Skip to main content
main-content

Über dieses Buch

This book presents an intensive study on the biogeochemical cycle of mercury in a river-reservoir system in Wujiang River Basin, the upper branch of the Yangtze River. Six reservoirs located in the mainstream of the Wujiang River and their corresponding inflow/outflow rivers were selected for inclusion in this study, which was conducted by researchers from the Institute of Geochemistry, Chinese Academy of Sciences. The concentration and distribution of Hg in reservoirs (the water column, sediment, sediment pore water), inflow/outflow rivers of reservoirs, and wet deposition in Wujiang River Basin were systematically investigated, and measurements were taken of the water/air exchange flux of gaseous elemental mercury (GEM). On the basis of the data gathered, a detailed mass balance of total mercury (THg) and methylmercury (MeHg) in the six reservoirs was developed. In addition, the book identifies the primary factors controlling Hg methylation in the river-reservoir system in Wujiang River Basin. The accumulation and bio-magnification of Hg species within food chains in reservoirs and human health risk of MeHg exposure through fish consumption are also included in this book.

Inhaltsverzeichnis

Frontmatter

Chapter 1. Introduction

Abstract
Newly built reservoirs favor mercury (Hg) methylation and then accumulation of methylmercury (MeHg) in food chains and therefore were regarded as “Hg sensitive ecosystems”. Construction of dams in rivers will have an effect on the biogeochemistry and eco-environmental evolution of river system. Wujiang River Basin is a typical impounded river system with cascade reservoirs in China. The background of the Hg biogeochemical cycle research in Wujiang River Basin was elaborated in this chapter.
Xinbin Feng, Bo Meng, Haiyu Yan, Xuewu Fu, Heng Yao, Lihai Shang

Chapter 2. Analysis of Mercury Species in the Environmental Samples

Abstract
Accurate analysis of mercury (Hg) species is the basis of understanding fate and behavior of Hg in aquatic environment. In this chapter, different Hg speciation systems were introduced according to analytical theory or research aim. In this chapter, we elucidate the detailed procedures, including the sample collection, preparation, and analytical methods in water, sediment, plankton, and sediment employed in this study.
Xinbin Feng, Bo Meng, Haiyu Yan, Xuewu Fu, Heng Yao, Lihai Shang

Chapter 3. Wet Deposition Flux of Total Mercury and Methylmercury in Wujiang River Basin

Abstract
Wet deposition is an important pathway for the removal of mercury (Hg) from the atmosphere and the loading of Hg to the terrestrial and aquatic ecosystem systems. In this chapter, we (1) measured total mercury (THg) and methylmercury (MeHg) in bulk precipitation at five rural sites in Wujiang River Basin; (2) studied the monthly and annual deposition fluxes of THg and MeHg at the sampling sites in Wujiang River Basin and the underlying factors, and (3) estimated the input of THg and MeHg to the studied reservoirs in Wujiang River Basin via wet deposition.
Xinbin Feng, Bo Meng, Haiyu Yan, Xuewu Fu, Heng Yao, Lihai Shang

Chapter 4. Water/Air Mercury Flux in Reservoirs

Abstract
Dynamics of mercury (Hg) in aquatic ecosystem is of particular concern because Hg delivered to watersheds can be converted to methylmercury (MeHg), a highly toxic, persistent, and bioaccumulative species that poses a serious threat to human health and wildlife by consuming fish. Emission of Hg from water is an important source of global atmospheric Hg budget and would also reduce the Hg burden in the water bodies which in turn decreases the MeHg production and bioaccumulation in aquatic ecosystem. Therefore, exchange of Hg between water and atmosphere plays a crucial role in cycling of Hg in aquatic ecosystem and the atmosphere. In this chapter, we (1) measured water/air exchange flux at eight reservoirs in Wujiang River Basin; (2) studied the diurnal and seasonal variations in water/air Hg flux and related factors; and (3) developed water/air Hg fluxes empirical models and estimated Hg emissions from Wujiang River.
Xinbin Feng, Bo Meng, Haiyu Yan, Xuewu Fu, Heng Yao, Lihai Shang

Chapter 5. Mercury in Inflow/Outflow Rivers of Reservoirs

Abstract
Rivers are major pathways for a variety of materials to flow in and out of reservoirs. Impounding rivers changes the characteristics of a water body from “rivers’’ to “reservoirs”, affecting not only their hydrology but also their physical, chemical, and biological characteristics. To understand the influence of damming on the distribution and methylation of Hg within a river-reservoir ecosystem, this chapter illustrates the spatial and temporal distributions of Hg species in the inflow–outflow rivers of the six cascade reservoirs in Wujiang River Basin, Southwest China. Furthermore, the influence of cascade reservoirs on the distributions of Hg species in rivers of Wujiang River Basin is elucidated as well.
Xinbin Feng, Bo Meng, Haiyu Yan, Xuewu Fu, Heng Yao, Lihai Shang

Chapter 6. Biogeochemical Process of Mercury in Reservoirs in the Main Stream of the Wujiang River

Abstract
To understand the biogeochemical process of mercury (Hg) in reservoir in Wujiang River Basin, Southwest China, six cascade reservoirs including Yinzidu Reservoir (YZD), Suofengying Reservoir (SFY), Hongjiadu Reservoir (HJD), Puding Reservoir (PD), Dongfeng Reservoir (DF), and Wujiangdu Reservoir (WJD) in the mainstream of Wujiang River were selected in this study. The primary objectives of this chapter were: (1) to investigate spatial and seasonal variations of Hg species in different sectors of reservoirs (e.g., water column, sediment, sediment pore water); (2) to reveal the processes of Hg methylation and their possible controlling factors in the reservoirs in the Wujiang River Basin, Southwest China.
Xinbin Feng, Bo Meng, Haiyu Yan, Xuewu Fu, Heng Yao, Lihai Shang

Chapter 7. Biogeochemical Cycling of Mercury in the Hongfeng, Baihua, and Aha Reservoirs

Abstract
To understand the biogeochemical process of mercury (Hg) in reservoir in Wujiang River Basin, Southwest China, three reservoirs including Hongfeng Reservoir (HF), Baihua Reservoir (BH), Aha Reservoir (AH), and Wujiang River were selected in this study. The primary objectives of this chapter were seasonal variations of Hg species in different sectors of reservoirs (e.g., water column, river water, sediment, and pore water), processes of Hg methylation and their possible controlling factors in the reservoirs in the Wujiang River Basin, in the branch of, (1) to investigate spatial and (2) to reveal the Southwest China.
Xinbin Feng, Bo Meng, Haiyu Yan, Xuewu Fu, Heng Yao, Lihai Shang

Chapter 8. Mercury Mass Balance in Reservoirs with Different Ages

Abstract
Reservoirs play a complicated role in the transportation of mercury (Hg) the river reservoir ecosystems. Under different environmental conditions, reservoirs can be a sink for Hg to the outflow river, a source of Hg to the inflow river, or a place for Hg to transform from inorganic Hg (IHg) to methylmercury (MeHg). The different pathways for regulation and operation in the reservoir lead to distinct water exchange frequencies and residence times as well as distinct source-sink characteristics for the reservoir. In this chapter, we (1) estimated the input/output fluxes of Hg species (THg and MeHg) in a reservoir and (2) assessed the role of different reservoir stages on the source/sink of Hg in the transportation and transformation of Hg in a river reservoir ecosystem.
Xinbin Feng, Bo Meng, Haiyu Yan, Xuewu Fu, Heng Yao, Lihai Shang

Chapter 9. Bioaccumulation of Mercury in Aquatic Food Chains

Abstract
Current paradigms regarding the bioaccumulation of mercury are rooted in observations that methylmercury (MeHg) biomagnifies along pelagic food chains. However, mechanisms regulating the bioaccumulation of MeHg in food chain, its initial incorporation at the base of pelagic food chains, and its subsequent trophic transfer remain controversial. Here we measured mercury (total mercury (THg) and MeHg) and stable carbon/nitrogen isotopes (δ13C and δ15N) and use these field data from seven reservoirs to understand the transport and accumulation and influence effectors of mercury in the aquatic food chain (plankton and fish) in Wujiang River Basin, and assessed the health risk.
Xinbin Feng, Bo Meng, Haiyu Yan, Xuewu Fu, Heng Yao, Lihai Shang

Chapter 10. Primary Factors Controlling Hg Methylation in Reservoirs

Abstract
In this book, we conducted an intensive study on the mercury (Hg) biogeochemical processes in a river-reservoir ecosystem in the Wujiang River Basin, Southwest China. The concentrations and distributions of Hg species in the reservoirs (water column, sediment, and sediment pore water), the inflow/outflow rivers of the reservoirs, wet deposition, and food chains within the Wujiang River Basin were systematically investigated (Chaps. 3, 5, 6, 7, and 9). Measurements of the water/air exchange flux of gaseous elemental mercury (GEM) were also conducted in the reservoirs (Chap. 4). A detailed mass balance of the total mercury (THg) and methylmercury (MeHg) in the selected six reservoirs was developed (Chap. 8). This chapter reveals the primary factors that controlling Hg methylation in reservoirs in Wujiang River Basin, Southwest China. To better understand the biogeochemical processes of Hg in Wujiang River Basin, a conceptual model of the Hg in the river-reservoir system was further developed in this chapter.
Xinbin Feng, Bo Meng, Haiyu Yan, Xuewu Fu, Heng Yao, Lihai Shang
Weitere Informationen