Major Ion Geochemistry of the Nansihu Lake Basin Rivers, North China: Chemical Weathering and Anthropogenic Load Under Intensive Industrialization
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Environ Earth Sci (2016) 75:453 DOI 10.1007/s12665-016-5305-2 ORIGINAL ARTICLE Major ion geochemistry of the Nansihu Lake basin rivers, North China: chemical weathering and anthropogenic load under intensive industrialization 1 1,2 3 1 1 Jun Li • Guo-Li Yuan • Xian-Rui Deng • Xiu-Ming Jing • Tian-He Sun • 1 1 Xin-Xin Lang • Gen-Hou Wang Received: 12 April 2015 / Accepted: 23 November 2015 / Published online: 10 March 2016 Ó Springer-Verlag Berlin Heidelberg 2016 Abstract To explore the chemical weathering processes 34 % was presumed to be originated from NCA, causing 9 and the anthropogenic disturbance of weathering, 20 water 2.74 9 10 mol/a of CO2 degassing. Moreover, industrial samples were collected from the tributaries in the Nansihu inputs could play a major role in the modification of the Lake basin, a growing industrial area. The major ions in chemicals in the water system, and they could even change river waters were analyzed to identify and quantify the the carbonate weathering rate in such an intensively contributions of the different reservoirs. Based on stoi- industrializing region. In North China, the chemical chiometric analyses and end-member determination, the weathering associated with NCA was found to be signifi- contributions of individual reservoirs were calculated for cant for the first time. each tributary. In the study region, the averaged contribu- tions of atmospheric inputs, anthropogenic inputs, evap- Keywords Water geochemistry Á Major ions Á Rock orite weathering, carbonate weathering and silicate weathering Á CO2 consumption Á Long term CO2 degassing weathering were 2, 37, 28, 25 and 8 %, respectively. Combined with information regarding runoff and drainage area, the annual average contribution of TDS to waters was Introduction estimated to be 1.90 ± 0.95 ton/km2 from silicate weath- ering, 5.68 ± 2.84 ton/km2 from carbonate weathering. The major chemical compositions of river waters can Furthermore, the associated consumption of CO2 was cal- reveal the natural weathering processes and anthropogenic culated to be approximately 7.50 9 109 mol/a. The activities on a basin-wide scale (Gibbs 1970; Stallard and industrial and mining activities were the main sources for Edmond 1983; Sarin et al. 1989; Brennan and Lowenstein anthropogenic inputs, and they produced non-CO2 acids 2002; Moquet et al. 2011). At the global scale, large rivers (NCA). Of all protons involved in chemical weathering, have been studied to estimate the weathering rates of dif- ferent rock types and CO2 consumption (Gaillardet et al. 1999; Roy et al. 1999; Moon et al. 2007, 2014; Noh et al. Electronic supplementary material The online version of this 2009; Moquet et al. 2011; Pattanaik et al. 2013). However, article (doi:10.1007/s12665-016-5305-2) contains supplementary material, which is available to authorized users. the small-scale studies have been considered to be better for understanding specific weathering and anthropogenic & Guo-Li Yuan processes under certain conditions (Barnes and Raymond [email protected] 2009; Gurumurthy et al. 2012; Price et al. 2013; Wu et al. 2013). In China, most researchers have focused on the 1 School of the Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China Yangtze River (Hu et al. 1982; Zhang et al. 1990; Chen et al. 2002; Li and Zhang 2005; Chetelat et al. 2008), the 2 State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing 100083, Yellow River (Hu et al. 1982; Zhang et al. 1990, 1995;Li China and Zhang 2005; Wu et al. 2005; Fan et al. 2014), and the 3 Shandong Provincial Institute of Land Surveying and Pearl River (Chen and He 1999; Zhang 1999; Zhang et al. Mapping, Jinan 250013, China 2007b). The historical data of these three large rivers had 123 453 Page 2 of 16 Environ Earth Sci (2016) 75:453 shown the increases in major ion concentrations during the associated CO2 consumption; (3) to study the anthro- past 20-30 years, such as chloride increasing around two pogenic influence on CWR; and (4) to estimate the con- times. Since the wastewater discharged into the Yangtze tribution of NCA to rock weathering at a basin scale. River basin and the Yellow River basin climbed from *10 billion and 2.2 billion tons in 1980 to 34 billion and 4.2 billion tons in 2010, respectively (Wang 2015), human Materials and methods activities were possible responsible for the elevated con- centrations. Recently, some studies have focused on the Geography and geology major chemical composition of river water in the upper Han River basin (Li et al. 2009) and the Huai River basin The Nansihu Lake basin (NLB) (34°240–36°190N, 114°520– (Zhang et al. 2011), because these two river basins are 117°420E), as one sub-basin of Huai River basin, is situated associated with China’s South to North Water Transfer in the North China Plain between the Yellow River and the Project (SNWTP). Huai River (the second- and third-largest rivers in China) Nansihu Lake is the largest freshwater lake in North (Fig. 1a). The total drainage area is 31,700 km2, covering China. The east line of the SNWTP will flow through this 32 counties with a population of 22 million in Jiangsu, lake, which serves not only as an important water trans- Shandong, Henan and Anhui Provinces. portation channel for the SNWTP but also as a storage lake Geologically, the NLB consists of various source rocks for the SNWTP. It is therefore important to identify and (Fig. 1b). The major lithologies exposed in the study quantify the chemical compositions of river waters flowing region are Cambrian and Ordovician carbonate rocks into Nansihu Lake. On the other hand, the modification by (limestones and dolomites) and Jurassic detrital sedimen- anthropogenic inputs of the chemical compositions of tary rocks (siltstones and sandstones), which are widely waters should be paid more attention, as human activities distributed in the basin and cover 35 and 30 % of the basin are becoming increasingly extensive in the region. Zhang area, respectively. The Precambrian outcrops covering et al. (2011) has emphasized the anthropogenic influence in about 12 % of the area, are mainly granite gneiss which this region. Therefore, it is necessary to differentiate the occurs in the eastern hills and mountainous areas. Carbonic industrial and agricultural inputs for major ions at a and Permian coal deposits are interbedded in shale strata regional scale and then individually estimate the contri- and are separately distributed in the eastern and western butions of weathering of different parent rocks (e.g., car- sections with approximately 4 % of the area. The Tertiary bonates, evaporites and silicates) and the associated CO2 rocks covering 5 % of the whole area, are mainly detrital consumption. rocks (shale and sandstone) and evaporites. The Quaternary In addition to carbonic acid, other acids (such as H2SO4 fluvial sediments occupying 14 % of the basin area, are and HCl) have recently been recognized as protons distributed over the whole plain. involved in rock weathering (Calmels et al. 2007; Xu and Liu 2007; Chetelat et al. 2008; Beaulieu et al. 2011; Lang Climate, hydrology and land cover et al. 2011). If these others acids contribute to chemical action, then carbonate weathering may lead to CO2 pro- This basin is subject to temperate monsoon climate, and the duction instead of CO2 sequestration (Li et al. 2008). annual mean temperatures is 12 °C in Jining City which Several studies of small and moderate water systems occupies the north section of the basin and 15 °Cin indicate the importance of non-CO2 acids (NCA) in Zaozhuang City for the south section. Average annual chemical weathering (Han and Liu 2004; Xu and Liu 2007; precipitation and evaporation vary from 685 and 900 mm Li et al. 2008; Meyer et al. 2009). In a heavily industrial- on the drier part to 900 and 1050 mm around the lake, and ized basin, the study of rock weathering by NCA helps us more than 80 % of annual precipitation falls during the to estimate the associated CO2 production and to observe flood season from May to September (Wu et al. 2010). In the influence of NCA on carbonate weathering rate (CWR). this basin, there are 13 tributaries encompassing a wide Then, the balance between CO2 production and consump- range of lithologies and land uses (Table S1 in supple- tion could be well understood at a basin scale. mentary materials, abbreviated as SM), including the In this study, the major chemical compositions of 20 Guangfu, Si, Baima, Guo, Xinxue, Dongyu, Zhuzhaoxin, sites were determined for the rivers flowing into the Nan- Dayun, Beijie, Beisha, Hanzhuang, Hui and Wanfu Rivers, sihu Lake basin. The main goals are (1) to identify their with the former eight tributaries being the major ones. The sources and quantify the contributions of the various average annual discharge input to the lake is reservoirs to the dissolved load, especially the anthro- 29.60 9 108 m3 (Wu et al. 2010). In addition, Li et al. pogenic contributions including industrial and agricultural (2011) reported that there were no thermal sources in the inputs; (2) to calculate chemical weathering rates and the NLB, and the groundwater did not have significant 123 Environ Earth Sci (2016) 75:453 Page 3 of 16 453 Fig. 1 a Map showing the rivers and sampling sites of the drainage basin of Nansihu Lake, China and b map showing the geology of the Nansihu Lake basin influence on the major ions in river waters, even though the first portion of the filtrate was discarded to clean the alluvial aquifer recharges the river water that is flowing membrane.