Taking charge of health: Growing heavy-metal-free veggies
Heavy metals as a health risk
Heavy metals in our soil pose serious health risks. As The Gold Report highlighted, they can cause,
“. . . nervous disorders, hormone imbalances, and respiratory disorders and heart disease, memory loss, various types of cancer and eventually death.
“Arsenic, lead and cadmium . . . cause hemoglobin biosynthesis disorders and anemia, increased blood pressure, kidney damage, miscarriage and premature birth, nervous system disorders, and brain damage, male infertility, reduced learning ability and behavioral disorders in children.”
Eating organic, The Gold Report related, does not mean your foods are heavy-metal free since they may still be grown in the same soil and water.
Clearing soil of heavy metals
The good news is that there are effective ways to detoxify our soil and protect our health. From natural remediation techniques to strategic gardening practices, we can take meaningful steps to ensure our food is safe and healthy.
Public awareness
Deyi Hou et al, in their article on heavy-metal contamination and soil remediation published in the journal Nature, examine the issue of contaminated soil around the world, emphasizing its seriousness and exhorting the international community to take action. Their "Key Points" are:
▪ Agricultural soil is a non-renewable natural resource that requires careful stewardship in order to achieve the United Nations’ Sustainable Development Goals.
▪ Global agricultural soil pollution by heavy metal(loid)s represents one of the biggest challenges to sustainable development, particularly in developing countries.
▪ Bioremediation, including phytoremediation and microbially mediated bioremediation, is a promising nature-based solution for treating heavy metal(loid) contamination.
▪ It is imperative that the international community realizes the seriousness of the heavy metal(loid)s contamination in soils, takes actions to prevent further pollution and instigates the remediation of contaminated sites with environmentally friendly techniques.
▪ Policymakers should foster a bioremediation-enabling environment through policy instruments and increased field-based research funding.
While greater awareness of the health hazards of contaminated soils may be required to ensure sufficient pressure to clean soil globally, many companies are stepping up to help clean contaminated areas. In the video below, TDJ Group shows how they remediate soil.
Natural methods
Natural methods of removing heavy metals from soil include bioremediation and phytoremediation. Bioremediation uses nutrients, oxygen, and microorganisms to stimulate the natural breakdown of heavy metals or immobilize them. It is preferred to chemical or physical treatments, since it is better for the environment, according to LinkedIn’s bioengineering community.
Bioremediation is more environmentally friendly, as it does not generate harmful by-products or residues. It is also more cost-effective, as it uses natural or renewable resources and does not require expensive equipment or chemicals. It is also more adaptable, as it can target specific pollutants and adjust to different soil conditions and contaminants. It can also improve the soil quality and fertility, by enhancing the microbial diversity and activity and restoring the nutrient and organic matter cycles.
Home gardeners and community-supported farmers
The US EPA, in “A citizen’s guide to phytoremediation,” states that plants can be used to clean up environmental pollution including “metals, pesticides, explosives, and oil. The plants also help prevent wind, rain, and groundwater from carrying pollution away from sites to other areas.” According to the guide, phytoremediation is most successful at sites with medium to low pollution levels.
GardenProfessors provides these tips for home gardeners.
▪ Cover exposed soil with ground covers and mulches (coarse organic or inorganic materials) to eliminate metal-laden dust.
▪ Create raised beds for edibles using untreated wood or other metal-free materials. Line the bottom of the bed with an impermeable membrane to prevent movement of soil-borne metals into the beds.
▪ If raised beds are not possible, use large containers to grow edibles.
▪ Avoid using galvanized tubs, as they will leach zinc (and sometimes chromium) into the soil.
▪ Fill beds and containers with clean (i.e., tested) soils or potting media.
▪ Don’t plant vegetables near roadways, which are a source of airborne lead.
Cornell University’s College of Agriculture and Life Sciences has these tips for small and urban farmers who wish to mitigate their exposure to contaminants or remediate the soil. It offers these tips:
Once urban farmers have determined their soil safety, and decided to pursue production, there are simple precautions you can take to minimize your exposure to contaminants and toxicity to plants.
▪ Plant crops away from building foundations, painted structures and heavily traveled roads;
▪ Remove obvious contaminants such as scrap metal and construction materials;
▪ Use mulch and cover crops to minimize exposure to contaminated dust, and to maintain high levels of organic matter;
▪ Because concentrations of heavy metals are highest in roots and leaves, avoid planting and eating leafy or root vegetable crops in soils with heavy metals above typical;
▪ Lime, compost, or amend soil to keep pH close to neutral, or even slightly alkaline, and ensure adequate draining to reduce the mobility and availability of lead and heavy metals;
▪ Do not use plants grown in contaminated soil for compost;
▪ Work in the garden only when soil is moist or damp;
▪ Wear gloves, long sleeves and pants while gardening to prevent skin exposure;
▪ Wash hands after gardening;
▪ Wash all vegetables thoroughly; and
▪ Remove gardening shoes and garments before entering the home, and wash gardening clothes separately from other clothing.
In the following video, "Testing Soils for Heavy Metals and Developing Effective Remediation Strategies," University of Louisiana at Lafayette professor Dr. Anna Paltseva encourages urban farmers to address soil contamination."
. . . I will tell you about the heterogeneity of urban soils, sources of heavy metals—both natural and anthropogenic—as well as how we measure heavy metals. We will discuss reference values and delve into plant contamination. Of course, I'll also cover how we can fix the problem.
The future?
Urban and small farmers, along with home gardeners, may benefit from collaborating and sharing knowledge within their communities. By engaging in local gardening groups and initiatives focused on soil health, individuals can exchange resources, techniques, and experiences to enhance their practices. These efforts may help mitigate the health risks associated with heavy-metal-contaminated foods and could inspire further initiatives to promote personal and communal health and well-being.
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