Multiple assessments, source determination, and health risk apportionment of heavy metal(loid)s in the groundwater of the Shule River Basin in northwestern China

Global ecosystems and public health have been greatly impacted by the accumulation of heavy metal(loid)s in water.Source-specific risk apportionment is needed to prevent and manage potential groundwater contamination with heavy metal(loid)s.The heavy metal(loid)s contamination status,water quality,ecological risk,and health risk apportionment of the Shule River Basin groundwater are poorly understood.Therefore,field sampling was performed to explore the water quality and risk of heavy metal(loid)s in the groundwater of the Shule River Basin in northwestern China.A total of 96 samples were collected from the study area to acquire data for water quality and heavy metal(loid)s risk.There was noticeable accumulation of ferrum in the groundwater of the Shule River Basin.The levels of pollution were considered to be moderately low,as evaluated by the degree of contamination,heavy metal evaluation index,heavy metal pollution index,and Nemerow pollution index.The ecological risks were also low.However,an assessment of the water quality index revealed that only 58.34%of the groundwater samples had good water quality.The absolute principal component scores-multiple linear regression model was more suited for this study area than the positive matrix factorization model.There were no obvious noncarcinogenic or carcinogenic concerns for all types of receptors according to the values of the total hazard index and total carcinogenic risk.The human activities and the initial geological environment factor(65.85%)was the major source of noncarcinogenic risk(residential children:87.56%;residential adults:87.52%;recreational children:86.77%;and recreational adults:85.42%),while the industrial activity factor(16.36%)was the major source of carcinogenic risk(residential receptors:87.96%;and recreational receptors:68.73%).These findings provide fundamental and crucial information for reducing the health issues caused by heavy metal(loid)s contamination of groundwater in arid areas.

Distribution of isotopes and chemicals in precipitation in Shule River Basin,northwestern China:an implication for water cycle and groundwater recharge

The distribution of stable isotopes and ions in precipitation in the Shule River Basin, northwestern China, were investigated to understand the regional water cycle and precipitation input to groundwater recharge. The study found that the mean annual concentrations of Ca2＋, Na＋, SO42-, CI-, Mg2＋, NO3-, and K＋ in the basin were lower than those in other arid areas of northwestern China. The average concentrations of ions in the lower reaches of the Shule River were higher than those in the upper reaches. The results showed that the main ionic concentrations decreased with the increase of precipitation amount, indicating that heavy precipitation cannot only wash crustal aerosols out of the atmosphere, but also create a dilution effect. CI- and Na＋ in precipitation had a strong and positive correlation, suggesting a common origin for the two ions. However, the excess of Na＋, combined with non-marine SO42- and NO3-, indicated that some ions were contributed by terrestrial origins. In the extremely arid regions of northwestern China, the evaporation process obviously changes the original relationship between δ2H and δ18O in precipitation, and leads to dexcess values 〈8‰. δ18O and temperature were significantly correlated, suggested that temperature strongly affected the characteristics of isotopes in the study area. The δ18O value indicates a dominant effect of westerly air masses and southwest monsoon in warm months, and the integrated influence of westerly and Siberian-Mongolian polar air masses in cold months. The d-excess values were generally lower in warm months than those in cold months, indicating that post-condensation processes played a significant role in the water cycle. The results provide reliable precipitation input information that can be used in future groundwater recharge calculations in the study area.

Sedimentary characteristics of distributive fluvial system in arid area: A case study of the Shule River distributive fluvial system, NW China

Based on detailed investigation of the modern sedimentation of the distributive fluvial system of Shule River and the data of unmanned aerial vehicle(UAV)aerial photography and satellite remote sensing,the sedimentary characteristics and differences of distributive fluvial system in arid areas are analyzed.By comparing the changes in slope,river morphology and sedimentary characteristics in different sections from the apex to the toe,the distributive fluvial system of Shule River can be divided into three facies belts:"proximal","middle"and"distal".The proximal belt has the largest slope and strongest hydrodynamic condition,mainly appears as large-scale braided river deposits;the fluvial bars in this belt are mainly composed of gravels,the gravels have good roundness and certain directionality,and are medium-large boulders,with low sand content;the main microfacies in this belt are braided channel and flood plain.The middle belt with slope smaller than the proximal belt,is mainly composed of braided bifurcating river deposits.Due to branching and infiltration,this belt has weaker hydrodynamic conditions,so some of the distributive rivers dry up,appearing as ephemeral rivers.This belt has small lenticular sandbodies,fine to medium gravels,higher sand content,and mainly braided channel,flood plain and aeolian dune microfacies.The distal belt has the smallest slope and flat terrain,where the river begins to transform from braided river to meandering river,the sediment is mainly sand.Due to the influence of slope,this belt has weaker erosion toward source and stronger lateral erosion,and point bars developing around the edge of the active lobes.In this belt,the river is completely meandering,and the main microfacies are braided channel,meandering channel,flood plain,aeolian dune,lake and swamp.

Assessment of sandy desertification trends in the Shule River Basin from 1978 to 2010

Sandy desertification in the Shule River Basin has expanded dramatically during the past 30 years. We evaluated the status, evolution, and main causes of sandy desertification by interpreting Landsat images which were acquired in 1978, 1990, 2000, 2005, and 2010, and analyzing the relevant meteorological data. The results show there was 3,477.95 km2, 3,733.32 km2, 3,620.29 km2, 3,565.65 km2, and 3,557.88 km2 of sandy desertified land in 1978, 1990, 2000, 2005, and 2010, respectively. From 1978 to 1990, not only the area of sandy desertified land （SDL） but also the degree of SDL levels increased. From 1990 to 2010 there was widespread restoration of SDL but the recovery trend of SDL gradually slowed. Although climate change contributes to expanding sandy desertification, human activities can either accelerate or reverse trends of natural sandy desertification. Some detrimental human activities can accelerate sandy desertification, but, conversely, desertification control measures such as the Three-North Shelter Forest Project and watershed rehabilitation programs in areas including the Shule River Basin resulted in many SDL being turned into grasslands or forest lands when shrubs and trees were planted to fix mobile sands at the edges of oases and cities. With population growth, much SDL has been reclaimed as farm land using water-saving agricultural methods or has been turned into built-up land as a result of urbanization.

Study on functions and rational allocation of Shule River Basin groundwater resources

Based on Investigation and Assessment on Rational Exploitation and Utilization of Groundwater Resources in Typical Areas of the Hexi Corridor, the thesis studies on groundwater and environmental problems arising from the large-scale agricultural development projects in Shule River Basin. The thesis analyzes problems in exploiting and utilizing water resources, defines the function zoning of groundwater resources in key areas and evaluates them. Finally, the thesis uses three-dimensional unsteady flow simulation and regional social and economic development plan to study on the allocation of groundwater in Shule River Basin. A proposal for rational allocation of Shule River Basin water resources has been put forward.

疏勒河流域径流量和输沙量变化规律

[目的]探索疏勒河流域水沙变化特性,可为国家实施西部生态安全战略提供科学支撑。[方法]基于疏勒河流域昌马堡、潘家庄、党城湾3个水文站的实测径流量和输沙量序列资料,运用滑动平均、Mann-Kendall突变趋势检验和小波分析法等方法,分析了疏勒河流域径流量和输沙量变化规律。[结果]疏勒河流域年径流量和年输沙量均呈递增趋势,且输沙量增大趋势大于径流量,昌马堡、潘家庄、党城湾3个水文站径流量分别在1999年、2016年、1982年发生突变,昌马堡和潘家庄年输沙量突变均发生在1998年,党城湾输沙量没有突变;疏勒河流域3个代表站的径流量和输沙量都呈现出多时间尺度的演化特征,昌马堡径流量主周期为58 a,31 a,14 a,9 a和5 a,输沙量主周期为48 a,23 a,14 a,7 a和5 a,潘家庄径流量主周期为59 a,32 a,14 a,输沙量主周期为37 a,14 a,8 a和5 a,党城湾径流量主周期为42 a和5 a,输沙量主周期为16 a和8 a。[结论]疏勒河流域水沙总体呈递增趋势,且存在明显的周期变化,除党城湾的输沙量没有突变发生以外,其余站点水沙均有突变发生,同一水文站输沙量的突变的发生滞后于径流量的突变。

基于RWEQ模型的疏勒河流域防风固沙功能价值评估

疏勒河流域地处西北内陆,是“一带一路”的关键节点。近年来随着全球变化与经济社会活动强度增加,导致建设用地快速扩张、土地沙化等问题,影响区域生态与经济社会的可持续发展。疏勒河流域处于北方防沙带中心,开展其防风固沙价值评估对于构建区域生态安全格局和保障流域可持续发展具有重要生态意义。基于修正风蚀方程模型(RWEQ)对2008—2018年疏勒河流域防风固沙功能及其价值进行评估。结果表明:(1)2008—2018年疏勒河流域防风固沙总量为43.927×10^(4)~129.530×10^(4)t·km^(-2),防风固沙量呈上升趋势。(2)2008—2018年疏勒河流域防风固沙价值快速增加,其多年平均价值占比由高到低依次为减少土地损失价值(99.46%)、保持土壤肥力价值(0.47%)、保持土壤有机质价值(0.04%)、减少交通运输经济损失价值(0.03%)。(3)流域防风固沙功能与土地利用密切相关,防风固沙能力较强的区域主要分布在草地、耕地等植被覆盖率较高区域;低值区主要分布在流域土地利用类型为未利用地区域。(4)相较社会因素,自然指标因子对流域防风固沙功能价值影响更大。研究结果可为确定流域生态补偿主客体及补偿标准提供依据。

1980-2020年疏勒河流域水面蒸发量变化趋势及预测

[目的]揭示疏勒河流域水面蒸发量的变化特征及未来演变趋势,以期更深入了解流域内水资源的动态变化,为该地区规划和管理水资源的利用提供决策支撑。[方法]基于1980—2020年昌马堡、双塔堡水库、党城湾、党河水库4个水文站逐月、逐年水面蒸发资料,采用线性倾向率、滑动t检验、R/S分析法、BP神经网络等分析方法对流域近40年水面蒸发变化特征进行了研究,并预测了未来水面蒸发量及其变化趋势。[结果](1)1980—2020年疏勒河流域各站点水面蒸发量年际变化整体均呈减少趋势,各站倾向率排序为:双塔堡水库站(-187.10 mm/10 a)>党河水库站(-178.20 mm/10 a)>昌马堡站(-33.00 mm/10 a)>党城湾站(-30.00 mm/10 a),其中双塔堡水库和党河水库站减少趋势十分显著。(2)昌马堡、双塔堡水库和党河水库站四季水面蒸发量均表现为减少趋势,党城湾站春季呈不显著增加趋势,其他季节呈下降趋势。(3)昌马堡、党城湾、双塔堡水库和党河水库4站突变年份分别为2004年、2015年、2007年和2007年。(4)流域水面蒸发量不均匀系数和集中度整体表现为减少趋势。(5)预测2021—2026年水面蒸发量将继续呈下降变化趋势。[结论]整体上,疏勒河流域全年和四季水面蒸发量呈减少变化趋势,且未来也表现为下降演变趋势。

疏勒河流域土壤保持服务供需风险探讨

土壤保持能力是疏勒河流域重要的生态系统服务之一,对流域的生态可持续发展至关重要。运用InVEST模型,对2000—2018年疏勒河流域土壤保持功能进行定量评估,并建立土壤保持服务供需风险框架,分析其供需风险时空变化特征。结果表明:1)2000—2018年,土壤侵蚀量呈先增加后减少的趋势,由2000年的3.73亿t减少到2018年的3.30亿t,流域侵蚀程度总体好转,其中,极强烈侵蚀和剧烈侵蚀面积减少14%;2)土壤保持总量呈增加-减少-增加的趋势,2010—2015年的降幅最大,共减少1.01亿t,降幅达29%,流域上游的土壤保持情况变化较为明显,主要受植被、地形和气候的影响,而中下游地区生态本底较差,土壤保持量较少且变化尚不明显;3)在供需风险方面,风险等级以危险和供给不足为主,2000—2018年,极度濒危和濒危的高风险地区面积由33%下降到12%,而风险等级为安全的面积变化较小。整体而言,疏勒河流域土壤保持服务供需风险等级水平下降,供需状况有所改善。

长喉槽量水堰水位测流断面与流量关系率定研究

通过对长喉槽量水堰在疏勒河双墩子断面和玉门关断面的实地观测与深入分析,运用Winflume软件进行建模和率定,建立了水位与流量之间的关系。结果表明:长喉槽量水堰在不同条件下均能够取得出色的测流效果,表现出卓越的可靠性和准确性。通过对1号和4号长喉槽的流量曲线和流量表进行详尽分析,验证其在设计流量范围内的普适性,1号长喉槽设计流量0~31.7 m^(3)/s范围内均适用,4号长喉槽设计流量0~34.5 m^(3)/s范围内水位流量关系同样适用。研究结果为疏勒河流域长喉槽量水堰提供技术支撑。

基于GTWR模型的疏勒河流域人均三维生态足迹动态变化及其影响因素分析

生态足迹是一种通过测量人类对区域自然资本利用程度评价该区域是否可持续发展的方法。疏勒河流域作为我国西北典型干旱区,分析其生态足迹的变化特征能够有效保障流域可持续发展。论文基于生产视角,通过土地利用数据、生物产品产量数据、社会经济数据和人口数据等,采用人均三维生态足迹模型对2000—2020年疏勒河流域人均足迹广度、人均足迹深度、人均三维生态足迹及自然资本存流量使用情况进行分析,探究流域人均三维生态足迹的动态变化特征,利用GTWR模型分析各因子的时空异质性。结果表明:2000—2020年,疏勒河流域人均足迹广度总体呈上—中—下游依次递减趋势;随着土地利用程度加深,人类对生物资源的占用速度超过其再生速度,流域人均足迹深度大于1;流域内各县人均三维生态足迹上升,生态压力增大,生态足迹重心总体自西向东北移动。在疏勒河流域,人均生态足迹主要受社会发展、民生福祉和工业发展三方面因素影响。

近65年疏勒河流域昌马堡水文站径流演变特征及变异诊断

为了掌握疏勒河昌马堡水文站的径流量演变特征,让水文更加有效地服务于经济社会发展及水资源管理,本文收集了昌马堡水文站近65a的实测径流资料,采用不均匀系数法、完全调节系数法、线性回归法、Lee-Heghinian法、Pettitt检验法、时序累积值法对径流量年内分配、年际变化趋势、序列变异进行了分析诊断。结果表明:径流量年内分配极不均匀,随着年份的增长,径流量出现年内分配不均匀且不集中特征;径流量年际变化小,随着年份增长出现增加趋势,1956—2020年共增加13.158亿m 3,多年平均增长率为0.202亿m 3/a;径流量在1998年出现显著性变异;径流量的增长与雪山融水的增加有很大关系,雪山融水增加是导致疏勒河昌马堡水文站径流量增长的主要原因。本次研究可为疏勒河流域在水资源合理配置、工农业生产方面提供数据支持。

疏勒河流域生态系统服务供需空间匹配特征

生态系统服务与人类可持续发展紧密相连,研究区域生态系统服务供需特征,了解其空间匹配状况是实现生态资源有效配置和推动区域生态安全的重要前提。基于多源数据,在InVEST模型、ArcGIS和GeoDA软件的支撑下,分析疏勒河流域产水服务、固碳服务、食物服务供需特征和空间匹配状况。结果表明:(1)除产水服务外,疏勒河流域其他各项生态系统服务供给均大于需求,但不同区域和生态系统服务间存在差异。(2)疏勒河流域综合服务供需比为0.063,不同生态系统服务的供需比由高到低依此为:固碳服务(0.1854)、食物服务(0.0078)和产水服务(-0.0043)。(3)产水服务和固碳服务空间匹配类型都主要以低高型空间错位和高低型空间错位为主,食物服务空间匹配类型主要以低低型空间匹配为主,其中产水服务的空间匹配错位现象最严重。

以疏勒河流域为例的“山水林田湖草”生态修复多尺度耦合框架及方法

为解决过去保护修复工程只考虑单要素、单一类型生态系统的问题,我国于2016年开展了“山水林田湖草”生态修复工程,旨在通过整体、系统、综合的方法对各类生态系统进行统筹治理。然而,目前的工程治理中仍然存在对系统内部及系统间耦合概念理解不充分、系统耦合机制不明晰、对“尺度”的关注不足、缺少科学的分析方法等问题,制约了保护修复的成效。对此,首先将多个尺度下的耦合研究方法进行归纳总结,并以国家重点冰川水源涵养区及生物多样性保护优先区——疏勒河流域为例,将耦合方法用于分析要素间、自然生态系统间的耦合关系,最后基于该实例研究,提出多尺度耦合分析框架与“升尺度”保护修复模式,以期帮助相关决策者明晰“山水工程”中要素、系统间的耦合关系,增强治理的科学性与有效性,进而推进我国社会与环境的可持续发展。

疏勒河流域农业水土资源时空匹配特征分析

水土资源是农业生产最重要的基础性资源,其空间的合理有效配置有利于资源的充分利用和区域可持续发展。以疏勒河流域为研究对象,基于水足迹理论核算流域农业生产水足迹变化规律,采用基尼系数和空间错配模型定量评估研究区2000—2020年农业水土资源的时空匹配动态趋势及其敏感性。结果表明:(1)2000—2020年疏勒河流域农业作物生产水足迹和作物种植面积总体呈波动下降趋势,作物生产水足迹峰值出现在2007、2018年,作物种植面积峰值出现在2009、2018年;流域年均蓝水足迹贡献率达90.9%,且与绿水足迹呈互补关系,表明蓝水是疏勒河流域农业用水的主要来源。(2)农业水土资源的空间匹配程度逐渐提高,总体处于较匹配的状态;蓝、绿水足迹与作物种植面积的空间不匹配程度逐渐得到改善,空间分布中均呈现出中部高、四周低的特点。(3)作物种植面积对作物生产水足迹变化呈中、高度敏感性的地区数量不断增加趋势。

疏勒河流域降水变化特征研究

基于疏勒河流域5个水文站1956—2020年逐年及其各月降水数据作为基础资料,采用线性倾向、滑动平均、累积距平、Mann-Kendall突变检验、小波分析等方法,对疏勒河流域降水量年际变化过程及其突变性、趋势性、周期性、持续性及不均匀性和集中度等变化特征进行研究。结果表明:疏勒河流域各站点年降水量呈现不同程度的增加趋势,并且各站点降水量分别呈现不同程度的突变性特征,整个流域近60 a降水在时间尺度上呈现出较不均匀分布,在空间尺度上呈现上游降水多、下游降水少的特性。其中,昌马堡站和党城湾站年降水量增长趋势明显,潘家庄站、双塔堡水库站和党河水库站增长趋势不明显。分析表明,未来一段时间内,流域降水将继续呈现增长趋势。

1951—2020年疏勒河流域气温时空变化特征

基于疏勒河流域敦煌站、瓜州站和玉门站1951—2020年气温实测数据,采用线性倾向、累计距平、MannKendall检验等方法,分析各站气温时空变化特征。结果表明:(1)疏勒河流域各站平均气温均呈显著上升趋势,倾向率排序表现为:敦煌站(0.244℃·(10a)^(-1),P<0.05)>瓜州站(0.209℃·(10a)^(-1),P<0.05)>玉门站(0.195℃·(10a)^(-1),P<0.05)。(2)敦煌站、玉门站四季平均气温呈显著上升趋势;瓜州站春季、秋季、冬季平均气温呈显著上升趋势,夏季平均气温呈不显著上升趋势。(3)疏勒河流域各站平均气温突变年份分别为1998年、1997年和1995年;第一主周期分别为58 a、30 a、13 a。(4)疏勒河流域全年及四季平均气温从东向西逐渐升高,不均匀系数和集中度均呈下降趋势。

疏勒河源区高寒草甸中型土壤动物群落特征及对土壤水分变化的响应

高寒草甸退化会引起土壤水分含量下降,这会强烈影响土壤动物多样性及其功能。然而,我们对高寒草甸土壤动物群落组成的认识十分有限,还不清楚高寒草甸退化过程中土壤水分变化对土壤动物分布及多样性的影响。本文以祁连山西段的疏勒河源区为研究区,于2021年6月和10月系统调查了沼泽化草甸、草甸、草原化草甸和沙化草甸4种草甸生境中型土壤动物群落组成及土壤水分含量变化,解析高寒草甸中型土壤动物多样性对高寒草甸退化的响应规律,确定高寒草甸退化过程中土壤水分变化对中型土壤动物群落特征的影响。结果表明:沼泽化草甸、草甸、草原化草甸和沙化草甸的中型土壤动物群落组成明显不同,6月和10月草原化草甸生境中型土壤动物密度、类群丰富度和多样性指数均显著高于其他高寒草甸生境,10月沼泽化草甸中型土壤动物密度和类群丰富度显著高于草甸和沙化草甸。中型土壤动物QBS-ar指数变化与中型土壤动物多样性指数变化一致,螨类和跳虫密度比值(A/C)变化与中型土壤动物QBS-ar指数相反。螨类对高寒草甸退化的响应模式不同并存在明显的季节变异,6月和10月革螨亚目的密度在草原草甸均显著高于其他生境;6月和10月甲螨亚目的密度在草原草甸均显著高于草甸和沙化草甸;6月辐螨亚目的密度在草原化草甸的密度显著高于沼泽化草甸,10月它在草原化草甸的密度显著高于草甸和沙化草甸。跳虫对高寒草甸退化的响应模式相近,6月和10月跳虫中的长角跳科和等节跳科在草原化草甸的密度均显著高于其他高寒草甸生境。土壤水分与中型土壤动物密度、类群丰富度、多样性指数和QBS-ar指数均呈显著的二次曲线关系,它们均随着土壤水分含量的增加先增后降。总之,高寒草甸退化过程中草原化草甸中型土壤动物密度、多样性和QBS-ar指数均较高,表明高寒草甸退化过程中土壤水分含量的适度降低可以提升中型土壤动物多样性及其功能。

疏勒河土著鱼类营养价值开发研究

疏勒河是甘肃省重要的内陆河流之一,为开发疏勒河土著鱼类食用价值,试验分析了野生祁连山裸鲤、河西叶儿羌高原鳅和黄河裸裂尻鱼的肌肉营养差异,并将祁连山裸鲤与裸鲤属其他鱼类进行营养品质比较研究。3种土著鱼类肌肉中水分、粗灰分、粗蛋白和粗脂肪含量呈现差异。氨基酸种类和数量一致,但氨基酸总量、必需氨基酸总量、呈味氨基酸总量和非必需氨基酸总量均在黄河裸裂尻鱼中最高。氨基酸评分(AAS)和化学评分(CS)均显示3种鱼类第一限制性氨基酸为缬氨酸。3种土著鱼类均含有丰富脂肪酸,而黄河裸裂尻鱼肌肉中饱和脂肪酸、单不饱和脂肪酸和多不饱和脂肪酸含量显著高于祁连山裸鲤和河西叶儿羌高原鳅(P<0.05)。祁连山裸鲤与其他裸鲤属鱼类肌肉营养品质比较发现一般营养物质在3种裸鲤属鱼肌肉中同样存在差异,氨基酸种类和数量一致,而必需氨基酸含量则在祁连山裸鲤肌肉中含量最高,且在祁连山裸鲤肌肉中检测出更多的脂肪酸种类。研究表明,疏勒河3种土著鱼类肌肉味道鲜美,均具有较高的食用价值和营养价值,属于优质的冷水养殖品种。同时祁连山裸鲤与青海湖裸鲤和花斑裸鲤营养价值相当,具有较高的开发价值。

数字孪生技术在疏勒河流域的应用和探讨

以疏勒河流域为研究对象,探索具有“四预”功能的智慧水利体系建设。通过信息化基础设施建设,搭建具有疏勒河流域特征的数字孪生平台,开发与流域水利业务相匹配的“2+N”智慧水务应用,在疏勒河流域形成从源头到地头的全过程水资源调配管理模式。通过疏勒河数字孪生系统建设,为流域智慧水利建设奠定基础,提升疏勒河流域现代化灌区建设水平。