Geochemical summary statistics for 18 elements in natural mateiials horn 117 landscape units have been compiled based on field and laboratory studies since 1958. Each landscape unit is brie f ly identified as to kind and location, and the expected concentration for one or more elements is gi\en together with factors indicating the degree of observed \ariation in the stuch and the degree of laboratory or "analytical" variation. Also listed are the observed lange and the total number of element analyses made in each study. The data on which these summaries are based have three attributes in common: They represent "large-scale" 01 legional geochemical studies; they represent background or "oidinary" natural geochemical \ariation; and they were collected according to objective sampling designs. The summaries clearly demonstrate the wide diveisity to be expected in elemental properties of landscape units and suggest that published element abundances for bioacl categoiies like1 "soil" or "carbonate rock" may be misleading. Fl F2 STATISTICAL STUDIES IN FIELD GEOCHEMISTRY One such study merits special mention. The U.S. Geological Survey has recently completed a geochemical survey of the State of Missouri, many aspects of which are unique to environmental geochemistry. It not only is a survey of a broad, geologically diverse area, but it was undertaken partly in support of active, trace-element related epidemiologic studies sponsored by the University of Missouri. Moreover, we think it is the first study of its kind in which an attempt has been made to characterize rocks, waters, soils, and plants chemically by a unified team approach using (and in part testing) efficient and objective sampling designs. Connor and others (1972) described this work in a preliminary way. Details of the study are available in a series of limited-distribution progress reports (U.S. Geological Survey, 1972a-f, 1973). The data tabulated in the present report represent the work of many people. Principal investigators are listed with a short description of each study, and authorship is cited for all published data. All unpublished data are preliminary. The reader is cautioned that some of the data summaries given here may be subject to minor revision. The sampling designs, data analyses, and geochemical summaries on which this report is based are statistical in nature; extended discussions of these subjects can be found in Miesch (1967a, b, 1972), Connor and others (1972), and Connor and Myers (1973). A proper list of acknowledgments for this report would comprise more than 100 people including computer programmers, specialists in data handling, and assistants in the field, laboratory, and office. Unquestionably, the most important contributors are the chemists, spectrographers, and other laboratory personnel who catalogued, prepared, and measured the concentrations of up to 69 elements in more than 8,000 samples of rocks, soils, and plant material over a period of more than 10 years.

As part of the special interest series, Public Issues in Earth Science, published by the U.S. Geological Survey (USGS), this Circular describes the importance of the earth sciences in the investigation of environmental problems. The report focuses on geochemistry-the study of the amounts, distribution, and cycling of chemical elements in the Earth and atmosphere-and how this science helps to evaluate critical issues that relate to our fragile environment. The mission of the USGS is to provide geologic, topographic, and hydrologic information that contributes to the wise management of the Nation's natural resources and promotes the health, safety, and well-being of our people. Part of this task includes characterizing the Nation's geochemical environment and understanding the dynamic processes responsible for change in that environment. One of our greatest assets at the USGS is our long tradition of excellence in unbiased earthscience research. Part of that legacy is our commitment to supply the geochemical information necessary to confront urgent environmental challenges. Geochemistry provides information on the distribution of chemical elements to help us define and understand environmental problems. This information then allows us to provide answers for their resolution and possible remediation. This Circular presents an overview of geochemistry and its application to various case studies that illustrate the use of geochemistry in examining environmental problems. Some new and exciting areas of environmental geochemistry are discussed, involving r(.)ck/water, soil / water, and plant/ soil investigations. These investigations focus on many of our natural resources including minerals, soil, water, air, and vegetation and examine environmental concerns-such as acid precipitation, mine drainage, and sources of contamination-from a "systems" or "holistic" approach. As the primary Federal earth-science agency, the USGS leads in the collection, interpretation, and dissemination of earth-science information. This report helps to define one area in which the USGS is an active participant-the application of geochemistry to environmental concerns.

Natural variation in the total elemental composition of the plow zone (approximately 6 in. (15 em) in deptp) of soils in Missouri has been examined using a five-level hierarchical analysis-of-variance design. This study is an initial investigation of the chemical variation in the soils and can serve as a basis for planning future intensive sampling. The design includes three levels (Suborders, Subgroups, and Series) of the Soil Taxonomy developed by the National Cooperative Soil Survey and permits an objective evaluation of the geochemical properties of the taxonomic system. Components of geochemical variance for 31 elements were estimated for differences between soil Suborders, between soil Subgroups, and between soil Series. Significant differences in composition between Suborders were found for 23 elements, including the trace metals arsenic, barium, chromium, copper, gallium, lanthanum, lead, scandium, selenium, strontium, vanadium, ytterbium, and zinc. Such differences, however, account for no more than 45 and commonly less than 35 percent of the natural variation (excluding analytical effects) of any element. Maps based on the distribution of Suborders, therefore, would not be particularly useful in interpretation of geochemical characteristics. Variation between soil Series is, for the most part, much larger than variation within a given Series. Only cobalt, nickel, lead, and zirconium were found to have variation within Series larger than that between Series. Thus, maps based on the distribution of Series might serve as fairly good geochemical maps for most elements.

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P re m atu re d ea th am ong hum an s in the state of M issouri ap p ears to have little relatio n to the com position of soils in the vicinity of th e ir usual residency. O u r conclusion contrasts w ith a considerable p a rt of th e literatu re, which implies th a t soil is a factor affecting h u m a n health. T h e difference may arise eith er because people living in a given env iro n m en t may not expose them selves in such a way as to be affected by the soil o r because o th e r im p o rta n t factors may overshadow th e effect of soils.O th e r studies have suggested a correlation betw een th e incidence of eith er h u m a n disease o r h u m a n m ortality an d soil characteristics. Most correlations have b een of th e simple bivariate type. T h e o p p o rtu n ity for a m ultivariate study has arisen only with the availability of chem ical d ata on soils an d m ortality rates of h u m an s from a com m on area.T h e distribution of elem ents in M issouri soils exhibits some regional p attern , b u t m ortality distribution p attern s are not regionally distinct. T h erefo re, stepwise m ultiple regression is used to d efin e possible subtle relationships. T his m ultivariate search tool identifies w hich of the 32 elem ents m easured in 1,140 soil sam ples collected th ro u g h o u t M issouri best relate to h u m a n m ortality risk. D ifferences in age, sex, an d race are closely associated with m ortality risk; adju stm en ts for these factors have been m ade by d irect m ethods. T h e re is a possibility th a t o th e r