Ingestion

For a chemical to affect health, a substance must come into contact with an exposed body surface. The three ways in which this happens are by inhalation, skin contact, and ingestion, the latter being rare. 

Carotene is found in plant chioroplasts. When ingested into animals it serves as a precursor of vitamin A (the transformation occurs in the liver). 

I6I C. Warfarin baits need contain only 0 025% active principle, and rats are killed after ingesting about 5 doses the bait can be left down and the risk of acute toxicity to man or domestic animals is not serious. In common with other coumarin derivatives, warfarin reduces the clotting power of blood and death is caused by haemorrhages initiated by any slight injury. Warfarin is a vitamin K antagonist, and large oral doses of the vitamin can be given as an antidote. 

The maximum permissible body burden for ingested polonium is only 0.03 microcuries, which represents a particle weighing only 6.8 x IO-12 g. Weight for weight it is about 2.5 x lOii times as toxic as hydrocyanic acid. The maximum allowable concentration for soluble polonium compounds in air is about 2 x lO-ii microcuries/cnu. 

Working with uranium requires the knowledge of the maximum allowable concentrations that may be inhaled or ingested. 

Animals that do not readily accept pelleted feeds may be enticed to do so if the feed carries an odor that induces ingestion. Color development is an important consideration in aquarium species and some animals produced for human food. External coloration is desired in aquarium species. Pink flesh in cultured salmon is desired by much of the consuming pubHc. Coloration, whether external or of the flesh, can be achieved by incorporating ingredients that contain pigments or by adding extracts or synthetic compounds. One class of additives that imparts color is the carotenoids. 

Propargyl alcohol is a primary skin irritant and a severe eye irritant and is toxic by all means of ingestion all necessary precautions must be taken to avoid contact with Hquid or vapors. The LD q is 0.07 mL/kg for white rats and 0.06 mL/kg for guinea pigs. 

Cosmetics and Pharmaceuticals. The main use of hexadecanol (cetyl alcohol) is in cosmetics (qv) and pharmaceuticals (qv), where it and octadecanol (stearyl alcohol) are used extensively as emoUient additives and as bases for creams, Hpsticks, ointments, and suppositories. Octadecenol (oleyl alcohol) is also widely used (47), as are the nonlinear alcohols. The compatibiHty of heavy cut alcohols and other cosmetic materials or active dmg agents, their mildness, skin feel, and low toxicity have made them the preferred materials for these appHcations. Higher alcohols and their derivatives are used in conditioning shampoos, in other personal care products, and in ingested materials such as vitamins (qv) and sustained release tablets (see Controlled RELEASE technology). 

Pentaerythritol and trimethylolpropane are classified as nuisance particulate and dust, respectively. They are both nontoxic to animals by ingestion or inhalation and are essentially nonirritating to the skin or eyes (2,74). 

R = N(CH2CH3 )2) (LSD-25, as the tartrate salt) could be absorbed through the skin with resulting inebriation. In a bold experiment, it was then demonstrated that oral ingestion resulted in symptoms characteristic of schizophrenia which, although temporary, were quite dramatic (64). 

Caffeine. About 3% by weight of the roasted coffee bean is caffeine (16). The second U.S. Department of Agriculture world coffee crop estimate for 1988—1989 was 4.24 x 10 kg (93.3 million 100-lb bags) (102). World coffee consumption was predicted to rise in the foreseeable future at the rate of 1—2% per year and thus the total amount of caffeine and related alkaloids ingested from this source can also be expected to increase. Caffeine and related bases (eg, theophylline) are also found in various teas but, because most of the major producers (India, China, etc) export relatively Htfle of thek crops and keep most for domestic consumption, accurate figures on year-to-year production are more difficult to obtain. Nevertheless, these crops are of significant economic import (103). 

Toxicity. Fluoroborates are excreted mostly in the urine (22). Sodium fluoroborate is absorbed almost completely into the human bloodstream and over a 14-d experiment all of the NaBF ingested was found in the urine. Although the fluoride ion is covalently bound to boron, the rate of absorption of the physiologically inert BF from the gastrointestinal tract of rats exceeds that of the physiologically active simple fluorides (23). 

Health and Safety Factors. The low solubiUty of calcium fluoride reduces the potential problem of fluoride-related toxicity. Water saturated with calcium fluoride has a fluoride concentration of 8.1 ppm as compared to the recommended water fluoridation level of 1 ppm fluoride ion. However, because the solubiUty of calcium fluoride ia stomach acid is higher, continued oral ingestion of calcium fluoride could produce symptoms of fluorosis. The adopted TWA limit for fluorides as F is 2.5 mg/m (68,69). 

Mild exposure to HF via inhalation can irritate the nose, throat, and respiratory system. The onset of symptoms may be delayed for several hours. Severe exposure via inhalation can cause nose and throat bums, lung inflammation, and pulmonary edema, and can also result in other systemic effects including hypocalcemia (depletion of body calcium levels), which if not promptly treated can be fatal. Permissible air concentrations are (42) OSHA PEL, 3 ppm (2.0 mg/m ) as E OSHA STEL, 6 ppm (5.2 mg/m ) as E and ACGIH TLV, 3 ppm (2.6 mg/m ) as E. Ingestion can cause severe mouth, throat, and stomach bums, and maybe fatal. Hypocalcemia is possible even if exposure consists of small amounts or dilute solutions of HE. 

Toxicity. The lethal dose of Mgp2 to guinea pigs by ingestion is 1000 mg/kg (17). 

Toxicology and Handling. The lethal dose by ingestion in guinea pigs is 150 mg/kg body weight (13). The TLV for KHF2 is 2.5 mg /m ... 

Over the years animal studies have repeatedly shown that perfluorinated inert fluids are nonirritating to the eyes and skin and practically nontoxic by ingestion, inhalation, or intraperitoneal injection (17,22). Thermal degradation can produce toxic decomposition products including perfluoroisobutene which has a reported LC q of 0.5 ppm (6 hr exposure in rats) (31). This decomposition generally requires temperatures above 200°C. 

Exposure to PTFE can arise from ingestion, skin contact, or inhalation. The polymer has no irritating effect to the skin, and test animals fed with the sintered polymer have not shown adverse reactions. Dust generated by grinding the resin also has no effect on test animals. Formation of toxic products is unlikely. Only the heated polymer is a source of a possible health hazard (120). 

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