Materials selection for a dry atmospheric mercury deposits sampler

In order to develop a sampler for measuring dry deposition rates for atmosp heric mercury, suitable materials are needed that neither adsorb nor releas e mercury. In this paper, four materials (polyvinyl chloride (PVC), acrylon itrile-butadiene-styrene (ABS), Teflon and glass) were tested. Each of the materials was placed in a beaker containing mercuric solution under varied conditions for pH, preservative concentration, initial mercuric concentrati on, temperature, acid type and contact time of the material. The concentrat ions of the mercuric solutions were determined using the cold-vapor atomic absorption (CVAA) technique. The experimental results show that glass has t he lowest absolute net adsorption rates (NARs) of 0.026-1.13 mug/m(2) among the materials tested. Teflon, PVC and ABS have NARs ranging from 0.54 to 1 0.4 mug/m(2) over an adsorption duration of one or two weeks. ABS has signi ficantly higher adsorption rates for mercury than PVC and Teflon, indicatin g its inappropriateness as the material for building the sampler. Teflon an d PVC will be the materials of choice for the sampler. The experimental res ults can also be used in establishing appropriate sampling conditions in th e field. (C) 2001 Elsevier Science Ltd. All rights reserved.