The element fluorine has long been recognised to have benefits for dental health: low-fluoride intake has been linked to development of dental caries and the use of fluoride toothpastes and mouthwashes is widely advocated in mitigating dental health problems. Fluoridation of water supplies to augment naturally low fluoride concentrations is also undertaken in some countries. However, despite the benefits , optimal doses of fluoride appear to fall within a narrow range. The detrimental effects of ingestion of excessive doses of fluoride are also well documented. Chronic ingestion of high doses has been linked to the development of dental fluorosis, and in extreme cases, skeletal fluorosis. High doses have also been linked to cancer (Marshall 1990), although the association is not well-established (Hamilton 1992).

Fluoride in Natural Waters

Geochemical processes controlling the elevated fluoride concentrations in groundwaters of the Taiyuan Basin, Northern China

Concentrations of cadmium, lead, copper, chromium and nickel were determined in the gill, liver and muscle of Cyprinus carpio, Barbus capito and Chondrostoma regium caught at 5 stations on the Seyhan river system. Heavy metal concentrations in the tissues tended to vary significantly among stations, and one station thought to be contaminated by hospital effluents showed particularly high metal concentration. Liver and gill tissues showed higher metal concentrations than muscle tissue. The ranges of mean metal concentrations (µg/g d.w.) were as follows: the range of cadmium concentration was 1.26-6.10, 0.96-4.72 and 0.51- 1.67, that of lead was 9.41-44.75, 5.22-37.15 and 2.94-13.73, that of copper was 5.43-58.63, 5.91-201.1 and 3.27-7.35, that of chromium was 1.72-6.10, 0.23-5.35 and 0.36-1.71 and that of nickel was 6.83-28.03, 3.42-27.05 and 1.62-13.35 in the gill, liver and muscle respectively. The concentrations of some metals in some tissues exceeded the acceptable levels for a food source for human consumption. The least contaminated part of the river system was found to be Seyhan Dam, which does not receive significant levels of effluents from industrial and domestic sources in Adana when compared to other stations. The results of this study indicated that the metals present in the river system were taken up by three fishes through food, water and sediment, as all the fish species, regardless of their biological needs, showed high metal concentrations.

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Levels of Heavy Metals (Cd, Pb, Cu, Cr and Ni) in Tissue of Cyprinus carpio, Barbus capito and Chondrostoma regium from the Seyhan River, Turkey

INTRODUCTION CHAPTER 1. AVERAGE ABUNDANCES OF CHEMICAL ELEMENTS IN THE GROUNDWATERS OF THE SUPERGENE ZONE 1.1. Method of Calculation of Clarke Values 1.2. Groundwaters of the Permafrost Province 1.3. Groundwaters of the Province of Tropical and Subtropical Climate 1.4. Groundwaters of the Provinceof Temperate Humid Climate 1.5. Groundwaters of Mountain Regions 1.6. Groundwaters of the Province of Arid Climate

Geochemistry of fresh groundwater in the main landscape zones of the Earth

Water quality deterioration due to acid mine drainage is of concern in the northeastern coalfield of India as the water in this area is severely polluted. The mine drainage water emanating from various collieries are highly acidic in character and contain high hardness, sulphate, total dissolved solids and iron coupled with low pH values—which further results in contamination of trace (heavy) metals at significant levels. Trace metals are highly toxic and undesirable and are injurious to human health.

Mine water quality deterioration due to acid mine drainage

Effects of coal mining on ground and surface water quality, Monongalia County, West Virginia☆

Fluoride contents range from <0.05 to 5.9 milligrams per liter (mg/1) based upon 255 water samples collected from wells in nine counties of northeastern Ohio. Only 16 samples had fluoride contents exceeding 1 mg/1, and all are from the southern trio of counties. Furthermore, all samples high in fluoride are from wells close to or penetrating the contact between the Allegheny and Pottsville Formations.

Data from a line of 34 wells for which logs were obtained indicate that high fluoride water occurs in either the lower part of the Allegheny Formation, or more probably, in the upper part of the Pottsville Formation.

Ground waters high in fluoride are related to the bedrock geology. Fluoride data, particularly in the area of potentially high values, are important to health professionals in the prescription of fluoride supplements for children. Such prescriptions should be made only after the water has been tested.

Fluoride in the Ground Water of Northeastern Ohio

Fluoride in ground water.

This field trip to the Cuyahoga Valley National Recreation Area in northeast Ohio has been prepared in association with the National Association of Geology Teachers' (NAGT) symposium entitled "Public Lands and the Teaching of Geology." Stops are in a logical sequence to examine the geologic section, glacial deposits, and the following habitats: slump, hemlock ravine, upland dry woods, floodplain, slope, old field and wetland. Activity by man is minimal; sites are accessible and protected from future development; and the sequence of stops follows ages of bedrock, oldest to youngest. In order to protect the sites, national park policy prohibits collection of samples. Shallow marine black shales of Devonian age, offshore marine, coastal, fluvial, and marine sedimentary rocks of Mississippian age, and braided stream sandstones of Pennsylvanian age are exposed in stream valleys. Stratified and unstratified deposits of Wisconsinan age cap the area. Three contradictory hypotheses (i.e., continental lower, marine upper; eolian; and fluvial and tidal channel) on the origin of Berea Sandstone are considered at field sites. Geologic terrain and geomorphic history have influenced development of the seven habitats. OHIO J. SCI. 88 (1): 40-47, 1988 INTRODUCTION The Cuyahoga Valley National Recreation Area (CVNRA) is in the glaciated part of the Allegheny Plateau in northeast Ohio. The Allegheny Plateau is characterized by relatively undeformed sedimentary rocks and is bound on all sides by a steep topographic descent to adjacent geomorphic regions characterized by older sedimentary rocks (Thornbury 1965). Igneous and metamorphic rocks underlie sedimentary rock at a depth of about 1,676 m in the CVNRA. Basement rock in Ohio, recognized from well borings, is composed of granite, gneiss, schist, and marble (Owens 1967). None is exposed in the CVNRA. Older Paleozoic rocks of Cambrian, Ordovician, Silurian, and Devonian age are at depth in the area of the CVNRA. Rock units of Devonian, Mississippian, and Pennsylvanian age and glacial deposits of late Wisconsinan glaciation are exposed in the CVNRA (Fig. 1) The Devonian system is represented by black shales which accumulated in shallow seas. The Mississippian system is represented by a basal shale interbedded with siltstone, overlain in sequence by sandstone, black shale, and silty, clayey, or sandy shale. The Mississippian sequence was deposited in environments changing from offshore marine, to coastal, to fluvial, and back to marine. The Pennsylvanian system is represented by a sandstone and conglomerate that were deposited by low-discharge braided streams. No younger sedimentary rocks occur within the CVNRA. Bedrock dips 3.8 m per km to the east and south-southeast (Manner 1987). Stream erosion incised a steep-sided river valley which in Pleistocene time was filled by glacial deposits. Evidence of early glacial activity is obscured, but events are known from deposits elsewhere in northeast Ohio. Landforms of late Wisconsinan glaciation occur as ground moraine, end moraine, kames, kame terraces, and kame deltas (Fig. 2). Outwash and lake plain deposits formed as the level of Lake Erie dropped. The present Cuyahoga River basin was formed after final retreat of the glaciers 14,000 years ago (Szabo 1987).

Geology and Habitats of the Cuyahoga Valley National Recreation Area, Ohio

Program assessment in higher education is looming on the horizon as a result of public demand for accountability of public institutions. Educators are finding it necessary to show that students have acquired the knowledge and skills expected from their education. Of the many means of showing achievement (employment records, exit interviews, terminal projects, exams, and so forth), few can quantitatively show knowledge or skill levels resulting exclusively from the major program. An assessment method using a three-part instrument that compares freshmen to graduating seniors is presented as a means of quantifying “value-added” for a geology program. The three parts include student self-evaluation of their competence and knowledge levels of geological topics, a multiple-choice exam, and an evaluation of field skills at the end of field camp. Topics and questions focus on written program objectives and expected student outcomes and test various levels of comprehension. Freshmen/senior comparisons can be made ...

Robert G. Corbett

Papers

Effects of coal mining on ground and surface water quality, Monongalia County, West Virginia☆

Fluoride in the Ground Water of Northeastern Ohio

Fluoride in ground water.

Geology and Habitats of the Cuyahoga Valley National Recreation Area, Ohio

A Student-Assessment Method Appropriate for a Geology Program