Planned landfill in the headwaters of the Río Huicha, Chiloé (Chile)

Leachates, which are a toxic mixture of chemical compounds, are formed in landfills of household and industrial waste, particularly in areas of high precipitation. These leachates can, despite the presence of landfill linings, directly affect groundwater quality and, consequently, have negative long-term impacts on the health of human populations as well as a detrimental effect on aquatic ecosystems 1-5. Studies have shown that certain substances in leachates such as surfactants affected the polymere bonds within linings of HDPE membranes, making them permeable with time1. Moreover, organochlorines that are common in leachates, diffuse through HDPE membranes of varying thickness6,7. These substances bioaccumulate in cell tissues causing serious long-term health effects.
Uncontaminated river systems are characterized by hundreds of different species 8 that are functionally linked and interconnected in complex trophic networks 8-11. The mostly groundwater-fed river catchment of the Río Huicha and its tributaries in the sector of San Antonio de Huelden (District of Ancud, Chiloé, Chile) is one of the few ecosystems in Chile with an intact link between the native rainforest and fluvial systems, which is characterized by a very high aquatic biodiversity (hotspot of biodiversity). Preliminary results obtained by analysing just five different sampling sites in the headwater region of this river catchment demonstrate the presence of > 400 species, which is far higher than that of any other river ecosystem studied in Chile, and possibly worldwide 12. Previous investigations into the species composition and their interconnections in fluvial systems have ignored the presence of micro- and meiofauna in Chile. Our preliminary results underline that these headwaters of the Huicha river basin are unique and pristine sites with several new species for science and > 90 new records for Chile . These species are important links within the aquatic food-web 9-11 contributing further downstream to fish, amphibians, birds and mammals, while many of those species are in vulnerable and endangered conservation categories in Chile.

Selected scientific publications

1. Sangam, H.P. & Rowe, R.K. 2001. Geotextiles and Geomembranes 19, 329.
2. Öman, C., Hynning, P.A. 1993. Environmental Pollution 80, 265.
3. Öman, C. & Rosqvist, H. 1999. Water Research 33, 2247.
4. Kjelsen, P. et al. 2002. Critical Reviews in Environmental Science and Technology 32, 297.
5. Öman, C. & Junestedt, C. 2008. Waste Management 28, 1876.
6. Müller, W. W. 2007. HDPE geomembranes in geotechnics., Springer Verlag, Heidelberg, Germany, pp.485.
7. Müller, W. W. 2009. Dichtungsbahnen zur Abdichtung von Deponien und Altlasten. en: Fachtagung "Die sichere Deponie 2009 – Abdichtung von Deponien und Altlasten mit Kunststoffen" Veranstalter: SKZ - ConSem GmbH, Würzburg und AK GWS Arbeitskreis Grundwasserschutz e. V, Berlin, 1.
8. Schmid, P.E. et al. 2000. Science 289, 1557.
9. Schmid-Araya, J.M. et al. 2002. J. Anim. Ecol. 71, 1056.
10. Schmid-Araya, J.M. et al. 2011. Austral Ecology 37, 440.
11. Schmid-Araya, J.M. et al. 2016. Ecology 97, 3099.
12. Schmid, P.E. & Schmid-Araya, J.M. in prep.