ENVIRONMENTAL FATE ASSESSMENT OF 2 SYNTHETIC POLYCARBOXYLATE POLYMERS

In order to estimate the proportion which may enter the aquatic enviro nment and characterize exposure potential, the environmental fate prop erties of two polycarboxylate polymers in activated sludge were determ ined. The polycarboxylates studied were a polymer emulsion (PE), a hig h-moIecular-weight polymer (MW 50,000-60,000), and a resin polymer (RP ), a low-molecular-weight polymer (MW 4500 to 9000), Both polymers exh ibited a high degree of sorption to sludge solids in a series of sorpt ion/desorption studies, indicating a high potential for removal during wastewater treatment, In isotherm tests, the adsorption coefficient, K-oc, was 1060 and 2730 for the RP and the PE, respectively, The biode gradation of the two polymers was measured under aerobic conditions in a 60-day semicontinuous activated sludge test and in a 60-day modifie d Sturm test using C-14-labeled compounds, In both studies, polymers a ccumulated in sludge solids over time and there was no evidence of sig nificant biodegradation, although small amounts of radiolabeled CO2 we re produced, suggesting the potential for biodegradation. Testing conf irmed that the lack of biodegradation was not due to inhibition of mic robial respiration by the polymers, High removals of PE and RP during wastewater treatment were confirmed in a field study at a facility rec eiving polymer inputs from households and manufacturing plants. (C) 19 97 Academic Press.