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Biodegradation of five herbicides, two acetanilides (propanil and propachlor), and three phenylureas (diuron, monuron, and fenuron) was analyzed in samples of river water during a period of 6-8 weeks. Concentrations of 0.2-5.0 mg/liter of the herbicides were used for biodegradation. Two types of river water samples with different numbers of microorganisms were collected from the Neris River: upstream and downstream of the city of Vilnius. The initial concentration of microorganisms varied from 4.7×105to 2.7×106cells/liter and from 1.4×108to 5.3×108cells/liter in water samples from the Neris River upstream and downstream of Vilnius, respectively. Chemical analysis was performed by the HPLC technique, using standards of herbicides and likely degradation products. Chemical parameters of different river water samples used in biodegradation experiments were analyzed. A second-order reaction rate model was used for the analysis of biodegradation data. Values of the first-order rate constants (Ka) revealed the following decrease in the biodegradation rate of herbicides: propanildiuron≥monuron=propachlor>fenuron. This sequence was constant for all water samples analyzed. The set of decreasing value of second-order biodegradation rate constants (Kb) differed from the set of first-order constants (Ka) because the total number of bacteria in the water samples varied by up to two orders of magnitude, and this variation influenced the calculated values ofKb. Thus, different sets ofKbvalues were obtained for the water samples from the river upstream and downstream of the city. Schemes of a variety of biodegradation models are presented,
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What are some examples of good leaving groups for SN1 reactions?
Some examples of good leaving groups for SN1 reactions include halides (such as chloride, bromide, and iodide), sulfonates (such as tosylate and mesylate), and triflates. These leaving groups are stable and can easily dissociate from the substrate to facilitate the SN1 reaction.
What are some non-examples of catalyst?
Substances like salt, which do not speed up chemical reactions, are non-examples of catalysts. In addition, compounds that hinder or slow down reactions instead of accelerating them are also non-examples of catalysts. Materials like water or inert gases that do not participate in the reaction are other examples of non-catalysts.
What are some kinds os chemical changes that release energy?
Some examples of chemical changes that release energy include combustion reactions (burning of fuel), oxidation reactions (rusting of iron), and exothermic reactions such as the reaction between acids and bases. These reactions typically result in the production of heat, light, or sound.
Which process involve the release of heat?
Exothermic reactions involve the release of heat as they proceed. This means that the reaction releases energy to its surroundings in the form of heat. Examples include combustion, some oxidation reactions, and neutralization reactions.
What are some examples of simple precipitation reactions?
Some examples of simple precipitation reactions include mixing silver nitrate with sodium chloride to form silver chloride precipitate, mixing lead nitrate with potassium iodide to form lead iodide precipitate, and mixing barium chloride with sodium sulfate to form barium sulfate precipitate.
What are some examples of college admissions oficers reactions to inappropriate postings?
What are some examples of college admissions oficers reactions to inappropriate postings?
What are the types of biodegradation?
there are two types of biodegradation
Are chemical reactions useful?
yes some chemical reactions are harmful to us. as digestion of food, photosynthesis, decomposition of organic waste are some examples of the useful chemical reactions.
What are some examples of endothermic reactions that are endothermic as well?
All ENDOthermic reactions are of course ENDOthermic by themselves, aren't they?
What are some fast reactions in everyday life?
Fireworks and wood burning are good examples of fast chemical reactions =]
What is an chimical reactions?
cooking a egg or even burning wood are some examples of chemical reactions. there are still many more out in the world
What are examples of a chemical change in matter?
Synthesis, decomposition, combustion, and oxidation are some examples of chemical changes (reactions) of matter.
What are some chemical reactions that occur outside the home?
One example would be: Burning petrol (In your car).
Where energy is given off?
Energy is given off during exothermic reactions, where the system releases heat to the surroundings. Examples include combustion reactions, neutralization reactions, and some types of nuclear reactions.
What useful reactions do you look for?
give four examples of reactions in nature and write the word equation for each give four examples of reactions in nature and write the word equation for each give four examples of reactions in nature and write the word equation for each
What comes out of chemical reactions?
Chemical reactions can produce a variety of products, including gases, liquids, solids, or energy in the form of heat or light. The specific products depend on the reactants involved and the nature of the reaction.
What are some examples of college admission officer reactions to inappropriate postings?
Not accepting your application
