Waste Material Behavior and Inorganic Geochemistry at the Puerto Rico Waste Dumpsite

Abstract

Samples of a pharmaceutical waste were taken prior to dumping at a site over the Puerto Rico Trench and analyzed for the cations Ag, Al, As, Ca, Cd, Co, Cu, Fe, Hg, K, Li, Mg, Mn, Mo, Na, Ni, Pb, Sb, Sr and Zn. Iron and Mn were found at concentrations of 170 ppm and 5.2 ppm respectively with the other heavy metals present at below 1 ppm. of the remaining cations, the most abundant were: Ca at 290 ppm, K at 340 ppm, Mg at 33 ppm, and Na at 9,900 ppm.

The major anions were C1⁻ at 8,000 ppm and SO₄ ²⁻ at 13,500 ppm. Total phosphorus was 105 ppm and PO₄ ³⁻−P was present at 53 ppm. The quantity of organic material, pH and physical characteristics were also determined. Analyses of surface water samples, after dumping, for Cd, Cu, Fe, Hg and Ni indicated only Fe levels were distinctly affected by dumping. The highest value noted in the study was 30 ppb, 30 minutes after a dump. The results suggest rapid depletion of surface Fe and indicate a plume surface half-life of about 2.4 minutes.

Suspected dump-induced iron contamination of Zooplankton was seen five hours after one dump but no effects were noted after 24 hours. The toxic trace metals were thus generally present in low concentrations initially and rapidly dispersed in the water after dumping.