[Assessment of annual exposure to noise and risk of occupational hearing loss among private farmers specializing in plant production].Med Pr. 2004; 55(2):175-82.MP
In agriculture noise is the most frequent hazard, but until now very poorly recognized. It affects the hearing organ in private farmers. Because of a great variety of machines used on farms and a changing magnitude of exposure to noise, this agent has to be studied over the whole annual cycle. The aim of the study was to recognize and evaluate annual exposure to noise among private farmers engaged in plant production.
MATERIALS AND METHODS
The study covered 17 family farms with arable land, ranging from 10 to 50 ha (mean, 22.3 ha). They were equipped with agricultural tractors and a set of agricultural accessories, wood-cutting saws, self-propelled and workshop machines. Based on detailed time-schedule records of agricultural activities and dosimetric measurements conducted during the whole year, two acoustic parameters were determined, total monthly exposure and equivalent daily exposure.
The study showed that the highest values of the total monthly exposure to noise (E(A,T)) occurred in the summer-autumn (July, September, October) and winter (December, January) seasons. During the former, the degree of noise load among farmers was directly associated with intensity of field works and transport activities, whereas during the latter with the frequency of using wood-cutting machines and repair activities. The calculated mean equivalent daily exposure to noise revealed the highest values in two months, December (6.01 Pa2 h) and September (5.51 Pa2 h), and the lowest values were observed in the other months (3.67-4.28 Pa2 h). The mean value for the whole year was 4.35 Pa2 h (the standard was exceeded by 4.4 times).
The study showed that the mean annual noise load among farmers engaged in plant production was characterized by the level equal to 91.3 dB-A with the highest hearing risk in December and September. In those two months, maximum allowable exposure to noise was exceeded by six times (E(A,8h)). Owing to the precision of the obtained values and their strong uniformity, they may be used in practice by relevant services to evaluate the degree of noise risk among private farmers engaged in plant production.