Hall Lenwood W, Anderson Ronald D, Killen William D, Balcomb Richard, Gardinali Piero
University of Maryland, Maryland Agricultural Experiment Station, Wye Research and Education Center, P.O. Box 169, Queenstown, MD 21658, United States.
Mar Pollut Bull. 2009 Jun;58(6):803-11. doi: 10.1016/j.marpolbul.2009.02.002. Epub 2009 Mar 17.
The objectives of this study were to: (1) measure water column concentrations of Irgarol 1051 and its major metabolite GS26575 annually (2004-2006) during mid-June and mid-August at 14 sites in a study area comprised of three sub-regions chosen to reflect a gradient in Irgarol exposure (Port Annapolis marina, Severn River and Severn River reference area); (2) use a probabilistic approach to determine ecological risk of Irgarol and its major metabolite in the study area by comparing the distribution of exposure data with toxicity-effects endpoints; and (3) measure both functional and structural resident phytoplankton parameters concurrently with Irgarol and metabolite concentrations to assess relationships and determine ecological risk at six selected sites in the three study areas described above. The three-year summer mean Irgarol concentrations by site clearly showed a gradient in concentrations with greater values in Back Creek (400-500ng/L range), lower values in the Severn River sites near the confluence with Back Creek (generally values less than 100ng/L) and still lower values (<10ng/L) at the Severn River reference sites at the confluence with Chesapeake Bay. A similar spatial trend, but with much lower concentrations, was also reported for GS26575. The probability of exceeding the Irgarol plant 10th centile of 193ng/L and the microcosm NOEC (323ng/L) suggested high ecological risk from Irgarol exposure at Port Annapolis marina sites but much lower risk at the other sites. There were no statistically significant differences among the three site types (marina, river and reference) with all years combined or among years within a site type for the following functional and structural phytoplankton endpoints: algal biomass, gross photosynthesis, biomass normalized photosynthesis, chlorophyll a, chlorophyll a normalized photosynthesis and taxa richness. Therefore, based on the above results, Irgarol adverse effects predicted from the plant 10th centile and the microcosm NOEC in the high Irgarol exposure area (Back Creek/Port Annapolis marina) were not confirmed with the actual field data for the receptor species (phytoplankton). These results also highlight the importance of unconfined field studies with a chemical gradient in providing valuable information regarding the responses of resident phytoplankton to herbicides.
（1）在2004 - 2006年期间，每年6月中旬和8月中旬，在一个由三个子区域组成的研究区域的14个地点测量烯酰吗啉1051及其主要代谢物GS26575在水柱中的浓度，这三个子区域被选来反映烯酰吗啉暴露的梯度（安纳波利斯港码头、塞文河和塞文河参考区域）；（2）通过将暴露数据的分布与毒性效应终点进行比较，采用概率方法确定研究区域内烯酰吗啉及其主要代谢物的生态风险；（3）在上述三个研究区域的六个选定地点，同时测量功能性和结构性的浮游植物参数以及烯酰吗啉和代谢物浓度，以评估它们之间的关系并确定生态风险。各站点三年夏季烯酰吗啉浓度的平均值清楚地显示出浓度梯度，后溪浓度较高（400 - 500纳克/升范围），与后溪交汇处附近的塞文河站点浓度较低（一般值小于100纳克/升），与切萨皮克湾交汇处的塞文河参考站点浓度更低（<10纳克/升）。对于GS26575也报告了类似的空间趋势，但浓度要低得多。超过烯酰吗啉植物第10百分位数193纳克/升和微观生态系统无可见效应浓度（323纳克/升）的概率表明，安纳波利斯港码头站点因烯酰吗啉暴露而面临高生态风险，而其他站点风险要低得多。对于以下功能性和结构性浮游植物终点，在所有年份合并的三种站点类型（码头、河流和参考）之间或站点类型内的年份之间，没有统计学上的显著差异：藻类生物量、总光合作用、生物量标准化光合作用、叶绿素a、叶绿素a标准化光合作用和分类群丰富度。因此，基于上述结果，在高烯酰吗啉暴露区域（后溪/安纳波利斯港码头），根据植物第10百分位数和微观生态系统无可见效应浓度预测的烯酰吗啉不利影响，并未得到受体物种（浮游植物）实际现场数据的证实。这些结果还突出了在有化学梯度的开放现场研究对于提供有关常驻浮游植物对除草剂反应的有价值信息的重要性。
