The Spatial Distribution Characteristics of BOD₅ and the Biodegradability of Seawater in Coastal Areas of Leizhou Peninsula, China in Summer

Abstract

According to the environmental survey in coastal areas of Leizhou Peninsula in July 2010, the content and the spatial distribution of five days biochemical oxygen demand (BOD5) were studied. The ratio of BOD5/TOC was applied to evaluate the biodegradability of seawater. The BOD5 in surface seawater ranged from 0.75 mg/L to 4.66 mg/L, with an average of 1.97 mg/L, however, in bottom seawater, the BOD5 varied from 0.09 mg/L to 6.22 mg/L, with an average of 2.16 mg/L. The BOD5 was in line with the second grade of national seawater quality standard of China at most stations. The BOD5 in coastal areas of west Guangdong was significantly different from that of Qiongzhou straits and Beibu Gulf (p<0.01), the highest BOD5 was revealed in the west Guangdong, followed by in Qiongzhou straits and in Beibu Gulf. The biodegradability in bottom seawater was better than that in surface.