Let’s start thinking about water!

Plastics in bays and estuaries

Plastics are everywhere in our daily lives and, as more and more studies show, everywhere in the biota, including your brain (and testicles!). Littered plastic or plastic introduced into wastewater (you do this every time you wash a load of clothes) works its way down the watersheds and rivers of the world and into the bays and into the seas, resulting in about 270 trillion microplastic particles circulating in the Earth’s oceans. Because 99% of plastic inputs into the world’s oceans are not observed on the ocean’s surface, particles may be appearing in ocean sediments. Although a lot of work has been done on characterizing coastal and deep-sea plastics, little has been done in bays and estuaries. Baily and his plastic hunters aimed to help fill that gap with a study of plastics in the sediments of Matagorda and San Antonio bays. They found low concentrations of microplastics in bay sediments (tens to hundreds of particles per kilogram), probably due to bay sediments (and plastics) flushing into the gulf.

Microplastics in rivers

Microplastics are also in our rivers. Owens takes a look at three in Texas—the Brazos, the Colorado, and the Trinity—as well as providing a nice literature review of microplastics in the environment. For her site work, she sampled sediments upstream and downstream of Austin (Colorado River), Dallas (Trinity River), and Waco (Brazos River). She found microplastics in almost all samples and found higher concentrations downstream of the cities than upstream. Microplastic concentrations were 38 times higher downstream of Dallas than above, 3 times higher downstream of Waco than above, and 2.5 times higher downstream of Austin than above. The Dallas results are surprising to me since one could argue that the Trinity isn’t upstream of urban development until it’s west of Fort Worth. Owens also quantified the color of microfibers with blue and red dominating Dallas and Waco and blue and white (not burnt orange!) dominating Austin.

Arsenic in aquifers (and urine)

As a carcinogen, arsenic in water is not a good thing. Unfortunately, arsenic is a naturally occurring constituent in several Texas aquifers, including in the southern Gulf Coast Aquifer. While public water systems are frequently tested and required to meet state and federal drinking water requirements, household wells or wells for small systems are on their own for ensuring safe drinking water quality. About 10 percent of private wells and 2 percent of public groundwater systems in Texas have arsenic above federal maximum contamination levels. Svetlik and friends sought to understand the potential exposure of private well owners to consistent low levels of arsenic as derived from their drinking water. To do this, they sampled wells and collected urine samples from 74 well users in five counties (Bee, Goliad, Refugio, San Patricio, and Victoria) over the Gulf Coast Aquifer. They found a correlation, albeit weak, between arsenic concentrations in water and arsenic in urine. They also found that PDGF(platelet-derived growth factor )-BB could be a potential biomarker for arsenic-related health impacts.