Nondestructive, minimal-disturbance, direct-burial solid-phase microextraction fiber technique for measuring TNT in sediment.
We explored a novel technique to deploy solid-phase microextraction (SPME) fibers to nondestructively measure the explosive compound 2,4,6-trinitrotoluene (TNT) and its nitroaromatic (NA) degradation products in laboratory sediment toxicity tests and field sediments in situ. SPME fibers within steel mesh envelopes were exposed statically via direct burial within sediment. Six fiber types (polymer coatings) were tested. Polyacrylate (PA) SPME fiber was sufficiently durable for this application, yielded the lowest detection limits, and exhibited a linear uptake relationship across toxicologically relevant sediment NA concentrations (100-2000 nmol/g dw (20-500 microg/g dw)). Temperature greatly influenced SPME absorption kinetics. Via evaluation of absorption at different temperatures, recommended sampling times needed to achieve steady-state equilibrium were 48 h for room temperatures (23-25 degrees C) and up to 7 d for cold (5 degrees C) temperatures. Although a comparison of TNT residues by SPMEs and TNT bioavailability and toxicity in sediments has not been completed, differences in SPME availability of TNT and its degradation products were found between two different TNT-spiked sediments. Our disposable SPME technique was slightly less expensive and as precise as the conventional extraction for total NAs and may prove to be a powerful exposure evaluation tool for assessing the ecological risk of these compounds.
Department of Biological Sciences, Institute of Applied Sciences, University of North Texas, P.O. Box 310559, Denton, Texas 76203, USA. jasonmconder@yahoo.com
Jason M
JM
Conder
Thomas W
TW
La Point
Guilherme R
GR
Lotufo
Jeffery A
JA
Steevens
D000042:Absorption; D002623:Chemistry Techniques, Analytical / Q000379:methods; D004784:Environmental Monitoring / Q000379:methods*; D019015:Geologic Sediments / Q000737:chemistry*; D007700:Kinetics; D011108:Polymers; D012680:Sensitivity and Specificity; D012989:Soil Pollutants / Q000032:analysis*; D013696:Temperature; D014303:Trinitrotoluene / Q000032:analysis*
D011108:Polymers; D012989:Soil Pollutants; D014303:Trinitrotoluene