A major activity of BCAA is the collection of samples from different Antarctic sites and representative of the various environmental compartments. The sampling activity has been carried out since 1994 and more than 3000 samples are currently stored in the BCAA facilities.
Distribution of the samples stored at BCAA according to the matrix
Sample collection is performed according to well-defined procedures aimed at guaranteeing their integrity for the analysis of chemical species. Due to the very low analytical concentrations, sample collection is always performed under ultra-clean conditions, with a strict control and evaluation of any possible source of contamination. The measures taken to minimize the contamination during the sampling activity include the extensive cleaning of materials, contamination checks and the use of clean room clothes. Field blanks are taken concomitantly with the samples. Details on the sampling procedures according to the matrix can be found in the publications listed here. Briefly:
Atmospheric particulate matter. The samples are collected on 0.3 µm cellulose filters by using a Grasbery-Andersen (PM10) High Volume Sampler (1.13 m3/min) with 1 impactor stage. The typical sampling period is 10-12 days. Each sample is divided into four parts, one of which is stored in polystyrene container at -25 °C, together with 1/4 of field blank (filter placed in the switched-off sampler for a few tens of minutes).
Surface snow. Samples are collected in 1-L low-density polyethylene bottles or 50-mL polypropylene graduated tubes, sealed inside double polyethylene bags and stored at -25 °C. Field blanks (empty sampling tubes opened and exposed in the field for a few minutes) are concomitantly collected.
Firn. The sampling is carried out by manually digging a trench, removing the potentially contaminated layers by means of a polypropylene scalpel and horizontally inserting 1-L low-density polyethylene bottles or 50-mL polypropylene graduated tubes to take the samples at the required depth. The samples are sealed inside polypropylene bags and stored at -25 °C. Field blanks (empty sampling tubes opened and exposed in the field for a few minutes) are concomitantly collected.
Lake water and suspended particulate matter. The surface water is collected near the lake shore into 1-L low-density polyethylene bottles and filtered under a laminar flow hood through polycarbonate membranes (diameter: 47 mm, porosity: 0.4 micron) using a teflon apparatus under nitrogen pressure. The water samples are collected into 0.5-L polyethylene bottles, sealed inside polypropylene bags and stored at -25 °C. The membranes are stored in polystyrene containers at -25 °C.
Lake sediment. The sampling is carried out near the lake shore by a polyethylene scoop. The samples (1 kg) are stored in polycarbonate containers at -25 °C.
Seawater and suspended particulate matter. Sea water is collected by 20-30L GO-FLO teflonated bottles (General Oceanics) at the required depth and filtered under a laminar flow hood through polycarbonate membranes (diameter: 142-mm, porosity: 0.4 micron) using a teflon apparatus under nitrogen pressure. The water samples are collected into 0.5-L polyethylene bottles, sealed inside polypropylene bags and stored at -25 °C. The membranes are stored in polystyrene containers at -25 °C. Occasionally, seawater and suspended particulate matter samples have been obtained by using the in-situ filtration system FIS-500.
Marine sediment. Surface sediment samples are collected using a stainless-steel grab and stored in polycarbonate containers at -25 °C. Sediment core samples are collected by a box-corer and stored in polyethylene tubes at -25 °C.
Marine organisms. Benthic organisms are manually collected at 10–30 m by scuba diving, sealed in polyethylene bags and stored at -80 °C. Fish specimens are caught by trammel net or fishing line, sealed in polyethylene bags or aluminum foil and stored at -80 °C.
Sea ice. Snow is cleared from the surface of the sea ice, and cores are collected by means of a manually driven 8-cm diameter titanium corer (Duncan, UK, Model BTC). Samples are handled using polyethylene gloves and stored at -25 °C in clean polyethylene bags until processing (cutting and sub-coring to remove eventual contamination due to sample collection).
Soil. The sampling is carried out by a polyethylene scoop. The samples (0.5 kg) are stored in polycarbonate containers at -25 °C.