Indicator chemicals

Transfer of AOX from facilities

The level of halogenated organic compounds (AOX) is a standard parameter in assessing water, waste water and sewage sludge. AOX is the sum of adsorbable organically bound halogens (X = halogen). In general, the main source is waste water from households and industrial operations. AOX is a parameter that includes a broad variety of different substances. The data is based on the SwissPRTR (Swiss Pollutant Release and Transfer Register).

Assessment of the state
impossible to evaluate impossible to evaluate
Assessment of the trend
impossible to evaluate impossible to evaluate
Transfer of AOX from facilities in kg 2016: 358969 Transfer of AOX from facilities in kg 2015: 357259 Transfer of AOX from facilities in kg 2014: 387985 Transfer of AOX from facilities in kg 2013: 420215 Transfer of AOX from facilities in kg 2012: 359834 Transfer of AOX from facilities in kg 2011: 411339 Transfer of AOX from facilities in kg 2010: 504840 Transfer of AOX from facilities in kg 2009: 206210 Transfer of AOX from facilities in kg 2008: 321359 Transfer of AOX from facilities in kg 2007: 254757

Data for the graph: Excel
Source: FOEN

In 2016, approximately 360,000 kg of halogenated organic compounds were reported as having been transferred to waste water. The quantity has hardly changed compared to the previous year.

At first glance, a reduction in the release of pollutants would seem to be a positive development for the environment, an increase negative. However, as a rule, it is not possible to judge the situation without knowing the reasons for the change and the consequences of it. It is particularly important to clarify whether a reduction is due to production being transferred abroad. If that is the case the pollutants are merely released abroad instead of in Switzerland. Switching to a different production method may bring about a decrease in levels of pollutants released, but cause an increase in other pollutants. The same considerations apply to volumes of pollutants in waste water. Furthermore, depending on the pollutant, treating the substance in waste water may be a preferable option to uncontrolled release to the atmosphere.

International comparison

Data on the release of pollutants and transfers of wastes are compiled in comparable ways in all countries where the PRTR Protocol has been implemented, and this includes all EU countries. However, since the figures are in absolute terms, a meaningful comparison cannot be made at the national level, because such a comparison would automatically favour smaller countries with less industry. Detailed data on individual operations can be compared, however.


The Swiss Pollutant Release and Transfer Register (SwissPRTR) provides information about releases of pollutants and transfers of wastes, and is updated annually. Facilities in certain industries and of a minimum size are required to report the quantities of 86 specific pollutants that were released into the air, water or ground by their operations in the previous calendar year. Threshold values specific to the different substances apply, which when exceeded trigger the reporting requirement. The data do not show directly how large the facilities in question are. Important parameters such as the production volume, number of workers or capacity of a facility influence the amounts of pollutants and waste produced directly or indirectly, and naturally vary greatly depending on the branch of industry. Industries’ self-reporting is based on measurements, calculations and estimates and is monitored by cantonal authorities.

Last updated on: 16.10.2018

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