Peat & Sediment Sampling

I’ve always mentally classified sediments as weak, less cohesive soils but recently over dinner in a hotel in Kolkata, India with two professors of Geography it was pointed out to me that soils are sediments. A heated discussion between these eminent academics ensued and I kept quiet but it ended abruptly when one of them said quite forcefully that he should know because after all he was a sedimentologist. Be that as it may, for the classification of the equipment we offer I find it easier to distinguish between soil and sediment by characterising them as more cohesive and less cohesive materials. To make it academically even more intolerable I will include peat or highly organic soils in with sediments.

Sediments present special challenges. Because they are weak and are not cohesive, retention of the sample is often difficult which means that it must be enclosed or captured in a liner as incorrect samples lead to errors in analysis and therefore the conclusions.  Peat soils can often be captured in gouge augers or a peat or Russian corer but where the sediments are very sloppy and especially when sampling below the water table different equipment is required.  Mostly these samples are taken with a piston sampler such as the Multisampler, Beeker sampler or Stitz corer.  They will be inserted in the material in a closed position and only opened at the start of the desired horizon. These samplers are also very useful in capturing the water/sediment interface which is often of immense importance to researchers to test if the contaminant is contained or occurs in both materials. Mostly, the use of these piston type samplers produce a virtually undisturbed sample but for rough and ready work Van Veen type samplers can also be used.