Figure 18 At the top of the diagram it says 'environmental Al (I I I )'. From here one arrow points to the left and one to the right. The left-hand arrow points to 'gastrointestinal apparatus' From here one arrow points left to 'faeces' while another, labelled 'Al (I I I )' points down to the top of a circle labelled 'bloodstream'. The right-hand arrow from the top points to 'respiratory apparatus'. From here one arrow points to the right to 'accumulation in lungs', while another, labelled 'Al (I I I )' points down to the circle labelled 'bloodstream'.
The arrows making up the bloodstream circle all point anticlockwise around the circle. From the top left of the circle an arrow points to the left to a rectangle labelled 'liver'. From here an arrow labelled 'via bile', points upwards and then joins the previously mentioned arrow which points to the word 'faeces'.
From the left-hand side of the 'bloodstream' circle, an arrow points to the left to a rectangle labelled 'heart muscle'.
From the bottom of the circle an arrow points down to a rectangle labelled 'brain'. To the left of this there is a rectangle labelled 'nose', and it too points to the 'brain' rectangle. From the right of the 'brain' rectangle, an arrow points to the right to the word 'accumulation'.
From the right-hand side of the bloodstream circle, an arrow points to the right to a rectangle labelled 'kidney', from which an arrow points to the right to the word 'urine'.