pollutants are harmful, nutrients beneficial. This is a lame distinction, because some pollutants are 'eaten' by organisms to clean up the site and some molecules are only pollutants in higher concentrations. hm! 0 of e.g. a pond, thoguh one can argue if this should be a quality instead 3-Chlorobenzoate, but the software did not accept a name starting with a number! so I thought I'll cleate the 3CBA as instance, but but rejected as well :( of some component in something else, such as pollutant concentration in the river at some time. or as a quality of the body it is dissolved/suspended in? either the water basin or the water-as-liquid has a concentration of some melecule. that's different levels of granularity (as one cna also say that detritus has a concentration) this class should be abstract, at least for hte time being, because I do not focus on the standard nutrients, therefore there is e.g. no multiple inheritance for amylose subsumed by nutrient. however, it allows for furhter expansion at a later date the exact difference between a lake and a pond is that the former is generally larger, and tends to have inflow of water from a river, need a clearer distinction. the function assigned to the molecule is the distinguishing factor for the organisation of its subclasses see comment Pollutant categorisation of its subclasses based on structural properties, here the division between organic (C-containing) and anorganic molecues (NH4, Zn etc.) the hasVolume is functional, because I do not consider time here (otherwise, one can monitor the volume at different times) intended for use with detritus is-part-of waterbasin, shore is-part-of waterbasin and molecule is-part-of liquidmixture so i thought O could make 3-Chlorobenzoate an instance then of Chlorobenzoate, but does not accept the starting name wiht a number here either so i thought O could make 3-Chlorobenzoate an instance then of Chlorobenzoate, but does not accept the starting name wiht a number here either