New Regulatory Testing For Heavy Metals In Agriculture

//New Regulatory Testing For Heavy Metals In Agriculture

New Regulatory Testing For Heavy Metals In Agriculture

Strict rules on heavy metal limits in produce are a source of anxiety for farmers. Positive detection of heavy metals within plant tissue may occur, circumstance to cleansing actions that plants naturally perform on top-soil. Plants grown in heavy metal contaminated soils, or fed with contaminated fertilizers, may have higher concentrations of heavy metals[1]. New mandatory category 3 testing for heavy metals in California began on January 1st, 2019.

Inductively coupled plasma mass spectrometer (ICP-MS) used for heavy metal analysis at the Cutting Edge Solutions laboratory

Metal in many forms is all around us, and necessary for numerous life functions. Metal ions are constantly flowing in our veins. Our blood contains iron, which is used by hemoglobin to transport oxygen throughout our bodiesThis process is part of cellular respiration in the Krebs cycle. Respiration does not occur without transition metals like iron. Plants use the transition metal, manganese for photosynthesis. Metal is even contained in table salt and soy sauce, in the form of sodium. Sodium is a good example of a necessary dietary metal, that may be poisonous if consumed in excess[2].

Let’s take a look at the most scrutinized heavy metals in agriculture:

Arsenic – Elevated levels are found in well-water across some regions of the United States[3]. Elevated levels of arsenic can be found in poultry. Organoarsenic drugs are commonly given to chickens raised on foreign farms, but usage was recently banned in the U.S.[4]. Eventually the arsenic in those drugs can collect within the bird’s feathers. Feathers are often used as a byproduct to produce organic feather-meal fertilizers, which may be a source of arsenic.

Lead – Commonly found in aging municipal water systems as well as old paints. Recently, New York’s Attorney General filed a lawsuit against a toy importer over the sale of lead-containing children’s toys[5]. Elevated levels of lead are known to cause developmental issues in children[6]. Cities have discovered lead levels in contaminated water that may not pass as a safe water source for growing biodynamic accumulator plants like wheat, comfrey, barley, or hemp.

Mercury – Detectable in both wild and farmed-raised fish, the reason why women are advised not to eat fish during pregnancy. Some may know the story of the ‘mad hatter’ affliction, experienced by some 19th century hatmakers. The use of mercury in the processing of felt was poisoning hatmakers of that era. Mercury may lead to developmental problems. Elemental mercury is volatile, and vaporizes if spilled at room temperature. Mercury vapor creates an invisible, odorless, toxic gas.

Cadmium – Highly toxic and commonly found in certain types of rechargeable batteries. Unlikely to be found in produce, but has been discovered in wheat grown within contaminated soil. Cadmium has been found in retired mine tailings, that can leach into groundwater used for agricultural or household purposes[7].

Green plasma torch burning in ICP-MS test

Heavy metals testing with ICP-MS plasma torch at the Cutting Edge Solutions laboratory

How we conduct heavy metal analyses:

The first step for our laboratory analysis of plants or soils is to place the material in a microwave digester. We use concentrated nitric acid with our sample in the microwave digester to dissolve the samples. After digestion is achieved, we then dilute the sample with nitric acid. The sample is then transferred into a test tube and loaded into the ICP-MS autosampler for analysis.

Microwave digestion system at the Cutting Edge Solutions laboratory

After the ICP-MS is calibrated, the instrument will first pull a nitric acid rinse to prevent any contamination from previous tests. The instrument then analyzes the individual sample in three replicates, pulling a nitric acid rinse between each test. A plasma torch within the ICP-MS operates at temperatures near 15,000 °F, which is used to introduce the sample into the mass spectrometer. 


ICP-MS calibration curves to detect arsenic (As), cadmium (Cd), mercury (Hg), and lead (Pb)


Cutting Edge Solutions® fertilizers and supplements have always been formulated and complexed with the purest agricultural raw materials available. All of our products are developed with a focus on preserving, and enriching, healthy microbiology in soil. Sourcing the highest purity inputs allows us to refine, complex, and blend the cleanest and safest fertilizers. Demand for our micronutrient fertilizers containing plant-necessary metals continues to grow, especially in hydroponics and aeroponics farming[8].

The premium quality of our products is demonstrated through ICP-MS heavy metal analysis. We analyze each batch of fertilizer we manufacture. Batch reports generated by our ICP-MS analyses allow us to screen for heavy metals in all Cutting Edge Solutions® nutrients and supplements. Farmers can rest assured that plants grown with our products will easily satisfy compliance regulations and ensure marketability.



[1] Contaminated soils –

[2] Sodium toxicity –

[3] Arsenic in ground water of the U.S. –

[4] Arsenic in feather-meal –

[5] Recent case of excessive lead in toys –

[6] Lead may cause childhood developmental issues –

[7] Cadmium in mines –

[8] Agricultural micronutrients market –


California Bureau of Cannabis Control Regulations on Heavy Metal Limits





2019-01-03T11:46:15+00:00December 20th, 2018|News|