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National Status and Trends

Integrated Response to Hurricane Katrina

Preliminary Results from NOAA National Status and Trends (NS&T) Mussel Watch Survey (9/29-10/10/05) and Joint EPA/NOAA National Coastal Assessment (NCA) Survey on OSV BOLD Cruise “Hurricane Katrina: Leg 2” (10/9-14/05)

Background

The National Oceanic and Atmospheric Administration (NOAA), U.S. Environmental Protection Agency (EPA), US Geological Survey (USGS), US Food and Drug Administration (FDA), and coastal States along the northern Gulf of Mexico are engaged in a comprehensive interagency effort to assess human-health and environmental impacts of Hurricane Katrina in affected coastal waters. The combined effort will seek to characterize the magnitude and extent of coastal contamination and associated human-health and ecological effects resulting from this unprecedented storm. This report provides a summary of some preliminary results on microbial indicators of human-health risks from samples collected during two recent field surveys conducted as a part of this overall coordinated effort (see Figure).

Regional map of sampling sitesThe first of these surveys was conducted September 29 — October 10 at 20 shallow-water sites where NOAA's National Status and Trends (NS&T) Mussel Watch Project has a 20-year record of chemical contaminant concentrations in tissues of shellfish. This provides a critical long-term baseline for comparison of chemical contaminant levels in the region affected by Hurricane Katrina. Objectives of this post-hurricane survey were to:

  1. Measure contaminant levels (DDT and other conventional chlorinated pesticides, PCBs, PAHs, metals) in tissues of oysters (Crassostrea virginica) and sediments collected from these historical sampling sites;
  2. Measure contaminant concentrations in shallow coastal waters,
  3. Measure human pathogen indicators at these sites;
  4. Assist the FDA with the collection of oysters for analysis of additional chemical and microbial indicators of seafood safety; and
  5. Perform bioassays (P450 and Microtox) on sediments to assess potential biological effects of contaminant exposure.

The second survey was conducted in partnership with EPA, from October 9-14, at 30 stations in deeper coastal waters of Lake Borgne and Mississippi Sound , using EPA's research ship the OSV BOLD. A focus of this survey was on the collection and analysis of water and sediment samples using protocols and indicators incorporated in EPA's National Coastal Assessment (NCA) program. Post-hurricane conditions measured from samples collected six weeks after the hurricane (and subsequently throughout the next year) will be compared to pre-hurricane conditions, based on prior NCA assessments in this same area, to provide a basis for assessing initial environmental impacts and recovery. A probability-based survey design, consisting of randomly selected sites, was used to support statistical estimates of degraded versus non-degraded condition relative to various measured indicators. These include sediment samples for the analysis of chemical contaminants as at the Mussel Watch sites, microbial/pathogenic indicators (Clostridium perfringens), condition of resident benthic fauna, and sediment toxicity (Microtox, P450 Reporter Gene, and sea-urchin fertilization/embryological development assays) as measures of contaminant exposure and biological effect. Water samples also were collected for standard hydrographic parameters (DO, salinity, temperature, pH, depth, turbidity), microbial/pathogenic indicators (Enterococcus , fecal coliforms, and viral indicators), nutrients, chlorophyll a, total suspended solids, dissolved organic carbon, and chemical contaminants (conventional organochlorine pesticides, PCBs, PAHs, oil and grease, metals). Additional samples were collected for analysis of newly emerging contaminants of concern, including flame retardants (PBDEs) in sediments, and pesticides fipronil and atrazine in sediments and water, respectively.

Preliminary results summarized here are only for microbial indicators of human health risks. The other analyses will require more time.

Preliminary Results

Fecal pollution indicator organisms, enterococci and fecal coliforms, were enumerated to assess potential risks of pathogen exposure (see Table below). Both the NS&T Mussel Watch and NCA assessments used membrane filtration and m FC agar to enumerate fecal coliforms (APHA, 1998). This method involved filtering multiple volumes of sample water through 0.45 µm nitrocellulose membranes. In this case, sample volumes ranging from 0.1-100 ml of sample water were filtered and each membrane was placed on appropriate media and incubated at 44.5 ± 0.5 o C for 24 ± 2 hours. Typical blue fecal coliform colonies were counted and the density of fecal coliforms (colony forming units -cfu) per 100 ml of sample was calculated.

The methods for enumerating enterococci differed between the two surveys due to unavoidable variation in supplies and equipment. Membrane filtration with m Enterococcus agar was used on the NS&T Mussel Watch cruise (APHA, 1998). This method involved filtering 0.1, 1, 10, 50 and 100 ml of sample water through a 0.45 µm nitrocellulose membrane. Each membrane was placed on m Enterococcus agar and incubated for 48 hours at 35 ± 0.5 o C. Pink and red colonies, enterococci, were counted and the number of enterococci cfu/100 ml of sample was calculated.

The Enterolert system was used for the analysis of enterococci during the NCA interagency assessment. Ten ml of the marine water sample were diluted in 90 ml of sterile water and pre-measured media was added to the sample. The mixture was then added to a specialized plastic tray containing one large well and 50 smaller ones. The tray was sealed and incubated at 41 ± 0.5 o C for 24 hours. Wells that are positive for bacterial growth will fluoresce under ultraviolet light. Accordingly, numbers of positive wells were counted and an MPN table was used to estimate the most probable number (mpn) of enterococci per 100 ml of water sample.

Fourteen samples (70%) from the NS&T Mussel Watch cruise tested positive for fecal coliforms, and all 20 (100%) samples were positive for enterococcus. Fecal coliform concentrations in positive samples from the NS&T Mussel Watch cruise ranged from 1-37 cfu/100 ml. Enterococci concentrations ranged from 6-673 cfu/100 ml. Only three samples (10%) from the OSV BOLD cruise were positive for fecal coliforms and concentrations for these samples ranged from 1-3 cfu/100 ml. Three samples (10%) were also positive for enterococci and the concentration in these samples (10 cfu/100 ml) was at the limit of detection.

Fecal coliform concentrations in water samples from the two cruises were compared to two criteria for shellfish harvesting waters (EPA 841-R-00-002). The first criterion (14 cfu/100 ml) is the 30-day median concentration, while the second (43 cfu/100 ml) is the criterion that should not be exceeded by >10% of samples collected during a 30-day period. Three of the samples from the NS&T/Mussel Watch cruise exceeded the first criterion and none of the samples from that cruise exceeded the second, higher number. None of the samples from the OSV BOLD/NCA cruise exceeded either of the criteria.

Enterococci concentrations in water samples from the two cruises were compared to EPA criteria for recreational water uses (EPA440/5-84-002). Concentrations in samples were compared to single sample maximum (SSM) criteria based on the frequency of exposure. Results were compared to both the SSM for a designated bathing beach area (104 cfu/100 ml) and the SSM for infrequent use (501 cfu/100 ml). Ten samples from the NS&T Mussel Watch cruise exceeded the criterion for a designated beach area and one sample (MRPL) exceeded the less-stringent criterion for infrequent use. None of the samples from the OSV BOLD/NCA cruise exceeded either of these criteria.

Both fecal-pollution indicator organisms were detected at a higher frequency and at higher concentrations in samples from the NS&T Mussel Watch cruise in comparison to the OSV BOLD/NCA cruise. This may be due both to the geographic distribution of the sampling sites for the two cruises as well as the timing of the cruises. In general, the NS&T Mussel Watch sampling sites represented more in-shore stations in closer proximity to land-based sources of fecal pollution, while the OSV BOLD/NCA sites were generally in more offshore waters. Additionally, the NS&T Mussel Watch cruise was conducted sooner after the landfall of Hurricane Rita which may have increased the inputs, distribution, and re-suspension of the indicator organisms in the water column.

These preliminary results should be used carefully since they reflect conditions at the sites at a single point in time and should be compared as needed with other data and criteria that are most appropriate for a given designated use within each watershed sampled. Also, final judgments as to the state of environmental conditions in these areas should be based on a weight-of-evidence from the multiple indicators that still need to be processed.

Fecal pollution indicator organism densities
Station # Date collected Latitude Longitude Fecal
coliforms *
cfu/100 ml
Enterococcus **
mpn or cfu/100 ml

Inshore Assessment (National Status and Trends Mussel Watch)

MRTP

29-Sep-05

29.154000

-89.427333

2

136

MRPL

29-Sep-05

29.089500

-89.074833

1

673

BSSI

29-Sep-05

29.405150

-89.484280

<1

38

BSBG

30-Sep-05

29.604257

-89.619487

<1

17

LBMP

30-Sep-05

29.866917

-89.679097

<1

14

LBGO

01-Oct-05

29.947337

-89.838493

2

8

LPNO

01-Oct-05

30.039047

-90.041437

4

20

TBLB

02-Oct-05

29.260417

-90.596377

1

158

TBLF

02-Oct-05

29.263883

-90.398293

1

347

CLCL

03-Oct-05

29.252237

-90.922137

<1

218

BBTB

04-Oct-05

29.511120

-90.080740

1

467

BBMB

05-Oct-05

29.277730

-89.942670

<1

163

ABOB

06-Oct-06

29.246473

-91.132173

1

213

BBSD

07-Oct-05

29.383840

-89.984755

1

180

MSPC

07-Oct-05

30.338017

-88.129827

37

350

MSPB

08-Oct-05

30.339640

-88.585703

1

9

MSBB

08-Oct-05

30.392823

-88.856387

23

11

MBDR

09-Oct-05

30.592487

-88.038857

1

7

MBCP

09-Oct-05

30.302673

-89.327797

<1

6

MBHI

09-Oct-05

30.565540

-88.074707

20

21

Offshore Assessment (Joint EPA Coastal Condition Assessment)

KAT-0001-1

11-Oct-05

30.288931

-88.311975

<1

<10

KAT-0002-1

12-Oct-05

30.036439

-89.530560

<1

<10

KAT-0003-1

12-Oct-05

29.999275

-89.696750

<1

<10

KAT-0004-1

10-Oct-05

30.243204

-88.910383

<1

<10

KAT-0005-1

12-Oct-05

30.002633

-89.614727

<1

<10

KAT-0006-1

11-Oct-05

30.272778

-88.610558

<1

<10

KAT-0007-1

11-Oct-05

30.129766

-89.337388

<1

<10

KAT-0008-1

10-Oct-05

30.302886

-89.126318

<1

10

KAT-0008-1dup

10-Oct-05

30.302886

-89.126318

<1

<10

KAT-0009-1

11-Oct-05

30.210963

-88.406535

<1

<10

KAT-00010-1

10-Oct-05

30.273865

-89.287131

<1

<10

KAT-00011-1

10-Oct-05

30.153992

-89.285613

<1

10

KAT-00012-1

10-Oct-05

30.339473

-88.960695

<1

<10

KAT-00013-1

12-Oct-05

29.986575

-89.807540

1

<10

KAT-00014-1

11-Oct-05

30.275511

-88.721902

<1

<10

KAT-00015-1

11-Oct-05

30.111663

-89.443503

<1

<10

KAT-00016-1

11-Oct-05

30.322856

-88.719387

<1

<10

KAT-00017-1

11-Oct-05

30.338312

-88.298280

<1

<10

KAT-00018-1

11-Oct-05

30.233615

-89.323682

<1

<10

KAT-00019-1

12-Oct-05

29.963979

-89.701180

<1

<10

KAT-00020-1

10-Oct-05

30.264562

-88.877270

<1

<10

KAT-00021-1

12-Oct-05

30.087257

-89.605562

<1

<10

KAT-00022-1

11-Oct-05

30.330691

-88.653465

2

<10

KAT-00023-1

11-Oct-05

30.191038

-89.363311

<1

<10

KAT-00024-1

10-Oct-05

30.366439

-88.984480

<1

10

KAT-00025-1

11-Oct-05

30.321060

-88.364936

<1

<10

KAT-00026-1

12-Oct-05

30.173045

-89.561024

3

<10

KAT-00027-1

10-Oct-05

30.235924

-89.162707

<1

<10

KAT-00028-1

10-Oct-05

30.255153

-88.949553

<1

<10

KAT-00029-1

12-Oct-05

30.043546

-89.768363

1

<10

KAT-00030-1

12-Oct-05

30.153198

-89.625060

<1

<10

* Fecal coliforms were enumerated by membrane filtration method using mFC medium
** Enterococci were enumerated by membrane filtration method using mEnterococcus medium for inshore cruise
** Enterococci were enumerated by the Enterolert method for offshore cruise samples (sample numbers KAT-xxxxx-1)