P-limitation of phytoplankton growth, whereas they were <16 in the open Baltic Proper, indicating potential N-limitation. On the basis of in situ phytoplankton primary production, phytoplankton biomass and nutrient concentrations, the large river plumes and the Gulf of Riga could be characterized as eutrophic and the outer parts of the coastal waters and the open sea as mesotrophic. Using salinity to define the border of the plumes, their mean extension was calculated by means of a circulation model. Taking into account the contribution of coastal waters, the primary production in the Baltic Proper and the Gulf of Riga was 42·6 and 4·3×10⁶ t C yr⁻¹, respectively. Hence, an annual phytoplankton primary production in the whole Baltic Sea was estimated at 62×10⁶ t C yr⁻¹. The separate consideration of the plumes had only a minor effect on the estimation of total primary production in comparison with an estimate based on open sea data only. There is evidence for a doubling of primary production in the last two decades. Moreover, a replacement of diatoms by dinoflagellates during the spring bloom was noticed in the open sea but not in the coastal waters. A scheme for trophic classification of the Baltic Sea, based on phytoplankton primary production and biomass, chl a and nutrient concentrations, is proposed.