Friday, February 10, 2017Register
The State of the Bay Galveston Bay Area Project

Bacteria

 

Overview

Fecal coliform bacteria are used as the primary indicator for determining whether surface water is contaminated by animal or human waste. Presence of coliform bacteria suggests that potentially dangerous pathogens could also be present.

Elevated bacteria concentrations are typically associated with slow flowing bayous concentrated on the western side of Galveston Bay where most of the human development is situated. Water samples taken from open bay waters show substantially lower fecal coliform concentrations. Elevated levels of fecal coliform contamination prompt:

  • The restriction or prohibition of portions of Galveston Bay waters to the harvest of shellfish 
  • A number of local bayous to be the subject of Total Maximum Daily Load studies

 

A Description of the Indicator

The Status and Trends Project compares concentrations of three bacterial parameters in Galveston Bay surface waters to Texas Commission on Environmental Quality (TCEQ) screening levels for contact recreation (e.g. swimming). The three bacterial parameters are:

  • Fecal coliform bacteria
  • E. coli (in freshwater)
  • Enterococci (in saltwater)

Major subbays and tributaries of the bay are rated based on the percentage of samples exceeding current TCEQ screening levels. Samples are collected by the TCEQ and Texas Department of State Health Services (DSHS) during the period 1970-2009.

 

What the Indicator Says

The indicator below compares bacterial contamination in the 1970s to bacteria levels in the 2000s (2000-2009). Pathogen concentrations are highest in the bayous that serve as tributaries to Upper and Lower Galveston Bay. Over the last 30 years, the five subbays of Galveston Bay have rated "Good" for pathogenic bacteria with nine percent or less of the samples exceeding the fecal coliform bacteria screening level. The major water quality problems with regards to bacteria are found in six bayous currently rate poor for fecal coliform bacteria: Dickinson Bay/Bayou, Clear Creek, Armand Bayou, the Houston Ship Channel, Buffalo Bayou, and Cedar Bayou. Chocolate Bayou/Bay, Oyster Bayou, and the San Jacinto River are currently rated as moderate, the remaining areas rate good.


pathogen indicator chart

 

 

 

 

 

 

Related Pages:

Nutrients
Water and Sediment Quality
Seafood Safety

 

The Houston Ship Channel as seen from the top of the San Jacinto Monument. Image courtesy Lisa Gonzalez.The Houston Ship Channel as seen from the top of the San Jacinto Monument. Image courtesy Lisa Gonzalez.

 

 

TCEQ logo Upper Coast Oyster Waters: A TMDL Project for Bacteria

 

 

 

Water and Sediment Quality Data Portal Map of subbays and tributaries featured in the Water Quality and Sediment Data Portal.  Image source: Houston Advanced Research Center.

 

 

 

Wade fishing in Galveston Bay. Image courtesy Roland Hubenak.Wade fishing in Galveston Bay. Image courtesy Roland Hubenak.

 
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