Calcium carbonate adverse effects

Although no adverse effects have been reported in the literature among workers exposed to calcium carbonate, high concentrations of the dust would be expected to act as a physical irritant to the eyes and skin. Fourteen British workers exposed to heavy calcium carbonate concentrations for 12-35 years showed no trace abnormalities due to dust or any clinical sign of pneumoconiosis or chronic bronchitis on X ray. Long exposure to high dust concentrations of pure calcium carbonate (quartz content less than 1.1%) did not result in lung fibrosis. 

A variety of adverse effects have been reported following the use of antacids. If sodium bicarbonate is absorbed, it can cause systemic alkalization and sodium overload. Calcium carbonate may induce hypercalcemia and a rebound increase in gastric secretion secondary to the elevation in circulating calcium levels. Magnesium hydroxide may produce osmotic diarrhea, and the excessive absorption of Mg++ in patients with renal failure may result in central nervous system toxicity. Aluminum hydroxide is associated with constipation serum phosphate levels also may become depressed because of phosphate binding within the gut. The use of antacids in general may interfere with the absorption of a number of antibiotics and other medications. 

The American Cancer Society states that there does not seem to be any relationship between caffeine and cancer. However, other adverse effects for women remain a concern, such as the possibility that large amounts of caffeine could contribute to osteoporosis (thinned and fragile bones), particularly in elderly women. As caffeine is a diuretic, which increases loss of fluids and electrolytes in the urine, it could rob the body of calcium. Nevertheless, a study published in 2001 concluded that the net effect of carbonated sodas on the body s calcium is negligible, and that the loss of calcium in urine due to carbonated drinks is too small to affect calcium balance. 

Fillers. Inert inorganic substances such as calcium carbonate, clay, silicates, and asbestos are often utilized in vinyl compositions where clarity is not a requirement. While the carbonates and clay are used ostensibly to reduce cost, beneficial results are forthcoming. The carbonates produce a dry, matte surface and are claimed, because of their alkaline nature, to benefit heat and light stability. Clay improves electrical insulation. Silicates enhance surface dryness. Asbestos fibers provide the reinforcement necessary for dimensional stability in floor tile. Antimony oxide, per se or as a surface coating on an inert carrier, provides flame retard-ance. Their only major adverse effects are to reduce tensile strength and elongation and require an increase in plasticizer level to compensate... 

Calcium has long been implicated as a dietary factor which inhibits the absorption of manganese. Since manganese is better absorbed in the oxidized (+2) than in the reduced state (+3 or +4), any factor which increases gastrointestinal tract pH (increases alkalinity) would be expected to inhibit manganese utilization. Calcium carbonate, a commonly used antacid by humans as well as a calcium nutrient supplement, has been found to have a greater adverse effect on apparent manganese absorption in humans than does milk. 

The strong adverse influence of calcium ions on the stability of lyophobic suspensions is predicted by DLVO theory, and has been demonstrated with many types of simple soils. That calcium ions have an overwhelming effect on the redeposition of carbon soil onto cotton tends to support the idea that DLVO theory is a principal key in explaining detersive action. The redeposition of carbon onto cotton has been correlated quantitatively with the calcium ion content of the system, both in the presence and absence of surfactant (95). The adverse effect of calcium ions on wet soil removal in practical washing has also been well established (96). The effect of calcium in detergency cannot be explained solely, however, by its shrinking of... 

Antacids are basic substances that reduce gastric acidity by neutralising HCl. The hydroxide is the most common base but trisilicate, carbonate and bicarbonate are also used. Therapeutic efficacy and adverse effects depend also on the metallic ion with which the base is combined, and this is usually aluminium, magnesium or sodium. Calcium and... 

Methods of fdler pretreatment choice of carbon black for conductive appheations is crucial because impurities on carbon black may have an adverse effect on mechanical properties aluminum oxide and calcium carbonate were coated by a hydrophobic layer of PDMS heat treatment of fumed sihca reduces its ability to reinforce polymer, especially in temperatures above 2OO C ... 

One method of increased interaction between filler and polymer is to use the third component, which has better interaction with filler. Chlorinated polyethylene is such a component and in addition it is an impact modifier of PVC. Calcium carbonate particles become coated with chlorinated polyethylene, CPE, which increases dispersion of CPE domains and the amount of calcium carbonate which can be used without adverse effect on the impact strength of material (Figure... 

Calcium carbonate is one of the most common minerals, and as such, it is recognized by all living organisms on earth. Doses of up to 40 g per day are known to have been taken by healthy adults without adverse effect. But in the case of some health conditions, even ten times smaller doses were found to affect health. Generally, the health effect of calcium is either due to its effect on the pulmonary system or its admixtures. 

Calcium carbonate is not toxie to animals, and its LD50 for oral rat is 6450 mg/kg. Similarly, there is no adverse environmental effect known to be caused by calcium carbonate. 

The presence of unbumt carbon in fly ashes has many adverse effects on concrete including the appearance of grayish blackness in mortars and concrete, need for higher w/c+f ratio to obtain required consistency, and decreased air entertainment. Thermogravimetric analysis has been developed to estimate hydrated lime, calcium carbonate, and unbumed carbon in fly ashes.The methodology is as follows ... 

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