The chemistry of the Vermilion River and its bottom sediments in an area south of Lafayette, Louisiana: A reconnaissance study

Abstract:
The objectives of this study were to examine the river water chemistry and bottom sediment chemistry and determine the chemical effects of bottom sediment in overlying Vermilion River water. This study is significant as dredging to control local flooding in the area is common in the Vermilion River, and metals within the bottom sediment are often released with serious effects to the river water chemistry.

River water and/or bottom sediment samples were collected south of Lafayette, Louisiana: 1) at Vermilionville; 2) north of Abbeville; 3) south of Abbeville; 4) north of Intracoastal City; 5) at Intracoastal City. River water samples were analyzed using Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES) techniques. High concentrations of Ca2- were observed upstream and are possibly associated with construction activities and potential wastewater input at the time of sampling. Bottom sediment samples were analyzed for clay mineralogy using x-ray diffraction (XRD); results indicated that the mineralogy paralleled that of the Mississippi River and smectites were dominant. Additional bottom sediment samples were analyzed for whole rock composition and trace metal content using x-ray fluorescence spectrometry. Both barium and zinc concentrations increased north of Intracoastal City, possibly due to drilling mud contamination.


To study the impact of bottom sediment metals on river water, both Vermilion River water and sediment chemistry were examined in perturbation experiments during a 24-hour period. Results from the perturbation experiments indicated an increase in metal concentrations in the perturbed river water and in mixtures of perturbed river water and bottom sediment when compared with unperturbed river water concentrations. The increased concentrations of Mn2+ and Fe2 during perturbation experiments are attributed to release of reduced pore water metals.

Citation: Mulvihill, Anna M. (2003). The chemistry of the Vermilion River and its bottom sediments in an area south of Lafayette, Louisiana: A reconnaissance study. MS, Geology, The University of Louisiana at Lafayette, Advisor: Renee Clary, 106 pages.

URL: Not available online, University of Louisiana at Lafayette Library LD 3091.L665 2003 mulv