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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.
On January 11th, 2011 The Nevada Division of Environmental Protection, Bureau of Mining Regulation and Reclamation (BMRR) issued a statement clarifying the acceptable methods for the analysis of Weak Acid Dissociable, or “WAD”, cyanide. The statement listed two acceptable methods: ASTM D2036-082 and SM 4500CN I.
Keep in mind this concerns only compliance monitoring samples that are being reported to BMRR. The issued statement doesn’t cover any sample that is not for compliance, or is being reported to any other agency.
Both acceptable methods are manual distillation methods that use a weak acid (glacial acetic acid) to break up easily dissociated cyanide complexes, capture the free cyanide in solution, and then analyze the solution using a few different techniques. These two methods have long been thought to be the most reliable techniques for the quantification of cyanide in waters. BMRR stated that only data obtained using one of these two methods would be acceptable for compliance monitoring.
Western Environmental Testing Laboratory (WETLAB) has been using SM4500CN I for the analysis of WAD cyanide for many years and is currently certified by the State of Nevada, Bureau of Water Quality Planning. Just like any method or technique that WETLAB wishes to use for compliance monitoring sample analysis, we have gone through a rigorous certification program that includes an on-site audit and the analysis of “blind” QC samples.
Over the last decade new techniques have been developed for the analysis of the easily dissociated cyanide complexes that WETLAB hopes become acceptable for BMRR reporting. One specific method is known as Flow Injection Ligand Exchange or F.I.L.E. cyanide. WETLAB is already certified and equipped to use this more efficient and environmentally sound testing method, which would provide clients with quicker turn-around time for results. Should BMRR choose to accept data generated from this technique, WETLAB will contact clients to inform them of our wish to change methodologies.
As always, if you have any questions regarding the information contained in this blog, don’t hesitate to call (775) 355-0202.
