Characteristics and sources of microplastic pollution in the water and sediments of the Jinjiang River Basin,Fujian Province,China

Microplastic pollution is widely distributed from surface water to sediments to groundwater vertically and from land to the ocean horizontally. This study collected samples from surface water, groundwater, and sediments from upper to lower reaches and then to the estuary in 16 typical areas in the Jinjiang River Basin, Fujian Province, China. Afterward, it determined the components and abundance of the microplastics and analyzed the possible microplastic sources through principal component analysis (PCA). As a result, seven main components of microplastics were detected, i.e., polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polyethylene terephthalate (PET), polyformaldehyde (POM), nylon 6 (PA6), and polystyrene (PS). Among them, PE and PP were found to have the highest proportion in the surface water and sediments and in the groundwater, respectively. The surface water, groundwater, and sediments had average microplastic abundance of 1.6 n/L, 2.7 n/L and 33.8 n/kg, respectively. The microplastics in the sediments had the largest particle size, while those in the groundwater had the smallest particle size. Compared with water bodies and sediments in other areas, those in the study area generally have medium-low-level microplastic abundance. Three pollution sources were determined according to PCA, i.e., the dominant agriculture-forestry-fishery source, domestic wastewater, and industrial production. This study can provide a scientific basis for the control of microplastics in rivers.©2022 China Geology Editorial Office.     

Microplastic pollution in surface water and sediments of Qinghai-Tibet Plateau: Current status and causes

To study the current status and causes of the microplastic pollution in surface water of the Qinghai-Tibet Plateau, this paper compared the average microplastic abundance in sediments and surface water of the Qinghai-Tibet Plateau and the results are as follows. First, the average microplastic abundance in surface water of the independent rivers and the whole area is 247–2686 items/m³ and 856 items/m³, respectively. The average microplastic abundance in sediments of independent rivers or lakes and the whole area is 0–933 items/m² and 362 items/m², respectively. Meanwhile, the degree of microplastic pollution in river sediments is higher than that in lake sediments, and the rivers suffering from microplastic pollution mainly include the Brahmaputra River, Tongtian River, and Nujiang River. Second, compared with the microplastic pollution in other areas of the world, the levelof microplastic pollution in the lakes and rivers of the Qinghai-Tibet plateau is not lower than that of well-developed areas with more intensive human activities. Finally, this study suggests that relevant government departments of the Qinghai-Tibet Plateau should strengthen waste management strategies while developing tourism and that much attention should be paid to the impacts of microplastics in the water environment.©2021 China Geology Editorial Office.     

Microplastic pollution in Yellow River,China: Current status and research progress of biotoxicological effects

This study aims to comprehensively assess the environmental risks of microplastics in the Yellow River, achieving the following results through comprehensive research. The average microplastic abundances in the river waters and sediments are 5358–654000 n/m³ and 43.57–615 items/kg, respectively, and there are fewer microplastics in water samples than in sediments. Microplastics in the study area can be divided into five types according to their occurrence morphologies, namely fragments, foams, films, fibers, and particles. The most widely distributed pollution types in sediments include debris, fibers, and particles. In contrast, fibers are the dominant type in water samples, accounting for 68.18% –98.93%. The chemical components of the microplastics include polyethylene, polypropylene, polystyrene, polyethylene terephthalate, and polyvinyl chloride. The microplastics are in four colors, with white accounting for a higher proportion. The grain size of the microplastics in tributaries or lakes of the Yellow River is less than 2 mm, which makes them liable to enter organisms for enrichment. Furthermore, the sources of the microplastics are closely related to agricultural and industrial production and biological activities in habitats and exhibit seasonal and hydrological characteristics. The microplastics in the study area show the adsorption of metals and nonmetals to different degrees, which increases the pollution risks of heavy metals combined with microplastics. In addition, microplastics can accumulate in organisms in the Yellow River and cause physical, biochemical, and other damage to aquatic organisms, thus further posing carcinogenic risks to human beings. Therefore, it is necessary to study, monitor, and control the pollution and effects of microplastics in the Yellow River, in order to provide theoretical references for the control of pollution and ecological risk of microplastics in the river.©2021 China Geology Editorial Office.     

Microplastic contamination in lacustrine sediments in the Qinghai-Tibet Plateau: Current status and transfer mechanisms

This paper aims to investigate the present situation and transfer mechanisms of microplastics in lacustrine sediments in the Qinghai-Tibet Plateau. The study surveyed the average abundance of microplastics in sediments. The abundance of microplastics in sediments of lakes from the Qinghai-Tibet Plateau is 17.22–2643.65 items/kg DW and 0–60.63 items/kg DW based on the data of the Qinghai Lake and the Siying Co Basin. The microplastic abundance in sediments from small and medium lakes is very high compared to that in other areas in the world. Like microplastics in other lakes of the world, those in the lakes in the Qinghai-Tibet Plateau mainly include organic polymers PA, PET, PE, and PP and are primarily in the shape of fibers and fragments. The microplastic pollution of lacustrine sediments in the Qinghai-Tibet Plateau is affected by natural changes and by human activities, and the concentration of microplastics in lacustrine ecosystems gradually increases through food chains. Furthermore, the paper suggests the relevant administrative departments of the Qinghai-Tibet Plateau strengthen waste management while developing tourism and pay much attention to the impacts of microplastics in water environments. This study provides a reference for preventing and controlling microplastic contamination in the Qinghai-Tibet Plateau.©2022 China Geology Editorial Office.     

Current status and cause analysis of microplastic pollution in sea areas in China

As a new type of pollutants in the marine environment,microplastics have attracted increasing attention from scientific researchers and environmental protection workers in China and abroad.However,for the microplastic pollution in sea areas in China,there are a very limited number of studies on its current status and few reviews of research on the microplastics.This paper reviews the surveys and researches of microplastics in the Bohai Sea,the Yellow Sea,the East China Sea,the South China Sea,and main estuaries in China carried out in recent years and proposes an outlook for future work,aiming to provide research suggestions and solutions for ecological protection against microplastic pollution in sea areas in China.Previous studies have shown that microplastics are widely distributed in water bodies and sediments in sea areas and major estuaries in China.The Pearl River Estuary,in the South China Sea suffers the most serious microplastic pollution,followed by the Bohai Sea.In contrast,the microplastic pollution in the Yellow Sea and the East China Sea is comparatively slight.Microplastics in sea areas in China are mainly fibrous and are concentrated in offshore areas with developed industry and a dense population(especially around estuaries and bays).In addition,they are widely affected by human activities,such as shipping,aquaculture,industry,and sewage discharge.Here the authors suggest unifying measurement units and research methods and developing related standard systems to carry out researches related to microplastics.Furthermore,this paper also suggests further deepening researches on both the source-sink process of microplastics and nanoscale microplastics while enhancing the development and implementation of related policies,aiming to promote researches and control of microplastics in sea areas in China.     

峨眉山玄武岩作为长江上游特征源岩对三峡贯通的指示

峨眉山玄武岩作为长江上游攀西地区广泛分布的岩类,具有形成环境独特、出露面积大、岩石易鉴定的特点,可作为长江三峡贯通物源示踪研究的指示标志.通过对长江中上游阶地和江汉平原周老孔第四纪岩心沉积物中的玄武岩砾石和岩屑(1~2 mm)进行研究发现,峨眉山玄武岩砾石在长江上游很常见,在三峡以下很少;玄武岩岩屑在长江上游沉积物中非常普遍,而且在周老孔岩心沉积物中的很多层位都有出现.对玄武岩岩屑基质中的斜长石做了微量元素微区原位分析(LA-ICP-MS),分析表明,在周老孔中含峨眉山玄武岩岩屑的岩心层位最大深度为156 m,该层位古地磁年龄约为1.7 Ma,此时长江已经形成且三峡已经贯通.      

长江流域水沙周期特征及可能影响原因

运用小波变换的方法研究了长江流域干流站(屏山站、宜昌站、大通站与汉口站)以及位于支流嘉陵江流域的北碚站近40年来月均流量与输沙率,研究认为:(1)水利工程(本文主要指水库)对下游河道输沙率的影响远远大于对流量的影响;(2)葛洲坝是低水头径流式发电站,对下游流量变化影响不大,虽然在建库初期对输沙率有一定影响,导致下游河床下切,但远未达到使输沙率固有的1年周期受到影响的程度;(3)三峡大坝的建设已经对下游输沙率产生严重影响,使其固有的1年周期消失,但三峡大坝下游河道输沙率对这种影响的响应与距三峡大坝的距离成反比,即愈往下游,输沙率受三峡大坝的影响愈小;(4)输沙率变化对水利工程影响的敏感程度受流域尺度的影响,流域尺度越大,其反应就愈迟钝,反之亦然。     

Research Progress on Source-to-Sink Transport Processes of Marine Microplastics

Microplastics in marine environment are global environmental issue and challenge and have received an extensive international concern. At present, most of researches focus on the investigation of microplastic abundance in the ocean surface water, and there is insufficient understanding of the distribution and transport processes of microplastics in the deep-sea environment. This paper reviewed marine microplastic studies carried out in the last decade, and summarized the source, global distribution and transport processes of microplastics. Field investigations showed that both surface water and water column were important accumulation areas for microplastics, while deep-sea surface sediments were final sinks for microplastic deposition and accumulation. Transport of microplastics to the deep sea included two modes: vertical settlement and lateral transport. Laboratory simulation showed that the sinking rate of microplastic particles in the ocean changed between 300 and 1 000 meters per day, and the sinking process was not solely controlled by particle physical properties such as particle density, but also influenced by ocean dynamic process, biological action and marine snow aggregation. Microplastics deposited on the seafloor could migrate laterally towards the deep sea with resuspended sediments, which were related to internal waves, deep-sea turbidity current or climatic events. However, there remain the key knowledge gaps in uncertain speed and quantity of microplastics moving to the deep sea, which is not conducive to the comprehensive understanding of the microplastic transport process from source to sink. Therefore, it is recommended to observe the vertical sinking flux of microplastics with layered sediment traps in order to study the source-to-sink transport processes of microplastics in deep-sea environment.     

长江三峡库区土壤与水系沉积物Cd地球化学特征

对长江三峡库区段不同介质中Cd的分布特征和长江水系沉积物在垂向、横向剖面上的元素分布特征的研究发现，残坡积型土壤与长江干流水系沉积物Cd含量差异较大，水系沉积物具明显的高Cd异常；各个沉积时期的水系沉积物中均存在Cd异常，上游来源的Cd是引起三峡库区水系沉积物高Cd异常的主要因素；人类活动对土壤和水系沉积物中Cd的含量影响明显，在厂矿、码头、生活垃圾场等地区土壤中Cd的含量远高于一般地区土壤中Cd的含量，城市排污水系沉积物Cd的含量也高于长江干流水系沉积物Cd的含量。自然源是沿长江流域Cd异常普遍存在的根本原因，而人为源却有可能是高Cd异常主要沿长江干流及支流两岸大中城市分布的重要影响因素。     

Provenance Study of Fe–Ti Oxide Minerals in the Quaternary Sediments in Yichang Area and Its Implication of Formation Time of the Yangtze Three Gorges, China

The Three Gorges are considered to be critical to understand the formation of Yangtze River. Recent research results suggest that the Yangtze Three Gorges was created during the Quaternary but the exact time is debatable. Fe–Ti oxide minerals are seldom used to study sediment provenance, expecially using scanning electron microscopy(SEM), and energy dispersive spectrometer(EDS). In this study, the provenance of Quaternary sediments in Yichang area, which is located to the east of the Yangtze Three Gorges, was investigated by using SEM and EDS to research Fe–Ti oxides. The Panzhihua vanadium titanomagnetite and Emeishan basalt outcrop are located to the west of the Three Gorges. Further, the materials from them are observed in the Quaternary sediments of Yichang area. Fe–Ti oxide minerals from the Huangling granite are observed in the Yunchi and Shanxiyao Formations, which were formed before 0.75 Ma B.P., whereas Fe–Ti oxide minerals from the Huangling granite, Panzhihua vanadium titanomagnetite, and Emeishan basalt are observed in the riverbed and fifth-terrace sediments of the Yangtze River, which were formed after 0.73 Ma B.P.. Thus, we can infer that the Three Gorges formed after the deposition of the Shanxi Formation and before the fifth-terrace; i.e., 0.75–0.73 Ma B.P..     

长江在三峡库区段实现东流过程探讨

三峡如何贯通并实现东流的问题历来是学术界关注和争议的问题。笔者认为,三峡的连通不是简单的江汉平原水系与四川盆地水系的连通,而是包括三峡库区段众多中小盆地及其水系的纵横交织性连通,连通过程中有地表水的溯源侵蚀作用,也有地下水的溶蚀、风化和侵蚀作用。地表水的流路与地下水的流路不尽相同,地下水的作用形成地下河,许多峡谷是地下河经进一步溶蚀垮塌形成的。地表河与地下河相连接构成长江主河道。虽然当时的水流有东西分流,但没有明显的分水岭,许多地段水流的方向因各盆地降雨量的变化而频繁改变。由于河流下切和新构造运动造成地表西升东降,最后流向四川盆地的水改向东流,形成统一的长江。三峡库区段是年轻的河段,成为完全地表河和东流的时间不长。这些认识对深化大江大河的成因理论具有重要的意义。     

江汉平原沉积物重矿物特征及其对三峡贯通的指示

江汉平原是长江穿过三峡区的第一个大型卸载盆地, 其沉积物必然反映长江流经的物源区的物源特征.通过对盆地中心周老孔第四纪岩心的重砂样品中0.125~0.063mm粒级的重矿物含量变化、ATi、GZi、ZTR指数和重矿物组合分析, 发现从钻孔岩心深度110m开始向上, 水动力条件加强, 沉积速率加快, 重矿物的数量特征发生明显突变, 特征矿物的组合与现代长江相同.表明在周老孔岩心深度110m (古地磁年龄1.1Ma左右) 位置处, 长江三峡开始贯通, 江汉平原开始接纳长江带来的三峡上游的物质.      

长江沉积物环境地球化学特征及生态风险评价

为了进行长江流域沉积物生态风险评价,对长江流域干流以及主要支流的沉积物统一进行采样分析。首先对其元素的组成特征及重金属元素的富集特征进行分析。常量元素含量在流域空间上的变化主要受其携带矿物含量变化的影响;Cu、Pb、Cd、As、Hg 5种微量元素富集程度较大,存在异常。同时采用潜在生态风险指数法对长江沉积物Cr、Mn、Co、Ni、Cu、Zn、Pb、Cd、As、Hg 10种元素进行了评价研究。结果表明,潜在生态风险指数较大的地区分布在湖南湘江、安徽铜陵等地区,中等的地区分布在四川、重庆及江西等地区,这些潜在污染指数与矿产的开采冶炼以及工业的布局有一定的关系,很大程度上是由人为因素造成的。从元素的潜在污染程度看,长江流域Cd、As、Hg污染程度较重,Cu、Zn、Pb次之,而Cr、Mn、Co、Ni基本没有污染。本研究为探讨长江流域沉积地球化学过程和环境保护提供了科学依据。     

三峡水库运用对鄱阳湖调蓄能力的影响

鄱阳湖调蓄能力受“五河”(赣江、抚河、信江、饶河、修水,以下简称五河)及长江干流的双重影响,三峡水库运用后,干流水文情势变化影响鄱阳湖与长江之间的水量交换。基于实测资料统计和湖口出流影响因素分析,建立了一种新的鄱阳湖出流及临界调蓄水位的计算公式,进而对三峡水库运用前后鄱阳湖各月调蓄水量的变化情况进行了定量分析。研究结果表明,长江干流和五河来流通过改变星湖落差和湖口水位来影响湖口出流及湖泊调蓄水量,但影响过程及影响量有所差异,若湖口水位不变,五河入流每增加1000m^3/s,湖口出流约增加304m^3/s,九江流量每增加1000m^3/s,湖口出流约减小723m^3/s。三峡水库运用会改变湖泊调蓄水量,年内各月相比,9月鄱阳湖水量减小约49.4%,5月鄱阳湖水量增加约47.7%。     

Comparison of detrital mineral compositions between stream sediments of the Yangtze River (Changjiang) and the Yellow River (Huanghe) and their provenance implication

A comparative comparative study on the detrital mineral composition of stream sediments of the Yangtze River (Changjiang) and Yellow River (Huanghe) shows that, light minerals of the Yangtze River basin were mainly quartz, feldspar, and detritus, the compositional characteristics of light minerals differed among tributaries, the main stream had a generally higher maturity index than tributaries; heavy mineral content tended to decrease progressively from the upper stream to lower stream of the Yangtze River, the primary assemblage was magnetite-hornblende-augite-garnet-epidote, and diagnostic minerals of different river basins were capable of indicating the nature and distribution of the source rock. Detrital mineral assemblages in sediments of tributaries and the main stream of the Yellow River were basically similar, Primary heavy mineral assemblage was opaque mineral-garnet-epidote-carbonate mineral and alteration mineral. Variations in the contents of garnet, opaque mineral, and hornblende mainly reflected the degree of sedimentary differentiation in suspended sediment and the hydrodynamic intensity of a drainage system. The heavy mineral differentiation index F revealed sedimentary differentiation of diagnostic detrital mineral composition due to changes in regional hydrodynamic intensity and can serve as an indicator for studying the dynamic sedimentary environment of a single-provenance river and the degree of sedimentary differentiation of its detrital minerals. Changes in detrital mineral content of the Yellow River was not completely controlled by provenance but reflected gravity sorting of the detrital mineral due to variations in the ephemeral river hydrodynamic intensity and sedimentary environment, however the index changing of Yangtze River were mainly influenced by the complex sediment sources. Therefore caution must be exercised in using the detrital mineral composition of marginal sea to determine the contribution of the Yangtze River and Yellow River.© 2019 China Geology Editorial Office.     

作图法求解库岸地下水的壅高值

利用河流水位和对应的库岸钻孔水位,做出关系曲线,可以推算出钻孔地下水位的壅高值。本文以三峡库区洛碛镇为例,利用作图法求解了地下水的壅高值。     

浅论长江中游洪灾高危险性

通过对长江洪水的致灾性、河道边界条件及其孕灾性、承载体易损性的分析,论述了长江中游为我国洪灾高危险区的必然性。分析了人类对河流的治理,使河道稳定性增加,减少了洪灾的风险,但是长江中游的局部河段却发生洪水位增高的趋势,又增加了洪灾风险,该区域高危险的基本特性犹存。研究了三峡运行后,长江中下游出现新的防洪形势:一方面三峡水库巨大的防洪库容拦蓄洪水,大大减少了中下游的洪灾,另一方面因河道的强冲刷,使河势变化剧烈、横向摆动增强,局部河段岸壁失稳,又增加防洪压力。同时因总体水面比降趋平,洪灾风险有向下游转移的趋势。未来长江中游仍为洪灾高危险区,仍应给予高度重视。     

基于污染负荷核算的岷江流域总磷污染成因分析及对策

总磷是长江流域水环境污染的首要超标因子,岷江作为长江上游流量最大的支流,总磷污染严重,对长江总磷污染贡献较大。为了解岷江流域总磷污染,采用排污系数法,计算得到2016年岷江流域污染源总磷入河量为1 154 t,以农村生活污染负荷占比最高(51.3%),其次为城镇生活源(28.7%)、农业非点源(8.24%)、工业源(9.57%)、畜禽养殖源(1.21%),城市径流源(0.99%)最低;在空间上岷江流域总磷污染负荷呈中游(64.2%)>下游(32.6%)>上游(3.1%)的特点,与岷江干流总磷浓度变化趋势相符,其中成都市总磷污染负荷最高(51.2%),与区域人口密度高、生产和生活活动密集有关。结合资料收集和现场调查,岷江流域总磷污染成因主要包括农村生活污染治理缺口较大、城镇生活污染处理基础设施建设不足、工业企业密布、部分支流总磷污染严重、水污染治理导向不全面。针对岷江总磷污染负荷分布特征及成因,提出“上游保护优质水体、中游治理重污染水体、下游恢复不达标水体”的分区污染防治对策,统筹流域监管体制机制,强化岷江流域水环境保护和治理。     

长江上游水系沉积物锶-钕同位素组成及物源示踪

泥沙资料表明,现代长江干流沉积物主要源自上游地区。因此,长江上游干支流沉积物主控关系及其源汇过程在长江水系沉积物物源示踪研究中极为重要。为探讨上述过程,详细测定了上游水系沉积物Sr-Nd同位素组成。结果显示,金沙江及闽江沉积物具有较高的εNd(0)值,主要受控于流域内大面积分布的峨眉山玄武岩的高εNd(0)背景值;嘉陵江水系沉积物具有相对较低的εNd(0)值,反映了其流域内源岩对沉积物Nd同位素组成的控制;与Nd同位素组成相比,水系沉积物87Sr/86Sr值具有更大的变化范围,表明除源岩因素外,沉积物Sr同位素组成受更为复杂的因素制约。支流与干流沉积物Sr-Nd同位素组成对比表明,长江上游干流沉积物主要来源于金沙江流域内的源岩,金沙江流域内的表壳岩系主导了上游干流沉积物的Sr-Nd同位素组成。     

红河盆地的化学风化作用:主要和微量元素地球化学记录

河流沉积物的元素含量有助于反映其流域的自然风化过程。红河是世界上重要的河流之一,但其沉积物的地球化学研究却几乎没有。本文通过开展红河盆地干流和主要支流40个样品的主要和微量元素地球化学分析,发现红河流域硅酸盐岩的化学风化作用为中等强度,与长江及亚马逊河的风化强度相近,而高于黄河,低于珠江;且化学风化作用受该区域的气候和构造作用控制。