Public Lab Research note


List of Methods for Lead Detection & Monitoring

by read_holman | | 161 views | 6 comments |

Read more: i.publiclab.org/n/17875


On-Site Methods + Products Commercially Available

The following is a list of on-site (aka: not mail-in) on-time lead testing methods leveraged by products that are currently on the market.

Note: There are a number of low-cost products currently available for purchase. A few examples are listed below. Importantly, none of these have been found to be reliable enough to have results verified by the EPA nor the Public Lab community. More formal research and studies with these is needed.

Water / Suspended Solids

Colorimetry

  • This method is based on spectrophotometry and is the most common low-cost method currently deployed. Products leveraging colorimetry require a user to compare the change of color in a tested strip ("dipstick") or swab with a reference. These are easily available online and in stores but are known to have reliability issues.
  • Detection limit: n/a
  • Cons: Only measures absorbed metals; does not measure particulates. Results are entirely qualitative. non-specific, and often difficult to interpret.

  • Example: WaterSafe Water Test Kit for Lead (amazon $9)

  • Example: LABTECH H2O OK Plus Complete Water Analysis Kit (HomeDepot | $30)

Voltammetry: Ion Selective Electrode (ISE)

Biosensors (e.g. DNA-based methods, Enzyme reaction mechanisms)

  • This method leverages microorganisms, enzymes, microspheres, and nanomaterials that have been developed to detect heavy metal.
  • Detection limit: 2 ppb
  • Cons: Due to its complexity and use of biomaterial, this method typically requires a professional lab setting to develop. Products are in their early stages of commercialization.

  • Example: Andalyze: "ANDalyze's proprietary Catalytic DNA sensors use a DNAzyme reaction mechanism that fluoresces in the presence of a target contaminant substance such as lead. The fluorescence of the reaction is measured to determine the toxicity of the target heavy metal and is reported in parts per billion (ppb)."

Paint / Surfaces

Colorimetry

  • As noted above, this method is based on spectrophotometry and is the most common low-cost method currently deployed. Products leveraging colorimetry require a user to compare the change of color on the swabbed or marked surface with a reference. These are easily available online and in stores but are known to have reliability issues.
  • Detection limit: n/a
  • Cons: Results are qualitative. non-specific, and often difficult to interpret. These are quite common but have mixed reviews.

  • Example: 3M LeadCheck Swabs (amazon | $22). EPA verified for NEGATIVE results, but not for positive findings. EPA analysis found high rate of false positives (source).

  • Example EschoTech D Lead Paint Test Kit (amazon). EPA verified for NEGATIVE results, but not for positive findings. EPA analysis found high rate of false positives (source).
  • Example: PRO-LAB Lead Surface Do It Yourself DIY Test Kit LS104 (Amazon | <$10)
  • Example: First Alert LT1 Premium Lead Test Kit (Amazon | $15)

Soil

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On-site Methods + Products in Research Phase

The following are DIY (aka: not mail-in) lead testing methods and/or low-cost products that are not currently commercialized but show promise through early research and/or testing.

Point in Time Testing (single use detection)

Smartphone Nanocolorimetry

  • Example from researchers at the University of Houston (source): A single-step sedimentation approach by mixing a controlled quantity of chromate ion (CrO42--) to react with Pb2+ containing solutions to form highly insoluble lead chromate (PbCrO4) nanoparticles as vivid yellow precipitates. This is followed by microscopic color detection and intensity quantitation at nanoscale level using dark-field smartphone microscopy.

DNA-based method: Microfluidic chip + Smartphone

  • Example from researchers at Hong Kong Baptist University (source): A plastic microfluidic chip pre-loaded with reagents and probes. The smartphone app compares the signal from the user's sample with that from the pre-loaded control sample

Biosensors (modified bacteria)

  • Example from the company FredSense (source): utilizes a tunable bacteria that can provide ultra-sensitive measurements of trace chemicals in a water. Currently have arsenic, iron, and manganese.

Arduino processor + carbon nanotubes\

  • Example: Tethys (source), an invention by 11-year old Gitanjali Rao.

Continuous Water Monitoring Technologies (Research phase only)

Sensors that can live within water systems, either within pipes or at the tap, that continuously monitor water quality and report that data to a central repository is an exciting and emerging area of research. The particular methods deployed may include the above. The below details a few different research activities that I'm aware of.

  • Example from researchers at the University of Michigan: Platinum electrodes for the detection of heavy metal contamination (source)

  • Example from researchers at the University of Wisconsin, Milwaukee (UWM): Graphene-based nanomaterial (source)

  • Example from researchers at Widener University: voltammetry / ISE + 24-bit analog digital converter and miniaturized open-source potentiostat. (source)


Existing Laboratory-based Methods + Products (Professional / not-onsite)

The following is a list of the most relevant *laboratory-based* methods, techniques, and technologies for testing samples for lead.

These require professional training and expensive machinery which means these are not available to the average person. These exist within most colleges and universities (particularly their chemistry departments), city/county-based chemical analysis labs, as well as within private, professional laboratories. Advancement of these methods and explorations of deviations of these methods is generally beyond the scope of the Public Lab community's work. However, I am posting here for reference.

Water / Suspended Solids

ICP-MS (Inductively Coupled Plasma - Mass Spectrometry)

ICP-AES (Inductively Coupled Plasma - Atomic Emission Spectroscopy)

FAA (Flame Atomic Absorption)

Paints / Solids

XRF Analyzer (X-Ray Fluorescence)

  • EPA Method 6200 (PDF):
  • Wikipedia article...
  • Detection limit: "This method is a screening method to be used with confirmatory analysis using other techniques" (from the above EPA Method file)
  • XRF Analyzers can be portable and are often used by professional home inspectors
  • Cost = ~$7,000+ used (ebay link)

6 Comments

Hi @read_holman -- I did find this XRF tool for soil testing: https://www.bruker.com/products/x-ray-diffraction-and-elemental-analysis/handheld-xrf/lead-testing-gun.html -- I assume it's pretty cost-inaccessible but just since you asked!


Wow, interesting; these "SprayView" kits have a great illustration of colorimetric detection:

https://www.chemsee.com/residential/detection-kits-for-lead/

Before-and-After-Small.png


Also the UMASS Amerst Soil Lab offers a $20 test for lead, although I don't know much more about it. It is a "mail-in" test though so perhaps outside the scope of this list, but maybe useful until we do find some soil tests that aren't lab-dependent:

http://ag.umass.edu/services/soil-plant-nutrient-testing-laboratory/ordering-information-forms


And the same page above lists Alternate EPA 3050B and 6010 methods for lead at $55.


Not really relevant. I was on the PublicLab Open Hour call and I asked a question but can't remember the answer. I asked about finding lead on twitter and you said something about element 82 because any search on lead wouldn't turn up the element.


There are several manufacturers of handheld XRF analyzers. And yes, they are usually cost limited. The cost can be reduced somewhat by renting, instead of buying.

The handhelds still have to be optimized for the element. Some use radioactive sources instead of xray tubes, and will be more sensitive to different elements because of this.

Often, the handhelds use beryllium windows. Beryllium is a nasty and expensive element. Something to watch out for when renting.

Regards


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