While many find heavy metal music very enjoyable to listen to, heavy metal particle accumulation from biological means is detrimental to our health and well being.
The F.D.A. does not require heavy metal testing, nor do they test for heavy metals in food, herbs, spices, or drugs. Heavy metal toxicity is a medical condition in which there is a high accumulation of toxic metals such as lead, arsenic, cadmium, and more in the body. These metals stack up and remain in the body because they do not metabolize, and they are not easy to excrete. They build up over time and have been found to increase risk of cancer, and cognitive as well as reproductive problems. This occurs even in in small amounts. Sadly, children up to the age of 6 are highly sensitive to heavy metals and it can effect them more severely. Samples of ingestible or topically absorbed products could be acquired and processed through laboratory means, to ensure all consumables are safe.
Where's the Breakdown?
A recent study by Consumer Reports has found that roughly 1/3 of herbs and spices on shelves today contain heavy metals. While the study was conducted on "seasonings", we can hypothesize that produce would also contain equal to or more than the aforementioned fraction. While surprising to some, the U.S.D.A.'s Organic spices and herbs were also on the toxic list from Consumer reports, which can be found here. According to the lead chemist at Consumer Reports, contamination is attributed to not only where spices were grown, but also during the manufacturing and packaging processes.
It is possible for plants to become contaminated with heavy metals even if the soil they are grown in is not contaminated. Heavy metals can enter plants through a variety of mechanisms, including absorption through the roots, uptake from the soil solution, and deposition from the air.
For example, atmospheric deposition of heavy metals from industrial or vehicular emissions can contaminate plants, even if the soil is uncontaminated. Similarly, irrigation water that is contaminated with heavy metals can also lead to plant contamination.
In addition, some plants are more efficient at accumulating and concentrating heavy metals in their tissues, a process known as phytoextraction. These plants, known as hyperaccumulators, can accumulate high levels of heavy metals in their tissues even when the soil is only mildly contaminated.
Therefore, it's important to consider the potential for plant contamination with heavy metals when assessing the overall risk of exposure, and to take appropriate measures to mitigate potential contamination, such as monitoring sources of water and air pollution and choosing appropriate plant species for specific growing conditions.
Hyperaccumulation = Speed Metal?
Hyperaccumulating plants are known for their ability to accumulate high concentrations of heavy metals in their tissues, which makes them useful for phytoremediation of contaminated soils. Here are some crops that are known to be hyperaccumulators:
- Sunflowers (Helianthus annuus) - lead, copper, zinc, chromium, and cadmium.
- Mustard greens (Brassica juncea) - lead, copper, and cadmium.
- Indian mustard (Brassica juncea) - lead, copper, zinc, and cadmium.
- Chinese brake fern (Pteris vittata) - arsenic.
- Alpine pennycress (Thlaspi caerulescens) - zinc, cadmium, and nickel.
- Pokeweed (Phytolacca americana) - zinc, cadmium, copper, and lead.
- Okra (Abelmoschus esculentus) - lead and cadmium.
- Amaranth (Amaranthus retroflexus) - lead and cadmium.
- Carrot (Daucus carota) - lead and cadmium.
- Tomato (Solanum lycopersicum) - lead, cadmium, and chromium.
Here are 20 hyperaccumulative herbs:
- Garlic (Allium sativum)
- Rosemary (Rosmarinus officinalis)
- Sage (Salvia officinalis)
- Thyme (Thymus vulgaris)
- Oregano (Origanum vulgare)
- Dill (Anethum graveolens)
- Mint (Mentha spp.)
- Basil (Ocimum basilicum)
- Parsley (Petroselinum crispum)
- Cilantro/Coriander (Coriandrum sativum)
- Chives (Allium schoenoprasum)
- Bay Laurel (Laurus nobilis)
- Marjoram (Origanum majorana)
- Lemon balm (Melissa officinalis)
- Savory (Satureja spp.)
- Tarragon (Artemisia dracunculus)
- Lavender (Lavandula spp.)
- Fennel (Foeniculum vulgare)
- Caraway (Carum carvi)
- Anise (Pimpinella anisum)
It's important to note that while these crops have the potential to accumulate high concentrations of heavy metals, they are not inherently toxic and can still be safely consumed as long as they are grown in non-contaminated soils. It's also important to ensure that any crops grown in contaminated soils are not consumed and are disposed of safely. Another interesting fact is that edible fungi may accumulate certain heavy metals to a limited extent, but they are not considered to be hyperaccumulators and are generally safe to consume. However, it's still important to ensure that the mushrooms are grown in non-contaminated soils and that they are properly identified as edible, cleaned and cooked before consumption.
So while we know that testing soil alone will not provide the final report of the end-crop’s metal composition; what do we do? Soil tests can serve as a starting point and can be performed every couple of years as precautionary diagnostics. Though further aspects need to be considered. Growing plants in areas with high potential for emission exposure, hazardous waste, or other contamination should be avoided. Such as along freeways, in very busy cities, or in unregulated countries that don’t enforce waste management or environmental protection laws. (Surprisingly this is a thing! For example, hazardous waste can be dumped in a river upstream from livestock and agricultural land and there are no repercussions, or respect for life.) Another potential contamination point can occur from processing equipment and from not only the packaging equipment, but the packaging itself. In order to obtain a definite answer, we will need to test the final retail-ready product, as well as the herbal plant matter itself.
Laboratory Testing the Riffs
You can send a soil or plant sample to a testing agency to receive professional laboratory test results. After much research, I found that sending samples away is the smartest, safest, most practical, and most exemplary (due to the third party involvement). Usually state college campuses offer these tests and they can range in price from $30-$160 USD (The Safe Urban Harvests Survey). The most common laboratory tests for heavy metals are the EPA Acid Digestion Method 3050/B or 6010, and the Mehlich Extraction. These are advanced tests that deal with high temperatures, strong acids and allot of specialty equipment. I tried to see if I could do any of these at home and I decided to leave it to the professionals. It involves allot of heat, and chemical applications, which are definitely doable in a makeshift home lab but when it gets to the final metal analysis, well that’s beyond my scope and available equipment.
Analyzing the filtered solution for heavy metals using analytical techniques at home can be extremely challenging and requires specialized equipment, reagents, and expertise. Laboratory scientists follow strict safety protocols and have access to fine tools such as a spectrophotometer, atomic absorption spectrometer, or inductively coupled plasma mass spectrometer (ICP-MS), as well as appropriate standards and calibration materials. Therefore, it's recommended that you seek professional help or use a certified laboratory for this type of analysis.
Are There Any ‘At Home’ Test Jams?
Unfortunately these are not very reliable as far as I can find. These tests only include a test strip procedure.
The accuracy of at-home test strips can vary depending on the type of test and the specific brand or product. Some at-home test strips can provide relatively accurate results for certain parameters, such as pH or nitrate levels in water or soil. However, tests for heavy metals or other contaminants, may not be as accurate or reliable.
It's important to keep in mind that at-home test strips are designed for general screening purposes and are not intended to replace laboratory analysis, which is generally more accurate and reliable. Additionally, the accuracy of at-home test strips can be affected by a number of factors, including user error, environmental conditions, and the age and quality of the testing materials.
Could the USDA Organic Certification help with Structure?
Starting costs for a produce farm to obtain an annual USDA Organic certification are $800 for a micro farm. These fees go up depending on farm size and produce type and include certification, record-keeping, required inspections and audits. Certification requires USDA to obtain soil tests to verify that the soil is free from prohibited substances such as synthetic fertilizers, pesticides, and genetically modified organisms (GMOs). The soil testing may also be used to assess the soil health and fertility. It seems logical to acquire soil, or possibly even plant heavy metal testing to their requirements.
Primum Non Nocere!
Food is medicine, and if the producers’ consumable goods are harboring toxic metals, then bioethically they are practicing maleficence. The time has passed to ignore the possibility of contamination, whether apathetically or otherwise. Let’s take responsibility as consumers and vote with our demand / dollars. As farmers, producers, and even importers or resellers, we need to produce and source safe food products because this problem is SYSTEMIC. Now that you know about it, you have the power to change it.
Wild Atoms' near term goals are to produce and include heavy metal tested products and to dive deeper into this research as well as further interdisciplinary ethnobotanical studies. What are you going to do with this information? What do you think are the right courses of action?
-Natalie Atoms
Reference:
Gill, L. (2021). Your Herbs and Spices Might Contain, Arsenic, Cadmium, and Lead. Consumer Reports. Sourced from web : https://www.consumerreports.org/food-safety/your-herbs-and-spices-might-contain-arsenic-cadmium-and-lead/
Johns Hopkins Bloomberg School of Public Health. The Safe Urban Harvests Study. A Guide to Testing Soil for Heavy Metals. Sourced from web : https://clf.jhsph.edu/sites/default/files/2019-03/suh-soil-testing-guide-2019.pdf
Yadav, S. K., & Shukla, S. (2018). Hyperaccumulators: The green solution to heavy metal pollution. In Heavy Metal Pollution (pp. 245-280). Springer, Cham.