Western Environmental
Testing Laboratory
Sample Integrity: Sample Collection

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.

WETLAB is pleased to announce a new certification.  We have expanded our testing abilities, and are now certified in Nevada to analyze Total Organic Carbon (TOC) by SM5310C.  Total Organic Carbon (TOC) is a measurement of organic or carbon-based contaminants in water that come from a variety of sources.  SM 5310C uses a UV-Persulfate TOC analyzer to measure total organic carbon in drinking water, surface water, ground water, and waste water.

At WETLAB, we are constantly trying new ideas, methods, and analyses to better serve our clients.  Contact us at (775) 355-0202 to find out how our new, in-house TOC analysis can help you get the environmental testing results you need.

Arsenic is a well-known inorganic element, and it is one of the many routinely monitored contaminants in drinking water.  WETLAB tests for Arsenic in drinking water through EPA Method 200.7 and 200.8.  But how does Arsenic make its way into drinking water, and what are the potential health effects from increased Arsenic load?

The EPA requires that ground water systems monitor for Arsenic every three years, and surface water systems every year.  These frequencies may be increased if  Arsenic is found to be at or above the MCL (Maximum Contaminant Level), defined as 10ppb (parts per billion).  This MCL was lowered from 50ppb in 2001 to better protect public health.

Arsenic is a naturally occurring element found in soils and rocks, and is also a by-product of several industrial and agricultural processes. Drinking water contamination can occur from naturally eroding deposits, and from runoff of various processes.  Some water will be naturally higher in Arsenic due to the rocks and soils that make up the aquifer.  Arsenic contamination can be treated in many ways, including Iron treatment and adsorption, which helps precipitate Arsenic out of water.

Ingesting water with Arsenic levels greater than the MCL can cause adverse health effects if the water is consumed for many years. These health effects include skin damage, circulatory problems, and an increased risk of various cancers.

To find out more about Arsenic in drinking water, visit this guide, published by the EPA.

Nitrate levels are regularly monitored in drinking water to ensure compliance with EPA standards.  WETLAB regularly tests for Nitrate, Nitrite, and Total Nitrogen concentration in water and soils using a variety of methods, including EPA 300.0, EPA 353.2, and EPA 9056. But how does increased Nitrogen load in drinking water occur, and what are the possible health risks associated with high levels?

Increased Nitrogen concentration in surface water is observed in areas with fertilizer runoff, often from agricultural areas.  Increased Nitrogen concentration in ground water is also observed in areas with farming, and areas with high concentrations of septic systems.  In farming and agricultural areas, fertilizers (such as potassium nitrate and ammonium nitrate) are essential for growing crops, but decompose into the soil to increase nutrient concentration.  This is also observed from decomposing animal manure, and from decomposing human sewage from septic tanks.

This increased Nitrogen concentration is often referred to as “Nutrient Pollution,” as Nitrogen and various other elements are essential to our soils and atmosphere, but can cause problems when the concentration reaches a certain threshold.  The EPA has defined this threshold for Nitrate as 10.0 mg/L, and for Nitrite as 1.0 mg/L.  Potential health effects from increased Nitrogen concentration are most often seen in infants less than 6 months old, resulting in methemoglobinemia, a temporary blood disorder referred to as “blue baby syndrome.” Adults are usually not as susceptible to this condition.

More information about Nitrate contamination in drinking water can be found through the EPA here.

Organic compounds are present in both indoor and outdoor environments, as they are necessary ingredients of products and materials we use every day.  Semi Volatile Organic Compounds (SVOC) are a subgroup of Volatile Organic Compounds (VOC) that have a higher molecular weight and boiling point (240-260 C to 380-400 C) and are present in everyday items like pesticides and fire retardants.

SVOCs are analyzed by sample extraction and the extract is analyzed by Gas Chromatography/ Mass Spectrometry (GC/MS).  The reported analytics can be separated into three groups (acids, bases, and neutrals) and are sometimes referred to as Base/Neutrals and Acids. WETLAB is currently in method development to perform the analysis of municipal and industrial wastewater by EPA 265 and solid waste, soils, and waste samples by EPA 8270.

At WETLAB, we are constantly trying new ideas, methods, and analyses to better serve our clients.  Contact us at (775) 355-0202 to find out how our new, in-house SVOC analysis can help you get the environmental testing results you need.

Lead is a commonly tested for contaminant in drinking water, and public water systems must test for it on a prescribed, regular basis.  WETLAB routinely tests for trace lead amounts in drinking water for many clients using two main methods- EPA 200.7 and 200.8.  These methods use ICP (Inductively Coupled Plasma) machines, which can detect very small amounts of trace metals in water.  But why is testing for lead important?  What are the potential health risks associated with lead, and when do we care about it?

Lead is most commonly introduced into drinking water from service pipes and solder containing lead that corrode.  The corrosion is often due to acidity in the water, which causes the lead to leach out of the pipe and into the water.  Lead can also be introduced into drinking water through erosion of natural deposits. The EPA has identified the maximum allowable content of lead in water to be 0 mg/L, and an “action level” as 0.015 mg/L.

Lead in children, even in very low levels, has been shown to cause erratic behavior, learning problems, and slowed growth.  Lead exposure is most dangerous to young children, infants, and fetuses.  For that reason, lead exposure is also a significant concern for pregnant women.  During pregnancy, lead amounts that have built up over a lifetime can leach out of the mothers bones and impact the growing fetus.  Lead can also be dangerous for adults, although typically in higher levels than in children.

To mitigate these potential health effects, it is imperative that lead levels are tested accurately and consistently. Public health agencies routinely monitor the results of these tests to ensure that action is taken before a crisis arises.

More information can be found on the Quick Reference Guide, published by the EPA.

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.