Robert C. Hale is a professor of marine science in the Department of Aquatic Health Sciences at William & Mary’s Virginia Institute of Marine Science. His research interests include environmental chemistry, biosolids, and the fate and availability of man-made compounds in aquatic environments.
In recognition of World Water Week, which kicks off Aug. 23, W&M News recently talked with Hale about the state of water in the world and the effect of pollutants — microplastics in particular — on that state.
Hale and his students have published multiple papers about those topics, with one of the most recent appearing in Nature Communications. As a result of his research and discoveries, Hale has been able to bring about industry and policy change. In 2019, he received a Plumeri Award for Faculty Excellence for his work as a scholar, teacher and mentor.
Water is one of four cornerstone initiative areas in William & Mary’s Vision 2026 strategic plan, with the goal being to help ensure the resilience of the world’s waters.
Q: In terms of pollution, what is the state of water in the world and what is the outlook for it?
A: Globally, only 50% of wastewater receives any treatment. As the world’s population is increasing, pollution pressures are as well. In the U.S., effectiveness of wastewater treatment varies locally and by contaminant. Regulations typically have focused on pollutants such as nutrients, biological oxygen demand (BOD) and a limited number of toxic pollutants (metals and organics on a list promulgated in the late 1970s).
We now talk about “emerging pollutants” (those not on that or other common lists) that include per-/polyfluorinated substances (PFAS), polymer additives such as flame retardants, pharmaceuticals and more. Some of these are persistent in the environment and are known as “forever chemicals” and are clearly global pollutants as they do not breakdown (or extremely slowly) and thus are relocated around the world from their point of release.
Air and land pollution are serious as well. Both are getting worse globally. In the U.S., more attention to air pollution has certainly been given than other nations in the developing world. However, climate change and wildfires are worsening this. Soil pollution is an emerging concern.
With respect to plastics, manufacturing is increasing, as are environmental levels … so that is not a good outlook. Their disposal is poorly controlled/regulated. Plastic debris and recycling and control efforts were hurt by our efforts to control COVID. The virus responsible for SARS itself is a pollutant of sorts.
Q: What are microplastics, and why are they such a threat? What is their effect on ecosystems and on the health of people in particular?
A: Microplastics are particles less than 5 mm. They may be made intentionally small for select uses or more commonly result from fragmentation of larger plastics. They are highly varied in size (down to 1 micron, beneath which they are called nanoplastics) and composition (different polymers with varied chemical additives therein, which may constitute percent levels).
Because they are so varied and long were considered non-toxic, we know far too little about their toxicity to humans or ecosystems. We recently published a paper in Nature Communications (co-authored by VIMS Ph.D. student Meredith Seeley) that described effects of microplastics on nitrogen processing in marine sediments, as well as effects on microbial communities. We have work in progress that shows that microplastics interact with a virus resulting in far greater fish mortalities than either alone.
Q: How are these plastics getting into our waters? And are they ending up more in fresh water or ocean/bay waters?
A: Inputs are varied. They include direct losses (via improper discard, fishing gear, etc.), but most enter from land-based sources. Entry into surface waters (e.g., rivers) is substantial. These then are carried to estuarine, coastal and marine waters. As microplastics are small and light, they are easily carried by surface runoff and aeolian processes.
Wastewater treatment is also a source. We discuss that (and other aspects) in our recently accepted review (co-authored by two VIMS students) in Environmental Science & Technology Letters. In advanced wastewater treatment, most (up to 90%) are captured in the sludge, but up to 60% of this is land-applied as a fertilizer in the U.S. These microplastics may later be transferred via stormwater runoff, aeolian and other processes to surface waters, restarting the cycle.
Q: What other pollutants are among the most significant threats to drinking water sources in the U.S.?
A: The emerging contaminants mentioned above are a growing and inadequately studied group. Some of these are highly toxic and may escape drinking water purification efforts.
Q: What steps are being taken in the U.S. or globally to combat plastic and other pollutants in these sources?
A: Understanding the diversity of contaminants is critical. If we do not know what is there, how can we protect ourselves? There are about 300,000 chemicals produced commercially. These may be degraded into additional chemicals. There are also impurities in products.
Prevention is always a better strategy than cleanup. There are, of course, international agreements on contaminants. Unfortunately, the U.S. is not a party to some. Some of this is discussed in out ESTL review. Unfortunately, plastic recycling is really not successful and fell to 6% of waste recently in the U.S.
Q: What can individuals do in their own lives to cut down on these pollutants?
A: We can recycle higher-value plastics and other materials (paper, cardboard, metal, glass). I tell people one of the more effective things is to use something twice, effectively reducing waste by 50% … that is much better than 6%.
Staff, University News & Media
