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Active Groundwater Sampling Standard Operating Procedure SWE-FSOP-401;Revision 1 Ahtna Southwest Environmental Operations permanent wells. Temporary wells include 1) PVC wells, with a slotted screen, installed using traditional drilling/hand-augering methods with/without a filter pack, or 2) a rigid rod and screen pushed, driven, or hammered into place to the desired sampling interval. Different manufacturers use proprietary products to install temporary wells, but their approach to sampling are similar. In cases where the temporary well is sampled immediately after installation, purging is conducted primarily to mitigate installation impacts. In most cases, temporary well installation procedures disturb the existing aquifer conditions, resulting in increased turbidity. Therefore, purging aims to reduce the turbidity and remove the volume of water in the area directly impacted by the installation procedure. The longer a temporary well/probe is in place and not sampled, the more stagnant the water column becomes and the more appropriate it becomes to apply, to the extent possible, standard permanent monitoring well, purging criteria to the well to return to representative aquifer conditions.The PL should determine appropriate purge parameters based on project requirements. Sample collection times in formations with low hydraulic conductivity may exceed several hours, compared to several minutes in high to moderate conductivity formations. 1. Groundwater samples can be obtained in several ways:, but a bailer or peristaltic pump is typically used. Bailer or Mini-bailer.The water sample is retrieved by lowering a standard-sized or mini-bailer (depending on inside well diameter) until its immersed in groundwater and allowing the bailer to fill with water.The water recovered in the bailer is then decanted directly into the appropriate sample containers from the bailer tip or sample valve inserted at the check ball, opening the valve, and pouring the sample. Peristaltic pump. Groundwater samples can be collected by attaching a peristaltic pump to the tubing and collecting the sample from the tubing outlet. 2. After samples are collected, water levels may be measured. Allow enough time for groundwater to fill and reach static water level conditions. Measure groundwater level. Decontaminate the sounder. 3. Document results on the appropriate form, as specified by the project-specific work plans. 4.7 Filling Sample Containers Use laboratory-supplied sample containers of the size/volume and containing preservatives (if required) specified in the project plans. Some preservatives are added after the sample is collected. When collecting samples to analyze VOCs or GRO, collect those first. Fill the VOC sample vials slowly until a meniscus forms over the vial lip. Cap the vial and invert to ensure no air bubbles are present. If an air bubble is present,the vial will be opened,topped off with an additional sample, and capped. Recheck for bubbles. Do not dump the vial contents, or the preservative will be lost. If air bubbles are still present,the VOC sample vial will be discarded and a new vial used.The VOC sample vial filling procedure is repeated. If the sample is effervescing, filling a vial without bubbles may not be possible. In that case, submitting a vial with air bubbles may be acceptable if approved by the FTL. Laboratories are required to document whether containers have bubbles greater than pea-sized. Page 12 of 14