Humus and humic acids in offshore sediments have certain indicative effects on marine environmental pollutions, which have great influences on migration and transformation of heavy metals and persistent organic pollutants. The compositions of humus in sediments were determined by the methods of sodium pyrophosphate-sodium hydroxide extraction and potassium dichromate volumetric; and the humic acids extracted by the method of NaOH alkaline extraction were characterized by the methods of elemental analysis, UV, Fourier transform infrared spectroscopy (FTIR), etc. The results showed that the content of humus was very low in surface sediments of Leizhou Peninsula, between 0.26%and 2.36%, with an average of 1.49%, in which fulvic acid accounted for 51%, humin accounted for 35% and humic acid accounted for 14%. Humic acids accounted for 65%of the total humus. Humic acids in marine sediments of Leizhou Peninsula were mainly fulvic acid and small organic compounds. The carbon content was high, and the sulfur content was low with benzene ring, carboxyl, hydroxyl, phenolic hydroxyl, carbonyl, and amine functional groups. Humic substances in offshore marine sediments of Leizhou Peninsula belonged to low degree of humification. These research results provided some guidance for coastal economic development and environmental protection of Leizhou Peninsula.%近海沉积物中腐殖质和腐殖酸对海洋环境污染具有一定的指示作用，其对重金属、持久性有机污染物的迁移转化具有较大的影响。文章采用焦磷酸钠-氢氧化钠提取重铬酸钾氧化容量法对沉积物腐殖质的组成进行测定， NaOH碱提取法对沉积物腐殖酸进行提取，使用元素分析、紫外光谱、傅里叶变换红外光谱(FTIR)等方法对提取的腐殖酸进行表征。研究结果表明：雷州半岛近海表层沉积物腐殖质含量较低，在0.26%~2.36%之间，平均值1.49%，其中富里酸占51%，胡敏素占35%，胡敏酸占14%，腐殖酸占整个腐殖质的比例是65%。柱状沉积物腐殖化程度高于表层沉积物。雷州半岛近海沉积物中腐殖酸以富里酸和小分子有机物为主，碳含量高，硫含量低，具有苯环、羧基、醇羟基、酚羟基、羰基及氨基等官能团，腐殖化程度不高。研究结果将为雷州半岛沿海经济的开发和环境保护提供一定的指导意义。
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