Total Dust Levels Research Articles

Studies with Clinoptilolite in Poultry. II. Effect of Feeding Broilers and the Direct Application of Clinoptilolite (Zeolite) on Clean and Reused Broiler Litter on Broiler Performance and House Environment ,

Three broiler experiments were carried out to determine whether various methods and uses of clinoptilolite (clin) application would affect broiler performance and house environment. Neither applications of clin on clean and reused wood shaving litter and clin as sole source of litter in the most frequented areas (1.82 m × 2.44 m) of the pens nor feeding 10% clin significantly affected mean body weight, feed conversion, and feed consumption. Total respiratory dust levels were generally much higher in pens where clin was applied on the clean or reused litter or primarily used as the sole source of litter. Applying clin on either unused or reused wood shavings litters reduced the incidence of foot pad burns; however, incorporating 10% clin in the ration and fed from 1 to 49 days of production (market age) significantly increased the incidence of foot pad burns. The contradictory observation may be attributed to the greater extent of caked litter in clin-fed pens. Litter moisture and ammonia-nitrogen (NH3-N) levels were lowered when clin was applied on clean wood shaving litter. The NH3-N levels were significantly lowered when clin was incorporated in the feed and fed from 1 to 49 days of production. Mortality was significantly increased when used primarily as a sole source of litter in a portion of two pens.Under the conditions of our experiments, the best method for the reduction of NH3-N and litter moisture is the application of clin or clean wood shaving litter at the rate of 5 kg/m2 after 28 days of production (28 days of age).

A survey of respiratory symptoms and lung function in ferrochromium and ferrosilicon workers.

Lung function and the prevalence of generalized obstructive lung diseases (GOLD) were studied in three groups of electrofurnace workers in a ferrochromium and ferrosilicon-producing plant. When compared with an internal reference group forced vital capacity was reduced in all groups. Compared with an external reference group the prevalence of GOLD was increased in all three groups. It is known that traces of chromates are present in the working atmosphere at the plant. No connection between the presence of chromates and GOLD could be documented. It is suggested that the documented adverse effects are due to high levels of total dust, possibly with an additional effect due to exposure to amorphus silica dust.

Composition of Weave-Room Dust

Total-dust samples were collected at four weave-room sites and one card room site in each of twelve southeastern U.S. cotton mills. The cotton content of the fabrics being produced ranged from 35% to 100%. Sizings were starch, polyvinyl alcohol (PVA), carboxymethylcellulose (CMC), and mixtures of starch PVA, starch CMC, and PVA CMC. A serial solvent extraction-gravimetric technique was developed for proximate analysis of samples. Sizing was extracted with boiling water. Iodometric methods were used to determine the extracted starch and PVA, and CMC was determined by titration of the free acid with NaOH. Weaving dust averaged 20-50% sizing, 10-30% cellulose, 0.4% synthetic fiber, and 1-4% protein. Higher total dust levels were'associated with starch sizing, increased loom speeds, and higher yarn counts. Fine dust levels increased with loom speed percentage of cotton in the product, and the use of starch as sizing. The major differences between carding and weaving dusts were the presence of sizing and the much higher average water solubility of weaving dust, 47% vs. 10%. The carding dust also contained small amounts of starch (1-2%) and protein (9-16%), plus traces of polyester in dust from card rooms in which synthetic was carded or blended simultaneously.

Respiratory health and dust levels in cottonseed mills.

Four cottonseed mills in the southern United States contained high levels of total and respirable dust. A survey of 172 workers showed low prevalences of byssinosis (2-3%) and chronic bronchitis (4%). Mean baseline (out of dust) lung function values were normal. Mean functional declines over the working shift were present on Monday and absent on Friday, indicating an acute bronchoconstrictor response. Despite limitations in translating measured dust levels into estimates of individual exposures, the overall dose-response relationship seems to differ from that found in the cotton textile industry.

Evaluation of detergent enzymes in air.

To assist in evaluation of the physiological aspects of exposure to detergent enzymes and the adequacy of industrial hygiene controls, a method for determining air concentrations of proteolytic enzymes was developed. Samples are taken by means of a high-volume sampling technique in which the dust is collected on glass fiber pads. The total dust level is determined gravimetrically; the amount of proteolytic enzyme is determined colorimetrically with dimethylated casein as the substrate and trinitrobenzene sulfonic acid sis the color reagent. Data describing analytical accuracy, precision, and detection limits are presented. Results over a 16-month period for key operating areas indicate a reduction in total dust and enzyme levels as well as a satisfactory position in terms of the TLV. An automated data handling system which serves individual plant and corporate needs is described.

An epidemiological study of respiratory symptoms in Lancashire mills, 1963-66.

Molyneux, M. K. B., and Tombleson, J. B. L. (1970). Brit. J. industr. Med., 27, 225-234. An epidemiological study of respiratory symptoms in Lancashire Mills, 1963-66. An epidemiological study of card and blowroom workers in 14 cotton spinning and two man-made fibre spinning mills in Lancashire has been carried out on a prospective basis of six-monthly examinations over three years. The number of operatives to be included was decided so as to give a sufficient sample for the statistical assessment of fall in FEV, at the same time allowing for population movement. The examination of each worker included a history, a questionnaire of respiratory symptoms, and a measurement of forced expiratory volume in one second. The results in this paper, which will be followed by others on other aspects of the survey, give the prevalence of both byssinosis and bronchitis, according to the definition given, in the 1 359 cotton workers and 227 man-made fibre workers, seen at least once, and also the dust levels in the mills. Eight of the mills processed coarse and six medium cotton. The total prevalence of byssinosis, as defined, is 26·9%, being higher in coarse than in medium cotton mills, and the occupational groups most affected are strippers and grinders, carders and undercarders, and draw frame tenters. In coarse mills symptoms develop in some men and women within the first four years of exposure, and in medium mills between five and ten years9 exposure. Repeat questionnaires in about half the population, two years after the first questionnaire, showed the development of symptoms of chest tightness in an appreciable number not previously affected. The incidence of bronchitis is increased in operatives with symptoms of byssinosis, but is influenced by age and smoking. Total dust levels averaged 3·1 mg/m 3 in coarse miles and 1·2 mg/m 3 in medium mills. The findings indicate that dust control measures, though they have produced considerable improvement, are not now fully effective with present methods of production.

STUDY OF RESPIRATORY SYMPTOMS AND VENTILATORY CAPACITIES AMONG ROPE WORKERS

In a rope works handling manila, sisal, and St. Helena hemps, the prevalence of respiratory symptoms and the change in forced expiratory volume (F.E.V._1·0) during the work shift were studied in a group of 41 women and 41 men who represented 93% of the population at risk. Dust concentrations, measured with a modified Hexhlet, ranged from 0·11 to 4·51 mg./m.³ for total dust and 0·02 to 1·46 mg./m.³ for fine dust. The highest concentrations were found in the preparing rooms, in which the workers, all of whom were women, showed on the average a fall in ventilatory capacity during the shift. The workers in the rope walk, all of whom were men, showed a rise in ventilatory capacity during the shift. The difference between the men and women was statistically significant (p < 0·05). No worker gave a characteristic history of byssinosis, although nine women complained of chest tightness associated with their work. Undue breathlessness on exertion and persistent cough and phlegm were also more common among the women, but they were on the average 18 years older than the men. When the ventilatory capacities and the prevalence of respiratory symptoms of women rope workers were compared with those of a group of women employed elsewhere in the dockyard, the only significant difference was that the rope workers had more chest tightness associated with their work (p < 0·02). Exposure of volunteers to St. Helena hemp, which is apparently the most likely of the hard hemps to give rise to respiratory symptoms, caused only a slight fall in ventilatory capacity and a small rise in airways resistance. A sample of St. Helena hemp assayed on guinea-pig ileum had only a relatively small degree of contractor activity. The evidence suggests that the dusts of hard hemps do not cause byssinosis under the conditions in this factory. However, the irritant nature of the dust indicates the need to prevent total dust levels exceeding about 2 mg./m.³.