Sources of sound in the laboratory animal environment: A survey of the sounds produced by procedures and equipment

Sounds in the laboratory and animal house environment were monitored for so und pressure levels over both low frequency (10Hz-12.5kHz) and high frequen cy (12.5-70 kHz) ranges and were recorded for frequency analysis over the r ange 10Hz-100kHz. Forty sources of sound were investigated at 10 different sites. Sources included environmental control systems, maintenance and husb andry procedures, cleaning equipment and other equipment used near animals. Many of the sounds covered a wide frequency band and extended into the ult rasonic (> 20kHz) range. Sound levels produced by environmental control sys tems were generally at a low level. High sound pressure levels (SPLs) up to and exceeding 85dB SPL were recorded during cleaning and particularly high levels were recorded from the transport systems studied. Equipment such as a tattoo gun, a condensation extractor system, a high-speed centrifuge, an d an ultrasonic disintegrator produced high levels of sound over a broad sp ectrum. As many laboratory animals are much more sensitive to a wider range of soun d frequency than humans, it seems likely that the levels of sound reported here could adversely affect animals through physiological or behavioural ch anges, or may even cause sensory damage in extreme cases. There appear to h ave been no studies on the minimal threshold levels for such adverse respon ses or on the long-term effects of exposure to the types of sounds recorded here. It is not yet possible to set realistic exposure limits for laborato ry animals.