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RESUMO O objetivo deste trabalho foi avaliar o potencial de produção de leite ha-1 de três consorciações de aveia-preta e leguminosas em detrimento da aveia-preta estreme fertilizada com N mineral. Os tratamentos utilizados foram: aveia-preta + 200kg de N ha-1 (Av+N); aveia-preta + trevo-branco (Av+Tb); aveia-preta + ervilhaca (Av+Er) e aveia-preta + trevo-vermelho (Av+Tv). As espécies foram implantadas em parcelas de 80m2, sob um delineamento de blocos ao acaso com quatro repetições. As amostragens foram realizadas previamente aos cortes, em três oportunidades, e o material foi avaliado quanto à produção de matéria seca, à composição químico-bromatológica (PB, EE, FDN, FDA, CNF, MM, digestibilidade estimada da matéria seca e digestibilidade do FDN em 48 horas) e à produção estimada de leite por área (kg ha-1). Os resultados foram submetidos à análise de variância, e as médias comparadas pelo teste de Tukey a 5% de probabilidade. A composição químico-bromatológica não diferiu entre os tratamentos Av+N e Av+Er em nenhum dos atributos avaliados. O tratamento Av+N proporcionou maior produção de leite por área em relação aos demais, explicado pela maior produção de MS.

A system has been developed for providing information regarding chemicals, their hazards, and safe handling requirements to employees of Johnson Wax. To initiate the development of a Chemical Material Handling Guide, physical, chemical, and toxicological information is acquired on the chemical raw material, intermediate, or finished product. The guide is prepared by members of a "guides" committee each of whom is responsible for completing one or more of its sections. The five major sections deal with identification, hazard ratings, protective equipment requirements, emergency procedures, and storage, handling and disposal requirements for the chemical material.

Gas chromatography was used to quantitate CO in air and also as an indirect means of determining %COHb in blood. The blood was then used to calibrate four CO-Oximeters used in a survey to determine average COHb levels in various segments of the U.S. population. Mean differences, both between the two methods of analysis and between pairs of CO-Oximeters were less than 0.1% COHb saturation. COHb values obtained on consecutive days using one CO-Oximeter were repeatable within a S.D. +/- 0.13% COHb.

Ten experimental human exposures to frichloro-ethylene vapor, 100 and 200 ppm, for periods of one hour to a five-day work week were conducted. At 200 ppm, untoward subjective responses were mild, inconsistently present, and of doubtful clinical significance. The only troublesome response was a sensation of mild fatigue and sleepiness in five subjects during their fourth and fifth consecutive days of exposure to 200 ppm. Analysis of expired breath of humans by infrared or gas chromatographic techniques provided a means by which to unequivocally establish a diagnosis of exposure. Serial measurements of the solvent present breath in the postexposure period provided the data from which to construct a family of breath excretion curves useful in estimating the magnitude of exposure. Measurement of urinary metabolites of trichloroethylene proved to be an unsatisfactory index of exposure.

The monomethyl ether of propylene glycol (PGME) is used as a radiator coolant Simulation of PGME coolant leakage on the engine of an idling truck resulted in a breathing zone concentration of 5 ppm in the cab. Under grossly exaggerated leakage conditions, a concentration of 460 ppm was reached when the coolant was pumped into the heater of an unventilated truck cab. In controlled human exposure studies to PQME vapor concentrations ranging from 50 to 2,000 ppm, the odor became transiently objectionable above 100 ppm. Eye, nasal, and throat irriation became objectionable prior to the first signs of central nervous system (CNS) impairment, which occurred at 1,000 ppm in one of two subjects. Alveolar breath samples must be obtained within 10 to 20 minutes following exposure because of the rapid decrease in solvent concentration.

Six healthy male human volunteers were exposed to seven high carbon monoxide (CO) concentrations ranging from 1,000 ppm for ten minutes to 35,600 ppm for 45 seconds. Carbon monoxide was rapidly absorbed and the increase in percent carboxyhemoglobin (COHb) saturation in venous blood per liter of CO mixture inhaled could be accurately predicted by the equation, log (Δ% carboxyhemoglobsn/liter) = 1.036 log (ppm CO inhaled) -4.4793. The abrupt increase in carboxyhemoglobin concentration of 11.6% and 9.1% saturation in two subjects produced the immediate onset of mild frontal headache. The subject exposed to 35,600 ppm demonstrated slight sagging of the ST-segsnent of lead II. This occurred 20 seconds after the exposure had started and persisted for ten minutes after exposure. Neither the spontaneous nor the evoked electrical activity of the brain exhibited significant changes which could be attributed to CO exposure over the range studied.

To determine the carbon monoxide exposure experienced by the residents of Chicago, Los Angeles, Milwaukee, and New York, venous blood samples were obtained from adults at arbitrarily chosen blood bank collection sites in the four cities and analyzed for circulating carbon monoxide, carboxyhemoglobin. For comparative purposes, blood was obtained from volunteers breathing carbon monoxide-free air and was found to contain 0.45 percent carboxyhemoglobin. By contrast a high percentage of all the nonsmoking blood donors breathing city air had carboxyhemoglobin saturations greater than 1.5 percent, which indicated that exposure to carbon monoxide in excess of that permitted by the quality standards of the Clean Air Act of 1971 was widespread and occurring regularly.

When an aerosol product is dispensed into the atmosphere a mixture of particles and propellent gases is released. The potential exposures resulting from normal use were measured and compared to the background and the exposure of the healthy industrial worker. This model can serve as a guide for assessing use exposures of aerosol products.

Acute exposures to isobutane, propane, F-12, and F-11 in concentrations of 250, 500, or 1000 ppm for periods of 1 min to 8 hr did not produce any untoward physiological effects as determined by the methods employed which included serial EKG's and continuous monitoring of modified V5 by telemetry during exposure. Repetitive exposures to these four propellants were also without measurable untoward physiological effect with the exception of the eight male subjects repetitively exposed to 1000 ppm, F-11, who did show minor decrements in several of the cognitive tests. Of particular importance is the observation that none of the subjects showed any decrement in pulmonary function or alteration in cardiac rhythm as the result of exposure to concentrations of the gases or vapors far greater than encountered in the normal use of aerosol products in the home.

Short-term 20-second exposure to hair sprays A and B failed to show significant decreases in maximum expiratory flow rates at low pulmonary volumes in normal subjects; however, significant decreases were observed with hair spray B in eight subjects with hyperreactive airways (abnormal response to inhalation of methacholine). On the partial flow-volume curves, flows at 40 percent and 25 percent of forced vital capacity decreased 8.9 to 10.3 percent and 14 to 18.7 percent, respectively. The hair sprays differed in their content of perfume and plasticizer, and since the latter is generally considered nontoxic at room temperature, the perfume may be the responsible agent It would appear from this study that normal healthy individuals are at little risk, at least from brief exposure to hair spray; however, in the presence of hyperreactive airways, as seen in asthmatic subjects and in some people with allergic rhinitis and viral respiratory infections, an immediate response of the airways may result from exposure to some hair sprays.

Eight adult volunteers of both sexes were exposed to isobutane in a controlled-environment chamber for the purpose of monitoring their physiological responses to a series of gas concentrations ranging from 250 to 1,000 ppm. First, the response to exposure periods of 1 min, 2 min, 1 h, 2 h, and 8 h were studied. There being no untoward responses to these acute exposures, the eight volunteers were exposed repetitively to isobutane at concentrations of 500 ppm, 1, 2 or 8 h per day, five days per week for two weeks. Then exposures to two mixtures of isobutane and propane for 1, 2 or 8 h per day for two days were studied. During the investigation all subjects were kept under comprehensive medical surveillance. No untoward subjective responses or abnormal physiological responses occurred during or following these exposures. Special emphasis was placed on evaluating the cardiac and pulmonary response to these exposures through the use of continuous ECG telemetry and serial computerized spirometric measurements. The following serial laboratory studies were unaltered by the exposures: complete blood count, urinalysis, serum alkaline phosphatase, SGOT, LDH, serum bilirubin, blood sugar, serum calcium, serum phosphorus, BUN, spontaneous electroencephalogram, visual evoked response, a battery of cognitive tests, and an ACTH stimulation test.

An environmental survey was conducted to determine the time-weighted average exposure (TWA) of a group of chemical plant workers to vinyl chloride (VCl) vapor. This survey featured continuous multipoint air sampling and analysis using an infrared spectrophotometer. The inhalation exposure data were digitized and recorded on paper tape for subsequent computer analysis and derivation of daily TWA values for each worker. A breath sampling program was conducted concurrently with the environmental survey, and a series of breath decay curves relating post exposure breath concentration to vapor exposure were derived from the data. To validate the breath curves derived from on-the-job data, post exposure breath curves were also constructed from breath data obtained following experimental human exposures to carefully controlled concentrations of VCl vapor. The close agreement between post exposure breath concentrations at the corresponding TWA's obtained by each of the methods suggests that either continu...

Inhalation of dichloromethane vapor in concentrations of 500 to 1000 parts per million for 1 to 2 hours promptly initiated the formation of significant quantities of carbon monoxide in human subjects. The evidence suggests that carbon monoxide may be a metabolite of dichloromethane and, that exposure to concentrations of dichloromethane below the industrial threshold limit values may result in the formation of carbon monoxide in amounts that exceed the allowable limits.

Human volunteers were exposed to carbon monoxide at concentrations of < 1, 25, 50, 100, 200, 500, and 1,000 ppm for periods of one-half to 24 hours. No untoward effects were observed in sedentary males exposed to 100 ppm for eight hours. Exposures producing carboxyhemoglobin saturations greater than 15% to 20% resulted in delayed headaches, changes in the visual evoked response, and impairment of manual coordination.

Inhalation of methylene chloride vapor In concentrations of 500 to 1,000 ppm for one to two hours was followed promptly by a sustained elevation of carboxyhemoglobin level in all 11 subjects studied. The evidence suggests that carbon monoxide may fee a metabolite of methylene chloride and that exposure to concentrations of methylene chloride that do not exceed the Industrial Threshold Limit Value for that solvent may result in a carboxyhemoglobin saturation level in excess of that allowable from carbon monoxide itself. In addition, methylene chloride produced signs and symptoms of central nervous system depression in subjects exposed to vapor concentrations of 1,000 ppm.

A national survey was conducted in 1969-1972 for the purpose of determining the range of carboxyhemoglobin (COHb) levels in various segments of the American population. Venous blood samples for COHb analysis were obtained from 29,000 blood donors living in urban, suburban, and rural communities across the United States. For comparative purposes, COHb measurements were made on samples obtained from 11 volunteers breathing air free of carbon monoxide (CO) or air with known concentrations of CO. The mean COHb saturation of four adults breathing CO-free air was 0.45%. Fortyfive percent of all the nonsmoking blood donors tested had COHb saturations of more than 1.5% This indicated that exposure to CO in excess of that permitted by the Air Quality Standards was widespread and occurring regularly. Tobacco smoking was the single most important factor responsible for the highest COHb saturations observed. The other chief factors influencing the COHb saturation were the geographical location of the individual, occupation, and the existing meteorological conditions. (JAMA229:1187-1195, 1974)