In common use the calculating model of the biggest fall consistency only snits single point polluting source,as for the multiple points using Ganssian normal model directly calculating practical method of the biggest consistency of comnibearing ground the method when programming and counting,it adopts style of distance (step doulbe cycle a.

This way makes the lowest examination density decreased by improving equipment of fixing arsenic and choosing arsenic high-interference ion of shelter reagent trial to recommend way of AG(DDTC) by Nanjing Chemistry & Industry Academy.