Hearing Acuity Loss Of Operators Of Food Grinding Machines In Calabar, Nigeria

Abstract

Summary: Noise has been generally found to cause hearing impairment. This was therefore a comparative study to determine whether chronic exposure to noise generated from food grinding machine can impair hearing acuity. Forty food grinding machine operators in Watt and Marian markets, Calabar, who were exposed to noise for at least 6 months formed the test subjects. Control subjects, however, were age-and sexmatched staff and students of the University of Calabar and University of Calabar Teaching Hospital, Calabar, who were exposed to low noise level. Results obtained showed that noise level in test sites (105.8 ± 9.24dB) was significantly higher than that in the control sites (55.5 ± 1.78dB; P< 0.001). At every frequency tested, the machine operators had poorer hearing acuity than control subjects. The hearing threshold of the machine operators positively correlated with their duration of exposure at 2000Hz and 4000Hz, (r = 0.357, P< 0.001; r = 0.444, P< 0.001 respectively) and age at 2000Hz, 4000Hz and 8000Hz (r = 0.266, P<0.05; r = 0.308, P<0.01, r = 0.292, P<0.01 respectively). The prevalence of hearing loss among the machine operators was significantly higher (62.5%), compared to control (15.79%; P<0.01). The incidence of symptoms such as tinnitus, insomnia and headache was also significantly higher in the test group (26.32%, 21.05% and 34.2%) than in the control (5.26%, 2.63% and 5.26% respectively; P < 0.01). Therefore, chronic exposure to food grinding machine noise at 105.8 ± 9.24dB can impair hearing acuity and associated risk factor appears to be prolonged exposure.

Noise exposure levels and health implications on daily road side petty traders at some major roundabouts in Ibadan, Nigeria

“…The standard measurement of noise exposure in relation to health of an individual in an environment should be in the range of 80 to 90 dBA. In a recent study of effects of noise on Nigerian workers, it was reported that 100% of workers which include the petty traders exposed to noise for a period of 14 years, developed hearing impairments (Ighoroje et al, 2004;Bisong et al, 2004). A similar result from a study was reported by Yesufu et al (2013).…”

Assessment of Air and Noise Pollution from Industrial Sources in Ibadan, Southwest, Nigeria

“…Ozer et al (2009) revealed a very high noise level in some areas of Tokat city, Turkey which includes public structures, hospitals, schools and houses with noise levels over 75 dB, while Osemeikhian and Anomohanran (2006) recorded noise levels above 90 dBA in Warri, Nigeria. High noise levels may predispose residents of this study area to health problems such as noise-induced hearing loss, tinnitus, insomnia and headache, as reported by Bisong et al (2004) that members of the community that are exposed to 105.8±9.24 dBA of noise level suffered from noise-induced hearing loss, tinnitus, insomnia and headache. There is a special concern for the children attending the various schools located very close to the industrial area as it could be a serious source of distraction among other effects.…”

Health Effects caused by Noise - The Case of Africa: Evidence in Literature from the Past 25 Years

“…In Calabar-Nigeria, operators of food grinding machines suffered health effects like hearing loss and symptoms such as tinnitus, insomnia and headache. Operators were exposed to noise for at least six (6) months at 105.8 dB [40]. Furthermore, researchers in Tanzania found out that the power plant section of a cement factory produced noise level of 104.8 dBA which exceeded the allowed limit value of 85 dBA as recommended by Tanzania Bureau of Standards (TBS).…”