Recently, the public was alerted to the expansiveness and uniqueness of the Qeat Lakes of North America, and told of extensive efforts to analyze past and current trends, all with an eye toward predicting future development (€SAT, September 1975, p 924). Those efforts have come not a moment too soon, since not too many years ago, one of these five magnificent lakes, Lake Erie, was proclaimed dead by the popular press. Even certain well-informed scientists, perhaps caught up in the excitement of Earth Day-1970, were willing to concede that Lake Erie’s days were numbered. In time, however, the urgency of that first Earth Day and its attendant publicity subsided, leaving the solution of environmental concerns to the long-term march of social and political history, coupled with natural and anthropogenic geochemical processes. Fortunately for the Great Lakes, however, scientific interest did not wane with the passing of the initial Earth Day. Lake Ontario, for example, was the scene of an intensive field year investigation in 1972 (International Field Year for the Great Lakes-IFYGL), with Canadian and U S . efforts joined in multidisciplinary activities. Thus, Lake Ontario can now be reasonably well evaluated on the basis of fact rather than on uninformed speculation. Perhaps similar approaches to the other Great Lakes will follow in time as research funds and scientific interests allow. With a view toward assessing current chemical research activity in the Great Lakes Basin, the 10th Great Lakes Regional Meeting of the American Chemical Society (ACS) sponsored an invited symposium that addressed various aspects of the theme Chemistry of the Great Lakes. The campus of Northwestern University located along the shoreline of Lake Michigan in Evanston, Ill., was an appropriate setting for this symposium. Attendees were offered a broad-based program that addressed a number of issues of current interest in the Great Lakes region. The rationale for this symposium was an interest to gather together environmental information produced by chemists and discussed within the context of an ACS meeting. Most conferences dealing with Great Lakes or general limnological topics are organized by scientists with primary interests other than chemistry, thus hindering the efforts of environmental chemists in informing other chemists about their research. Of additional concern was the knowledge that almost 70 areas within the five 986
Environmental Science 8 Technology
What the pollutants are and where they go is what an ACS Regional Meeting discussed
Joseph J. Delfino Laboratory of Hygiene University of Wisconsin Madison, Wis. 53706
Great Lakes still fail to meet the objectives defined by the 1972 Canadian-US. Water Quality Agreement. Many of these areas of poor chemical water quality, as determined by the International Joint Commission (IJC), can be directly attributed to specific discharges of effluents containing various chemical components. Other areas show symptoms of more generalized problems such as non-point source runoff and contributions from atmospheric precipitation and fallout. Yet another example of one of the most urgent problems is one that is least visible to the public-the contamination of sport and commercially important species of fish with potentially toxic chemicals such as PCBs and other chlorinated organic compounds. A plea was made to those developing data on the Great Lakes to ensure that reports of their studies be widely disseminated to the scientific community. There are now many groups studying the Great Lakes, ranging from universities and governmental agencies (state and federal) to corporations that perform work themselves, or through contracts with consulting firms. Many
times, these groups produce data that overlap the work of others; this is an expensive duplication of effort that cannot continue indefinitely. Perhaps this duplication has developed because of the inability of the private and public sectors to coordinate their efforts, caused to a certain degree by the adversary climate now inherent in environmental matters. An ideal situation would be the founding of a clearinghouse of Great Lakes research and monitoring activities that would act as a neutral, objective cataloger and disseminator of information, yet be free from institutional or regulatory conflicts of interests. Watershed studies Interest in watershed-wide studies in the Great Lakes region has been stimulated recently by the Pollution from Land Use Activity Reference Group of the IJC (PLUARG). These studies are underway pursuant to part of the 1972 Water Quality Agreement. Actual field studies were initiated in 1974, with a final report due in 1978. One of the watersheds selected in the U.S. is the Menomonee River watershed, which includes much of the Greater Milwaukee, Wis., area. John Konrad of the Wisconsin Department of Natural Resources, outlined the study's objectives: to determine the types and quantities of potential pollutants moving within the watershed and ultimately reaching Lake Michigan to identify the sources and characteristics of pollutants entering Lake Michian as a function of various land usages to develop models that can extrapolate the findings from this pilot watershed to other urban watersheds. Konrad illustrated the variety of land uses within this selected watershed, which encompasses urban, suburban, rural, and agricultural, as well as heavy industrial activity. In order to document the incremental effects of these activities on various reaches of the Menomonee River, a number of sampling stations, including some with continuous sampling devices, have been established. To date, over one year's data have been gathered. One feature of this pilot study is the use of remote sensing and aerial photography to categorize land-use activities. According to Konrad, the goal is to couple water-quality observations with land-use data files compiled by computer-based techniques.
Additional activities include the use of remote sensing to follow runoff-generated plumes directly into Lake Michigan, with satellite, airplane, and shipboard measurements being gathered simultaneously. Within the scope of this PLUARG-sponsored project are a number of individual research projects being performed by different universities in Wisconsin. One of these projects involves investigating the sources, transport, and fate of sterols in the Menomonee River. This work is being conducted by University of Wisconsin-Madison researchers John Hassett and Marc Anderson. Hassett said that two non-polar sterols were selected for study-coprostanol and cholesterol. He indicated that each of these substances have some common sources, as well as different points of origin. For example, within the Menomonee River watershed, coprostanol coulcl originate in sewage, manure, and feedlot runoff; whereas cholesterol could be found in the same sources, as well as dairy waste discharges, excretion from higher plants and algae, and similar materials. The sterols were identified by gas chromatography following various clean-up steps. Hassett found the concentration of coprostanol during the past year to range 1.O-8.0 pgll in the Menomonee River. Three sewage treatment plant effluents enter the stretch of the Menomonee River selected for study by Hassett and Anderson. They are calculating sterol concentrations on the basis of flow dilution of sewage in an attempt to determine that the sole source of coprostanol in the river is from sewage treatment plants. Based on the initial studies, it seems clear that the three sewage plants are the sole sources of coprostanol in the river. In addition to gas chromatographic methods, Hassett has Seen using gel permeation columns to look for the distribution of sterols in various molecular weight fractions. Preliminary indications are that cholesterol, for example, is associated with the high molecular weight fractions of the column eluates. One of the more puzzling aspects of the data on hand is that the sterols may be incorporated with the dissolved organics in the river; yet they follow a behavioral pattern closely tied to the particulate material. Hassett explained that he would like to utilize coprostanol as a tracer for the sewage treatment plant effluents in an effort to delineate the relative contribution of sewage effluents to river flow. Volume 10, Number 10, October 1976
987
Atmospheric study aims to determine the quantities of material entering the Great Lakes from the atmosphere to identify the probable sources(s) of these materials to develop models that can forecast future loadings on the lakes.
One of the scientists involved in studying atmospheric loadings to the Great Lakes is James Kramer, of McMaster University. Kramer told the symposium about an extensive project that involved an assessment of atmospheric loadings on the upper Great Lakes (Lakes Superior and Huron). This study involved a number of different agencies, consulting firms, and US. and Canadian state, provincial, and federal agencies. There were two amroaches taken bv this arouD. One was to develop a model reiying on puol shed dati for scavenging coefficients, emission inventories. and meteorological information. all independent of the field measurements. The second tack utilized direct field measurements run independently. with compar'sons made with the model calculations at the end of the study. Kramer discussed the various parameters used in the study's enaineerina mass-balance techniaue. which looked at chemical data in b o k the atmosphere and water regimes. There were some striking differencesbetween the two: for example, the pH of rainfall averages between 3 and 5, whereas the average pH of the lakes was between 7 and 8. Rainfall DossesSes essentially no buffering alkalinity, whereas the average alkalinity of the I&& is about 2 meali. In discussing potential sources of atmospheric pollutants, Kramer noted that materials carried to the Great Lakes could originate from distances 500 to 1000 km away. The literature data, including emission sources, used in the modeling efforts involved a 1000 km radius from the upper Great Lakes. This included regions ranging from the Province of Manitoba to Cincinnati and St. Louis in the U S . in extrapolating the findings in terms of ambient air-quality standards, Kramer estimated that rural regions could face the Drobiem of air-quality violations before the end of the century if funher controls are not implemented. Commenting on the loading of inland lakes, he preaicted that certain of the smaller lakes were prObaDly oeing too heavily loaded from the atmosphere at the present time (corroboratingevidence from other research projects 'n the northeastern US.). whereas the Great Lakes themselves were sti,l a long way from oeing excessively loaded via the atmospheric route. The approach to the upper Great Lakes as described by Kramer has analogs in studies being performed in the Lake Michigan Basin. Presenting data on behalf of his research group at the University of Wisconsin-Madison, Anders Andren discussed recent computations which indicate that aluminum, cadmium, copper, iron, lead, titanium, vanadium, and zinc have equal or greater atmospheric loadings to Lake Michigan, as compared with tributary contributions. Andren addressed the problem of differentiating between wet and dry deposition and pointed out that measurement techniques for assessing dry deposition are still in the developmental stage. it was also disclosed that there has been a paucity of aerosol measurements in mid-lake areas. Most Lake Michigan atmospheric data have been accumulated from shoreline or coastal sampling stations. Andren and his colleagues are also involved in mass balance investigations. Results to date verify that atmospheric aerosols ~~
988
Environmental Science 8 Technology
Sampler. Its data help to shed more light on the Great Lakes' changing chemical make-up are important considerations in the attempt to understand the total elemental loading to Lake Michigan. When looking for the sources of the material in tne atmosphere that eventually enter the lake. Andren determined that dust from terresnial soils could account for about 18% of tne atmospheric paniculates. Sulfates and organic carbon together represent about 24-30% of the atmospheric loadings, while automobile exhausts, normally a significant factor in atmospheric chemistry in the U.S., perhaps generate only about 3% of the atmospheric material found in the study. Another proponent of atmosiiheric research in the Lake Michigan Basin is Thomas Murphy of De Paul University. He has ...,b"..". .^ ".A .,.,,A.,.*:""+.A pY,ln lllsIITu been following the quantities of pt,YDIJIIYIYD biphenyls (PCBsJentering Lake Michigan in recent years. Murphy has focused on preciptation inputs so far while leaving the measurement of dry deposition parameters to other investigators. In amplifying the importance of atmospheric studies, Murphy pointed out that about 50% of the water entering Lake Michigan arrives via the atmosphere. Murphy discussed his recent measurements of PCEs in atmospheric precipitation. He reviewed current data, which showed the anomalous behavior of PCEs when compared with DDT and its analogs. The use of DDT has been curtailed in the US.,and its concentration in Lake Michigan fish has shown a gradual decline since 1970. The use of PCEs in 'open" systems has likewise been restricted. bur such decrease in Concentration in fish has yet to oe seen. Part of the difficulty in making accurate estimates of chlorinated hydrocarbon concentrations is tied directly to limitations in analytical methodology. Further cornp icating the issue is the large number of potential PGE isomers that are possible, and the fact that most commercial PCB preparations contain mixtures of many isomers. In an attempt to filter out some of these difficulties, Murphy was willing to make some approximations based on the data at hand. He emphasized that his results did not include the dry deposition component, but, accordingto precipitation sampling, he estimated that about 650 kg of PCEs enter Lake Michigan annually from the atmosphere. In discussing previous reports of the possible tranformation of DDT and its analogs to PCE-like compounds, Murphy related that he was unable to demonstrate such a phenomenon during a variety of laboratory experiments. Aquatic studies The atmospheric chemical research activities mentioned above represent a relatively new endeavor for environmental scientists. In contrast, there has been a considerable amount
of research performed in a more traditional area of water research; i.e., studying what is in a lake proper rather than measuring what is impinging on its surface. One symposium participant, Jerome Nriagu of the Canada Centre for Inland Waters (this issue, p 1061), bridged this interface by looking at both the inputs to certain of the Great Lakes as well as transformations within the lakes themselves. Nriagu has been interested in the sulfur cycle in lakes for some time. He discussed research done in the Lake Erie and Lake Ontario basins. One of the interesting aspects of Nriagu’s studies was the use of a powerful analytical tool-applying the ratios of natural isotopic abundances of sulfur to geochemical processes. By looking at the ratio of 34Sto 32S,he and R. D. Coker were able to study the biogeochemical partitioning of sulfur in the lake basins. Nriagu postulated historical baseline sulfate concentration of 6-7 mg/l while present levels range between 17-23 mg/l. Nriagu’s isotopic studies confirm that approximately 60-70% of the sulfur in Lake Erie water originates from pollutional sources. In Lake Erie, the general trend of water movement is from west to east and the sulfate concentrations show a decided increase in that direction, most likely because of pollution inputs along that survey route. The macro-contaminants such as sulfur, studied by Nriagu, stand in stark contrast with a relatively new area of Great Lakes research. This is the concern over micro-contaminants such as trace levels of chlorinated organic chemicals and heavy metals. The concentrations of such substances in the open waters of some of the Great Lakes are generally below the analytical detection limits of most commonly used techniques. However, through the process of bio-concentration, easily detectable amounts of these chemicals can be found in Great Lakes fish. The fact that many desirable species of fish in Lake Michigan exceed the Food and Drug Administration’s limit (5 ppm or pg/g) for PCBs in commercial sales illustrates the importance of looking into the sources, transport, and fate of these so-called micro-contaminants. David Armstrong and his research group at the University of Wisconsin-Madison have been investigating various aspects of the micro-contaminant problem. In recounting what Murphy had described about the apparent stability of PCBs in the Lake Michigan ecosystem, Armstrong identified the possible processes that control the removal of PCBs from lakes: discharge in water leaving the lake deposition into the sediments biodegradation fish harvesting. It was pointed out that very little data exist to document these processes, but based on some initial measurements, some estimates can be made. For example, Armstrong figures that some 152 000 kg of PCBs are present in Lake Michigan water, based on an average concentration of 32 kg/m3. He estimated that at least 60% of the PCBs are present in the particulate fraction. As part of an attempt to compute a mass balance for PCBs, Armstrong utilized literature data in conjunction with his data and tentatively suggested that the PCB settling rate to the sediments was 20-40 pg/m2/yr. The nature of organic matter in natural waters has intrigued aquatic scientists for many years. Significant progress has been made and is continuing to occur as advances in instrumentation and experimental design appear each year. Of considerable ecological significance are the synthetic organics that are appearing in larger numbers and in increasing concentration. It is this class of compounds that interests regulatory agency scientists, particularly those in the EPA. The work of four chemists at EPA’s Environmental Research Laboratory in Duluth, Minn., was presented at the symposium by Gary Glass.
In discussing a number of hazardous or potentially hazardous synthetic organic compounds extracted from Great Lakes fish, Glass first covered the exacting analytical requirementsthat are needed in such research. The Duluth scientists have a sophisticated gas chromatographic-mass spectrometric (GC-MS) system that combines commercially available instrumentation with in-house adaptations. It emphasizes computer-driven automation and data-retrieval systems. But even this extensive hardware is of little value unless the samples are cleaned-up properly, prior to being introduced to the GC-MS system. While that is an obvious precaution in work of this type, Glass explained that some of the compounds being isolated and identified are present at low enough levels to make concern for contamination a primary issue. One of the more intense environmental issues in the early 1970’s concerned the potential impact of heated power-plant effluent on the process of eutrophication.Lacking a suitable data base, scientists nonetheless argued the issue for some time. Now, evidence is at hand to show that some natural lake processes can influence aquatic algal productivity as much as anthropogenic influences can. The relationship between thermal effluents and nutrients in causing changes in phytoplankton productivity under upwelling and non-upwelling conditions in Lake Michigan was addressed by Elsa Yaguchi of the Argonne National Laboratory. Yaguchi told the meeting that natural fluctuations in temperature and nutrient availability could affect the response of phytoplankton to waste heat discharged by a power plant. She selected a power plant site on the southwestern shoreline of Lake Michigan to perform her experiments. This area is known to experience periodic upwelling conditions (upwelling is the ascending motion of subsurface water, carrying higher nutrient concentrations and lower temperatures in coastal regions). In summarizing her findings, Yaguchi recountedthat upwelling conditions had prevailed for about onethird of the 1975 summer season in the study area of southwestern Lake Michigan. Substantial differences in physical, chemical, and biological parameters were measured when upwelling and non-upwelling conditions were compared. During upwelling: Water temperature, primary productivity, phytoplankton specific growth rate and assimilation ratios were lower. Phytoplankton diversity, cell number, and concentrations of chlorophyll a, carotenoids, phaeo-pigments, amorphous silica, reactive silicate, and ammonia were greater than in non-upwelling periods.
What was found in Lake Michigan diameter lese
Source:Andren and coworkers
Volume 10, Number 10, October 1976
989
Micro-contaminants in fish Fish samples subjected to extensive scrutlny were
0
naphthalene trichlorobenzene DDT and analogs phenanthrene hexachlorobenzene
0
0
chloroblphenyls dlbutylphthalate chlordane toxaphene components
Only minor differences were attributable to the thermal discharge of the power plant, including increased temperature and amorphous silica concentration in the plume. Yaguchi observed that productivity quotients in the plume were increased over those in the control area only during upwelling. As a result, nutrient limitation was implicated as an important factor when assessing the response of phytoplankton to locally increased temperature. She concluded that there are many potential sources of variation, including physical, thermal, and chemical nutrient factors that could either mask or nullify some of the possible effects of a thermal discharge located in an upwelling region in Lake Michigan. Sediment studies To the casual observer of the Great Lakes environment, the sediments of the lakes might best be described as “out of sight-out of mind.” After all, the lakes are deep, with Lake Michigan, for example, having a depth maximum of more than 900 ft. Some scientists are not deterred by this, as the results of presentations to the symposium illustrate. Morris Wahlgren of the Argonne National Laboratory graphically illustrated the importance of studying lake sediments; in this case Lake Michigan. The sediments contain an excellent record of the cultural usage of certain heavy metals and thus, the art of reading the structure of lake sediments has now evolved into a sophisticated science. Wahlgren, presenting material co-authored by David Edgington and John Robbins, reviewed the work that established trace metal inputs to Lake Michigan via tributaries and also commented on estimated loadings of lead to Lake Michigan during the period 1840-1976. He stated that the rate of sedimentation in Lake Michigan was relatively consistent from year to year, but there was evidence of unequal distributions of cesium in the sediments. Thus, 137Cs was selected as a time marker. Among the inter-relationships investigated were those involving 137Cs,210Pb(lead), and 239Pu(plutonium), as well as stable lead. Wahlgren and his co-workers found that the correlation of Cs and Pu deposition to the Lake Michigan sediments was very high, even though the two elements demonstrate dissimilar chemical behavior and food chain activity. Of interest were a series of continuities and discontinuities in 210Pbprofiles. The aperiodic occurrences of the 210Pbdiscontinuities appar990
Environmental Science & Technology
ently were reflections of major storm events in the lake and could be found along a transect across the lake’s basin. Results of I3’Cs studies involving in situ sediment traps verified the existence of an annual resuspension of the surface sediments of the lake. Since the top layer of the sediments is generally flocculant in nature, it is not too difficult for resuspension to occur in response to physical stresses. Wahlgren produced further evidence of this based on Pu concentration data. Plutonium seems to be stored in the upper sediment layers and appears to exist in a state of dynamic equilibrium, going through an annual process of resuspension and sedimentation. This process of resuspension is all but proven now, because the input of these radioisotopeshas greatly decreased; yet they show persistent recycling within Lake Michigan each year. Wahlgren stated that in 1972, the anthropogenic lead flux into the southern basin of Lake Michigan was 1.3 pg/cm2/yr, whereas the natural flux was about 0.16 lg/cm2/yr. He also showed that the resuspension phenomenon occurred in water depths down to at least 70 m. John Robbins of the University of Michigan reported on his research into the role that sediments play in supplying silica to overlying lake waters. Robbins has studied silica in Lake Michigan and Huron sediment cores, and has developed silica balance models for the two lakes. His research area is important in understanding the productivity of these two lakes, since there is concern that silica depletion could alter the diatom communities and eventually lead to the emergence of less desirable genera of algae as the dominant flora of the lakes. Two additional papers were presented at the symposium on topics related to Great Lakes chemistry but with a more general application to the field of natural water chemistry. Michael Crosser and Herb Allen of the Illinois Institute of Technology discussed research on metal-organic complexes. While they haven’t done extensive work within the Great Lakes Basin yet, they plan to apply their ion-exchange equilibration technique to these waters, looking for trace metal-ligand associations that might exist. Mark Carter of the EPA’s Central Regional Laboratory in Chicago discussed the results of analytical studies concerned with the preservation and analysis of many water analysis parameters. Carter and co-workers feel that the increased emphasis on Great Lakes research will generate a considerable amount of data, and they are working toward ensuring the quality of the data. Certain preservation techniques were shown to be inadequate, and Carter discussed how to study such phenomena under the great variety of environmental conditions encountered by water analysts. Where they agreed When the symposium ended, the attendees found that they could agree on at least two main points, despite some very tentative conclusions drawn from some of the field work: The Great Lakes are still very much alive, in spite of abuse at the hands of mankind. Chemical research in the Great Lakes Basin is very productive and looks forward to a promising future. Joseph J. Delfino holds a joint appointment at the University of WisconsinMadison. He is associate professor in the Water Chemistry Program and is also Chief, Environmental Sciences Section at the Wisconsin Laboratory of Hygiene. Dr. Delfino organized the symposium that served as the basis of this article. Coordinated by JJ
