Identification of Free Organic Chemicals Found in Composted Municipal Refuse

Abstract

AbstractComposted municipal refuse can be considered as a low‐grade fertilizer, but its use on land is limited by the level of contamination from heavy metals and toxic chemicals. In order to evaluate the qualitative composition of the organic fraction of these materials, three Spanish refuse composts were analyzed.The samples were sequentially extracted with ether and ethanol, which constitute the total lipids extract. The nonsaponifiable fraction is made up of n‐alkanes, in the range of C18 to C32, as well as olefins. The saponifiable fraction contains n‐fatty acids from C14 to C26 and some branched fatty acids. The method used for separation and identification of specific organic compounds in sediments was adapted for municipal composts and the resulting methylene chloride extract subjected to gradient chromatography on alumina. The fractions eluted from the column with pentane, and pentane‐methanol contained aliphatic hydrocarbons; the benzene fraction was made up of phthalate esters, and the benzene‐methanol and methanol fractions contained a mixture of aliphatic hydrocarbons, phthalate esters, n‐fatty acid methyl esters, and some individual compounds. The presence of aliphatic hydrocarbons and fatty acids in municipal composts suggested a microbial origin, while phthalate esters may arise from the debris of plastic packaging.