Stephen E. Musson

Pharmaceutical compound content of municipal solid waste.

The occurrence and fate of pharmaceuticals in landfills has been largely neglected. Once discarded in municipal solid waste (MSW), pharmaceuticals within a landfill may undergo degradation, adsorption, or enter the leachate and eventually exit the landfill. The active pharmaceutical ingredient (API) concentration of MSW was predicted using available statistics on medication usage and directly measured by a MSW composition study. Estimation calculations resulted in a potential concentration of APIs from 7.4 to 45 mg/kg of MSW, varying with the percentage of dispensed medications assumed to become unused. Direct measurement resulted in the collection of 22 APIs comprising a total of 22,910 mg. This resulted in a final concentration of 8.1 mg/kg within MSW. Additionally, 45 empty medication containers were collected which potentially contained 33 differing APIs upon disposal.

Assessment of the anaerobic degradation of six active pharmaceutical ingredients

Research examined the anaerobic degradation of 17 alpha-ethynylestradiol, acetaminophen, acetylsalicylic acid, ibuprofen, metoprolol tartrate, and progesterone by methanogenic bacteria. Using direct sample analysis and respirometric testing, anaerobic degradation was examined with (a) each compound as the sole organic carbon source and (b) each compound at a lower concentration (250 microg/L) and cellulose serving as the primary organic carbon source. The change in pharmaceutical concentration was determined following 7, 28, 56, and 112 days of anaerobic incubation at 37 degrees C. Only acetylsalicylic acid demonstrated significant degradation; the remaining compounds showed a mixture of degradation and abiotic removal mechanisms. Experimental results were compared with BIOWIN, an anaerobic degradation prediction model of the US Environmental Protection Agency. The BIOWIN model predicted anaerobic biodegradability of the compounds in the order: acetylsalicylic acid > metoprolol tartrate > ibuprofen > acetaminophen > 17 alpha-ethinylestradiol >progesterone. This corresponded well with the experimental findings which found degradability in the order: acetylsalicylic acid > metoprolol tartrate > acetaminophen > ibuprofen.

A Continuous Collection System for Household Pharmaceutical Wastes: A Pilot Project

Abstract A 5-month “self-serve” pilot project was implemented to properly dispose of old and unwanted prescription and nonprescription medications. Obstacles encountered during the program included reluctance by major drug store chains to participate, regulatory and legal restrictions on pharmaceutical handling, and collection of detailed data from participants. Despite these difficulties, a total weight of 305 lb of discarded pharmaceuticals was collected during the pilot program period from an estimated 500 participants. A survey of participants indicated that discard of pharmaceuticals to the sanitary sewer, a newly discovered environmental hazard, is commonplace, with approximately 50% of participants using this method previously. The average age of the patients using the disposed medication was approximately 64 yr old, with the large majority being above 50 yr in age. The majority of participants learned of the program through newspaper advertisement. The average age or time after purchase of the medication was approximately 3 yr, and the primary purpose cited for its disposal was that the medication had exceeded its expiration date.

Destruction of trichloroethylene during hydration of calcium oxide.

Quicklime (calcium oxide, CaO) is often used as part of soil cleanup operations to remove contaminants or to create more favorable physical soil conditions for treatment. The extent to which quicklime chemically reacts with trichloroethylene (TCE) was evaluated by reacting CaO with a TCE-water mixture in test vessels designed to minimize volatilization loss. The impact of excess water and the presence of air were evaluated. During the hydration of CaO, a fraction of the spiked TCE was destroyed, and several different byproducts were detected (chloride and several organic chemicals). The primary organic byproduct was dichloroacetylene (DCA). In the presence of air, the degradation of DCA resulted in the formation of perchloroethylene (PCE), hexachloro-1,3-butadiene (HCDE), and chloroacetylene (CA). The maximum amount of TCE degradation occurred with a CaO/H(2)O ratio of 1:1 in the presence of air. The formation of DCA was hindered by the presence of excess water. In the presence of excess water (a CaO/H(2)O ratio of 1:2) the detected byproducts accounted for less than 4% of the total chlorine originally spiked as TCE.