Wang Xiaofeng, Parkpian Preeda, Fujimoto Naoshi, Ruchirawat Khunying Mathuros, DeLaune R D, Jugsujinda A
Environmental Toxicology, Technology and Management, Asian Institute of Technology, Pathum Thani, Thailand.
J Environ Sci Health A Tox Hazard Subst Environ Eng. 2002 Aug;37(7):1181-207. doi: 10.1081/ese-120005980.
Three heptapeptide toxins, microcystin-RR, microcystin-RY and microcystin-LR, which can cause health problems in animals and humans were monitored in Bang Phra Reservoir, Thailand using reversed-phase high performance liquid chromatography. The concentrations of the three toxins in the reservoir varied greatly depending on location and time water samples were collected. Water quality parameters such as light intensity, temperature, pH, dissolved oxygen, suspended solid, chemical oxygen demand, dissolved organic carbon, total nitrogen, total phosphorus, ammonia, nitrate, phosphate, total dissolved nitrogen, total dissolved phosphorus and chlorophyll-a were also measured in parallel with microcystin determinations. Relationships among water quality parameters, toxins and chlorophyll-a were established. Toxin concentration increased in proportion to increases in total phosphorus, fraction of dissolved phosphorus, but was inversely correlated with water pH and total suspended solids. The other measured parameters in the study showed no correlations to toxin level in reservoir water. Significant correlations between chlorophyll-a and suspended solids, phosphate, nitrate and ammonia were observed suggesting that nitrogen and phosphorus are the two major nutrients governing growth of algae in the reservoir. This relationship suggests that algal production as well as toxin concentration are dependant on nutrient levels in the water body, since both measured light intensity and temperature level was favorable for algal growth. A small algal bloom observed in the rainy season of each year (lasting for only a couple of months) paralleled measured increases in toxin concentration, chlorophyll-a, TP and TN in the water column. Toxin level in the water column remain detectable for 3-4 months period following the initiation of algal bloom. Results indicate that major blooms are likely to occur following the raining season which usually occurs near the end of October when runoff would increase nutrient level entering the reservoir. This study also demonstrated that an ongoing field-monitoring program is needed in these lakes and reservoirs for predicting toxic level of microcystin production for use in risk assessment and for alerting the public to potential health hazards. Concentration of toxin in the reservoir can perhaps be controlled by reducing non point source nutrient input within the watershed.
使用反相高效液相色谱法对泰国邦帕水库中三种能对动物和人类健康造成问题的七肽毒素——微囊藻毒素-RR、微囊藻毒素-RY和微囊藻毒素-LR进行了监测。水库中这三种毒素的浓度因采集水样的位置和时间不同而有很大差异。与微囊藻毒素测定同时，还平行测量了水质参数，如光照强度、温度、pH值、溶解氧、悬浮固体、化学需氧量、溶解有机碳、总氮、总磷、氨、硝酸盐、磷酸盐、总溶解氮、总溶解磷和叶绿素-a。建立了水质参数、毒素和叶绿素-a之间的关系。毒素浓度与总磷、溶解磷比例的增加成正比，但与水体pH值和总悬浮固体呈负相关。研究中测量的其他参数与水库水中的毒素水平无相关性。观察到叶绿素-a与悬浮固体、磷酸盐、硝酸盐和氨之间存在显著相关性，这表明氮和磷是控制水库中藻类生长的两种主要营养物质。这种关系表明，藻类产量以及毒素浓度取决于水体中的营养水平，因为测量的光照强度和温度水平都有利于藻类生长。每年雨季观察到的小范围藻华（仅持续几个月）与水柱中毒素浓度、叶绿素-a、总磷和总氮的测量增加情况一致。藻华开始后，水柱中的毒素水平在3 - 4个月内仍可检测到。结果表明，主要藻华可能在雨季之后发生，雨季通常在10月底左右，此时径流会增加进入水库的营养水平。这项研究还表明，需要在这些湖泊和水库中开展持续的现场监测计划，以预测微囊藻毒素产生的毒性水平，用于风险评估并提醒公众注意潜在的健康危害。水库中的毒素浓度或许可以通过减少流域内非点源营养物质的输入来控制。
