SAMPLING AND ANALYSIS OF STORM SURGE TRANSPORTED SEDIMENT DEPOSITED IN VERMILION PARISH, LOUISIANA BY
HURRICANE RITA

By:  Wilma Subra

For:  Louisiana Environmental Action Network
November 21, 2005

     Six samples of Hurricane Rita undisturbed storm surge transported sediments in Vermilion Parish were collected by Wilma Subra of Subra Company on October 23, 2005 for Louisiana Environmental Action Network (LEAN).  Pace Analytical of New Orleans, Louisiana tested the sediment samples for heavy metals (US EPA Method 6000/7000 Series) and semi-volatile organics (US EPA Method 8270).

     The six samples of sediment were collected from the following locations on October 23, 2005:

L-01 Isodore Street in Delcambre,  1005 hours
        Latitude 29o 56.783’ North
        Longitude 91o 59.040’ West

L-02  St. Elmo near the intersection with
         Demosthese in a residential area
         south of Erath, 1040 hours
         Latitude 29o 55.360’ North
         Longitude 92o 00.745’ West

L-03  St. John’s Church in Henry, 1200 hours
          Latitude 29o 52.907’ North
          Longitude 92o 04.758’ West

L-04  5826 LA 330, residential area in
          Henry, 1225 hours
          Latitude 29o 52.975’ North
          Longitude 92o 04.224’ West

L-05  St. James Chapel, Esther, 1505 hours
          Latitude 29o 50.607’ North
          Longitude 92o 10.398’ West

L-06  Gallet Road near Hwy. 35 in
         Cow Island, 1630 hours
          Latitude 29o 61.615’ North
          Longitude 92o 16.790’ West

     All of the sediment samples were collected from areas undisturbed since Hurricane Rita struck the area.  Sediment samples were collected from undisturbed areas of two church properties due to the fact that the sediments in the residential areas around the churches had been disturbed by debris handling activities.

     The physical description of each of the sediment samples were as follows:

L-01  Sediment 1/2” thick consisting of light gray
          material. Top 1/4” dry, under portion moist.

L-02   Sediment 1/2” thick consisting of light gray
          material. Top 1/8” dry, under portion moist.

L-03   Sediment residue 1 inch thick, ranging from
          gray to dark brown and from moist to dry.

L-04   Beige sandy residue 1/2” thick, dry on
           surface and under portion moist.

L-05   Gray sediment 1 inch thick ranging from wet
         to dry.

L-06  Sediment 1/4” thick, dry and gray on
           surface, wet under dried surface.

     The heavy metals contained in the sediment samples are presented in the attached table.  Semi-volatile organic chemicals were not detected above the detection levels in any of the six samples.

    The sediment samples exceeded the EPA Region VI Soil Screening Level for Arsenic at all 6 sampled locations.  The sediment in the right-of-way of the residential area along LA 330 in Henry contained the highest concentration of Arsenic, 12.4 mg/kg.  The Arsenic concentration was 32 times the EPA Region VI Soil Screening Level of 0.39 mg/kg. 

     All six sediment samples contained detectable levels of Barium, Chromium and Lead.  The values for Barium, Chromium and Lead were below the EPA  and LA DEQ soil standards.   The sediment in the church yard of St. John’s Church in Henry contained the highest concentration of Barium (460 mg/kg) which was 84% of the LA  DEQ standard.  The sediment in the church yard at St. James Chapel in Esther contained the highest concentration of Chromium  (13.2 mg/kg)  which equaled 57% of the LA DEQ standard.  The sediment in the residential area along LA 330 in Henry contained the highest level of Lead (18.2 mg/kg) as well as the perviously presented highest concentration of Arsenic.

CONCLUSION

     All six locations sampled in Vermilion Parish (Delcambre, south of Earth, Henry, Esther and Cow Island) had storm surge deposited sediments with Arsenic concentrations in excess of the EPA Region VI Soil Screening Level.  The sediments also contained elevated levels of Barium,  Chromium and Lead which added to the cumulative impacts associated with the Arsenic contaminated sediments.

             LEAN Vermilion Parish Storm Surge
                    Sediment Samples

                                 Heavy Metals (mg/kg)

Location         Arsenic    Barium    Chromium     Lead
L-01               3.94*       246            11.4        16.2
L-02               5.11*       328            11.4        14.0
L-03               2.90*       460            8.91        13.5
L-04               12.4*       237            12.0        18.2
L-05                 4.8*       171            13.2        14.8
L-06               3.33*       136            10.6        16.3

LA DEQ Soil Recap Screening Standards
                         12         550            23          400

EPA Region VI Soil Screening Levels
                        0.39    5,500          210          400

*  Exceeded Standard