High-density polyethylene tubing (HDPE) and low-density polyethylene tubing (LDPE) are both types of polyethylene, a polymer of ethylene. HDPE and LDPE are distinguished by their molecular structures. LDPE has a more branched structure, whereas HDPE consists of long chains with minimal branching. As a result of these structural differences, HDPE molecules are packed tightly (high-density) and therefore have a greater tensile strength than LDPE. This means that HDPE is often used in applications where environmental and operating conditions are rougher, and durability or heat resistance is required. On the other hand, LDPE is used where the material is required to be flexible. Additionally, HDPE is less likely to leach PFAS (per-fluoroalkyl substances) than LDPE.
Foot valves are used to prevent water from flowing backwards when the pump is not in use. They operate by opening during the downstroke and closing on the upstroke so that water continually travels up the tube and samples can be brought to the surface. Preventing backflow helps ensure neither the well or samples are contaminated and ensures the pump remains primed for accurate and reliable samples to be collected.
Groundwater sampling bailers are simple, portable devices used to collect water samples from monitoring wells. They consist of a hollow tube with a check valve at the bottom, which allows water to enter when lowered into the well and prevents it from escaping when retrieved. Bailers can be used both for collecting samples and purging wells.
The personal protective equipment (PPE) required depends on several factors including the type of sampling and the environment where the sampling is undertaken. Disposable rubber gloves should always be worn for water sampling as the water can be hazardous, particularly if contaminated, and also to prevent contamination of the sample. Other PPE is dependent on the sampling environment such as no slip shoes, waders or eye protection.
Calibration solutions are used to calibrate groundwater monitoring or water quality equipment. These solutions provide a known parameter such as the pH level to ensure that the instrument is measuring that parameter accurately.
A range of calibration solutions for various water quality parameters such as pH, turbidity, conductivity and salinity are available for sale at Air-Met Scientific. Contact your local rental team for an extensive list or to enquire about your specific needs.