A Little Info on Lead Arsenate

Currently, in your local hardware store, or even in your local Wal-Mart or K-Mart, there are many products under the term “pesticide”. Among those products available are fungicides, herbicides, and insecticides. All of these products, at one time or another, in North America, have contained raw materials within their chemical makeup that has been hazardous to human health and/or environmentally unfriendly.

Lead Arsenate (AsHO₄Pb) is an inorganic chemical compound composed of the elements Arsenic (Ar), Hydrogen (H), Oxygen (O) and Lead (Pb). Lead Arsenate can be used as a raw material for many different kinds of pesticides, including herbicide, insecticide and as growth regulator. Typically lead arsenate is used as an insecticide.

(Compound structure of Lead Arsenate)

Its first introduction as an insecticide was in 1908, when the toxic product was created by Cal Spray, a branch company of the chemical conglomerate, Chevron Chemical Company. It was used to kill coddling moths in the Pajaro Valley apple orchards. Typically, throughout its commercial use, lead arsenate has been used to kill bugs and regulate growth in fruit and vegetable orchards where massive amounts of commercial crops are grown. It has also been used to kill off bugs and critters from tobacco plantations.

Lead arsenate is no longer used in many parts of North America, including many states in the USA, some of which have had the substance banned since the 1950’s for fears of its hazardous effects to humans.

While lead arsenate does eliminate bugs and rodents from fields, it also has a lot of negative effects, both to the environment and to humans. This pesticide is composed in such a way that the lead and arsenic bind tightly to the soil surface, where they may remain for decades, without any real possibility of removal. The longer a particular region remains an orchard using this pesticide, the more concentrated the lead arsenate becomes within the soil, and this can create serious health effects for children who play in that soil. Typically, in regions where this substance has been used, have reported higher rates of cancer among both the elderly and the young.

When regions that were once orchards and fields that used this compound are transformed into subdivisions and parks, the effects of the lead arsenate remain. This may result in great amounts of health hazards to children, as they become exposed to such contaminants. The substance is also carcinogen, and therefore may create high cancer rates in regions it was once used.

As a result of its environmental and human health effects, North American, as well as foreign governments finally banned the use of this product as a pesticide. After the 1950’s, however, governments were introduced to another product that could act as an insecticide in a similar fashion to that of lead arsenate, this was DDT (dichlorodiphenyltrichloroethane). DDT proved just as, if not even more effective, until it was realized that DDT’s were an even greater hazard to the ozone layer. It turned out that the chlorine in the DDT would rise up to the atmosphere and break up O3 (ozone) bonds, leading to the eventual hole in the ozone layer.

So far, no pesticides have been quite as effective as lead arsenate, yet still environmentally friendly and humanly safe. The only one that came close was DDT, but that has been banned since the 1990’s. There are though, many alternatives to lead arsenate insecticides currently available on the open market, including acephate, carbofuran, dimethoate, endosulfan and methyl parathion, as well as many others. The aforementioned, though, have not been banned in North America and Europe, the way DDT and lead arsenate have.