A: The simple answer is ideally yes, but there are other considerations. Because the DGT assembly is thin it does not contain a lot of oxygen and, within a short period of time, (say 30 minutes) the oxygen within the DGT gels will be consumed by the oxygen diffusing out into the sediment and electron donors diffusing into the gels. Clearly this will compromise the DGT measurement of redox sensitive and secondary affected components (e. g. trace metals) within this 30 minute time period of initial accumulation. However, DGT is usually deployed for times in excess of a day. Therefore, this initial period where the presence of oxygen can have an effect on the DGT accumulation will only represent about 2% of the total accumulation time. Consequently the effect on the DGT measurement is likely to be negligible.  There is an urgent need for work to be done to verify experimentally the effect of preliminary deoxygenation on DGT measurements.

Even deoxygenation of the DGT probes is not so straightforward because it will only be effective if the transfer of the DGT probes from their deoxygenation solution to the sediment can be done within no more than a few 10s of seconds. Exposure of the probe to the air for longer times will quickly replenish the oxygen, as demonstrated in Davison, W., Zhang, H. & Grime, G.W. (1994).  Performance characteristics of gel probes used for measuring the chemistry of pore waters. Envi. Sci. Technol. 28, 1623-1632.