Ouyang Ying, Feng Gary, Parajuli Prem, Leininger Theodor, Wan Yongshan, Jenkins Johnie N
Center for Bottomland Hardwoods Research, USDA Forest Service, 775 Stone Blvd., Thompson Hall, Room 309, Mississippi State, MS 39762, USA.
USDA-ARS, Crop Science Research Laboratory, 810 Hwy 12 East, Mississippi State, MS 39762, USA.
Water Air Soil Pollut. 2018 Nov 3;229(11):1-13. doi: 10.1007/s11270-018-4022-8.
Assessment of surface water quality in the Mississippi Delta is essential to quantify the eutrophication of the Gulf of Mexico. This study estimated the characteristics and variations of surface water quality at three study sites in the Big Sunflower River Watershed (BSRW) within the Mississippi Delta using Kruskal-Wallis, Dunn, Mann-Kendall, and Pettitt tests. In general, contents of some water quality constituents such as nitrate-nitrogen ( - ) and total phosphorus (TP) in the BSRW varied from site to site each year, whereas variations of other constituents such as pH and dissolved oxygen (DO) each year were basically not significant. The highest median concentrations were found in spring for - and total nitrogen (TN); in summer for specific conductance (SC), Na, and Cl; and in winter for DO. Mann-Kendall trend analysis revealed that there was an increasing annual trend at Leland but a decreasing annual trend at Merigold for - concentrations even though such changes were very small, whereas there was no annual trend for TP at any of the three study sites. Pettitt's test further identified that the - concentrations had an abrupt increase in February 2009 at the median value of 0.44 mg L in Leland and an abrupt decrease in June 2012 at the median value of 3.65 mg L in Merigold. A very good linear correlation exited between total dissolved solid (TDS) and magnesium (Mg) in the BSRW, which could be used to estimate TDS from Mg concentrations for this watershed when the data for TDS are absent.
评估密西西比三角洲的地表水质量对于量化墨西哥湾的富营养化至关重要。本研究使用Kruskal-Wallis、Dunn、Mann-Kendall和Pettitt检验，估算了密西西比三角洲内大向日葵河流域（BSRW）三个研究地点的地表水质量特征和变化情况。总体而言，BSRW中某些水质成分的含量，如硝酸盐氮（ - ）和总磷（TP），每年因地点而异，而其他成分如pH值和溶解氧（DO）每年的变化基本不显著。 - 和总氮（TN）的中位数浓度在春季最高；特定电导率（SC）、钠（Na）和氯（Cl）在夏季最高；DO在冬季最高。Mann-Kendall趋势分析表明，尽管变化非常小，但 - 浓度在利兰有上升的年趋势，而在梅里戈尔德有下降的年趋势，而三个研究地点中任何一个的TP都没有年趋势。Pettitt检验进一步确定， - 浓度在2009年2月在利兰中位数为0.44 mg/L时突然增加，在2012年6月在梅里戈尔德中位数为3.65 mg/L时突然下降。BSRW中总溶解固体（TDS）与镁（Mg）之间存在非常良好的线性相关性，当没有TDS数据时，可用于根据该流域的镁浓度估算TDS。
