SLEW-3: Estuarine water reference material for trace metals

This certified reference material is primarily intended for use in the calibration of procedures and the development of methods used for the analysis of seawater for trace metals.

SLEW-3 is the third estuarine water certified reference material for trace metals prepared by NRC. Unlike the previous two samples, this water was gathered in the San Francisco Bay at the 5 m level near Pt. Molate at latitude 37° 57.470' and longitude -122° 25.703'.

The water was peristaltically pumped through cleaned polyethylene lined ethylvinyl acetate tubing and 0.45 μm acrylic copolymer filters. It was acidified to pH 1.6 with ultrapure nitric acid during its immediate transfer to 50-litre acid leached polypropylene carboys. The water was later refiltered through 0.2 μm porosity acrylic copolymer filters and homogenized in a 400-litre polyethylene tank in a clean room at NRC in Ottawa. It was subsequently bottled in cleaned 500 mL polyethylene bottles and gamma irradiated with 25 kGy at the Canadian Irradiation Centre, Laval, Québec, to inhibit any bacterial action. The salinity is 15.

Keywords: Environmental material, Natural water, Seawater , Trace elements, Heavy metals