Garth Rattray | What is in our soil?

Aside from genetics, which we can do nothing about, many things impact our physical and mental health. Things like stress, micro-organisms, the chemicals that we swallow, inhale, or come into contact with, and radiation from several sources may all have deleterious effects on our bodies. They may lead to physical problems (like organ diseases and/or cancers), and mental problems (like learning disabilities, behavioural problems, and even criminality).

Many years ago, when I interviewed one of our Ministry of Health (as it was called back then) officials, he explained that it is plausible that the combinations, concentrations and accumulation of all the man-made environmental toxins and radiations are causing or triggering several, perhaps many of the cancers that we are seeing today.

Everything that we eat comes from the soil. Fruits, vegetables, grains, roots, and tubers come directly from the soil. People who eat animals are eating the food that is processed from the soil by them. This is how we may be affected by pesticides and heavy metals. We can’t get away from some of the chemicals found in soil; fortunately, they are not usually a problem when they exist in low concentrations. However, health problems arise when they are in large concentrations.

PESTICIDES

Pesticides are – any chemical substance, biological agent such as a virus or bacterium, antimicrobial, trap, disinfectant or any device intended for preventing, destroying, repelling or disturbing the mating pattern of or mitigating any pest. Some small farmers opt for natural pesticides like liquid soap, tobacco, alcohol, salt, garlic and onion spray preparations. These are safe in non-toxic concentrations.

However, large-scale farmers utilise unnatural (manmade) pesticides, which are potentially dangerous. These leave Persistent Organic Pollutants (POPs) … the toxic (harmful) chemicals that remain in the soil and the environment. They can accumulate in plants and animals.

Aside from the intended targeted use as herbicides, insecticides and so on, and mode of application (contact or systemic), pesticides are classified according to how hazardous (or toxic) they are – from “extremely hazardous” to “unlikely to present acute hazard”. The more toxic pesticides are being phased out and we may be left with only fumigants in that class.

Jamaica utilises a large and variable number of pesticides, the most toxic one (Lannate) has a short residual action and rapidly disintegrates (in one to two days) into water and carbon dioxide. Less toxic pesticides take longer to disintegrate (three to seven days) but sunlight and heat accelerate their breakdown. Washing and cooking destroys most pesticides and peeling fruits removes them.

Soil in Jamaica contains several heavy metals, primarily due to natural geological formations and human activities. Some of the common heavy metals found in Jamaican soil include – Lead (often found in residential areas and associated with industrial activities), Cadmium (present in certain regions and can be harmful to both plants and animals), arsenic (naturally occurring but can be elevated due to mining activities), copper (found in areas with bauxite deposits), zinc (an essential micronutrient for plants, but toxic in excessive concentrations, and can be relatively high, particularly in areas with bauxite deposits), and mercury (which can be present due to industrial pollution). These metals can be harmful to both plants and animals. Because they pose risks to the environment, and consequently, to human health, their levels should be monitored and managed.

TOXIC ELEMENTS

Professor Gerald Lalor conducted extensive research on the presence of potentially toxic elements in Jamaican soil, particularly focusing on cadmium and lead. His work underscored the importance of understanding the geochemistry of the local environment and its effects on human health. His research has been instrumental in highlighting areas of concern and guiding efforts to mitigate the impact of these toxic elements on the Jamaican population. For example, an islandwide study identified 230 children out of a sample of 1081 with blood lead levels above the accepted limit of 10 μg/dL!

From the work of Professor Lalor et al and highlighted by Dr Homero Silva (Pan American Health Organisation Environmental Health Advisor), we are reminded that Jamaica has high levels of cadmium, manganese, copper, arsenic and lead, individually or combined in several areas. Only Japan has higher cadmium levels than we do. Jamaica is 10,099 square kilometres, of which 5,130 square kilometres are being used for agriculture. However, according to Dr Silva, only 159 square kilometres is safe from too much heavy metal contamination ... and this appears to be within an urban area not traditionally used primarily for agriculture.

High levels of heavy metals have been found in plants and animals. They bioaccumulate and are neurotoxic in elevated amounts – causing IQ reduction, anaemia, Attention Deficit and Hyperactivity Disorder (which is reportedly found in 12 per cent of our children – only Taiwan has a higher percentage of ADHD). There are other implications for our physical health and for the levels of violence that we experience here.

Although some local crops are routinely tested for pesticide residue, under normal circumstances, the likelihood of health problems from them appear to be extremely low. But that may not be true for health concerns from our heavy metal contamination. The concern for heavy metal soil contamination was highlighted in a Jamaica Observer article (Cancer in the soil – farmers not aware of contamination – published on March 11, 2012).

Between soil degradation (and resultant inadequate human nutrition), POPs, and heavy metal concentrations, there is cause for genuine concern. This begs for further investigation and monitoring with a view to reducing the associated health risks to our population.

Garth Rattray is a medical doctor with a family practice, and author of ‘The Long and Short of Thick and Thin’. Send feedback to columns@gleanerjm.com and garthrattray@gmail.com