DDT in New Zealand
Encyclopedia
The use of DDT in New Zealand was banned in 1989 due to negative environmental impacts.
(POP) with a half life of 2-15 years. Concerns were raised about its use in the 1940's but the publication of Rachael Carson's book Silent Spring
was the catalyst leading to DDT being banned. DDT was first banned in Hungary in 1968 then in Norway and Sweden in 1970, the US in 1972 and the United Kingdom in 1984.
s was being applied annually by 1959. By the 1970s its use was restricted and it was finally banned in 1989.
DDT passes up the food chain and organisms at higher trophic level
s end up with high concentrations of the pesticide.
Some Canterbury and Southland farms have elevated levels of DDT and a programme run by the Ministry of Agriculture ensures that exported meat and dairy produce have low levels of these residues. During dry periods animals ingest soil since grass is shorter and sparser and the DDT residue on the soil is retained by the animal. In the 1980s 40% of the lambs in Canterbury, a region with low rainfall and occasional droughts, had DDT levels that were above the European Union
's permitted limit but still acceptable under safe tolerance limits for New Zealand.
Mapua
was one of the most contaminated sites in New Zealand due to pesticide residues in the soils from a now defunct factory. In the 1940s organomercury
and organochlorine pesticides, including DDT
, DDD
, dieldrin
, 2,4-D
and paraquat
, were produced. The factory closed in 1988 and the site was subjected to a major clean up operation in the 2000s.
DDT has also been found in the endangered Hectors dolphin which inhabits the coastal regions on New Zealand.
which controls the production and use of persistent organic pesticides, and therefore includes DDT. It came into law on 23 December 2004. Article 3.1(b) of the Convention restricts the production and use of DDT but since there is no intention to use DDT in New Zealand there is no action required under the Convention.
DDT
DDT is an organochlorine insecticide that does not occur naturally. It is a persistent organic pollutantPersistent organic pollutant
thumb|right|275px|State parties to the Stockholm Convention on Persistent Organic PollutantsPersistent organic pollutants are organic compounds that are resistant to environmental degradation through chemical, biological, and photolytic processes...
(POP) with a half life of 2-15 years. Concerns were raised about its use in the 1940's but the publication of Rachael Carson's book Silent Spring
Silent Spring
Silent Spring is a book written by Rachel Carson and published by Houghton Mifflin on 27 September 1962. The book is widely credited with helping launch the environmental movement....
was the catalyst leading to DDT being banned. DDT was first banned in Hungary in 1968 then in Norway and Sweden in 1970, the US in 1972 and the United Kingdom in 1984.
Usage
DDT was used extensively for agricultural use in the 1950s and 1960s to control grass grub and porina moth. It was also used on lawns and for market gardens. Some 500 tonTon
The ton is a unit of measure. It has a long history and has acquired a number of meanings and uses over the years. It is used principally as a unit of weight, and as a unit of volume. It can also be used as a measure of energy, for truck classification, or as a colloquial term.It is derived from...
s was being applied annually by 1959. By the 1970s its use was restricted and it was finally banned in 1989.
Residues
There was increasing evidence, especially in the 1970s, that there was DDT residues in aquatic organisms, including trout and eels. Being bioaccumulativeBioaccumulation
Bioaccumulation refers to the accumulation of substances, such as pesticides, or other organic chemicals in an organism. Bioaccumulation occurs when an organism absorbs a toxic substance at a rate greater than that at which the substance is lost...
DDT passes up the food chain and organisms at higher trophic level
Trophic level
The trophic level of an organism is the position it occupies in a food chain. The word trophic derives from the Greek τροφή referring to food or feeding. A food chain represents a succession of organisms that eat another organism and are, in turn, eaten themselves. The number of steps an organism...
s end up with high concentrations of the pesticide.
Some Canterbury and Southland farms have elevated levels of DDT and a programme run by the Ministry of Agriculture ensures that exported meat and dairy produce have low levels of these residues. During dry periods animals ingest soil since grass is shorter and sparser and the DDT residue on the soil is retained by the animal. In the 1980s 40% of the lambs in Canterbury, a region with low rainfall and occasional droughts, had DDT levels that were above the European Union
European Union
The European Union is an economic and political union of 27 independent member states which are located primarily in Europe. The EU traces its origins from the European Coal and Steel Community and the European Economic Community , formed by six countries in 1958...
's permitted limit but still acceptable under safe tolerance limits for New Zealand.
Mapua
Mapua, New Zealand
Mapua is a small town in the South Island of New Zealand.It is to the west of Nelson on State Highway 60 and on the coastline of Tasman Bay. The 2006 census gave a population of 1878, up 16.1 percent since the 2001 Census.:...
was one of the most contaminated sites in New Zealand due to pesticide residues in the soils from a now defunct factory. In the 1940s organomercury
Organomercury
Organomercury refers to the group of organometallic compounds that contain mercury. Typically the Hg-C bond is stable toward air and moisture but sensitive to light. Important organomercury compounds are the methylmercury cation, CH3Hg+; ethylmercury cation, C2H5Hg+; dimethylmercury, 2Hg,...
and organochlorine pesticides, including DDT
DDT
DDT is one of the most well-known synthetic insecticides. It is a chemical with a long, unique, and controversial history....
, DDD
Dichlorodiphenyldichloroethane
Dichlorodiphenyldichloroethane is an organochlorine insecticide that is slightly irritating to the skin. DDD is a metabolite of DDT. DDD is colorless and crystalline; it is closely related chemically and is similar in properties to DDT, but it is considered to be less toxic to animals than is DDT...
, dieldrin
Dieldrin
Dieldrin is a chlorinated hydrocarbon originally produced in 1948 by J. Hyman & Co, Denver, as an insecticide. Dieldrin is closely related to aldrin, which reacts further to form dieldrin. Aldrin is not toxic to insects; it is oxidized in the insect to form dieldrin which is the active compound...
, 2,4-D
2,4-Dichlorophenoxyacetic acid
2,4-Dichlorophenoxyacetic acid is a common systemic pesticide/herbicide used in the control of broadleaf weeds. It is the most widely used herbicide in the world, and the third most commonly used in North America...
and paraquat
Paraquat
Paraquat is the trade name for N,N′-dimethyl-4,4′-bipyridinium dichloride, one of the most widely used herbicides in the world. Paraquat, a viologen, is quick-acting and non-selective, killing green plant tissue on contact. It is also toxic to human beings and animals...
, were produced. The factory closed in 1988 and the site was subjected to a major clean up operation in the 2000s.
DDT has also been found in the endangered Hectors dolphin which inhabits the coastal regions on New Zealand.
Stockholm Convention
The New Zealand government has signed and ratified the Stockholm ConventionStockholm Convention
Stockholm Convention on Persistent Organic Pollutants is an international environmental treaty, signed in 2001 and effective from May 2004, that aims to eliminate or restrict the production and use of persistent organic pollutants .- History :...
which controls the production and use of persistent organic pesticides, and therefore includes DDT. It came into law on 23 December 2004. Article 3.1(b) of the Convention restricts the production and use of DDT but since there is no intention to use DDT in New Zealand there is no action required under the Convention.