05.Classes of chemicals
Classes of chemicals
Organophosphates inhibit an enzyme, cholinesterase, required for normal nerve function in their target pests. They are more toxic than pyrethrins, pyrethroids and carbamates. Organophosphates such as chlorpyrifos and malathion/maldison are used in domestic pest control products in Australia. Chlorpyrifos has been banned in the US for domestic use since 2000, after authorities found unacceptable risks to children’s neurological and behavioural development. In 2007, under its Biocidal Products Directive, the EU decided to remove from the market pest control products containing chlopyrifos.
Pyrethrins and their synthetic derivatives, pyrethroids, also interfere with the nerve function of their target pests. Because of their low toxicity to humans and other mammals, synthetic pyrethroids such as allethrin, bioresmethrin and permethrin have long been hailed as safer alternatives to organophosphate pesticides. However, recent studies have highlighted problems with their long-term safety and endocrine disruptive effects.
Carbamate pesticides also work by inhibiting cholinesterase. Various carbamates are used in domestic pest control. In Australia, fenoxycarb is commonly found in ant killer and roach bombs. However, in the EU, insecticides containing fenoxycarb have not been approved for use in such products since September 2006.
Which is the least hazardous to humans?
At the very top of any label, the signal heading with a hazard warning indicates how poisonous a product is.
- No signal heading indicates the lowest hazard.
- CAUTION means it’s a low hazard with some potential for causing harm.
- POISON is the strongest warning, implying it’s a moderate hazard with a strong potential for causing harm.
The Australian Pesticides and Veterinary Medicines Authority (APVMA) recently added a section to its website designed to assist consumers to choose a product that’s right for them.