Pollution sampling

Measuring pollutants requires
1. Proper sampling to avoid contaminating the samples
2. Careful laboratory analysis

1. Sampling

There are a variety of sediment and water samplers to collect samples. We use VanVeen Grabs and Smith MacIntyre Grabs to collect sediment, and Niskin bottles or Rosette samplers to collect water.

2. Laboratory Methods

Organics

The sediments are weighed, then organic solvents are added to get the organic compounds of interest out of the sediments and into a liquid form. The samples are then filtered through silica columns, concentrated, and injected into either a Perkin-Elmer Gas Chromatograph-Mass Spectrometer or a Perkin-Elmer Gas Chromatograph-Electron Capture Detector for analysis.

Trace Metals

Sediment samples are first measured for grain size, using Elzone analysis. (Why does grain size matter?)
They are then measured for organic carbon content, using loss-on-ignition and a carbon-hydrogen-nitrogen analyzer. (Why does organic carbon matter?)
Samples are then digested using acids, in order to get the metals of interest out of the sediment.
Extracts are injected into a Graphite Furnace Atomic Absorption Spectrometer (GFAA) and an Inductively Coupled Plasma Atomic Emission Spectrometer (ICP-AES) for measurement.

Tissue

The tissues of quahogs (Mercenaria mercenaria) are blended to a fine baby-food-like consistency. After this, they are treated the same way as the sediment, with the normal extraction procedures. Lipid content is also analyzed.