In our blog posts Lessons From the Lab we answer frequently asked questions from clients.  Find all installments of Lessons From the Lab here. 

Cyanide sampling requirements have become stricter over the years. The Nevada Division of Environmental Protection (NDEP) issued guidance in October of 2015 that cyanide analysis must be collected correctly in the field so as not to have samples rejected by the analytical laboratory, or by the state due to incorrect sampling procedures.

NDEP stated, “If you are analyzing Cyanide samples for compliance with a Nevada program, (SDWA, CWA, RCRA, Mining) samples must be collected as described below (ASTM D-7365-09).  Data obtained from samples not collected as described in ASTM D-7365-09 will be rejected.”

“ASTM D-7365-09 8.2.1 states that sample containers shall be made of materials that will not contaminate the sample, cleaned thoroughly to remove all extraneous surface contamination prior to use.  Chemically resistant glass containers as well as rigid plastic containers made of high density polyethylene (HDPE) are suitable.  Samples should be collected and stored in amber gas tight vials or narrow mouth bottles to minimize exposure to ultraviolet radiation and to minimize headspace in the sample containers (for example, amber open top VOA vials, amber Boston round bottles, or amber narrow-mouth HDPE bottles).”

“All certified Laboratories must reject samples not collected in suitable containers.”

What does this mean? All samples, regardless of matrix (drinking water, wastewater, ground water, surface water, aqueous, soil, sludge, etc.), must be collected in an amber narrow mouth container to minimize UV radiation exposure and to minimize headspace in sample containers.  Samples not collected in the correct containers must be rejected by the laboratory and the sample should be collected in the correct containers, as described above. Furthermore, as dictated by the method cited by NDEP, chemical preservation is also required for aqueous samples.  Aqueous samples must be preserved with sodium hydroxide (NaOH) to pH >10 at the time of collection, and then chilled on ice.

At WETLAB, we provide the appropriate bottles and preservative (NaOH) needed for your cyanide analysis, and are happy to answer any questions you may have regarding cyanide sampling containers.

Please call us at any at 775-355-0202 to request sample containers.

Oil & Grease

Method: EPA 1664
Volume: 1L for RL = 1.5mg/l, 2L for RL = 1.0mg/l
Preservation: HCl, 2-6 degrees C, Amber glass bottle
Special Requirements: for every set of samples submitted (1 to 20 samples) a duplicate sample must be submitted for internal laboratory QA/QC requirements. The client is not charged for this duplicate sample.

Western Environmental Testing Lab carries certification in NV and CA for the analysis of water samples for oil and grease by method EPA1664. WETLAB utilizes the “Solid Phase Extraction” or SPE technique. This method is used for determining n-hexane extractable material (HEM) which includes some non-volatile hydrocarbons, vegetable oils, animal fats, waxes, soaps, greases, and related materials.

In order to perform the oil and grease analysis we filter the client sample through a specially prepared filter that has the ability to hold onto oils and greases. Once the sample has been filtered through, we extract from the filter all the oil and grease using three portions on n-hexane. The n-hexane extracts are combined in a pre-weighed tin and evaporated. Once all the n-hexane is evaporated what is left is any oil and grease from the original sample. We determine the amount of oil and grease by comparing the final weight of the tin to the original weight. This is known as a gravimetric determination.

There are two very important requirements of the method that the client needs to be aware of concerning Oil & Grease. The first is that the client must collect the sample in a 1-liter glass container. Plastic does not work since it is more susceptible to oils and greases sticking to the inside of the container. The second requirement is that the lab must analyze a second 1-liter sample (one for every 20 samples analyzed) as part of the QA/QC requirements of the method. This is an issue since we usually only receive one sample per site from the client. We generally send out an extra 1-liter sample container per bottle kit to the clients that is labeled as a QA/QC sample (or “Duplicate”). This sample is not actually used as a laboratory duplicate and should not replace any field duplicates required by your sampling protocols, it is simply used to provide additional sample volume to run the method required QA/QC. Please remember we do not charge the client for this extra sample, it is simply a sample that we need to satisfy all method requirements.