Background, generally distribution studies

Figure 14. Case study 1 contaminated situations. Geographic distribution of arsenic contents in different environmental compartments of the Malcantone area, Ticino /Switzerland soils, river sediments and aquatic mosses. Data from this study. State Laboratory, Canton Ticino, and Martini and Fillet (1996).The whole area is naturally contaminated with arsenic originating from numerous smaller and larger ore deposits dominated by Fe, As, Zn, Pb and Sb (indicated with black spots). The general background of As in the till material forming the aquifers varies between 50 and 150 ppm, but locally values up to 500 ppm occur.

Animals live in a world of chemical communication and receive both olfactory and visual cues that indicate appropriate host plants. When the animal has located the flower against the generally green background, it may be attracted to the nectar by nectar guides on the petals. These are derived from differential distribution of pigments within the flower tissue. The biochemistry of plant pollination mechanisms has not been studied extensively. 

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