Hemp phytoremediation

Soil contamination is increasing at an alarming rate, due to a number of human activities. The release of industrial effluent, municipal waste and sludge enriched with heavy metals and chemicals contaminate surrounding environments and farming regions. Once these contaminates are in the soil, they will remain a potential threat to sustainable crop production for many years. Phytoremediation is an environmentally friendly and cost effective technology.

Many plant species have the ability to grow in contaminated soils and some are able to accumulate high concentrations of heavy metals in their tissues. To promote and enhance phytoremediation, it is key to find hyper-accumulator plants that have the ability to grow fast and accumulate high levels of soil contaminates like heavy metals. Currently, more than 400 species of hyper-accumulator plants have been reported in the botanical literature.

Ideally, a plant should have high, yet fast, biomass production, a high tolerance to heavy metal stress and be capable of accumulating high amounts of contaminants. Whilst remediating soils, hyper-accumulator crops are sequestering large amounts of carbon from the atmosphere and dispersing it back into the soil. Hemp (Cannabis sativa L.) is an annual crop used in both food and non-food industries. Hemp is one of the most suitable and viable bio-accumulators.

There are certain characteristics which make hemp very suited to phytoremediation, such as high biomass, long root system and short life cycle (120-160 days). Hemp has the ability to absorb very high amounts of heavy metals like lead, nickel, cadmium, zinc and chromium. Also, the deep root system of the plant encourages aeration of the soil whilst absorbing contaminants and dispersing organic matter. 

One of the greatest examples of phytoremediation was in the late 1990’s. US company Phytotech began experimenting with industrial hemp in polluted and contaminated regions of Ukraine. Phytotech was able to use hemp to remove radioactive waste with great success at Chernobyl. Globally, there are millions of sites that require phytoremediation. With regard to Australian soils, the mining sector has experienced many years of favourable resource yields yet lacked environmental responsibility. Large areas of damaged, contaminated and useless land is the result.

It goes without saying that hemp used for phytoremediation should not be used for food or cannabinoids, but it can be used for biofuel. Hemp biofuel is made from the plant cellulose; 80% of the hemp plant is cellulose. With correlating benefits in phytoremediation, hemp is a great plant for biofuel production. Although little research has been conducted on how hemp stacks up against other plants in regards to biofuel efficiency and viability, current trials and research projects hope to deliver data driven results to prove this.

Original source: Heavy metals trapped in our soils | Is Hemp a simple solution?

Share this page: