Clyde W. Frank

The Effect of Dental Amalgams on Mercury Levels in Expired Air

The expired air of a group of 48 persons, 40 with and eight without dental amalgam restorations, was analyzed for its mercury content before and after chewing. Expired air samples were collected in polyethylene bags, and a known quantity of each was pumped into the mercury detector for measurement. The results showed that examined subjects with dental amalgams had higher pre-chewing mercury levels in their expired air than those without amalgams. After chewing, these levels were increased an average of 15.6-fold in the former and remained unchanged in the latter group. It was concluded that in situ dental amalgams can increase the level of mercury in expired air.

Exhaled mercury following removal and insertion of amalgam restorations

P atient exposure to mercury from dental amalgam and restorative procedures has not been studied as extensively as mercury exposure to dental personnel. One. study found that in a group of 114 adults not undergoing dental treatment, only six had measurable mercury in the urine, and one of those persons was using a mercurial diuretic.’ This was compared to a group of 24 persons currently undergoing dental treatment. Of that group five showed mercury in the urine before and after treatment. The possibility of mercury absorption from sources other than dental amalgam, such as mercurial antiseptics and germicides, was discussed. The study concluded that dental amalgams do not appear to be an important source of mercury absorption and excretion. In another study Frykholm2 used a radioisotope of mercury in placing four or five amalgam restorations in each of five patients. The urinary excretion of radioactive mercury gradually increased for each individual and reached an average peak of 2.5 pg/liter on the fifth day following treatment. In each case the level then dropped to zero by the seventh or eighth day, at which time the radioactive amalgams were removed to avoid further exposure. On the day following removal, urinary levels of mercury rose to 5 pg/liter and then dropped to zero in 2 days. Some investigators have found urinary excretion of mercury to be quite irregular and therefore an unreliable measure of quantity absorbed. Following exposure there is an early rapid phase of urinary excretion followed by a slower phase that may account for more

Quantitative Measure of Mercury Vapor Emission from Setting Dental Amalgam

The rate of mercury vapor emission from setting dental amalgam was measured by use of an ultraviolet light absorption technique under nondiffusion-controlled conditions. An average of 0.3 X 10-6 gm mercury per square centimeter was emitted at the experimental temperature. At 37 C, this amount was estimated to be 1.2 × 10 -6 gm/ cm2.

Atmospheric benzene depletion by soil microorganisms

Gaseous benzene was rapidly depleted in exposure chambers containing viable soils and plants. When separate components of the system were analyzed, no benzene was detected in soils, plants, or water. Soil microorganisms were shown to be responsible for metabolizing benzene, yielding CO2 as the main product. The rates were sufficiently rapid to suggest that this reaction forms a major pathway for the elimination of benzene from the environment.

Retrospective monitoring: A review

The development of chronological reference points to which present levels of inorganic pollutants can be compared is increasingly needed. This review is directed toward biological samples which are datable and have been characterized for one or more elements.

Introduction to Analytical Chemistry

This chapter focuses on the knowledge and experimental techniques of analytical chemistry that are most often encountered in the field of chemistry, pharmacy, medical technology, medicine, and the biological sciences. There are four major areas of analytical chemistry that are of importance in their application to diverse scientific disciplines. These areas are spectroscopy, acid-base methods, potentiometry, and chromatography. Analytical chemistry deals with the solving of qualitative and quantitative problems. In qualitative analysis, the goal is to determine what the constituents are in the sample. On the other hand, in quantitative analysis, the goal is to determine how much of each constituent is in the sample. An analytical chemist deals with inorganic and organic mixtures composed of metallurgical, biochemical, pharmaceutical, or medicinal compounds. The importance of analytical chemistry in related scientific areas is explained by considering its impact on clinical analysis, in pharmaceutical research and quality control, and in environmental analysis.

Chapter Two – Development of an Analytical Method

Publisher Summary The first step in solving analytical problems is the identification of the problem. Once the problem is defined the important factors that are considered in choosing the analytical method are: concentration range, required accuracy and sensitivity, selectively, time requirements, and cost of analysis. There are two types of analytical methods: chemical and instrumental methods. Chemical methods depend on chemical operations in combination with the manipulation of simple glassware and the simplest of instruments. An instrumental method encompasses the use of more complicated instrumentation based on electronic, optical, or thermal principles. The chapter also discusses quantitative analysis, which is based upon the measurement of a property that is related, directly or indirectly, to the amount of the desired constituent present in the sample. There are five basic types of techniques that are important to analytical chemistry: gravimetric, volumetric, optical, electrical, and separation.

Integration of modeling, monitoring and laboratory observation to determine reasons for air quality violations

An attempt was made to explain ambient air quality violations in the vicinity of industrial plants. Micrometeorology, diffusion calculaations, ambient readings, and plant engineering data are all taken into consideration to ascertain whether the plant is or is not the principal offender.Scrutiny of hi-vol filters using scanning electron microscopy for particle size analysis and particle chemical make-up as an assessment technique is also described.Case histories using the above analytical techniques are discussed.

Chapter Twenty – Spectroscopy of Atoms

Publisher Summary This chapter explains atomic spectroscopy, which is primarily used for the determination of trace metals in many types of samples composed of organic or inorganic matrices. The techniques used for this purpose are atomic emission spectroscopy and atomic absorption spectroscopy. The chapter discusses the basis for the observation of atomic emission and atomic absorption. In emission, the atoms of interest are vaporized by the input of thermal energy by either combustion or electrical discharge. The emission intensity, which is observed in the form of line spectra, is proportional to concentration and is dependent on the temperature of the system. In absorption radiation, the incident on the metal vapor causes electronic transitions from the ground state to selected excited states. The measurement of the ratio of the transmitted power to the incident power is proportional to concentration. The chapter also explains atomic fluorescence spectroscopy. In this method, radiation impinging on a vapor metal sample causes the promotion of electrons into excited states.

Chapter Ten – Oxidation–Reduction Equilibria

Publisher Summary An oxidation-reduction reaction (redox) is one in which the reactants undergo changes in the oxidation state. The gain of electrons is a reduction process, while oxidation is the loss of electrons. Both processes occur in a redox reaction. Reduction does not take place in the absence of oxidation or vice versa. The total number of electrons lost is equal to the total number of electrons gained. The substance that decreases in the oxidation state is the oxidizing agent, while the substance that increases in the oxidation state is the reducing agent. An oxidizing agent causes another substance to be oxidized, while it itself is reduced. In contrast, the reducing agent causes another substance to be reduced, while it itself is oxidized. This chapter discusses the arrangement of oxidizing agents and their reduced forms according to their ability to gain and lose electrons. The chapter also illustrates an arrangement of a selected group of half-reactions, which is called the Table of Standard Reduction Potentials.