Degree Name

Master of Science (MS)

Semester of Degree Completion


Thesis Director

L. Stephen Whitley


A study was made to determine the effect of lead, nickel and pentachlorophenol, at varying pH levels, on the respiration rate of this family of aquatic oligochaetes. Respiration was measured as the ul. of oxygen consumer per mg. of live tissue per hour of exposure.

Worms were found to decrease their rate of respiration in the presence of lead nitrate. This was demonstrated at three pH levels: 6.5, 7.5 and 8.5. It was concluded that this drop was due to the action of lead on the enzymes of the metabolic systems and on the characteristic of lead which stimulates the production of mucus, which prevents normal oxygen diffusion through the body wall.

Nickel chloride initiated a drop in respiration at the pH levels of 7.5 and 8.5. Nickel, classified as a metal activator, inhibited this experiment as a result of the short length of time at which the worms were exposed to the toxicant.

Sodium pentachlorophenate acted as an activator at pH levels of 8.5 and 9.5. The worms respired a higher rate at 9.5.

Included in

Zoology Commons