02 August 2019 Bulletin

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Dichlorvos

Dichlorvos or 2,2-dichlorovinyl dimethyl phosphate is a organophosphate with the molecular formula C4H7Cl2O4P. [1] Dichlorvos is an insecticide that is a dense colourless liquid. It has a sweetish smell and readily mixes with water. Dichlorvos used in pest control is diluted with other chemicals and used as a spray. It can also be incorporated into plastic that slowly releases the chemical. [2]

 


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Featured Articles

Views sought on reassessment of methyl bromide

New Zealand’s Environmental Protection Authority (EPA) is seeking submissions on an application for the reassessment of the hazardous substance methyl bromide. Methyl bromide is used as a fumigant in the quarantine and pre-shipment treatment of logs, produce, flowers and other goods. The EPA’s chemical reassessment programme reviews hazardous substances already approved in New Zealand. Under New Zealand law, a chemical's approval does not expire. Reassessment is the only formal legal process we can use to review the approval of a chemical classed as a hazardous substance. In April 2018, the EPA decided that grounds existed for a reassessment of methyl bromide, following an application by Stakeholders in Methyl Bromide Reduction Inc (STIMBR). Grounds to reassess were granted based on data that showed New Zealand’s use of the fumigant has increased from over 400 tonnes a year in 2010, to more than 600 tonnes in 2016. One of the criteria to meet grounds for reassessment under the Hazardous Substances and New Organisms Act is a significant change in the quantity of substance imported into, or manufactured in, New Zealand. Earlier this year, STIMBR applied for a reassessment of the approval for methyl bromide. The EPA is processing this application as a modified reassessment. This means that the reassessment will only consider specific aspects of the approval, such as the required controls. The approval to import or manufacture methyl bromide cannot be revoked in this type of reassessment. Users of methyl bromide in New Zealand are required to recapture and safely dispose of the gas used in their fumigation activity from October 2020. The timeframe was set by the 2010 reassessment decision, to allow for the development, acquisition and installation of suitable equipment for recapture. Submissions on the reassessment application close at 5.00 pm on 29 August 2019. Further information is available at:

• Visit the consultation page for more information, including submission guidelines and a timeline.

• See information on the chemical reassessment program.

http://www.epa.govt.nz

 

Researchers Just Showed Bacteria Can Produce Wonder-Material Graphene

We already know what a wondrous material graphene can be – filtering water, dyeing hair, super-strengthening substances – but now scientists have figured out a way to produce it much more cheaply: with the help of bacteria. When mixed with oxidised graphite, which is relatively easy to produce, the bacterium Shewanella oneidensis removes most of the oxygen groups and leaves conductive graphene behind as a result. It's cheaper, faster, and more environmentally friendly than existing techniques to make the material. Using this process, we might be able to create graphene at the sort of scale necessary for the next generation of computing and medical devices – utilising graphene's powerful mix of strength, flexibility, and conductivity. "For real applications you need large amounts," says biologist Anne Meyer from the University of Rochester in New York. "Producing these bulk amounts is challenging and typically results in graphene that is thicker and less pure. This is where our work came in." Using the new method, Meyer and her colleagues were able to make graphene that's thinner, more stable, and longer-lasting than graphene that's produced by chemically manufacturing. This opens up all kinds of possibilities for the cheaper, bacteria-produced graphene. It could be used in field-effect transistor (FET) biosensors, devices that detect particular biological molecules, such as glucose monitoring for diabetics. Because the bacteria production process usually leaves behind certain oxygen groups, the resulting graphene is well-suited to being able to bind to specific molecules – exactly what an FET biosensor needs to do. This kind of graphene material could also be used as a conductive ink in circuit boards, in computer keyboards, or even in small wires to defrost car windshields. If needed, the bacteria process can be tweaked to produce graphene that's only conductive on one side. Graphene was first produced by using sticky tape to extract it from graphite blocks. Nowadays it's made via a number of different chemical methods that are applied to graphite or graphene oxide, but this newly discovered technique could be the most promising one yet – and without any of the harsh chemicals. As this is the first study to investigate the bacteria approach, plenty more research will need to be done before it can be scaled up and used to build the next generation of laptops. Nonetheless, the future of this incredible material continues to look bright. "Our bacterially produced graphene material will lead to far better suitability for product development," says Meyer. The research has been published in ChemistryOpen.

 

http://www.sciencealert.com.au

 

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