海南某海水浴场水质变化规律及微生物指标的影响因素

Fluctuation of Water Quality and Impact Factors of Microbial Indicators in a Bathing Beach of Hainan

[目的]了解海南某海水浴场水质变化规律及微生物指标的可能相关因素,为海水浴场环境监管提供依据。[方法]于2013—2014年5—11月于该浴场近岸点、浴者密度最大点及浴场最远点,每周一次采集水样,共162份。进行采样现场即时降雨量、水温、透明度、溶解氧、粪大肠菌群的检测;于2014年6月(丰水期)及10月(平水期)于近岸点的潮上带、潮间带和潮下带采集沉积物及近岸区的水样,各18份,进行粪大肠菌群和粪肠球菌的检测。各指标组间进行t检验、方差分析或Pearson相关分析。[结果]该浴场两年度在所监测时段水质为优级。2014年水质总体较2013年好:两年度粪大肠菌群含量分别为(108.1±67.2)、(64.4±20.8)cfu/L;透明度分别为(7.95±2.52)、(9.49±0.92)m。近岸点水样溶解氧含量低于浴者密度最大点(P=0.019)及浴场最远点(P=0.049)。丰水期水体透明度大于平水期(P<0.001)。粪大肠群与透明度(r=-0.381,P<0.001)、溶解氧(r=-0.235,P=0.003)均呈负相关,与水温及即时降雨量不相关(P>0.05)。粪大肠菌群及粪肠球菌含量在潮上带沉积物中较高,分别为19 000、300 cfu/kg。[结论]该浴场水质有提升,监测水体透明度可一定程度指示该浴场细菌的含量。潮上带粪大肠菌群及粪肠球菌均较高,应该加强对浴场沉积物及沙滩的微生物检测。

[Objective] To investigate the fluctuation patterns of water quality and impact factors of microbial indicators in a bathing beach of Hainan, and to provide a basis for environment supervision in bathing beaches. [Methods] Water samples were collected at a nearshore spot, a spot with the highest density of swimmers, and a spot with the remotest distance in the bathing beach, respectively, once a week, from May to November of 2013-2014. A total of 162 water samples were collected to detect precipitation, water temperature, transparency, dissolved oxygen, and fecal coliforms（FC）. In June（wet season） and October（level season） 2014, 18 sediment samples were collected at supratidal, intertidal, and subtidal zones nearshore, respectively, to detect FC and Enterococcus（EC）. Analyses included t-test, analysis of variance, and Pearson correlation analysis. [Results] The water quality of the bathing beach was graded as excellent in 2013 and 2014, and it was even better in 2014 than in 2013. The FC for 2013 and 2014 was（108.1±67.2） and（64.4±20.8） cfu/L respectively. The transparency was（7.95±2.52） and（9.49±0.92） m respectively. The dissolved oxygen at nearshore spot was lower than that at the densest spot（P=0.019） and the remotest spot（P=0.049）. In wet season the transparency was greater than that in level season（P〈 0.001）. FC was negatively correlated with transparency（r=-0.381, P 〈0.001） and dissolved oxygen（r=-0.235, P〈 0.001）, but irrelevant with water temperature and real-time rainfall（P〈0.05）. Higher levels of FC and EC were found in supratidal sediment, which were 19 000 and 300 cfu/kg respectively. [Conclusion] The water quality of the bathing beach is improved. Transparency could indicate microbial contamination of water. However, higher FC and EC levels are detected in supratidal sediment, and great attention should be paid to monitoring microbial contamination in sediments and sands.