Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Uncalculated Risks in Some Pesticides

18.01.2005


Some Compounds Show Dramatic Differences in Toxicity And Rate of Break Down Between Isomers




Researchers at the University of California, Riverside have demonstrated that isomers – or the mirror-image structures – of some pesticides, although chemically identical, have very different biological and environmental impacts between the two sides. This may have significant implications for risk assessment and research and development directions of new products.

The environmental risks of pesticides have been traditionally evaluated on the basis of their specific chemical structure, according to Jay Gan, a UCR professor of environmental chemistry. He found, however, that this group, known as chiral pesticides, including many widely used organophosphates and synthetic pyrethroids, pose previously uncalculated toxic risks due to the differing biological reactions of the isomers in the environment.


A characteristic of chiral compounds is that they occur as isomers with two (or more) identical but mirror-image structures that, as Gan’s research indicates, while chemically identical, may behave biologically differently. These mirror-image molecules are known as enantiomers. Currently about 25 percent of pesticides fall into this classification and this ratio is expected to increase as new products are being introduced into the market.

Gan’s findings add weight to the argument that regulators should consider whether a product is a chiral compound when assessing its risk, and that the chemical industry should pursue the value of producing single isomer products instead of mixed isomer products.

By using pesticides with just the active isomer, farmers will likely achieve the same degree of pest control at a much-reduced rate of chemical use. This will have environmental benefits as much less chemical is introduced into the environment.

The findings were published in a paper titled Enantioselectivity in Environmental Safety of Current Chiral Insecticides in last week’s online edition of the Proceedings of the National Academy of Sciences. Gan published the paper in cooperation with a team of UCR colleagues including Daniel Schlenk, professor of aquatic ecotoxicology; Soil Physics Professor, William A. Jury; and visiting professor Weiping Liu.

Gan and his colleagues at UC Riverside decided to look at chiral insecticides that are widely used today. They examined five common insecticides, including the organophosphates, such as profenofos, and synthetic pyrethroids, such as permethrin. For all these compounds, one of the optical isomers, or enantiomers, was consistently over 10 times more toxic than the other to Ceriodaphia, a small crustacean often used to assess water toxicity.

The researchers also found that a specific enantiomer lingered longer in the environment than the other enantiomers, making one enantiomer of permethrin almost twice as prevalent in sediment or runoff water. This means that the environmental impact of these pesticides may depend on the behavior of a particular enantiomer instead of the whole compound, the team concluded.

Regulators currently examine the safety of the pesticide straight from the factory, in which both enantiomers are normally present in an equal ratio. On the other hand, knowing about such selectivity would be valuable for the chemical industry. For instance, if only one enantiomer is known to contribute to the pest control efficacy, it would be environmentally advantageous to manufactured products containing just the active component. The rate of use may be cut in half, and the chemical load into the environment will also be halved.

“The difference in terms of pesticide regulation and future R&D directions could be pretty drastic for chiral pesticides,” said Gan.

Ricardo Duran | EurekAlert!
Further information:
http://www.ucr.edu

More articles from Ecology, The Environment and Conservation:

nachricht Bioinvasion on the rise
15.02.2017 | Universität Konstanz

nachricht Litter Levels in the Depths of the Arctic are On the Rise
10.02.2017 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Stingless bees have their nests protected by soldiers

24.02.2017 | Life Sciences

New risk factors for anxiety disorders

24.02.2017 | Life Sciences

MWC 2017: 5G Capital Berlin

24.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>