Study of Mercury in Whatcom Fish Began With Public Disclosure

Al Hanners, a graduate of the University of Wisconsin-Madison, is a writer and retired geologist.

Two studies by the Washington Department of Ecology and others in years 1998 and 2000 found mercury in fish from Lake Whatcom significantly higher than the national average and high enough to be hazardous to fetuses and young children. In response to public concern, the U.S. Geological Survey (USGS) was engaged to investigate the mercury source. Plans for a joint study by the USGS, Washington State Department of Ecology, and Whatcom County Health Department were disclosed at a meeting on May 14, and public comment was given.

“The most remarkable thing about the meeting was that it was held,” said Marian Beddill. I feel that all environmentalists join us in thanking those responsible for an early opportunity for public understanding and comment.

Here is a summary of possible sources of mercury in fish from Lake Whatcom quoted from a memorandum handed out at the meeting:

“Some of the possible sources of mercury in Lake Whatcom are atmospheric deposition from global and local sources, discharges from tributaries (including the diversion from the Nooksack River), landfills, dumpsites, and local mining operations. Of these possible sources, local interest has focused on a chloralkali plant that operated in the city of Bellingham and discharged mercury to the atmosphere from early 1960s until the late 1990s. A major element of this study will be to assess the importance of this source.”

A great deal of information was presented by expert USGS testimony, and like the quotation above, some was general, some was specific. It was not easy to “connect the dots.” County Councilmember Dan McShane tried unsuccessfully to get the USGS to specify probable sources of the mercury in Lake Whatcom fish. The response always was an adamant, “All sources will be looked at.”

However, public questioning subsequently revealed that the “Y” Road dump will not be investigated. “Too expensive.” Landfills and other dumpsites will not be investigated. “Too many.”

This article gives a brief summary of my understanding of the principal focus of the plan based on what will and will not be done. Indeed, airborne metallic mercury from Georgia-Pacific’s chlorine plant, no longer operational, seems to be the major candidate for the source of mercury in Lake Whatcom.

Airborne metallic mercury from the ore smelter in Tacoma, now also shut down, is not far behind. For mercury to get into fish, it must be in the form of methylmercury. Where mercury becomes methylated and how it got into Lake Whatcom are perhaps equally important issues to be investigated. Brief comments on evidence, techniques, and issues are given below.

Significant mercury does not get into fish and humans unless it is first converted to methylmercury. One man at the May 14th meeting observed that employees at the Georgia-Pacific chloralkali plant (chlorine plant) in Bellingham showed no effects of mercury. That was metallic mercury, not methylmercury. His observation corroborates the widely held belief that mercury must first be converted to methylmercury.

Conversion requires the presence of metallic mercury, organic matter, and anaerobic bacteria in an oxygen deficient condition. The methylmercury is taken up by plants (algae), eaten by small creatures, and passed up the food chain to fish eaten by humans.

Wetlands, dumpsites, landfills, and some lakes meet these requirements. Whether methylmercury in Lake Whatcom originated from conversion in the lake itself or was transported to the lake from wetlands is a matter that will be addressed to some extent by the USGS study. Dumpsites and landfills will not be studied.

There are moderate amounts of mercury in the atmosphere from unidentified sources just about everywhere. Those are called “global” sources. Hence, mercury contamination exceeding “global” source background must be suspected to have come from a “local” source.

Given that we are on the West Coast of North America and in the belt of prevailing westerly winds, where did our “global” sources come from? However, atmospheric scientists are said to be able to detect when Chinese begin to till their fields in spring. Coal usually contains mercury, and burning it releases mercury to the atmosphere. An article on global polluion published by The Bellingham Herald on 5/26/02 said, “For the United States, China is a major source.” China has little petroleum and natural gas, and burns much coal. Hence, our “global” source might be from China. Some could be from unidentified industrial sources along the West Coast.

The USGS study will test the possibility that airborne mercury from Georgia-Pacific’s chlorine plant is the source of mercury in Lake Whatcom. One core will be taken from the bottom of each of five lakes upwind and downwind from the Georgia-Pacific plant, and three cores will be taken from Lake Whatcom.

•Ten horizons (narrow zones) from each of those cores will be analyzed for total mercury, total lead, lead-210, and total organic carbon. Five horizons from each core also will be analyzed for the cesium-137 isotope. Fish will be analyzed for mercury.

•These dates are important in determining when the mercury was deposited in Lake Whatcom, and hence, the source of the mercury:

•The cesium isotope is said to have been spread in the atmosphere as the result of testing atomic bombs in Western U.S.A.

•Use of leaded gasoline in new cars was banned in the year 1975. The Georgia-Pacific plant discharged mercury into the atmosphere from the early 1960s to the late 1990s.

Hence, for example, mercury deposited after 1975 in Lake Whatcom or in one of the other lakes, especially those downwind from Bellingham, would be strongly suspect of having come from the Georgia-Pacific plant. The lakes to be cored are in the direction prevailing winds blow from the Tacoma smelter. Hence, a possible by-product of this program may be information on airborne mercury from that smelter.

Problems arise from where airborne mercury settles out, where it is temporarily stored, and then subsequently transported. As watersheds draining into lakes normally greatly exceed the areas of the lakes themselves, mercury falling out of the atmosphere into a watershed normally greatly exceeds that falling directly into a lake.

Moreover, where in a watershed the mercury falls, in wetlands, uplands, grasslands, forests, or urban areas, has a considerable effect on what is found in a lake. A great deal of work on a watershed would be required to have full confidence in an interpretation of mercury in a lake itself. The following quotation from the handout at the May 14 meeting illustrates one problem:

“The second study (year 2000) confirmed that mercury concentrations in smallmouth bass from Lake Whatcom are elevated relative to the national average concentration of 0.34 micrograms. The average concentration was 0.49 micrograms, and the maximum concentration was 1.84 micrograms. Results from the second study also raised interesting questions because concentrations in some fish tissue samples from basin 3 were elevated relative to those in basins 1 and 2.

This result was somewhat unexpected because basin 3 is large and the contributing drainage area to basin 3 has a smaller percentage of urban land use than basin 1. The reasons that concentrations were higher in basin 3 were not determined, but Serdar and others (2001) conjectured that transport of mercury to the lake from tributaries or diversions, or processes that convert mercury to methylmercury in the lake or in connected wetland might be contributing factors.

In fact, bottom sediments of lakes in urban areas tend to have higher concentrations of total mercury, but lower concentrations of methylmercury because urban land-use practices tend to disrupt the ecosystems that most readily convert inorganic mercury to methylmercury (David Krabbenhoft, U.S. Geological Survey, written communication, April 2002).”

Understandably, the USGS, Department of Ecology, and Whatcom County Health Department investigation will test for mercury and other metals in mud, water, and tissue from fish. However, for some purposes, tests of leaves, lichens, and wood could provide more direct results.

For example, tests for mercury in cores from trees could provide dating the peak time of mercury contamination from an airborne source to the nearest year by utilizing annual growth rings in the cores. Researchers in Minnesota successfully tested for both metallic and methylmercury at levels of nanograms, not micrograms, according to on article in Science News of 3/9/02. If that can be done in Minnesota, it can be done here.

In addition, a good two-dimensional control of airborne pollution may be possible by using trees. On the contrary, cores from lakes upwind and downwind from Bellingham would at best provide control in a single, linear direction. Moreover, results would be uncertain because of unequal contributions from different watersheds.

Wetlands, dumpsites, and landfills emit methane, the gas at one time called marsh gas. If mercury is present, methylmercury is emitted along with methane. Testing for mercury in plants would determine whether there is significant current local airborne mercury pollution in excess of that from “global” sources. It could help to resolve the debate over whether mercury found in soils is from “natural” sources or simply fell out of an atmosphere loaded with industrial pollution, and whether airborne mercury pollution stopped at the divide between the Lake Whatcom and Nooksack watersheds.

The role of mercury in leaves might shed some light on peaks in the amounts of mercury found in streams draining into Lake Whatcom. Researchers in Minnesota reported in Science News of 3/9/02 that metallic mercury in the Cobb River peaked in May and June when metallic mercury washed into the river. Methylmercury peaked in November when metallic mercury in dead leaves had been converted to methylmercury.

Subsequent to writing this article, on May 21 the Whatcom County Council appproved $152,248 for further mercury testing in the “Y” Road dumps. Let us hope it includes testing for airborne methymercury that comes off with methane. In any case, I concur with County Councilmembers who approved the expenditure. While I doubt that significant mercury will be found, it might be. Public conceptions do matter and we need to bring the issue to closure. u