Using Rn-222 to estimate submarine groundwater discharge (SGD) and the associated nutrient fluxes into Xiangshan Bay, East China Sea

Continuous radon (Rn-222) monitoring was conducted at two stations (site A and site B) with different perpendicular distance from the shoreline in Xiangshan Bay, East China Sea. Based on a Rn-222 balance model (various sources and sinks of Rn-222 in coastal water), the average rate of SGD was estimated to be 0.69 cm/day and 0.23 cm/day for site A and site B, respectively. The results from a nutrient analysis of the groundwater indicate that the associated nutrients fluxes loading through the SGD pathway were 4.27 x 10(6) mol/day for DIN, 2.24 x 10(4) mol/day for DIP and 1.82 x 10(6) mol/day for DSi, respectively, which were comparable to or even higher than the levels observed in the local streams. Therefore, adequate attention should be paid to the importance of SGD as one source of nutrients during the eutrophication control process in this area. Published by Elsevier Ltd.