Comparing representations of the environmental spatial scale of organic chemicals

Long-range transport potential is one of the criteria proposed to identify chemicals as persistent organic pollutants. Here, different approaches to d etermine the spatial scale of an environmental area or region that can be i mpacted by an emitted chemical are investigated. A ranking of chemicals acc ording to the spatial range R on a limited scale, as suggested by Scheringe r, Ls equivalent to the characteristic travel distance L according to Benne tt et al. on a linear, open scale. However, the methods are different with respect to the weighting of differences between the chemicals and according to their comparability with persistence. The characteristic travel distanc e L and the overall persistence a-re both plotted on open log-linear scales , whereas the spatial range R is represented on a limited scale. Various ap proaches of how to account for the mode of entry of chemicals are compared, and it is argued that relative measures are more appropriate to describe t he long-range transport potential of chemicals than absolute numbers.