This document applies to the use of the grass Lolium multiflorum ssp. italicum designated hereafter as Italian ryegrass for the bioaccumulation of substances liable to cause atmospheric pollution. It is an active biomonitoring approach insofar as the plants used are first cultivated in set conditions before being exposed at the monitoring locations in the field. The plants then record any pollution events that occur while they are being exposed, allowing such events to be accurately dated.

The method described in this document can be applied for identification and localization of one or more single pollution sources and the tracking of their “plume” on a local or regional scale. It also offers a tool to monitor sites in the long term by the repeated application of a clearly defined procedure and to describe the local or regional air pollution situation.

The method applies to solid and gaseous substances deposited on plants, where they may accumulate on their surface or in their tissues. These substances include sulphur, chloride, fluoride and especially metals as well as low volatile organic and halo-organic compounds such as polycyclic aromatic hydrocarbons (PAH), polychlorinated biphenyls (PCB), polybrominated diphenyl ethers (PBDE), polychlorinated dibenzo dioxins (PCDD) and polychlorinated dibenzo furans (PCDF). It is as well possible to verify pesticides which are used in plant protection products. The range of potential substances may be expanded according to the task at hand and the capabilities of conducting trace analyses and assessment.

The method described in this document allows spatial and temporal comparisons and allows for screening, thus providing a first indication of risk. The results of grass culture studies can suggest risks to biota (e.g. via the food chain) which require further investigation.

The method described in this document does not replace physico-chemical methods of direct measurement or modelling of air pollutants and cannot be replaced by them for its part; it complements them by indicating biological effects.

Potential areas of deployment are:

- Permit procedures related to air pollution legislation;

- Preservation of evidence related to the code for protection from pollution;

- Monitoring of emission sources and performance control;

- Assessment of local-scale emission transport;

- Evidence of causation, e.g. related to environmental liability;

- Air quality maintenance plans/strategies;

- Long-term monitoring of ecological effects of atmospheric depositions;

- Detection and assessment of local, regional, and countrywide effects of atmospheric depositions;

- Assessment of risks for humans and/or animals via the food chain.

This document is of interest to those involved in environmental monitoring.