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Silty soil materials were deposited as loess on the surfaces of two sandstone ridgetops during the Wisconsin Glacial period (10,000 to 20,000 years B.P.). Between A.D. 900 and 1450, Mississippian Indians occupied the Millstone Bluff summit site near Dixon Springs, Illinois, and built huts with floor

The Twenhafel Mound, a Middle Mississippian burial mound in Jackson County, Illinois, was most likely built between A.D. 500 and A.D. 900. The existence of the mound has been known since the French settled in the nearby town of Cahokia in 1699. Since the time of European settlement, the mound has not been legally protected from treasure hunters. The land was privately purchased and settled in the 1850s. Many similar and adjacent mounds were excavated in a search for treasure or artifacts, leveled for farming, or hauled away. The primary objectives of this research are to determine the extent and time of mixing by excavation and/or tillage, the source of the mound materials, and the rate of diagnostic soil horizon formation. Fly ash was used as a time indicator. The depth of fly ash in the soil on the summit of the mound is consistent with the soil being tilled and mixed to a 40-cm depth. The sideslope of the mound has a similar significant depth of occurrence but has a higher amount of fly ash in the surface layer, suggesting that some tillage translocation and erosion of the summit soil has resulted in deposition on the sideslope. The soil developed in the alluvial fan adjacent to the mound has a similar texture and supports the theory that the mound was constructed from soil materials obtained from this alluvial fan rather than the theory that earth was carried from the adjacent bluffs formed in loess. Radiocarbon analysis of charcoal and organic matter found in the 80 to 130-cm layer suggests that 99% of the carbon is modern (

About 1000 years ago, Mississippian Indians built what are now designated Mounds 69 and 70 at Cahokia near Collinsville, Illinois. Loamy soil materials were placed on the mounds by Mississippian Indians before A.D. 1100, and the site was inhabited until approximately A.D. 1300. The general objective of this study was to determine the potential of using archaeological mounds or sites to obtain information on soil development and erosion processes. Our specific objectives were to determine: (i) the extent of soil formation during the past 900 years, (ii) the time period and extent of disturbance by human activities, including tillage and digging by treasure hunters and looters, and (iii) the erosion phase of soils on mound sideslopes and the amount of soil loss from accelerated erosion. The vegetation and distribution of organic C in soil profiles suggests there has been no tillage since the 1970s and little soil erosion of either the summit or the sideslope of Mound 69. The adjacent alluvial plain is still being cultivated. Fly ash, particulate matter resulting from high-temperature coal combustion, was used as a time marker in soil and sediment. Fly-ash distributions in the upper 20 cm of Mound 69 support the theory that cultivation occurred between the 1850s and the 1970s. Based on the fly ash data, approximately 55% of the original surface soil layer remains on the sideslope of Mound 69 (compared with the uncultivated sideslope of Mound 70). There has been substantial deposition of sediment rich in fly ash onto the footslope of Mound 69 (from the cultivated sideslope) and the toeslope of Mound 70 (from the cultivated footslope). The fly ash and organic C data for the summit soil profile on Mound 70 suggest treasure hunters and looters disarranged the soil profile completely. The uncultivated sideslope with a 23% slope had a 40-cm surface layer rich in fly ash. The fly-ash content and thickness of the footslope soil surface layer was reduced as a result of tillage and erosion from the 1850s to the 1970s. Fly ash-enriched sediment accumulated on the toeslope and created a 60-cm surface layer. The current vegetation and the decrease in organic C with depth on the footslope and toeslope of Mound 70 suggest that no tillage has occurred since the 1970s. Fly ash presence within soil layers indicates which layers have been exposed at the soil surface since the 1850s and the extent of soil mixing. Archaeological mounds with known dates of construction can be used to obtain information on soil development and erosion processes.

The severity of accelerated erosion is affected by slope gradient, slope shape, slope length, and tillage practices. Fly ash, the product of high temperature coal combustion, has been used previously as a sedimentation marker, but it has never been used on the upland as an indicator of soil loss fro

With funding from The Robert Wood Johnson Foundation's Generalist Physician Initiative, the Pennsylvania State University College of Medicine created a community-based primary care clerkship in general pediatrics, general internal medicine, and family and community medicine, in which third-year students spend a month in a small town, rural area, or urban underserved medical community. In addition to linking students with preceptors who would teach the clinical skills essential to primary care practice, the medical school set out to teach and to evaluate knowledge, attitudes, and behaviors unique to primary care. This paper describes the three-part teaching tool/evaluation developed to address (1) a student's recognition of the characteristics of primary care (learning objectives assignment), (2) a student's ability to appreciate the multiple nonmedical factors influencing a patient's health and experience of illness (family project), and (3) a student's ability to solve clinical problems (clinical reasoning examination). The authors describe how these evaluation methods are linked with the clerkship's goals and objectives and how they yield a richer portrait of the student's performance than the traditional preceptor's evaluation alone can provide. They also discuss the relationship between students' performances on the primary care clerkship and their performances in other clinical clerkships. Similar clinical experiences in primary care should focus on features unique to primary care medicine in both teaching and evaluation.

People might be exposed to elemental or inorganic mercury in the environment, or to the organic form methylmercury. The latter, found especially in fish, is known to be neurotoxic to humans, and the fetus is quite sensitive to its adverse effects. This study sought associations between total blood mercury levels, a reasonably good indicator of methylmercury exposure, and both sociodemographic features and fish consumption. Data covering the years 1999-2000 were taken from a cross-sectional survey of the U.S. population, the National Health and Nutrition Examination Survey (NHANES). Participants included 2314 women 16-49 years of age and 1250 children aged 1-5 years. Data on blood mercury estimates, household interviews, and physical examination were available for 705 children (56% of the total) and 1709 women (74% response rate). Non-Hispanic black and Mexican-American children had significantly higher total blood mercury levels than did non-Hispanic white children. Women had blood mercury levels approximately 3-fold higher than those in children; respective mean concentrations were 1.02 μg/L and 0.34 μg/L. Children who had eaten fish in the past month had mean mercury levels approximately twice as high as other children. Women who had eaten 3 or more servings of fish in the past month had geometric mean blood mercury levels nearly 4-fold higher than those eating no fish in this period (1.94 μg/L vs. 0.51 μg/L). An effect of fish consumption on blood mercury levels was found for all race and ethnic groups, and in each of these groups, there was a positive association of age with blood mercury. Levels of blood mercury observed in this survey were generally below the point of concern, but levels exceeding the reference dose recommended by the U.S. Environmental Protection Agency (5.8 μg/L) nevertheless were documented in approximately 8% of women. Women who are pregnant or who are planning pregnancy should follow guidelines that make it possible to consume a moderate amount of fish while avoiding the high-mercury varieties.

In a greenhouse experiment, we evaluated the effects of scrubber sludge on the aggregation and the porosity in various combinations of dredged sediments and topsoil in the presence of sudangrass roots. As expected, the water-stable aggregates increase with increasing percentage of topsoil. For all combinations, scrubber sludge decreased aggregation. The topsoil had a total porosity similar to the sediments at the completion of the study in the absence of scrubber sludge. The total porosity increased with additional quantities of scrubber sludge for all combinations of topsoil and sediments. Transmission (>50 μm), water storage (50 to 0.5 μm), and residual (