Tender For proficiency testing samples for laboratories - waste water havy metals , waste water biological , waste water herbicide , waste water pesticides 1 , waste water pesticides 2 , waster water physicochemical 1 , waster water physicochemical 2 , waster water physicochemical 3 , surface or ground water heavy metals 1 , surface or ground water heavy metals 2 , surface or ground water biological , surface or ground water herbicide , surface or ground water pesticides 1 , surface or ground water pesticides 2 , surface or ground water physicochemical 1 , surface or ground water physicochemical 2 , surface or ground water physicochemical 3 , soil and solid wastes sludge slurry powder heavy metals , soil and solid wastes sludge slurry powder physicochemical 1 , soil and solid wastes sludge slurry powder physicochemical 2 , air stack emissions 1 , air stack emissions 2 , air stack emissions 3 , air ambient air 1 , air ambient air 2 , air ambient air 3 , air ambient air 4 , air ambient air 5