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Post-Katrina Water Quality Assessment: Lake Pontchartrain and Surrounding Water Bodies

Post-Katrina Water Quality Assessment: Lake Pontchartrain and Surrounding Water Bodies. Louisiana Department of Environmental Quality Water Quality Assessment Division September 20, 2005. A partnership for water quality assessment: . Louisiana Department of Environmental Quality

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Post-Katrina Water Quality Assessment: Lake Pontchartrain and Surrounding Water Bodies

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  1. Post-Katrina Water Quality Assessment: Lake Pontchartrain and Surrounding Water Bodies Louisiana Department of Environmental Quality Water Quality Assessment Division September 20, 2005

  2. A partnership for water quality assessment: • Louisiana Department of Environmental Quality • U.S. Geological Survey • Lake Pontchartrain Basin Foundation • Louisiana Department of Agriculture and Forestry • U.S. Environmental Protection Agency

  3. Approach to Lake Pontchartrain Damage Assessment Historic Ambient Water Sites and 5 Post-Katrina Sites

  4. Conventionals, Field Dissolved Oxygen* Temperature* pH* Salinity Conductivity Oil Sheen (presence or absence)* Metals# Arsenic* Cadmium* Chromium* Copper* Lead* Mercury* Nickel* Zinc* Parameters being analyzed *Has Louisiana water quality standards #All sites analyzed for dissolved metals; two canal sites analyzed for total metals

  5. Conventionals, Laboratory Fecal Coliform* Turbidity* Chloride* Sulfate* Total Suspended Solids Total Solids Total Dissolved Solids* Biological Oxygen Demand Alkalinity Nitrate-Nitrite Total Kjeldahl Nitrogen Ammonia Nitrogen Total Phosphorus Hardness Chemical Oxygen Demand Total Organic Carbon Color* Parameters being analyzed * Has Louisiana water quality standards

  6. Organic parameters being analyzed (66 compounds) * Has Louisiana water quality standards

  7. Alachlor (Lasso) Aldrin* Atrazine Bifenthrin Imidacloprid Carbaryl (Sevin) Chlordane* Chlorpyrifos (Dursban) Cypermethrin Diazinon Permethrin Dieldrin* Endosulfin* Endrin* Fipronil (and metabolites) Heptachlor* Lindane* Malathion Metolachlor (Dual) + about 60 other pesticides… Pesticides analysis by the Louisiana Department of Agriculture and Forestry * Has Louisiana water quality standards

  8. Additional sampling capabilities provided by USGS USGS is providing boats and crews specifically for bacterial sampling in the entire region USGS also brought in a mobile analytical lab to provide quicker access and turnaround of bacterial samples

  9. Magnitude of LDEQ Laboratory Analyses: Water only as of September 18, 2005 • Organic compounds – 144 samples (7,521 analyses) • Conventional parameters – 333 samples (1,313 analyses) • Metals – 47 samples (104 analyses) • Total samples – 524 samples (8,938 analyses)

  10. What we expected • Hurricane damage • Increases in organic loading • Decreases in dissolved oxygen • Fish kills • Increases in fecal coliform • Impact of floodwater discharges into lake • Decreases in dissolved oxygen • Fish kills • Increases in fecal coliform and other urban nonpoint source pollutants (metals, pesticides, oil and grease)

  11. Volume of floodwaters into Lake Pontchartrain is minimal compared to the volume of the lake

  12. Northshore Water Quality Assessment

  13. Summation of water quality assessments for Pontchartrain region: Northshore • Except Tangipahoa River, Northshore streams impacted by low dissolved oxygen • Woody debris • Resuspended sediments • This situation will resolve as the debris decays or is removed • Reported fish kills in the Northshore area are the result of low DO • Slightly elevated levels of fecal coliforms were detected but are not unusual for the area • No detectable concentrations of organic compounds

  14. Western Region Water Quality Assessment

  15. Summation of water quality assessments for Pontchartrain region: Western Region • Incidences of low dissolved oxygen levels may occur as tributaries to Lake Maurepas carry organic loading (due to decaying vegetation) into the lake

  16. Lake Pontchartrain Causeway Water Quality Assessment

  17. Swimming standard is 400 colonies/100 mL. Maximum observation was 5 colonies/100 mL.

  18. Turbidity standard is 50 NTU. Maximum value observed was <11.

  19. Summation of water quality assessments for Pontchartrain region: Causeway • Dissolved oxygen, fecal coliforms, and turbidity meet water quality standards • Water quality parameters across the causeway have remained at or near values expected for this time of year • There have been no detectable concentrations of organic compounds along the causeway • There have been no reports of oil sheen on the water

  20. ½ mile Off Southshore Water Quality Assessment

  21. Summation of water quality assessments for Lake Pontchartrain region: Near- Southshore • Water quality parameters are at or near expected values for this time of year • There have been no reports of oil sheen on the water

  22. Southshore Canal Water Quality Assessment

  23. Summation of water quality assessments for Lake Pontchartrain region: Southshore Canals • Dissolved oxygen levels have been slightly depressed due to high organic loading • There have been no reports of oil sheen on the water • Fecal coliform results have been somewhat elevated

  24. Eastern Region Water Quality USGS has been able to sample this region for bacteria samples only once due to accessibility and sample time issues. Water bodies will continue to be sampled as accessibility improves.

  25. Eastern Region Water Quality Assessment

  26. Swimming standard is 400 colonies/100 mL. Maximum observation was 6 colonies/100 mL.

  27. Organic Compound Analysis

  28. Organic Compound Analysis in the Lake and tributaries • Of the approximately 6,000 analytical results (144 samples) for organic compounds in ambient water, nearly all have been below detection levels • When detected, none have exceeded water quality standards

  29. Biotoxicity test results • Toxicity tests were completed on canal water pump stations and lake sites • Of these only Suburban Canal showed toxicity for one test species • Other test species showed no toxic effects at 100% canal pump water • Chemical data will be assessed to determine possible causes of this toxicity • All other sites showed no toxic effects even at 100% canal pump water • Biotoxicity testing will continue

  30. Field observations • As of September 19, 2005 there were no algae blooms observed • Numerous bait fish and mullet observed • Live crabs found in traps along the Southshore • Good visibility in water column

  31. Conclusions • Northshore Lake Pontchartrain – most impact • Low dissolved oxygen • High bacteria counts (i.e., fecal coliform) • Organic and toxic compounds • Ambient results mostly non-detect, no exceedences of water quality standards • Most impacts seen thus far were a result of the hurricane and not a result of the pump down of floodwaters

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