하계 영산강, 하구호 및 하구 퇴적물 내 인의 생지화학적 특성

초록

To understand the behavior of phosphorus in the sediment of the Yeongsan River (YR), Lake (YL) andEstuary (YE), we investigated the characteristics of geochemical constituents and solid phase phosphorus. Ahypoxic condition was confirmed in the lake sediment near the dyke (YL, 10 μM), where, freshwater discharge had not occurred for the 15 days prior to sample collection, whereas the dissolved oxygen concentration at the estuarinesite (YE) was relatively high (165 μM). The high values of NH4+ (65.7 mmol m-2) and Fe2+ (14.9 mmol m-2) was integratedin the pore water at the lake (YL). On the other hand, PO43- in pore water was relatively at least 4-8 times higher inthe estuary sediment (YE). Phosphorus release rates were twice as high in the estuary (0.047 mmol m-2 d-1 ) as thelake (0.021 mmol m-2 d-1), while the total phosphorus in the sediment was higher in the lake (6,665 mmol m-2) anddecreased rapidly in the estuary (1,000 mmol m-2). After analyzing the speciation of phosphorus in the sediment,aluminum bound phosphorus (YR: 66%, YL: 40%) and iron bound phosphorus (YR: 17%, YL: 30%) were domi-nant for the Yeongsan river and lake, whereas the estuary dominated iron (43%) and authigenic calcium boundphosphorus (29%). Although the lake was a hypoxic environment, phosphorus in the sediment combined with alu-minum to maintain a relatively stable form, limiting the process of phosphorus separated into the pore water andreleased into the water layer. Whereas, the ratio of iron binding in the phosphorus form in the estuary was domi-nant, but shows the adsorption of phosphorus to iron oxide might be relatively limited because release of phospho-rus to the pore water might occur during the bonding process of iron and hydrogen sulfide. These results suggestenvironmental changes (e.g., environment of hypoxic, supply of sulfate) due to the construction of estuary dikescan act as a major factor in controlling phosphorus behavior.

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