中文摘要：

应用高效液相色谱,对华北地区某水库5个采样点水体中微囊藻毒素（MC-LR、RR和YR）3种异构体进行了为期1a的监测,研究3种异构体随时间的变化规律及相互关系。结果表明,水体中3种异构体（-LR、YR和RR）含量分别为0.941±1.338、0.365±0.647和（2.893±5.387）μg·L-1;3种异构体出现时间不一样,LR异构体出现时间最早,在4月下旬即可检测到,而RR和YR异构体则需到5月中旬才能检测到;3种异构体峰值出现时间也不一致,LR和YR异构体峰值出现在8—9月,而RR异构体出现时间较晚,到10—11月才达到全年最高值;LR和RR异构体的含量比较高,是主要毒素,5—11月,其比值由2.20降到0.04,这与水体中的N/P比值有关,它随N/P比值的减少而减少。

英文摘要：

The high performance liquid chromatography（HPLC）was used to monitor three isomers（-LR,-YR,-RR）of microcystins（MCs） within one year in five sampling cites in a reservoir in the northern part of China.The rule of the three isomers changed with time and their relationship were explored.The results were shown as follows：the concentrations of three isomers were 0.941±1.338、0.365±0.647 and 2.893± 5.387 μg·L-1,respectively.The first detectable time of three isomers in the reservoir was different.The MC-LR could be detected on late April, but MC-YR and MC-RR was detected until the middle ten days of May. Annual varying regulations of three isomers had many obvious differences and there were obvious fluctuations within one year. Before the middle ten days of August, three isomers contents order was： MC- LR〉 MC-RR〉MC-YR and then the order changed：MC-RR〉 MC-LR〉MC-YR. Their peak contents appeared at different time. The peak contents of MC-YR and MC-LR occurred from August to September, but MC-RR occurred from October to November. The mean proportions of three isomers in total MCs were 32. 4%, 8.7% and 58.9%, respectively. So, the MC-LR and MC-RR were the main toxins of MCs, but their proportions to the total concentration of MCs were not fixed and the ratio of MC-LR to MC-RR descended from May to December. The ratio was affected by the rate between nitrogen and phosphate（N/P） and correlated well with N/P.