Total Polychlorinated Biphenyl (PCB) Concentrations in Fish from the Davis Pond Freshwater Postdiversion Sampling (2007-2009) with a Comparison to Prediversion Levels (2001)

The diversion of freshwater from the Mississippi River is intended to mitigate saltwater intrusion from the Gulf of Mexico and to lessen the concomitant loss of wetland areas. Though effective, freshwater diversion can affect wildlife and habitat; therefore, prediversion and postdiversion data collections are necessary to identify effects. The Davis Pond freshwater diversion area is located between the Mississippi River and Bayou Lafourche and extends to Barataria Bay Basin, Louisiana. Results and interpretations from the prediversion biomonitoring done in 2001- which included data on fish, eagles, and bivalves - are presented in the U.S. Geological Survey (USGS) Scientific Investigations Report 2008-5067, "Davis Pond Freshwater Prediversion Biomonitoring Study: Freshwater Fisheries and Eagles." The postdiversion data generated approximately 6 years later from the sampling of fish whole bodies are presented here in this USGS Data Series. An accompanying log of postdiversion study site photographs was also produced in USGS Data Series 605, "Photographic Images Captured While Sampling for Bald Eagles near the Davis Pond Freshwater Diversion Structure in Barataria Bay, Louisiana (2009-10).

Figures 5A and 5C represent the concentration of polychlorinated biphenyls (PCBs) detected in largemouth bass, blue catfish and striped mullet samples collected in 2007-2009, approximately six years after the Davis Pond freshwater diversion structure was operational. Figure 5B compares these concentrations to those collected in the 2001 prediversion study. Samples are from the Mississippi River, Lake Cataouatche, Bayou Couba, and Lake Salvador.

从密西西比河调配淡水，旨在缓解墨西哥湾带来的盐水入侵问题，并减少随之发生的湿地面积损失。尽管淡水调配工程效果显著，但可能会对野生生物及其栖息地造成影响；因此，开展调水前与调水后的相关数据采集工作，对识别该工程的生态影响而言至关必要。戴维斯塘淡水调配区地处密西西比河与拉福什巴尤（Bayou Lafourche）之间，延伸至路易斯安那州的巴拉塔里亚湾盆地。2001年实施的调水前生物监测工作涵盖了鱼类、鹰类及双壳类生物的相关数据，其结果与解读已发表于美国地质调查局（U.S. Geological Survey, USGS）《科学调查报告2008-5067：戴维斯塘淡水调水前生物监测研究：淡水渔业与鹰类》。约6年后通过对鱼类整体样本采样所获取的调水后数据，收录于本次美国地质调查局数据系列报告中。同期配套的调水后研究地点摄影日志，也发表于美国地质调查局数据系列605：《2009-2010年路易斯安那州巴拉塔里亚湾戴维斯塘淡水调配设施附近白头海雕采样期间拍摄的影像资料》。
图5A与图5C展示了2007-2009年（即戴维斯塘淡水调配设施投用约6年后）采集的大口黑鲈、蓝鲶与条纹鲻鱼样本中检测到的多氯联苯（polychlorinated biphenyls, PCBs）浓度。图5B将该浓度数据与2001年调水前研究中的检测结果进行了对比。本次采样点位涵盖密西西比河、卡托瓦奇湖、库巴巴尤与萨尔瓦多湖。