COMPLIANCE INFO - Laserfiche WebLink

Home Browse Search

SAMPLING AND ANALYSIS PLAN OF POTENTIAL TOXIC PIT CLEANUP ACT (TPCA) SURFACE IMPOUNDMENTS The objective of this sampling and analysis program is to determine if liquid hazardous waste or hazardous waste containing free liquids (as defined in the California Administrative Code (CAC), Title 22, Division 4, Chapter 30, Articles 9 and 11) are present in surface impoundments at a facility.• Specifically, the sampling and analysis program must provide samples of the liquid wastes and solid waste containing free liquids which are representative of the average properties of all of the waste in the surface impoundment. The samples must be collected such that they are representative of spatial (horizontal and vertical) and time variability. Sampling accuracy (the closeness of a sample value to its true value) and sampling precision (the closeness of repeated sample values) are crucial to determining if the samples provide reliable estimates of the chemical properties of the wastes., Site Sample Selection Methods detailed in EPA Document SW -846, Test Methods for Evaluating Solid Waste, Physical/Chemical Methods, 2nd Ed., should be used for sample site selection. SW -846 outlines three basic strategies: Simple Random Sampling, Systematic Random Sampling, and Stratified Random Sampling. Simple Random Sampling is the best method to use when potentially unrecognized trendsor cycles occur in a waste population. Simple and Systematic Random Sampling can be used for wastes which are known to be essentially random in its heterogeneity, but Stratified Random Sampling must be utilized when wastes are thought to be non -randomly distributed over space and time. These sampling strategies apply to the liquid as well as the solid wastes in the surface impoundment. Sampling Solid Wastes 'Pond sediment or sludges' describe all of the solid materials which occur in the ponds. Pond sediments may consist of sludge from treatment processes or other' solids *suspended in the liquid discharge, accumulations from earlier discharges, as well as, wind transported silt and clay. It is important to establish pond sludge thickness and the presence or absence of layering in the sludge. Such distinctive layers, if present, must be sampled and analyzed separately. Other aspects of the sampling should consider: 1. Regardless of sample site selection methodology, the area of the depositional fan occurring near the vicinity of the pond inlet should be sampled. The sample site should be located in the area of maximum sludge accumulation produced by discharge into the pond. The area near the discharge from the pond should be sampled as well. 2. An appropriate number of samples should be collected from the surface impound- ment to achieve precision. Maximizing sample size (weight or volume) increases sampling precision, which in turn increases accuracy. A minimum of four samples should be collected at each pond. 3. The entire vertical thickness of the sludge column should be collected in the sample. If there are discreet layers, these layers should be collected and analyzed separately in accordance with guidelines for stratified samples. If