Sources of Heavy Metals in Surface Sediments and an Ecological Risk Assessment from Two Adjacent Plateau Reservoirs

Abstract

The concentrations of heavy metals (mercury (Hg), cadmium (Cd), lead (Pb), chromium (Cr), copper (Cu) and arsenic (As)) in surface water and sediments were investigated in two adjacent drinking water reservoirs (Hongfeng and Baihua Reservoirs) on the Yunnan-Guizhou Plateau in Southwest China. Possible pollution sources were identified by spatial and statistical analyses. For both reservoirs, Cd was most likely from industrial activities, and As was from lithogenic sources. For the Hongfeng Reservoir, Pb, Cr and Cu might have originated from mixed sources (traffic pollution and residual effect of former industrial practices), and the sources of Hg included the inflows, which were different for the North (industrial activities) and South (lithogenic origin) Lakes, and atmospheric deposition resulting from coal combustion. For the Baihua Reservoir, the Hg, Cr and Cu were primarily derived from industrial activities, and the Pb originated from traffic pollution. The Hg in the Baihua Reservoir might also have been associated with coal combustion pollution. An analysis of ecological risk using sediment quality guidelines showed that there were moderate toxicological risks for sediment-dwelling organisms in both reservoirs, mainly from Hg and Cr. Ecological risk analysis using the Hakanson index suggested that there was a potential moderate to very high ecological risk to humans from fish in both reservoirs, mainly because of elevated levels of Hg and Cd. The upstream Hongfeng Reservoir acts as a buffer, but remains an important source of Cd, Cu and Pb and a moderately important source of Cr, for the downstream Baihua Reservoir. This study provides a replicable method for assessing aquatic ecosystem health in adjacent plateau reservoirs.

Heavy metals in surface sediments of the shallow lakes in eastern China: their relations with environmental factors and anthropogenic activities

“…Natural emissions of heavy metals must be considered when assessing heavy metals in the local and global environment (Adnano 1986). However, anthropogenic sources of heavy metals are usually considered to be the major causes of heavy metals in the environment being higher than background concentrations (Wu et al 2014). Anthropogenic sources of heavy metals can be divided into three groups: releases of heavy metal impurities during the production of power and heat from coal, mining activities, and other metallurgical activities; releases during the intentional extraction and use of heavy metals (such as during the mining of heavy metals, the production of leather, electroplating processes, and the manufacture of products containing heavy metals); and releases from landfills and plants such as waste incinerators.…”

Heavy Metals Pollution Influence the Community Structure of Cyanobacteria in Nutrient Rich Tropical Estuary

“…Under normal conditions, the heavy metals discharged to the estuary are immobilized in the sediment or accumulated in benthic organisms. Disturbing the system by either physical or chemical forces, i.e., resuspension of sediments by dredging operation or tidal mixing or adjusting the pH or redox conditions by discharging acidic wastes, may trigger the release of significant amount of heavy metals to the water column [45][46][47]. The resuspension of sediment due to continuous dredging operations could be the reasons for pulsed level of heavy metals in S1 during wet season.…”

Assessment of pollution and identification of sources of heavy metals in the sediments of Changshou Lake in a branch of the Three Gorges Reservoir

“…Studies on heavy metal pollution in a reservoir after dam construction have received increasing attention, and geochemical approaches and multivariate statistical analyses have been widely used (Wildi et al 2004;Wu et al 2014;Zhang et al 2012;Zhu et al 2013). The sediment pollution index (SPI) and the geoaccumulation index (I geo ), which are defined as the observed metal to reference metal ratio in the sample sites, have been applied as indexes to assess the status and degree of sediment heavy metal pollution in lakes and reservoirs and in riverine, estuarine, and coastal environments (Ao et al 2014a, b;Hakanson 1980;Kim et al 2010;Singh et al 2002).…”

“…The sediment pollution index (SPI) and the geoaccumulation index (I geo ), which are defined as the observed metal to reference metal ratio in the sample sites, have been applied as indexes to assess the status and degree of sediment heavy metal pollution in lakes and reservoirs and in riverine, estuarine, and coastal environments (Ao et al 2014a, b;Hakanson 1980;Kim et al 2010;Singh et al 2002). Multivariable statistical analyses, including factor analysis (FA) and factor analysis-multiple linear regression analysis (FA-MLR), have been widely applied to distinguish pollution sources and to quantify their contributions (Shafie et al 2013;Wu et al 2014;Ye et al 2011). After these techniques were performed, valuable tools are available for the development of appropriate strategies for the effective management of sediment and water conservation in aquatic ecosystems.…”

“…The main water resource originates from the Longxi River, and the water volume varied with the changes in climate observed among different seasons, which result in decreases and increases in precipitation. Previous research has suggested that industrial activities, fishery breeding, and domestic consumption in the reservoir region may discharge heavy metals, which accumulate in the water environment; nevertheless, flooding may play an important role in heavy metal discharge from the upper water basin in the wet season (Hu and He 2012;Weiyang et al 2011;Wildi et al 2004;Wu et al 2014). Previous studies have reported that the sediments in the reservoir of Changshou Lake are slightly polluted by industrial wastewater, fishery waste, and domestic sewage from the Dianjiang, Liangpin, and Changshou districts, which have a population of 2 million and many industries in the upper region.…”