Using sulfur and oxygen isotopes to analyze the source of sulfate
associated with the Eastern Route of the South-to-North Water Diversion
Project in China
Abstract
Since the Eastern Route of the South-to-North Water Diversion Project
(SNWD-ERP) officially began operation, it was found that the
concentrations of sulfate rapidly increased after water transfer from
Jiangsu Province to Shandong Province, especially in Nansi Lake (NSL).
The direct and original sources of sulfate in NSL and its surrounding
inflowing rivers were investigated by analyzing the hydrochemical
properties of the water bodies and sulfur and oxygen isotope
compositions of dissolved sulfate during nondiversion and diversion
water periods. During the diversion water period, the largest direct
source of high SO42- concentrations in NSL was evaporite dissolution,
accounting for 52.18% of the total contribution. In contrast, during
the nondiversion water period, the maximum contribution of SO42- came
from inflowing river inputs. To ensure the safety of the water supply of
the SNWD-ERP, some measures must be taken to decrease the sulfate inputs
from inflowing rivers, such as formulating strict discharge standards to
reduce the direct discharge of sewage into the inflowing rivers around
NSL.