Occurrence of total phosphorus in surface sediments of Chinese lakes and its driving factors and implications

Abstract

In contrast to instantaneous concentration of phosphorus in water columns, sediments record valuable information on occurrence and sources of phosphorus for a long period associated with human activities and environmental protection. However, much less attention has been paid to phosphorus in sediments. To date the relative contributions of driving factors for TP concentration in sediments has not been elucidated. We investigated the occurrence and driving factors for TP in 270 surface sediments of 83 lakes in the catchments of two large rivers (Yangtze River and Huaihe River) in China, identified the relative contributions of the driving factors, and discussed the implication. The average TP concentration in the surface sediments of these lakes was 0.82 ± 0.04 mg gdw−1. The average TP concentration in the surface sediments of the urban lakes was larger than that in the rural lakes. Mitigation measures, human activities, and lake characteristics contributed 59.0%, 20.5%, and 20.5% to the variation in sediment TP concentration. The average TP concentration in the surface sediments significantly decreased with the percentage of annual investment in pollution control to GDP of the cities where the lakes are located. For the first time we find mitigation measures have exceeded human activities, and lake characteristics to dominate the variation in TP concentration in surface sediments of Chinese lakes. Given the annual investment in pollution control only accounted for 1.14% ± 0.06% of GDP in China from 1991 to 2018, higher percentage would be beneficial to reduce TP concentration in sediments of Chinese lakes.