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Investigation of Cyanobacteria and Cyanotoxins in Drinking Water Systems

Absrtact	Two major groups of cyanobacteria metabolites, microcystins and 2-MIB, and their associated toxin producers were monitored in 10 major drinking water reservoirs and corresponding waterworks nation-wide. Monitoring results from chemical analysis suggested that the algal metabolites monitored were present in most of the source water. Long-term monitoring data for two of the reservoirs indicated that the concentration of both 2-MIB and microcystins followed the trend that higher concentrations were present in warmer seasons. Strong correlations among 2-MIB concentration, microcystin concentration, and ambient temperature were found in the water samples. For the sampling in Tai Lake, Kin-Men Island, no strong correlations were observed for most of the algae and algal metabolites measured. However, a good correlation between microcystis sp. and microcystins concentrations was found. For the treatment efficiency in the waterworks, an up to 60% of microcystins removal efficiency for the waterworks with conventional treatment processes, 46-76% for the conventional waterworks with floatation and slow sand filtration units, and around 70 to >90% for the advanced waterworks. To identify the microcrocystin producers in the source waters, water samples from several reservoirs were analyzed following the procedures of DNA extraction, polymerase chain reaction (PCR) amplification, denaturing gradient gel electrophoresis (DGGE) screening, DNA sequencing, and comparison with DNA database. Some of the reservoirs were also confirmed to have microcystis aeruginosa and microcystis sp. in the water. These techniques will be employed in the future for monitoring the community and quantity of toxic microcystis. For the management of cyanobacteria and cyanotoxins in the drinking water systems, documents relevant to regulation, guidance and early warning and response were collected from more than 10 countries or organization. Based on the information, a framework was suggested for the management of cyanobacteria and cyanotoxins in drinking water systems for different agencies.
Keyword	Cyanobacteria,microcystis,microcystin,algal toxin,drinking water,raw water

Absrtact

Two major groups of cyanobacteria metabolites, microcystins and 2-MIB, and their associated toxin producers were monitored in 10 major drinking water reservoirs and corresponding waterworks nation-wide. Monitoring results from chemical analysis suggested that the algal metabolites monitored were present in most of the source water. Long-term monitoring data for two of the reservoirs indicated that the concentration of both 2-MIB and microcystins followed the trend that higher concentrations were present in warmer seasons. Strong correlations among 2-MIB concentration, microcystin concentration, and ambient temperature were found in the water samples. For the sampling in Tai Lake, Kin-Men Island, no strong correlations were observed for most of the algae and algal metabolites measured. However, a good correlation between microcystis sp. and microcystins concentrations was found. For the treatment efficiency in the waterworks, an up to 60% of microcystins removal efficiency for the waterworks with conventional treatment processes, 46-76% for the conventional waterworks with floatation and slow sand filtration units, and around 70 to >90% for the advanced waterworks. To identify the microcrocystin producers in the source waters, water samples from several reservoirs were analyzed following the procedures of DNA extraction, polymerase chain reaction (PCR) amplification, denaturing gradient gel electrophoresis (DGGE) screening, DNA sequencing, and comparison with DNA database. Some of the reservoirs were also confirmed to have microcystis aeruginosa and microcystis sp. in the water. These techniques will be employed in the future for monitoring the community and quantity of toxic microcystis. For the management of cyanobacteria and cyanotoxins in the drinking water systems, documents relevant to regulation, guidance and early warning and response were collected from more than 10 countries or organization. Based on the information, a framework was suggested for the management of cyanobacteria and cyanotoxins in drinking water systems for different agencies.

Keyword

Cyanobacteria,microcystis,microcystin,algal toxin,drinking water,raw water