Municipal landfill leachates: a significant source for new and emerging pollutants

Landfills have historically remained the most common methods of organized waste disposal and still remain so in many regions of the world. Thus, they may contain wastes resulting from several decades of disposal and decomposition with subsequent release of organic compounds that may have environmental, wildlife and human health consequences. Products containing different types of additives with unique beneficial improvement properties are in daily use. However, when these products are decomposed, additives are release into the environment, some of which have been shown to have negative environmental impacts, resulting in the ban or at least restricted application of some chemicals. New and emerging compounds are continuously discovered in the environment. Herein, we report qualitative and quantitative data on the occurrence of new and emerging compounds with increasing environmental and public health concern in water- and particle phase of landfill leachates. Under normal environmental conditions, several of these chemicals are persistent high-volume products. Identified chemicals in the leachates at nanogram (ng) or microgram (microg) per liter levels include - chlorinated alkylphosphates such as tris(1-chloro-2-propyl) phosphate (TCPP), N-butyl benzensulfonamide (NBBS), the insect repellent diethyl toluamide (DEET) and personal care products such as the non-steroidal anti-inflammatory drug ibuprofen and polycyclic musk compounds. Among new and emerging contaminants, perfluorinated compounds (PFCs) were measured in the water phase at concentrations up to 6231 ng/L. Compared with the other chemicals, PFCs were primarily distributed in water phase. An effective removal method for PFCs and other polar and persistent compounds from landfill leachates has been a major challenge, since commonly used treatment technologies are based on aeration and sedimentation. Thus, the present study has shown that municipal landfill leachates may represent a significant source of concern for legacy, new and emerging chemicals in groundwater.