toxicity - pesticides, herbicides and insecticides - Blackherbals.com

Continued from page 52 – Persistent Organic Pollutantsaccumulate in the body fat of people, marine mammals,and other animals and are passed from mother to fetus;and they can travel great distances on wind and watercurrents.Even small quantities of POPs can wreak havoc inhuman and animal tissue, causing nervous systemdamage, diseases of the immune system, reproductiveand developmental disorders, and cancers.Of the numerous POPs that are prevalent in ourenvironment, 12 of the most persistent, bioaccumulativechemicals have been identified for priority action.These 12 POPs are targeted in a new internationaltreaty. The Stockholm Convention on PersistentOrganic Pollutants will phase out and eliminate theproduction and use of those chemicals, as well as newones that would be added once the treaty is in force.The 12 targeted POPs include eight pesticides (aldrin,chlordane, DDT, dieldrin, endrin, heptachlor, mirex,and toxaphene), two types of industrial chemicals(polychlorinated biphenyls or PCBs andhexachlorobenzene), and two chemical families ofunintended by-products of the manufacture, use, and/orcombustion of chlorine and chlorine-containingmaterials (dioxins and furans).All 12 targeted POPs are also endocrine disruptors,chemicals that can interfere with the body’s ownhormones. Endocrine disrupting chemicals can behazardous at extremely low doses and pose a particulardanger to those exposed in the womb. During prenatallife, endocrine disruptors can alter development andunderm ine the ability to learn, to fight disease, and toreproduce.http://wwf.panda.org/about_our_earth/teacher_resources/webfieldtrips/toxics/our_chemical_world/pops/☻☻☻☻☻Organic Pesticides: Not anOxymoronBy Maureen LangloisJune 17, 2011It may seem counterintuitive, but foods that are grownto organic standards can contain commerciallymanufactured pesticides.A U.S. Department of Agriculture survey of producethat found nearly 20 percent of organic lettuce testedpositive for pesticide residues piqued our interest. Lotsof the lettuce contained quite a bit of spinosad, apesticide marketed by Dow Chemical under the brandname Entrust.So we called, Jeff Gillman, a professor of nurserymanagement at the University of Minnesota who haswritten about organic practices for lay readers. Right offthe bat he told us:When people are buying organic food, they often make theincorrect assumption that there are no pesticides. It's truethat organic production often uses fewer dangerouschemicals, but certain pesticides are allowed.It turns out that a key factor in chemicals being cleared foruse on organic crops is whether they occur naturally.Spinosad, for example, comes from the soil bacteriumSaccharopolyspora spinosa. It can fatally scramble thenervous systems of insects. It's also poisonous to mollusks.The USDA maintains an official list of substances that canand can't be used for organic farming. Other potent naturalextracts that have been approved for use as pesticidesinclude pyrethrin, derived from chrysanthemums, andazadirachtin, from the Asian neem tree, which was alsodetected on some samples of organic lettuce.All three of these substances are considered slightly toxicby the EPA.Synthetic compounds can also make it onto the list aspesticides, if they are relatively nontoxic combinations thatinclude minerals or natural elements, such as copper orsulfur. But some naturally occuring substances, such asnicotine and arsenic are off limits.Are naturally derived pesticides less toxic than syntheticones? The answer depends a lot on the dosage, saysGillman. "To control fire blight on the same acre of land,"he explains, "I could use a tiny amount of a potentsynthetic that has proved safe over the last 50 years, or amuch larger amount of an organic pesticide." He demurson saying which is better, saying, "I want people to knowthat there are definitely tradeoffs."In the USDA tests, there was ten times as much spinosadon organic lettuce than was found on conventionallycultivated fruits and vegetables.Gillman wasn't alarmed by the spinosad finding:It's a relatively new chemistry, relatively safe, andextremely effective against some pests. Now, if I heardabout high levels of copper being detected, I'd be morescared than for this stuff.Copper compounds are used to fight fungal and bacterialdiseases in plants. Copper isn't very toxic to humans, hesays, but it can accumulate in the soil and eventuallyContinued on page 5453-- Traditional African Clinic July 2013