By, Frank Carl

The Olin Corporation uses mercury cell technology in the chlorine manufacturing process, but mercury-cell technology is outdated. It was invented in 1894 and 90% of the chlorine produced in the US today is done in plants using updated technologies, primarily membrane technology. There are only eight plants left in the US that use mercury in the production of chlorine, and two of these will be phased out within two years, one is shutting down and the other is converting to membrane technology. We are encouraging Olin to convert its two remaining mercury-dependent plants located in Augusta, GA and Charleston, TN to membrane technology. If they do so, there will be only four plants (of 60 total) left to convert. For more information about the mercury cell process and other chlor-alkali plants go to Ocean's website or click here.

Because of its physical properties, mercury is difficult to control. Chlor-alkali facilities use tons of mercury to produce chlorine on a daily basis, but to protect our unborn, they need to insure that gram quantities are effectively controlled. It is estimated (by Olin) that they release 6 to 12 lbs of mercury per year directly to the water. They release much more to the air, most of which ends up in the water. But just twelve pounds of mercury is enough to contaminate four million pounds of fish to a level that would trigger a fish consumption warning (0.3 mg mercury/kg fish tissue). The daily release of mercury that accounts for 12 lbs/year is about 15 g. To assure acceptable levels of mercury in the river, the release levels would have to be considerably less than 15 g/day. Even one gram per day puts 200,000 lbs of fish tissue at risk annually. Then consider trying to use and manipulate 10 tons of mercury every day while trying to limit the release to less than one gram. That is like trying to prevent any of the dirt on a city bus from washing off into the street in a torrent during rush hour.

Unfortunately, the physical properties of mercury aggravate the problem. Elemental mercury is a liquid at room temperature. That property makes it useful in the chlor-alkali process, but liquid mercury also has a significant vapor pressure at room temperature causing hundreds of grams per day to evaporate, hence the need for an air permit. In fact, the air permit at 5 lbs/day (see below) is much greater than the waste water permit (0.1 lb/day) which itself is too high to adequately protect the river. While elemental mercury (Hgo) is less toxic than reactive mercury (Hg2+), which, in turn, is somewhat less toxic than methylmercury (CH3Hg+), the less toxic forms of mercury are readily converted to the more toxic forms in the environment. Methylmercury is a potent neurotoxin.

Significant portions of the mercury released from the Olin plant are converted to methylmercury in the environment. Methylmercury bioaccumulates up the aquatic food chain reaching toxic concentrations in larger fish and animals that feed on fish. The EPA has calculated an accumulation factor (water column to bass tissue) in the Savannah River of 4,000,000, i.e. methylmercury is 4 million times more concentrated in the fish tissue than in the water column. After December 19, 2006, the Olin Air Permit will be based on chlorine production (69 mg/ton of chlorine). Thus, the standard is based on a production standard, not on an environmental standard, theoretically allowing Olin to expand its chlorine production and its mercury pollution indefinitely without violating the standard. Environmental protection standards must be based on limits that are calculated to protect the environment. Additionally, the amount of chlorine produced by Olin is considered privileged information and is not available to the public, thus making it impossible for the public to determine if the permit has been violated. The second part of the air permit requires only monitoring and washing down of the cell room periodically. No limit is placed on the emissions from that area of the plant. The permit can be found here.

Studies of sediment mercury concentrations, done by Lauren Smith for her Davidson School of Fine Arts Science Fair Project with the help of the Savannah Riverkeeper and the Savannah River Ecology Laboratory, showed that the mean sediment dry weight concentration of mercury upstream of Olin was 24 ppb, downstream of Olin was 47 ppb, and in the Olin outfall channel was 62,000 ppb. (See Augusta Chronicle). 500 ppb is considered by the National Oceanic and Atmospheric Administration (NOAA) to be lethal to macroinvertebrates in sediments. An Olin contracted study confirmed Ms Smith’s results. These numbers require clean up under the Resource Conservation and Recovery Act (superfund). The Georgia Environmental Protection Division has ordered a clean up. Olin has proposed a clean up method, but it has been sent back by EPD for rework. The Riverkeeper has commented on Olin’s proposal. Biochemically, both ionic (reactive) mercury and methylmercury bind very strongly to organic sulfides in the body. This binding accounts both for bioaccumulation (it slows the excretion of the mercury by binding it) and the toxicity (the mercury binds strongly to organic sulfides that are intimately involved in protein function thus inhibiting that function. There are over 600,000 births in the US annually to women whose fetuses have mercury levels above the threshold for toxicity. In Georgia one in seven births are at risk for mercury toxicity. One of the most sensitive developmental problems affected by mercury toxicity is intelligence. IQ of the child can be affected by maternal mercury concentrations, and unfortunately, damage to the developing nervous system is generally permanent. While mercury has other effects on the developing nervous system (behavioral effects and motor skill development), the costs of just the IQ effects to society have been calculated at $8.7 billion annually (see here). Riverkeeper studies of fish in the river downstream from Olin indicate that 55% of the catfish and 62% of the bass caught randomly (no screening for size other than the legal size) had concentrations of mercury that would trigger a fish consumption warning, i.e. not more than one meal per week.

The conclusion is that mercury is just too difficult to control and should not be used in the biosphere unless absolutely necessary. Hospitals have discontinued the use of mercury for that reason. Mercury switches are being phased out of cars and coal-fired power plants are installing scrubbers to reduce mercury emissions. Olin can do their part and convert to mercury-free technology.