The role of human excretion, drinking water, and deposition as a source of heavy metals to municipal sewage was investigated and compared with common levels in sludge for soil application. These ...sources contributed more than half of the copper (Cu), zinc (Zn), and lead (Pb) content of municipal sewage sludge for soil application, while other sources dominated the fluxes of chromium (Cr) and cadmium (Cd). Drinking water was an important source for Cu and Zn. Deposition contributed about 40% to the Pb flux. Faecal excretion commonly caused less than 10% of the heavy metal load, while urinary excretion was here a negligible heavy metal source.
The cumulative urinary excretion of four different aspirin products (two tablets, a capsule, and a timed-release tablet) was determined in a crossover study using five subjects. Comparison of in vivo ...results showed a significant difference in cumulative urinary excretion levels at only 1 hr. The excretion from the two regular tablets was significantly different from the timed-release tablet, but the capsule showed no significant difference from the other three products. Each product was tested in the USP, Levy beaker, and the regular and large magnetic basket dissolution apparatus. Analysis of variance of the in vitro results showed a significant difference between the aspirin products and the dissolution methods at selected times. In vitro comparison with in vivo results for the four products showed that a regression analysis can be used to determined which dissolution methods produce a significant correlation with urinary excretion.
