Rio Grande / Rio Bravo Toxicity Survey Phase II (Follow-up)

1. Purpose and Objectives: The purpose of this study is to implement a second phase of the binational program to determine the presence of toxic substances in the waters of the Rio Grande/Rio Bravo in its international boundary reach. The goals of this study are as follows: 1) To exchange a draft U.S. report by November 1, 1996, 2) to have a binational technical meeting the week of November 25, 1996, 3) to prepare a draft report by January 1997, and 4) to finalize a binational report by April 1997.

2. Funding: EPA has provided about $500,000 for the follow-up study.

3. Partners: IBWC, TNRCC, and EPA

4. Description: IBWC Minute No. 289 authorized the observation of water quality along the US/Mexico border, and initiated a toxicity survey of the Rio Grande/Rio Bravo along its international reach which was carried out from November 1992 through March 1993. The second phase of this toxicity survey intended to: 1) monitor for the presence of toxic substances at areas previously determined to be of high to moderate concern; and 2) more completely characterize the international reach through the addition of new sampling additions. The sampling for the second phase was accomplished between May and December 1995.

5. Results: 6) The data from the U.S. and Mexican laboratories has been exchanged and discussed. 7) A Joint Report of the IBWC Principal Engineers Relative to the Second Phase of the program to observe for the presence of Toxic Substances in the Rio Grande/Rio Bravo in its International Reach was finalized on May 12, 1995. 8) Sampling was completed between May-December 1995. 9) U.S. data was provided to Mexico on May 13, 1996 and June 11, 1996. 10) Mexican data was exchanged on April 23, 1996 and October 15, 1996.

6. Status: The final report is still being printed.

7. U.S. Contacts: Sylvia Waggoner, IBWC, (915) 534-6704; Fax: (915) 534-6680 Carl Young, EPA, (214) 665-6645 Patrick Roques, TNRCC, (512) 239-4604