A remotely operated airboat for metal-free, ultraclean water sampling for trace elements in lentic waterbodies: from design and fabrication to operation in the field

The mitigation of contamination during water sampling remains one of the primary challenges for trace elements research. In shallow water bodies, it is especially important to avoid disturbing the sediments to avoid the introduction of particles and colloids containing trace elements to the water column. Traditional sampling protocols can stir up sediments, and conventional equipment containing metal alloys presents additional sample contamination risks. Here we describe the design, construction, and testing of a metal-free unmanned, remotely operated airboat for sampling lentic freshwater habitats. The SWAMP airboat consists of two pontoons that support a water sampler containing four winches to lower and raise 60 mL bottles to sample from desired depths. The airboat is driven by two motorized propellers and is equipped with Cube Autopilot to stabilize the airboat during sample collection. • A 3D printer was used to construct plastic components for the airboat, composed of polyethylene terephthalate glycol (PETG), PolyMide™ CoPA nylon, high density polyethylene (HDPE), and polycarbonate (PC) carbon fiber. • Solenoids were programmed to remotely open and drop weights that open valves on the 60 mL sampling bottle to collect water at specified depths. • The SWAMP airboat was successfully field-tested at two locations in Alberta, Canada.