Point source sampling is ideal for obtaining high quality, representative samples of groundwater from specific depths. It allows the collection of water that has just flowed into a well at the desired sampling point. This can avoid purging and disposal of purged water.
The Point Source Bailer can be used to profile an open borehole or screened well, collecting samples from distinct levels or points of inflow. Sample biases due to mixing of the sample with water from different levels in the well is minimized.
For point source sampling, Solinst also manufactures the Solinst Model 425 Discrete Interval Sampler
which is pressurized before lowering into the well. This prevents water from entering the sampler until the desired depth has been reached. (See Model 425 Data Sheet
Point Source Bailer Design
The Solinst Point Source Bailer has dual ball valves, top and bottom. It is a simple and cost effective device for aquifer profiling. It needs no costly or hard to transport ancillary equipment, making it ideal for point source sampling in hard to access locations.
The miniature 0.5" (12.7 mm) diameter model is ideal for use in narrow tubes and direct push devices.
Method of Operation
The bailer is lowered slowly to the desired sample depth on a support line. As the bailer is being lowered, both ball valves open, allowing water to flow through the sampler.
On reaching the sampling depth, the bailer is raised slowly and steadily. The weight of water and upward movement of the bailer keep both ball valves closed. The top ball valve prevents the sample in the bailer from mixing with water at higher levels in the borehole. The bottom valve prevents the sample from leaking out of the bailer.
Once at the surface, the bailer is emptied by opening the top vent, and allowing the water to drain slowly through the sample release device into a sample container.
The Point Source Bailer can then be decontaminated before taking the next sample.