Abstract Detail

4D Botany of the Anthropogenic Environment

DEVALL, MARGARET S [1].

Metal transport into Bayou Trepagnier wetlands in Louisiana.

Establishment of a petroleum refinery in 1916 near the headwaters of Bayou Trepagnier, with subsequent dredging of the bayou, resulted high levels of Pb and other metals. Substantial quantities of pollutants (Pb, Zn, Cr, other metals and polyaromatic hydrocarbons) were released into the bayou. Cores were taken from baldcypress [Taxodium distichum (L.) Richard] trees growing in the swamp alongside the bayou and trees growing along a 610-m transect (nine trees) and a 183-m transect (six trees) running perpendicular from the spoil bank into the swamp. The cores were crossdated, annual rings were measured, and 5-yr segments of the cores were prepared and analyzed for metals. Heavy metals and organic pollutants from oil refineries and other sources contaminated the annual rings of the trees, beginning in the early 1900s. Levels of Pb and Zn in Bayou Trepagnier swamp trees were compared to levels in nine baldcypress trees growing along Stinking Bayou, a reference area. An historical record of levels of pollution was produced, showing high levels of Pb as well as Zn correlated with the establishment of petroleum refineries and dredging. Trees in the upper portion of the bayou (near the refinery) averaged more than twice as much Pb as trees in the lower portion. Baldcypress trees growing near the refinery on the spoil bank along the bayou averaged 4.5 mg/kg Pb, and trees along Stinking Bayou averaged 2.1 mg/kg. In contrast to Pb, concentrations of Zn did not correlate with distance from the refinery and were similar to levels in the reference area. Trees in Bayou Trepagnier swamp soil with 10 to 425 mg/kg Pb concentrated much more Pb than trees growing on the heavily polluted bank. Greater uptake of Pb by trees in the swamp is discussed in terms of soil dynamics and Pb sources.

1 - U.S. Forest Service, Center For Bottomland Hardwoods Research, PO Box 227, Stoneville, MS, 38776, USA

Keywords:
pollution
baldcypress
metals.

Presentation Type: Symposium Presentation
Session: SY1, 4D Botany of the Anthropogenic Environment
Location: Sundance 3/Omni Hotel
Date: Monday, June 26th, 2017
Time: 8:30 AM
Number: SY1002
Abstract ID:342
Candidate for Awards:None