Effects of Sulphur Dioxide on Guinea Pigs and Swine

Guinea pigs and swine were exposed to sulphur dioxide concentrations varying from 5-40 P.P.M. The average daily weight gains of young guinea pigs were impaired by gas concentrations of 10 P.P.M. and 18 P.P.M. for periods of 96 hours or more. A single experiment failed to indicate any synergism between sulphur dioxide and hydrogen sulphide. Studies on the effect of exposure to 5 P.P.M. for an extended period were inconclusive. Young swine under seven days of age were exposed to sulphur dioxide concentrations of 5, 10, 20, and 40 P.P.M. for a single eight-hour period for each group. All concentrations caused the animals to display some evidence of irritation from the gas, ranging from eye irritation, nasal secretion, salivation and altered respirations at levels of 10 P.P.M. and higher to slight eye irritation and salivation at levels of 5 P.P.M. Haemorrhage and emphysema were present in the lungs of swine exposed to 40 P.P.M., and sacrificed at twenty-four hours and seven days post-exposure. At 158 days post-exposure, two of two swine exposed to 40 P.P.M., and one of two swine exposed to 20 P.P.M. showed a pulmonary fibrosis that was attributed to the gas. Impaired weight gains of exposed animals raised to market weight (158 days) could not be attributed to the gas.