[Relation between distribution of phosphorus form in the sediment of typical urban shallow lakes and eutrophication].

The forms of phosphorus in the surface sediments were extracted and determined sequentially with ethylene dinitrilo tetracetic acid (EDTA) technique in three urban shallow lakes: Lake Xuanwu, Lake Mochou and Lake Daming. The results showed that the iron and calcium-bound phosphate, about accounting for 80%, were the main forms of total phosphorus. The contents of iron bound phosphate in Lake Xuanwu and Lake Mochou were higher than that of Lake Daming, reaching 30%-40%. The organic phosphorus existed mainly in the form of alkali extractable phosphorus, while the contents of acid extractable organic phosphorus were low. However, the proportion of acid extractable organic phosphorus to the total phosphorus can indicate the degree of lake eutrophication.