MANDEVILLE, Manchester — ONE year after revealing that sections of the soil in some farming communities in St Elizabeth and Manchester were contaminated with poisonous metals, Northern Caribbean University (NCU) scientists have revealed the names of the affected crops and the communities from which they came.

Two Manchester communities — Grove Place and Green Vale — were the most alarming, showing high levels of the deadly chemical arsenic, the cancer-causing cadmium, and the brain-altering metals lead and mercury, in a number of popular Jamaican staples. Sweet potatoes, yellow yam, cassava, coco and pumpkin were the crops most affected, with sweet potatoes having the highest levels of arsenic, lead and mercury, while yellow yams had the highest levels of cadmium, and coco was most vulnerable to lead.

All the crop samples from Grove Place — yellow yam, cassava, coco, sweet potato and pumpkin, had levels of arsenic way above the world- recommended standards, while the same crops grown in both Grove Place and Greenvale had cadmium levels above the acceptable international standards.

Leading scientist and Dean of the College of Natural and Applied Sciences at NCU, Dr Vincent Wright, who brought the issue to public attention last March, told the Jamaica Observer that the details of the study have been published in the Bulletin of Environmental Contamination and Toxicology, an international academic journal.

The article, which was authored by Wright and another NCU scientist, Stephen Jones, said soil and crop samples were taken from 10 farms in Comfort Hall and Balaclava in St Elizabeth, and Mile Gully, Grove Place, Maidstone, Williamsfield, Green Vale, Hatfield and Christiana in Manchester. The samples were collected and tested over a 10-month period.

Arsenic, a known poison, is a silver-grey substance which develops naturally in the earth’s crust, as well as in plants and animals. It can also be released into the environment through natural activities, such as rock erosion and forest fires, or through human actions, including copper smelting, mining and coal burning. It is also used in paints, dyes, metals, drugs and soaps.

Arsenic attacks the body’s vital organs, cripples the body’s immune system and can cause cancer of the bladder, lungs, skin, kidney, nasal passages, liver, and prostate. Depending on the severity of exposure, affected persons may suffer from head and stomach aches, convulsions, severe diarrhoea and change in pigmentation, especially in the fingernails, and drowsiness.

According to the World Health Organisation (WHO), “long-term human exposure, through drinking of contaminated water, is an important public health problem in some regions and countries”. The United States Centre for Disease Control says high levels of arsenic can also come from certain fertilisers and animal feeding operations.

Cadmium, the lesser known, but equally harmful substance, is a known cancer-causing heavy metal, which can lead to softening of the bones, severe kidney problems and spontaneous abortions. It is found in electronics, including batteries. A diet high in zinc is said to be able to combat cadmium symptoms.

Lead, another toxin found in the study, is no stranger to Jamaica. In 2004, environmental scientists at the University of the West Indies (UWI) found a large concentration of lead in sections of Mona Commons and Kintyre, communities close to the UWI. A number of children were affected, and residents in the two communities were evacuated. The NCU study found that sweet potato from Grove Place had the highest concentration of lead.

Mercury, which is found mostly in fish products, has similar effects to lead, and has been found to affect children in particular. Long-term exposure can affect the nervous system and cause brain and kidney damage. High-level exposure can affect the reproductive health of both men and women and the growth and learning ability in children. The study showed that mercury was at its highest in all crops in Grove Place and Williamsfield.

Mikael Phillips, who is Member for Parliament for North West Manchester, in which both communities fall, told the Sunday Observer, that he was not aware of the problem. “North West Manchester solely depends on agriculture. It’s the largest producer of sweet potato and irish potato, so when I hear about sweet potato, it’s a concern,” he said, pointing out that he would readily take money from his Constituency Development Fund (CDF) to help deal with the problem. “We would have to get constituency sensitised, get the agencies involved … I’d want to be at the forefront of the fight,” he told the Sunday Observer.

But Head of the Rural Agricultural Development Authority (RADA) in Manchester Samuel Harris, scoffed at the NCU study, referring to it as ‘stale news’. He said that the University of the West Indies (UWI) had done a study in 2005, which had revealed that “the whole northern belt… from Mandeville, to bits of Trelawny and a little part of St Elizabeth” had cadmium. He said that at the time, the UWI had said that, “it wouldn’t affect human beings. They even did autopsies on humans and found that people were living to a hundred and odd,” he stated.

Harris said since then, RADA had done nothing to deal with the problem and he insisted that he was “comfortable with the conclusion of the UWI study that it wasn’t affecting humans, besides what could we do? move the soil?” He said at the time, the UWI study had indicated that the levels of cadmium were higher than acceptable world standards

But in the NCU study, both scientists expressed concern that the high levels of lead and cadmium found in some crops, “may be of great concern since exposure to those toxic metals has been shown to negatively impact human health globally”, especially since “we also noted a strong co-relation between soil and agriculture produce cadmium concentrations”. This means the crops were more susceptible to be affected by this metal once the soil was contaminated.

The study suggested that more attention must be paid to selecting land and food crops “with suitable sustainable agriculture practices” to “mitigate the metal content.

“This is important because chronic consumption of these crops with high levels of toxic metals, especially cadmium, lead, arsenic and mercury, may be deleterious to human and animal health,” he said.

Last year, Dr Wright expressed alarm about the arsenic levels in particular, but had refused to disclose the actual communities affected, out of “fear of raising alarm” among residents. At the time, he noted that not even farmers were aware of the soil contamination.