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Scientific Investigations Report 2008–5031

Publications Warehouse SIR 2008–5031

In cooperation with Missouri University of Science and Technology

Environmental Chemical Data for Perishable Sediments and Soils collected in New Orleans, Louisiana, and along the Louisiana Delta following Hurricanes Katrina and Rita, 2005

By Emitt C. Witt III1 , Honglan Shi2 , Krista A. Karstensen1, Jianmin Wang2, and Craig D. Adams2
1 U.S. Geological Survey   2Missouri University of Science and Technology

SIR 2008-5031


In October 2005, nearly one month after Hurricanes Katrina and Rita, a team of scientists from the U.S. Geological Survey and the Missouri University of Science and Technology deployed to southern Louisiana to collect perishable environmental data resulting from the impacts of these storms. Perishable samples collected for this investigation are subject to destruction or ruin by removal, mixing, or natural decay; therefore, collection is time-critical following the depositional event.

A total of 238 samples of sediment, soil, and vegetation were collected to characterize chemical quality. For this analysis, 157 of the 238 samples were used to characterize trace element, iron, total organic carbon, pesticide, and polychlorinated biphenyl concentrations of deposited sediment and associated shallow soils. In decreasing order, the largest variability in trace element concentration was detected for lead, vanadium, chromium, copper, arsenic, cadmium, and mercury. Lead was determined to be the trace element of most concern because of the large concentrations present in the samples ranging from 4.50 to 551 milligrams per kilogram (mg/kg). Sequential extraction analysis of lead indicate that 39.1 percent of the total lead concentration in post-hurricane sediment is associated with the iron-manganese oxide fraction. This fraction is considered extremely mobile under reducing environmental conditions, thereby making lead a potential health hazard. The presence of lead in post-hurricane sediments likely is from redistribution of pre-hurricane contaminated soils and sediments from Lake Pontchartrain and the flood control canals of New Orleans. Arsenic concentrations ranged from 0.84 to 49.1 mg/kg. Although Arsenic concentrations generally were small and consistent with other research results, all samples exceeded the U.S. Environmental Protection Agency’s Human Health Medium-Specific Screening Level of 0.39 mg/kg. Mercury concentrations ranged from 0.02 to 1.30 mg/kg. Comparing the mean mercury concentration present in post-hurricane samples with regional background data from the U.S. Geological Survey National Geochemical Dataset, indicates that mercury concentrations in post-hurricane sediment generally are larger. Sequential extraction analysis of 51 samples for arsenic indicate that 54.5 percent of the total arsenic concentration is contained in the extremely mobile iron-manganese oxide fraction. Pesticide and polychlorinated biphenyl Arochlor concentrations in post-hurricane samples were small. Prometon was the most frequently detected pesticide with concentrations ranging from 2.4 to 193 micrograms per kilogram (µg/kg). Methoxychlor was present in 22 samples with a concentration ranging from 3.5 to 3,510 µg/kg. Although methoxychlor had the largest detected pesticide concentration, it was well below the U.S. Environmental Protection Agency’s High-Priority Screening Level for residential soils. Arochlor congeners were not detected for any sample above the minimum detection level of 7.9 µg/kg.

Posted August 2008

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Table of Contents



2005 Hurricane Season

Hurricane Katrina

Hurricane Rita

Study Area

Method of Collection and Analysis

Sample Collection

Laboratory Analysis

Moisture, pH, and Total Organic Carbon

Trace Element and Iron Single Extraction

Trace Element and Iron Sequential Extraction

Exchangeable Fraction (F1)

Bound to Carbonate Fraction (F2)

Iron and Manganese Oxides Fraction (F3)

Organic Matter Fraction (F4)

Residual Fraction (F5)

Pesticide and Polychlorinated Biphenyl Extraction

Gas Chromatograph-Electron Capture Detection

Gas Chromatograph-Mass Spectrometry

Chemical Data Quality Assurance

Total Organic Carbon and Inorganic Carbon Data Quality

Trace Element and Iron Data

Instrument Calibration

Method Detection Limit

Laboratory Reagent Blank

Reference Standard Samples

Laboratory Fortified Samples

Laboratory Fortified Blanks

Calibration Check

Precision of Duplicated Samples

Pesticide and Polychlorinated Biphenyl Data Quality

Gas Chromatograph-Electron Capture Detection

Instrument Calibration

Method Detection Limit

Laboratory Fortified Blank

Laboratory Fortified Sample

Gas Chromatograph-Mass Spectrometry Method

Instrument Calibration

Method Detection Limit

Environmental Chemical Data

Total Organic Carbon Results

Trace Element and Iron Single Extraction Results

Trace Element and Iron Sequential Extraction Results

Pesticide and Polychlorinated Biphenyl Results

Pesticides in Sediment

Polychlorinated Biphenyl in Sediment

Summary and Conclusion




Suggested citation:

Witt, E.C., Shi, Honglan, Karstensen, K.A., Wang, Jianmin, and Adams, C.D., 2008, Environmental chemical data for perishable sediments and soils collected in New Orleans, Louisiana, and along the Louisiana Delta following Hurricanes Katrina and Rita, 2005: U.S. Geological Survey Scientific Investigations Report 2008–5031, 56 p.

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