Water Quality
Fishing for Public Health
By Debbie Dotson, Water Quality Officer
Eastern Shawnee Tribe’s Water Quality Monitoring Program collects fish annually as a way of studying contaminants in Spring River. It also addresses public health concerns for fish consumption advisories. U.S. Environmental Protection Agency (EPA), through a Clean Water Act 106 grant, provides funding for the Water Quality Monitoring Program, including the fish collection and laboratory analyses on the fish.
The collection part of the study is a one-day event, usually in late spring. A partner agency assists with electroshock equipment to catch several of the same species quickly. Targets are usually a predator species like bass, channel catfish if possible, and a bottom-feeder like smallmouth buffalo or sucker fish, or flathead catfish.
The fish are sent to a laboratory to determine the amount of arsenic, cadmium, lead, zinc, mercury, and methylmercury in each fish. These contaminants are all related to mining and mining waste. About 12 fish are submitted each year to the lab to represent what is caught from Spring River. Both the tissue (filet meat) and the whole fish (blended) are analyzed. Results are compared to fish consumption guidelines and to past years’ results. Eastern Shawnee results from fish tissue analyses are made public through a nationwide database and provided in a final report to U.S. EPA each year.
It is up to each state to provide the information for fish in their state to US EPA and to establish Fish Consumption Advisories. Oklahoma Department of Environmental Quality (ODEQ) sets those guidelines in Oklahoma, and we have a lot of lakes that are monitored on a regular basis for contaminants in fish.
A major contaminant of concern nationwide is mercury. Mercury is not poisonous when found in its natural state. It becomes poisonous as it is processed, like at coal fired power plants and mining sites. The poisonous form, or methylmercury, is dispersed into the air and settles on the ground and in the water. It accumulates in fish tissue at higher concentrations than in the water and can persist for years in the bottom sediments. The bottom dwelling fish and creatures eat from that sediment, and then when they are eaten, it is passed on to the next fish. Eventually, it gets down the food chain to people.
If you visit ODEQ’s website, you will find the 2017 Oklahoma version of “Mercury in Fish.” 54 lakes are on the list of Oklahoma lakes with consumption advisories for mercury. The good news is that Grand Lake is not on that list.
However, Grand Lake is a part of the Tar Creek watershed and is included in a lead consumption advisory just for the Tar Creek area in Oklahoma. Lead in any amount is considered harmful and we do see lead in the fish from the waters in this area. It is mostly found in the non-game fish that are less popular to eat, like carp, drum, sucker, and buffalo. All of the lead advisories in the Tar Creek area are for limits on fish preparations with bones, except for the non-game fish in Spring River.
From the analyses of fish caught during the Eastern Shawnee collection events, higher lead results are found in smallmouth buffalo or sucker fish from Spring River. Last year, 4 out of 7 smallmouth buffalo had lead content above consumption guidelines set by ODEQ, mostly in the whole body samples. Lead results have been comparable for the past 4 years, and always in the sucker fish or smallmouth buffalo. Spring River mercury results from 2017 are less than half what they were in 2010 and none have exceeded the consumption guidelines for several years. Overall, contaminants are still found in Spring River water and fish, but seeing improvement over time and a downward trend in concentration levels.
One way to greatly reduce the risk of metal consumption from fish is in preparation. Metals accumulate in higher concentrations in the bones, organs, and skin of fish. Cleaning the fish and removing skin, organs, and bones, and eating only the filets can greatly reduce the metals intake. That is not always traditional eating for many cultures in the world, including area tribal people, so testing of the whole body and filets is still needed.
See the ODEQ website for more information on fish consumption advisories in Oklahoma, www.deq.state.ok.us. You can go online to the National Water Quality Monitoring Portal to find all of the water quality monitoring data, including fish tissue, for the Eastern Shawnee Tribe. You can also contact me at the Eastern Shawnee Water Quality Office at 918-666-5151 ext. 1044, or at ddotson@estoo.net.