Review Domestic waste composting facilities: A review of human health risks José L. Domingo ⁎, Martí Nadal Laboratory of Toxicology and Environmental Health, School of Medicine, “Rovira i Virgili” University, Sant Llorenç 21, 43201 Reus, Catalonia, Spain abstract article info Article history: Received 28 May 2008 Accepted 2 July 2008 Available online 12 August 2008 Keywords: Municipal solid waste Organic fraction Composting facilities Chemical risks Biological risks In the management of municipal solid waste (MSW), the sorting–composting approach presents many advantages. However, since MSW contains a number of chemical and biological agents, the compost should not be necessarily a harmless product. These contaminants may expose different populations to health hazards, ranging from the composting plant workers to the consumers of vegetable products grown in soils treated with compost. Recent information concerning health risks derived from occupational exposure to organic dusts, bioaerosols and microorganisms in MSW composting plants is here reviewed. An evaluation of the potential health risks of volatile organic compounds (VOCs) released during composting is also included. Taking into account the potential biological and chemical risks, an exhaustive control of the workers employed in MSW composting facilities is clearly recommendable. Moreover, because the compost derived from the organic fraction of MSW can contain a number of metals and persistent organic pollutants, as well as microbial and fungi toxins, any compost that may mean a health risk for the population should not be commercialized. © 2008 Elsevier Ltd. All rights reserved. Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 382 2. Composting facilities and chemical risks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 383 3. Composting facilities and biological risks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 384 4. Composting facilities and the surrounding environments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 386 5. Summary and research directions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 387 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 388 1. Introduction Currently, the major methods of waste management are: a) recy- cling—the recovery of materials from products after they have been used by consumers, b) composting—an aerobic, biological process of degradation of biodegradable organic matter, c) sewage treatment— a process of treating raw sewage to produce a non-toxic liquid effluent which is discharged to rivers or sea, and a semi-solid sludge, which is used as a soil amendment on land, incinerated or disposed in a landfill, d) incineration—a process of combustion designed to recover energy and reduce the volume of waste going to disposal, and e) landfill—the deposition of waste in a specially designated area, which in modern sites consists of a pre-constructed ‘cell’ lined with an impermeable layer (man-made or natural) and with controls to minimize emissions (Rushton, 2003). Because of the operative easiness and the low economic costs in most cases, during many years landfills have been among the most extended forms of disposal of municipal solid waste (MSW). Until recent years, it was still considered that about 95% of the generated MSW on world-wide scale was still being deposited in landfills (El- Fadel et al., 1997). However, it is well known that generation of gas and leachates mainly due to microbial decomposition, climatic conditions, and the own characteristics of the waste, are inevitable consequences of the disposal in landfills. The risks for the public health due to the potential exposure to pathogenic agents, toxic substances, and gases, together with the annoyances derived from the bad odors, the migration of gases and leachates outside the limits of the landfill, and their release to the surrounding environment, raise a number of important environmental questions including the possibility of fires Environment International 35 (2009) 382–389 ⁎ Corresponding author. Tel.: +34 977 759 380; fax: +34 977 759 322. E-mail address: joseluis.domingo@urv.cat (J.L. Domingo). 0160-4120/$ – see front matter © 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.envint.2008.07.004 Contents lists available at ScienceDirect Environment International journal homepage: www.elsevier.com/locate/envint 32