Assessment of background levels and pollution sources for arsenic and fluoride in the phreatic and confined groundwater
- PDF / 3,108,325 Bytes
- 13 Pages / 595.276 x 790.866 pts Page_size
- 80 Downloads / 164 Views
WATER ENVIRONMENTAL POLLUTION AND STATE OF THE ART TREATMENT TECHNOLOGIES
Assessment of background levels and pollution sources for arsenic and fluoride in the phreatic and confined groundwater of Xi’an city, Shaanxi, China Yanyan Gao 1,2 & Hui Qian 1,2 & Haike Wang 1,2 & Jie Chen 1,2 & Wenhao Ren 1,2 & Faxuan Yang 1,2 Received: 9 May 2019 / Accepted: 15 October 2019 # Springer-Verlag GmbH Germany, part of Springer Nature 2019
Abstract The presence of arsenic and fluoride in groundwater and their impacts on human health have been reported in many countries worldwide, but little information is available on As or F− contamination in Xi’an city. This study highlights the distribution and sources of As and F− anomalies in different aquifers of Xi’an city, based on the assessment of natural background levels (NBLs) and threshold values (TVs). Groundwater samples collected from phreatic and confined aquifers were analyzed to evaluate NBLs and TVs, using median + 2MAD, Tukey inner fence (TIF), and percentile-based methods. Results showed that NBLs and TVs of As and F− in the phreatic aquifer were lower than those in the confined aquifer, indicating importance of the geological effects on the enrichment of arsenic and fluoride in the confined aquifer. Combined with hydrogeochemical methods, the distributions of As and F− anomalies show that high concentrations of As in both aquifers and F− in the confined aquifer can be attributed to the upward flow of geothermal water through faults and ground fissures, while high concentrations of F− in the phreatic aquifer may be greatly influenced by contaminated rivers. Although geological structures such as faults and ground fissures contribute to the high concentrations of potentially toxic elements, anthropogenic activities cannot be ignored because over exploitation of groundwater accelerates the development of ground fissures and results in the upward flow and mixing of geothermal water with groundwater in the upper aquifers. Keywords Arsenic . Fluoride . Natural background values . Threshold values . Geological structures . Xi’an
Introduction Arsenic (As) and fluoride (F−) are reportedly two of the highest priority contaminants in groundwater worldwide, due to their toxic effects (Armienta and Segovia 2008; Borzi et al. 2015; Kumar et al. 2016a; Kumar et al. 2016b). According to public health research, As exposure leads to an increase in infant mortality rates, a decline in intellectual Responsible editor: Severine Le Faucheur * Hui Qian [email protected] 1
School of Environmental Science and Engineering, Chang’an University, Xi’an 710054, Shaanxi, China
2
Key Laboratory of Subsurface Hydrology and Ecological Effect in Arid Region of Ministry of Education, Chang’an University, Xi’an 710054, Shaanxi, China
function in children, and an increase in cardiovascular disease, as well as lung, liver, and bladder cancer (Borzi et al. 2015; Wang et al. 2007). Fluoride is beneficial to human health in trace amounts (< 1.5 mg/L), serving to strengthen the apatite matrix of teeth and
Data Loading...
