Temporal-spatial distribution, environmental significance and release risks of phosphorus in the sediments of a tropical mountain’s deep drinking water reservoir in southeastern China

Abstract

In this study, the fractionation and distribution of phosphorus (P) in the core sediments of the Shanmei reservoir were investigated by using the chemical extraction method in directions for the first time in order to understand its bio-availability, adsorption characteristics, potential release and environmental significance. The results of the study showed that P in the sediments mainly consisted of inorganic phosphorus (IP) and that IP mainly consisted of non-apatite phosphorus (NAIP). The horizontal and temporal distributions of the P fractions were different from each other, but the vertical distribution was similar, which indicated a trend of stabilization after falling. The content of total phosphorus (TP), IP, organic phosphorus (OP), NAIP, apatite phosphorus (AP), and bio-available phosphorus (BAP) in the sediments during the three seasons ranged from 193.85 to 1664.05 mg·kg−1, 126.90 to 1127.70 mg·kg−1, 43.74 to 669.29 mg·kg−1, 57.62 to 937.07 mg·kg−1, 32.58 to 250.71 mg·kg−1, and 41.06 to 871.82 mg·kg−1, respectively. NAIP contents in the sediments accounted for more than 50% of TP. Using an analysis from three aspects, the eutrophication risk index (ERI) could be used to assess the potential release of P in the sediments, and there was a high release risk of P in the sediments in the Shanmei reservoir.

Keywords

• Phosphorus
• temporal-spatial distribution
• drinking-water reservoir
• equilibrium phosphate concentration(EPC0)
• phosphorus sorption index(PSI) and degree of phosphorus saturation (DPS)