Concentrations of chrysotile asbestos fibers in surface waters in California are estimated from a mass‐balance model that takes into consideration natural weathering of serpentine rock in the Sierra Nevada and coastal mountains and removal of fibers by coagulation in reservoirs. Fiber concentrations range from 108/L in waters from the western slope of the Sierra Nevada foothills in the central part of the state to 1012/L in rivers in the northwest part of the state. As predicted, fiber removals of from 90 to 99.8 percent were observed in reservoirs with detention times of from 0.5 to 3 years. Removal of submicron‐sized fibers in water treatment plants also ranged from 90 to 99.8 percent, depending on the degree of coagulation prior to filtration.

Belt filter presses were placed into operation at the Robert A. Skinner Filtration Plant in 1985 as part of a renovation of the plant's sludge‐handling processes. Through a series of tests, operational parameters such as solids feed, sludge flow rate, polymer dosage, and belt speed and tension were identified as being critical to belt filter press efficiency and optimization. Although sludge production and cake solids have not met specifications, operation of the belt filter presses at this plant are considered successful.

The refractive index of marine diatoms is measured by immersing them in a solution of pyridine and water. As the refractive index of the solution approaches that of the diatoms, the diatoms tend to disappear. Using this method, the refractive index of Skeletonema sue. was measured to be 1.457 * 0.005