YIN Xin-ya1,2 , TAO Fa-xiang 1
（1.State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China；
2. Graduate University of the Chinese Academy of Sciences, Beijing 100049, China）
Abstract: In this second part, our main purposes are: (1) to further ascertain ten-day-scale variations in hydrochemistry in the downtown section of the Nanming River after sewage interception; (2) to screen out hydrochemical imprints for indicating human impacts on the Nanming River. Sampling sites were arranged at only two sections, e.g. site 1 (the Sifang River, as the inlet of the downtown section) and site 8 (the Tuanpo Bridge, as the outlet of the downtown section). Water samples were collected on a ten-days scale during the period from October 20, 2008 to October 20, 2009. From the inlet to the outlet, some major ions such as Na+, Cl-, NO3-, and SO42- increased by 53%, 65%, 52%, and 47%, respectively. The other ions K+, Ca2+, Mg2+ and HCO3- showed slight elevations while pH displayed a mild decrease. The peak for Na+ in June and July most possibly resulted from the widespread use of disinfectants (such as sodium hypochlorite) for the control over bird flu epidemic situation, as verified by a very good positive correlation of Na+ with Cl-. Another piece of evidence was the good negative relation between Na+ and NO3-, demonstrating adverse effects of disinfectants on ammonifying or nitrifying bacteria responsible for the production or conversion of ammonia and ammonium to nitrite and nitrate. Dry and wet acid deposition originating from the burning of high-sulfur coal was regarded as a main reason for increases in SO42-. Those ions pertaining to urban activities, such as Na+, Cl-, NO3- and SO42- , can be used as hydrochemical imprints.
Key words: urbanization; hydrochemistry; interception sewer; Naming River
EARTH AND ENVIRONMENT Vol. 40, No.4, Tot No.290, 2012, Page 524-528
