Abstract
Chemical analyses were done on cores
of bottom sediment from three locations in Lake Livingston,
a reservoir on the Trinity River in east Texas to identify
trends in water quality in the Trinity River using the
chemical record preserved in bottom sediments trapped
by the reservoir. Sediment cores spanned the period
from 1969, when the reservoir was impounded, to 1992,
when the cores were collected. Chemical concentrations
in reservoir sediment samples were compared to concentrations
for 14 streambed sediment samples from the Trinity River
Basin and to reported concentrations for soils in the
eastern United States and shale. These comparisons indicate
that sediments deposited in Lake Livingston are representative
of the environmental setting of Lake Livingston within
the Trinity River Basin. Vertical changes in concentrations
within sediment cores indicate temporal trends of decreasing
concentrations of lead, sodium, barium, and total DDT
(DDT plus its metabolites DDD and DDE) in the Trinity
River. Possible increasing temporal trends are indicated
for chlordane and dieldrin. Each sediment-derived trend
is related to trends in water quality in the Trinity
River or known changes in environmental factors in its
drainage basin or both.
Environmental Geology 28
(4) December 1996
P.C. Van Metre (corresponding author)
USGS
NAWQA
8011 Cameron Road
Austin, TX 78754-3898
USA
E. Callender
USGS
National Research Program
12201 Sunrise Valley Drive
Reston, VA 22092-0001
USA
|
