Isotopic characteristics of groundwater in Changzhou, Wuxi and Suzhou area and their implications

Based on the study of groundwater isotope( 2 H and 18 O, 34 S, 15 N, 3 H, 14 C) in Changzhou, Wuxi and Suzhou area, it is found that the deep confined groundwater has no pollution on the whole, whereas the shallow groundwater is polluted to a different degree in the area. The deep confined aquifers (main exploitation aquifers) in Changzhou area and in Wuxi and Suzhou area likely belong to two different aquifers. The main exploitation aquifers in Changzhou area are not connected with those in Wuxi and Suzhou area, or they are connected but not expedited. The lateral run-off of groundwater is at present directed to the exploitation center because of overexploitation of the deep groundwater for a long time, but the flowing speed of groundwater is still extremely slow. The deep confined groundwater is in a close to half close state. The 14 C age of groundwater varies from 10000 a BP to 38000 a BP, with the oldest groundwater found at the nearest exploitation center (along the line of three cities of Changzhou, Wuxi and Suzhou) and the youngest at the furthest exploitation center.