广东省水库有机类异味物质2-甲基异莰醇和土臭素空间分布及影响因子研究

Spatial Distribution and Influencing Factors of Odorous Substances 2-methylisoborneol and Geosmin in Reservoirs in Guangdong Province

2-甲基异莰醇(2-methylisoborneol,2-MIB)和土臭素(geosmin,GSM)是导致水库水源异味事件的主要有机类异味物质,探究两者的空间分布特征对供水安全保障有重要意义。2-MIB和GSM的主要生产者之一是蓝藻,蓝藻是广东省水库浮游植物的主要组成。为明确广东省水库两种有机类异味物质的分布及影响因子,本研究通过调查广东省33座水库中两种异味物质、蓝藻丰度及环境因子,运用多元统计分析2-MIB和GSM的空间分布特征及主要影响因子。结果表明,67%水库检出有机类异味物质2-MIB,21%水库检出有机类异味物质GSM,其中40%水库2-MIB或GSM超过10 ng/L且以2-MIB超标为主。共检到产2-MIB或GSM蓝藻5属,包括能够产生2-MIB的泽丝藻(Limnothrix)、假鱼腥藻(Pseudanabaena)、浮鞘丝藻(Planktolyngbya)和浮丝藻(Planktothrix)以及产GSM的长孢藻(Dolichospermum)和浮丝藻(Planktothrix)。统计分析表明,广东省水库水体中2-MIB和GSM的产生与产异味蓝藻显著相关,水体富营养化通过促进这些蓝藻优势,增加水库异味物质超标风险。

2-methylisoborneol(2-MIB) and geosmin(GSM) are the main odorous substances causing the odors outbreak of reservoir water source in Guangdong Province.Understanding the distribution and concentrations of these substances is crucial for ensuring the safety of water supply.Cyanobacteria,a primary component of phytoplankton,are identified as the main producers of these odorous compounds.To gain insights into the spatial patterns of 2-MIB and GSM,as well as the factors influencing their concentration levels,a comprehensive study was conducted across 33 reservoirs in Guangdong.This study involved measuring the concentrations of these odors,assessing environmental conditions and evaluating cyanobacteria abundance.Advanced multivariate statistical analysis helped in uncovering the characteristics of their distribution and identifying the key factors affecting their presence in the reservoirs.The study found that 67 % of the 33 surveyed reservoirs contained 2-MIB,while 21 % exhibited traces of GSM.Notably,40% of these reservoirs had odor levels surpassing 10 ng/L,predominantly due to 2-MIB.Among the reservoirs,five genera of filamentous cyanobacteria known for producing odors were identified.Limnothrix,Pseudanabaena,Planktothrix and Planktolyngbya were linked to 2-MIB,and Planktothrix and Dolichospermum were associated with GSM.The statistical analysis showed that 2-MIB and GSM concentration level were significantly correlated with the filamentous cyanobacteria abundance.The study suggests that eutrophication,or the excessive richness of nutrients in water,favors the proliferation of cyanobacteria,thereby elevating the risk of odor outbreaks in reservoirs.