Custom Soils lock up CO2

Using calcium-rich soil in landscaping and agriculture could fix thousands of tons of carbon dioxide in the ground each year, compensating for a significant fraction of annual greenhouse gas emission. The approach can be put into practice quickly and with limited investment, scientists report this month.

A team from Newcastle University in the U.K. says custom soils can remove carbon from the atmosphere, permanently and cost-effectively. This has never previously been attempted anywhere in the world.

Exploits Natural Cycle
The concept underlying the initiative exploits the fact that plants, crops and trees naturally absorb atmospheric carbon dioxide (CO2) during photosynthesis and then pump surplus carbon through their roots into the earth around them. In most soils, much of this carbon can escape back to the atmosphere or enters groundwater.

But in soils containing calcium-bearing silicates (natural or man-made), the team believes the carbon that oozes out of a plant’s roots may react with the calcium to form the harmless mineral calcium carbonate. The carbon then stays securely locked in the calcium carbonate, which simply remains in the soil, close to the plant’s roots, in the form of a coating on pebbles or as grains.
The scientists are investigating whether this process occurs as it may encourage the growing of more plants, crops etc in places where calcium-rich soils already exist. It would also open up the prospect that bespoke soils can be designed (i.e. with added calcium silicates, or specific plants) which optimise the carbon-capture process. Such soils could play a valuable role in carbon abatement all over the globe.

Making Custom Soils
The team will first try to detect calcium carbonate in natural soils that have developed on top of calcium-rich rocks or been exposed to concrete dust (which contains man-made calcium silicates). They will then study artificial soils made at the University from a mixture of compost and calcium-rich rock. Finally, they will grow plants in purpose-made soils containing a high level of calcium silicates and monitor accumulation of calcium carbonate there.

Study Links Pesticides to Parkinson’s

Another study has linked exposure to insecticides and herbicides with Parkinson’s disease. Landscape use of the chemicals thought to be responsible is less than it once was, but the findings should remind professionals to limit pesticide use and to always use protective gear.

Of interest to landscapers is the apparent relationship between Parkinson’s and chemicals used on turfgrass, trees and shrubs. Newer classes of insecticides and herbicides are often used today in these settings, however.

Organophosphate Link

“Similar to previous studies, both herbicide and insecticide use were shown to have significant positive associations with Parkinson’s disease, although the association was stronger for insecticide use,” the authors note.

“Two insecticide classes (the organochlorine and organophosphorus classes) were shown to significantly increase Parkinson’s disease risk.”

The report appears in the online open access journal BMC Neurology.

Parkinson’s disease is a common neurological disorder affecting about 1 million people in the U.S. The disorder typically develops in later life resulting in symptoms such as tremors and muscle rigidity

Multiple Causes

The majority of Parkinson’s disease cases are thought to be due to an interaction between genetic and environmental factors.

“Previous studies have shown that individuals with Parkinson’s disease are over twice as likely to report being exposed to pesticides as unaffected individuals” says the study’s lead author, Dana Hancock, “but few studies have looked at this association in people from the same family or have assessed associations between specific classes of pesticides and Parkinson’s disease.”

The authors detected an association between pesticide use and Parkinson’s disease. Among these, the strongest were between the disorder and use of herbicides and insecticides, such as organochlorides and organophosphates. No association was found between Parkinson’s disease and well-water drinking or living or working on a farm, which are two commonly used proxies for pesticide exposures.

Questions Remain

Many studies have supported pesticides as a risk factor for PD, but “biological evidence is presently insufficient to conclude that pesticide exposure causes PD”, says Hancock. “Further investigation of these specific pesticides and others may lead to identification of pertinent biological pathways influencing PD development.” In addition future genetic studies of Parkinson’s disease should consider the influence of pesticides, since exposure to pesticides may provide a trigger for the disease in genetically predisposed individuals.