|OUYANG, YING - Us Forest Service (FS)|
|PARAJULI, PREM - Mississippi State University|
|LEININGER, THEODOR - Us Forest Service (FS)|
|WAN, YONGSHAN - Environmental Protection Agency (EPA)|
Submitted to: Water, Air, and Soil Pollution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/22/2018
Publication Date: 11/3/2018
Citation: Ouyang, Y., Feng, G.G., Parajuli, P., Leininger, T., Wan, Y., Jenkins, J.N. 2018. Assessment of surface water quality in the Big Sunflower River Watershed of Mississippi Delta using nonparametic analysis. Water, Air, and Soil Pollution. 229. Article 373. https://doi.org/10.1007/s11270-018-4022-8.
Interpretive Summary: Assessment of surface water quality in Mississippi Delta is essential to evaluate streams and rivers pollution due to anthropogenic activities and also is a key to quantify the contamination and eutrophication of the Gulf of Mexico. We observed that the concentrations of nitrate and total phosphate in the streams varied with sites each year, whereas the pH and dissolved oxygen in the streams had slight variations with sites each year. The highest median concentrations were observed in spring for nitrate and total phosphate, in summer for CL and Na, and in winter for dissolved oxygen at all of the three study sites.
Technical Abstract: 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 trivial. 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 (i.e., decreasing or increasing) 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-1 in Leland and an abrupt decrease in June 2012 at the median value of 3.65 mg L-1 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 when the data for TDS are absent.