Sample Collection is the first, and perhaps the most important step in the analytical process. Poor sampling inhibits the labs ability to produce representative data of a sampling source. Sampling is comprised of 5 main steps:
1. Create a Field Sampling Plan
2. Contact lab to order bottle kit and discuss any scheduling complications
3. Conduct sampling following instructions from Field Sampling Plan and the lab
4. Release Custody of Samples to the lab, or a third party shipper
5. Review Sample Receipt to ensure correct analyses are ordered

What do each of these steps mean? Let’s take a closer look.

1. Field Sampling Plan- This is necessary to succeed in sampling, and generally should include the following:

• General Facility Info or Sampling Locations
• Contact Person and Samplers Name
• Sampling Objectives
• Facility of Location Information (PWS codes for drinking water)
• Data Quality objectives
• Sampling Points
• Sample Collection Procedure
• Sample Handling Procedure
• Equipment Checklist
• Equipment Preparation and Cleaning Procedures

 

2. Ordering Bottles and Scheduling Sampling- Call us to order your sample containers. The bottles provided will be bagged together into “sets” to keep each site organized. A cooler will also be provided. The lab will generally need the following information:

• What are you sampling for?
• How many sites do you intend to sample?
• When are samples being collected and when will they be delivered to the lab?
• Are any additional sampling supplies required (COCs, gloves, extra coolers, ice packs, custody seals, Ziploc bags, etc.)?

Depending on the situation, more coordinating and information may be required! For example:

Courier Pick Up or Drop Off– If you need sample containers dropped off at your site or picked up from a courier, it is wise to plan sampling around your labs standard courier routes. You can find WETLAB’s standard courier schedule here.

Sample Shipping– If samples are being shipped to or from a remote location, consider the amount of time samples will be in transit. If you are sending short-hold samples, selecting a “next day delivery” option may be necessary.

Subcontracted Work– Most subcontracting is shipped to southern CA and NV, therefore, factor this extra time in transit when making your sample plan. Furthermore, avoid delivering samples requiring subcontracting on Fridays, as they cannot ship out until the following Monday.

Weekend Work– Weekend work is not ideal, however, it is sometimes unavoidable! It is important, however, to notify your lab as soon as possible about weekend work so that staff can be scheduled to accommodate the request.

 

3. Sampling- Once the game plan is set, it is time to execute your sampling project.

• Follow the steps outlined in your Sampling Plan and make sure to follow any special instructions provided by your lab.
• Take note of the weather conditions, high and low temperatures can drastically affect how you pack and transport your samples.
• Wear PPE! Gloves, glasses, masks, hairnets… they all serve a purpose to keep you safe and/or your samples clean.
• Make sure to add the proper preservatives to your samples in the field, add custody seals to bottles or coolers if your sample plan requires them, and make sure to use bubble packaging for glass containers.

 

4. Releasing Custody of Samples- An additional responsibility of a sampler is properly documenting sample information and signing for any change of sample custody. The analytical Chain of Custody (or COC) is a required legal document submitted with samples to the laboratory. This document is a requirement for any sample submission to a lab, and serves numerous purposes:

• Client and Reporting information
• Turnaround time, compliance needs for reporting, report format, and QC requirements
• Sample ID, Date/Time, Preservatives, Matrix, Number of Containers, and required tests
• Miscellaneous comments, including hazard warnings, reporting requests, sample return requests, preservative notes, etc.
• Relinquishing custody of the samples

 

5. Review Sample Receipt- WETLAB can send you an electronic “ sample receipt” which will list the entered information from your Chain of Custody, the receiving conditions of your samples (including anomalies), and an itemized list of all the analytical testing slated for your samples.
This is the final check before the testing will commence, so it’s important to review as soon as possible and contact the lab with any questions or concerns.

Contact WETLAB at (775)355-0202 to discuss your sampling requirements and project needs.

What is a holding time, and why do I need to know about it? A “holding time” is the elapsed amount of time from the point of collection to the moment of preparation or analysis. Note that this is not the date/time of receipt at the lab! If samples are analyzed beyond an analytical holding time, the data will be qualified on the analytical report and may not be usable for compliance.

The analytical hold time to a sample is like an expiration date to a carton of milk; past the hold time, analysis technically can still be performed (just as milk may be consumed after it expires), the results, however, in both cases may be unsavory. There are very few allowances for missed hold times and in almost every case, resampling is required.

You should get samples to the lab as quickly as possible, as holding times are different for volume received unpreserved. For example, metals shrink from 6 months to 7 days, nutrients from 28 days to 48 hours, others hold times may even shrink to 24 hours or less! Find out more about preservatives and sample bottles here.

Holding times are easily accessible, as the information is constantly needed (and important!):
From WETLAB’s website here
From the EPA under 40CFR, part 136, Table II
From the NDEP website here
Or, get a hard copy sheet on your next stop into WETLAB

Be aware, hold times can change as methods are updated, so you should contact WETLAB for the most up to date information before you develop your sampling plan.

 

What is a preservative, and why is it important? According to the EPA, methods of preservation are relatively limited and are intended generally to (1) retard biological action, (2) retard hydrolysis of chemical compounds and complexes, (3) reduce volatility of constituents, and (4) reduce absorption effects.

In other words, the purpose of a preservative is to “freeze” the sample chemistry at the point of sampling so that what gets analyzed at the lab is as similar to the source as possible, despite the unavoidable delay between the sampling and analysis.

Some common preservatives include:

• Sulfuric Acid (H2SO4)
  • Preservative for Nutrients: Total Nitrogen, Ammonia, Phosphorus, TKN, etc.
• Nitric Acid (HNO3)
  • Preservative for Metals: Arsenic, Sodium, Lead, Copper, Iron, Mercury, etc.
• Sodium Thiosulfate (Na2S2O3)
  • Preservative for Bacteria: Total Coliform, E. Coli, Fecal
• Sodium Hydroxide (NaOH)
  • Preservative for Cyanide: Total CN, Free CN, WAD CN, etc.
• Hydrochloric Acid (HCl) in VOA vials
  • Preservative for Volatile Organics: VOCs and Gasoline
• Hydrochloric Acid (HCl) in Amber Glass
  • Preservative for Organics: Oil & Grease, Diesel, Oil, etc.

 

However, the most important, but often overlooked, preservative is ice. Keeping a sample cold (between 2-6C) is a requirement for nearly every analytical test we perform EXCEPT for metals analysis. It is generally preferable to use wet ice instead of ice packs when possible.

Sample containers, just like preservatives, are designed to inhibit the natural chemical changes which will occur in a sample as time passes. In addition to that, sample containers also serve a few other purposes:

• To ensure proper volume is provided to a lab (all tests have a minimum required volume)
• To ensure the lab has enough volume to perform the proper quality control
• Some containers limit a samples exposure to UV rays
• Some containers are designed to prevent sample contact with air
• Some are sterilized and sealed to prevent bacteria contamination
• Some containers are designed to limit sample absorption (plastic vs. glass)
• Some are specifically designed to be loaded directly into an instrument (or even an autosampler for composite samples)

 

But how do I know which sample bottle and preservative to use? Simple, you ask the lab! By contacting WETLAB before you begin your sampling process, you will help ensure that you use the correct bottle and preservative. Our staff can also help you review your permit making sure the correct samples are taken at the correct time of the year (DPBs, LCR, SOCs), and making sure the correct methods are used for your sample matrix (drinking water, waste water, haz waste). We can even help with sampling requirements making sure your samples are collected as intended by your permit (LCR first draw, grab vs. composite), saving you valuable time that can be lost from unintended mistakes.

Be aware, preservatives and hold times are dictated by the analytical method and enforced by state/federal agencies and the laboratory. Cyanide species, Volatile Organics, Dissolved Oxygen, Bacteria, SOCs, DBPs, and many other tests absolutely require correct bottles and preservatives to analyze for compliance.

Contact WETLAB at (775)355-0202 to discuss your sampling needs. Our seasoned staff can help you determine which samples you need, how they need to be collected, and provide you with all the right bottles and preservatives to make sure your procedures remain in compliance.

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.

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

It is important to know the differences for the client and the lab when the topic of compliance vs. non-compliance comes up. The simplest way to view it from a client perspective is that compliance data would be data that any type of regulator would review. It could be a state regulator or sometimes the EPA itself. Many times, compliance data will be sent directly to the state by WETLAB. In a more complex twist we have seen this past month NON-compliance data be subpoenaed to US District Court. This proves that even if the client indicates non-compliance we should be following all the normal rules as we do for compliance samples. All samples should certainly be collected properly as far as container and preservative types go and correct sample volume should be provided. From a lab perspective whether or not a sample is for compliance doesn’t really get discussed too often. It is simpler, and safer, to treat all samples the same. In rare occurrences, with lab and QA management oversight, protocols may be altered for non-compliance samples.

At WETLAB, we believe that good communication is a critical part of ensuring our clients receive good data.  Our QA manager and sales team presented on this topic in March at the Nevada Rural Water Association Conference in Reno, NV. Below is a small synopsis of this presentation. 

Good communication appears to be a simple goal, but can be difficult to achieve.  There are many players involved at every stage, and one small miscommunication can result in the end product not being what is needed.  The —ultimate goal is to produce legally defensible results that meet Data Quality objectives.

It is imperative that clients and the lab communicate clearly- WETLAB strives to ensure that all of our clients understand what data they need to satisfy regulatory requirements. The regulatory landscape concerning water is ever-changing, and can be confusing.  At WETLAB, we stay up to date with the latest changes so that we can help our clients get the results they need.  Outside of the lab, we talk to our clients and their regulators to determine needs.  Inside of the lab, we discuss projects clearly throughout all departments.

The critical point of communication occurs between the client and the lab.  Providing WETLAB with the appropriate documents helps to clearly show objectives. These documents include: a detailed Client Information Sheet, a Sampling Analysis Plan, the Scope of Work, and the Chain of Custody.  Having an accurate and clear Chain of Custody is imperative to retain legal defensibility of sample results.  Our staff reviews all Chain of Custody forms to make sure they are clear and fully completed.

If all participants communicate as clearly as possible, the goal of regulatory compliance can be achieved.  Contact WETLAB to see how we can help you achieve your goals.

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

What is Trace Metals Analysis?

Trace Metals analysis may be performed on a variety of aqueous matrices. Depending on the objective of your sampling, WETLAB can perform total recoverable or dissolved metals analysis. For total recoverable or total metals analysis, the sample must be preserved with the addition of nitric acid (HNO₃) to lower the pH of the sample to <2. Dissolved metals require an additional step prior to the addition of HNO₃. Samples for dissolved metals must be filtered using a 0.45 µm filter, after the sample has passed through the filter, the sample must be preserved with HNO₃. In SW-846, the EPA recommends that samples are field filtered. If field filtration is not possible, clients may submit an unpreserved sample to WETLAB and we can filter the sample using 0.45 µm filters and preserve with HNO₃. If field preservation is not possible, the EPA recommends in EPA 200.2, “Preservation may be done at the time of sample collection, however, to avoid the hazards of strong acids in the field, transport restrictions, and possible contamination it is recommended that the samples be returned to the laboratory within two weeks of collection and acid preserved upon receipt in the laboratory. Following acidification, the sample should be mixed and held for 16 hours.” Aqueous samples that have been properly preserved for trace metals analysis by EPA 200.7 and/or EPA 200.8 may be held and analyzed up to six months after collection date.

 

 

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

What is a Reporting Limit?

A Reporting Limit (RL) is defined as the smallest concentration of a chemical that can be reported by a laboratory. If a laboratory is unable to detect a chemical in a sample, it does not necessarily mean that the chemical is absent from the sample altogether. It could be that the chemical concentration in the sample is below the sensitivity of the testing instrument. Concentrations below the RL are reported as not detectable at the RL or “less than” the RL. The RL value is often defined be each specific laboratory, so it is not uncommon to come across different RL’s when testing the same compound. RL’s act as safety protocols that allow laboratories to efficiently communicate the different variables correlated with testing and analyzing samples from a wide variety of sources and factors. It is important to identify the limit of concern that the client has when testing their sample to ensure that the RL is less than the regulatory limit. That enables a laboratory to identify whether a concentration of the chemical in question is above the regulatory limit of concern.

This is the final installment of our ongoing series Life of a Sample, which explores what happens behind the scenes at WETLAB.  If you missed parts one through five, check them out here!

Our sample has now been received, prepped, distilled/ digested, analyzed, and entered.  The final, and terminal step, is reporting.  At this point, samples will have been validated, which means that QA/QC parameters have been checked to ensure they are within acceptable ranges.  These parameters include checking total versus dissolved solids, Maximum Contaminant Levels (MCLs) for drinking water, cation versus anion balances, and several others.  If any of these validation measures are outside of acceptable or expected limits, QA staff will determine if the sample needs to be re-analyzed.  If the sample passes the validation check, the data is ready to be reported to the client and regulating agency. Our client services staff ensures that clients are provided with a complete and accurate report of all results, and they understand what they have been provided with.  If the sample is being analyzed for compliance, such as drinking water for a public water system, the results are also provided to the regulating agency.  After reporting is finished, our sample’s life cycle is complete!

Our ongoing series Life of a Sample explores what happens behind the scenes at WETLAB.  If you missed parts one through four, check them out here!

At this point in our sample’s life cycle, the sample has been received, prepped, distilled/ digested, and analyzed.  The next step is entering all the collected data so that it can be transmitted to clients.  During this step, all the raw data is double-checked for inaccuracies and to ensure that all quality control samples have been included.  All data that can’t be migrated digitally is hand-entered by lab technicians, which is then checked for input errors such as incorrect dates or mis-typed numbers.  Catching these small errors is critical for ensuring data is reported correctly and on time for our clients.  This step is typically completed by the end of the day the sample finishes analysis.  After data entry, our sample will reach its terminal stage- reporting.