Exploring every day products in Texas bays and estuaries
By Cindie Powell, Texas Sea Grant
How much of the chemicals in the products Texans use every day — prescription drugs, soap, even the caffeine and sweeteners in their morning coffee — are ultimately making their way to the state’s bays and estuaries, and what effects do they have on fish and other wildlife?
Funded by a grant from Texas Sea Grant, researchers led by Dr. Bryan Brooks, Professor of Environmental Science and Biomedical Studies and Director of the Environmental Health Science Program at Baylor University, are studying the water flowing into four major Texas estuaries to learn more about the pharmaceuticals and personal care products, known collectively as contaminants of emerging concern (CECs), that are entering Texas coastal ecosystems.
“If we think about our rivers as they make their way into the estuaries along the coast, what’s happening is the base flows are becoming reliant on reclaimed water — water that has been used, treated and released by cities upstream,” Brooks said.
Most wastewater treatment plants aren’t designed to completely remove everything from wastewater or to remove these types of compounds. In other parts of the country, increased levels of estrogen in water from CECs have been found to lead to male fish acquiring feminine characteristics, even producing eggs, affecting fish populations over time. Brooks’ study — the first of its kind in the Gulf of Mexico — is designed to determine the amounts of CECs flowing into the bays, discover how the chemicals might be accumulating in some species or transferring through the food web, and predict the risk of exposure to fish in Texas coastal ecosystems.
The researchers collected water samples in all four seasons to get a complete picture of CEC loading during times when the river flow consisted only of the base flow — dry-weather flow from groundwater seeping into the river — and when the base flow was supplemented by runoff from rain. To develop estimates of the loading of CECs into the different bays over the course of the year, they used representative chemical tracers as indicators of upstream urban water use and effluent discharge.
“Using caffeine and sucralose as molecular markers, you can get a really good sense of our anthropogenic footprints in an urbanizing water cycle,” Brooks said. Sucralose, the artificial sweetener sold under the name Splenda, dissolves in water but is not metabolized by humans or marine organisms, and it is not fully broken down during water treatment.
They also examined marine life in the downstream estuaries and found chemical signatures of some pharmaceuticals at high levels in fish blood plasma. Brooks said they found one calcium channel blocking medicine, which can be prescribed to treat conditions including high blood pressure and migraines, in multiple fish at multiple sampling sites at levels exceeding those that cause physiological changes in humans.
The group is continuing to analyze the potential impact of these chemicals on specific marine species and identifying susceptible habitats for restoration. Brooks said the issue will continue to be a growing concern in Texas as river base flows become increasingly reliant on discharges from wastewater treatment plants.
“How will these initial observations change as we double the size of the population in the state of Texas?” he said. “We need to protect and restore the quality of habitats for our coastal fisheries and the other uses that we depend on, but at the same time we live in a state that is facing the largest factors affecting the world’s water resources — population growth and urbanization, and climate stress.”
To increase understanding of CECs and their impacts on aquatic species, Melissa Mullins, Environmental Education Specialist at the Center for Reservoir and Aquatic Systems Research at Baylor University, Brooks and Texas Sea Grant staff presented a one-day workshop for Texas educators. Mullins and Brooks also supported development of an online module for the ProjectWET (Water Education for Teachers) program about these contaminants in urban water supplies, including the proper disposal of unused medicines and personal care products, and Brooks contributed to a panel discussion titled “Defend Your Drain” with Philippe Cousteau and EarthEco International with the Seventh Generation Foundation.
