Great Lakes Binational Toxics Strategy

Draft Report and Findings on U.S. Challenges

Preliminary Findings with Respect to the OCS Challenge

INTRODUCTION

The Great Lakes Binational Toxics Strategy sets forth "challenges" for persistent, toxic, and bioaccumulative substances, within a ten-year timeframe, on the path toward their virtual elimination. The United States challenge for octachlorostyrene is:

By the end of 1998, confirm that there is no longer use or current release from sources that enter the Great Lakes Basin of the industrial byproduct/contaminant octachlorostyrene (OCS).

The U.S. Environmental Protection Agency has commissioned a report, "Great Lakes Binational Toxics Strategy Octachlorostyrene (OCS) report: a review of potential sources." This draft report assembles information on OCS levels in the environment, pertinent environmental regulations, and past, present, probable, and possible sources of OCS. Based on this report and on underpinning scientific literature, the following preliminary findings are drawn.

PRELIMINARY FINDINGS

Based on available information, it is reasonably likely that there are current releases of OCS within the United States, which contribute OCS to the Great Lakes watershed. OCS has never been deliberately produced as a commercial product and its release is essentially unmonitored. Yet, there is a considerable body of scientific literature suggesting past, current, probable, or possible sources of OCS, and conditions under which it forms. At the same time, it is welcome to note that the limited temporal data on environmental levels of OCS suggest that it has substantially declined during the past three decades, at least in the component of the Great Lakes for which there is historical perspective (Lake Ontario).

DISCUSSION

Polychlorinated styrenes are a class of polychlorinated hydrocarbons, containing carbon and varying numbers of hydrogen and chlorine atoms. OCS has the most chlorine atoms, eight. It has never been deliberately produced as a commercial product and its release is essentially unregulated. OCS was first noted in birds from the River Rhine in Germany sampled during 1966 and identified in 1973.

Subsequently, OCS was reported in Great Lakes fish, birds, and sediments. Locally elevated levels were found near petrochemical factories in Ashtabula, Ohio; Sarnia, Ontario; and Niagara Falls, New York. Though higher in Lake Ontario, OCS was also found in Lake Superior fish.

Outside the Great Lakes region, OCS was found in fish obtained during 1986-89 near Seattle, WA; Jamaica Bay, NY; and Corpus Christi, TX. With compounds such as HCB and polychlorinated napthalenes, OCS was reported in the Calcasieu River, LA. Lesser chlorinated styrenes, HCB, and hexachlorobutadiene are often found with OCS. Beyond the United States, OCS has also been reported in many studies around the North Sea, in such countries as Germany, Norway, and the Netherlands.

Little is known about the physical-chemical properties of OCS, which would help predict its fate within the environment. There are locations where OCS levels have been found to be higher than HCB levels, yet other relatively pristine locations where HCB is higher, lending some support to the hypothesis that polychlorinated styrenes primarily have a local, as opposed to widespread, environmental fate. Human body burdens of OCS have been found to be highest on a local scale, near to sources. In Canada, sampling of human milk found OCS only in the Province of Ontario.

There is not much information that indicates temporal trends in the abundance of OCS in the environment. An exception is a 1984 study of dated sediment cores from Lake Ontario, which found the onset of OCS to be the late 1940s, rising to a peak about 1960, followed by a substantial (90%) decline by 1980. It has been suggested that this reduction may result from adoption of metallic electrodes by chlor-alkali factories, which once formed OCS and other polychlorinated hydrocarbons when factories employed graphite electrodes with coal tar pitch binder. Another possible explanation is that lower OCS levels in Lake Ontario are related to reduced production of chlorinated benzenes in Niagara Falls, NY. A second temporal study, from Norway, found a substantial decline in OCS by the late 1970s near a magnesium factory, presumably after a process change reduced or eliminated its formation.

In general, within the United States and other nations, potential sources do not monitor their releases of OCS. Yet during the past 25 years, numerous scientific studies have concluded or hypothesized that a wide range of activities generate OCS, among them: chlorinated solvent production; production of chlorine using graphite electrodes; semiconductor manufacturing; production of aluminum, magnesium, synthetic graphite, and fire retardant; and waste incineration. Many of these studies are cited in the draft "Review of Potential OCS Sources", November 1998, provided at this web site. This paper also suggests that OCS may be formed during processes which generate other polychlorinated hydrocarbons, such as HCB and chlorinated dibenzo-dioxins. Thus, even where there are no directly relevant studies on releases by some sector, the paper estimates OCS emissions on the basis of EPA’s emission inventories for HCB and dioxins.

It should be noted that production technologies both change over time and vary widely between factories. Thus if OCS is found near one, it is not necessarily generated at all others within a given industrial sector. With that proviso, it still seems reasonably likely, owing to the wide number of processes potentially or strongly linked to formation of OCS, that OCS is currently generated within the Great Lakes watershed and within the United States.

Given this likelihood, we consider that there is a continuing need to pursue the four-step analytic process for OCS set forth under the Binational Toxics Strategy. Examples of recommended activities and information needs that would support this process include continued assessment of potential sources, consideration of reduction methods if current sources are identified, and evaluation of environmental progress.

COMMENTS WELCOME

Please provide comments on the draft OCS report and/or this preliminary findings statement. These may be sent to Frank Anscombe:

• via email to "anscombe.frank@epa.gov"
• by fax to (312) 353-2018
• or in writing to:

Frank Anscombe
U.S. EPA
77 W. Jackson Blvd. (G-17J)
Chicago, IL, 60604

Comments are requested by March 1, 1999.