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Pesticides
Published in José L. Tadeo, Analysis of Pesticides in Food and Environmental Samples, 2019
José L. Tadeo, Beatriz Albero, Rosa Ana Pérez
Nitroanilines are a group of herbicides with similar physicochemical properties, such as a low water solubility and a high octanol–water partition coefficient. These compounds are soil-applied herbicides used to control annual grasses and many broad-leaved weeds in a wide variety of crops. The 2,6-dinitroanilines possess a marked general herbicide activity. Substitution at the third and/or fourth position of the ring or on the amino group modifies the degree of herbicidal activity. In general, they have a certain persistence in soil and are normally soil incorporated due to their significant vapor pressure (Table 1.6).
Biochar and retention/efficacy of pesticides
Published in Johannes Lehmann, Stephen Joseph, Biochar for Environmental Management, 2015
Ellen R. Graber, Rai S. Kookana
The nature and extent of the effects of biochars on pesticides depends not only on the properties of biochars but also on the chemistry of the pesticide molecule. For example, Nag et al (2011) evaluated biochar produced from wheat straw at 450°C for its ability to influence efficacy of two commonly used herbicides (atrazine and trifluralin) with different mode of actions in controlling annual ryegrass (Lolium rigidum) in two contrasting soils. In terms of aqueous solubility, atrazine (35mg L-1) and trifluralin (0.022mg L-1) are very different. Atrazine affects photosynthesis by blocking electron flow that results after the leaf absorbs light energy, eventually leading to cell membrane disruption and leaf death. The dinitroaniline herbicides (e.g. trifluralin), on the other hand, inhibit root formation by interrupting mitosis in root tips in susceptible plants (Ashton and Crafts, 1981; Grover et al, 1997). Bioassays were conducted on soils amended with different rates of biochar (0, 0.5 and 1.0 per cent w/w) and herbicides (0, 0.5, 1, 2 and 4 times the recommended dosage). The addition of biochar to soil was found to increase ryegrass survival rate and above-ground biomass at most herbicide application rates. A dose-response analysis (Figure 23.5) showed that in the presence of 1 per cent biochar in soil, the value of GR50 (i.e. the dose required to reduce weed biomass by 50 per cent) for atrazine increased by 3.5 times in comparison to control soil (no biochar), whereas in the case of trifluralin GR50 increased only by a factor of 1.6. The difference between the two herbicides was ascribed to the greater mobility of atrazine and consequently greater contact with biochar. Since trifluralin acts via root contact, its reduced mobility meant that it had less contact with the biochar and hence was more plant available.
Effects of the herbicide trifluralin in the initial development of Piptadenia gonoacantha (Fabales: Fabaceae)
Published in International Journal of Phytoremediation, 2019
Naiane Maria Corrêa dos Santos, Wander Gladson Amaral, Fillipe Vieira de Araújo, Evander Alves Ferreira, Bárbara Monteiro de Castro e Castro, José Cola Zanuncio, Israel Marinho Pereira, José Barbosa dos Santos
The chemical control of grasses in forest crops is a fast, efficient, and economical method and, therefore, widely used (Mueller et al. 2014). The herbicide glyphosate is not selective to forest crops and does not leave residues in the soil to control grasses in succession (Doust et al. 2006). Herbicides selective to forest species have the potential to control grasses instead of glyphosate. Trifluralin, a pre-emergent graminicide herbicide with high adsorption and low mobility in the soil, is of the dinitroaniline chemical group and inhibits the mitotic cell division process (Fernandes et al. 2007). Forest species tolerance to trifluralin is poorly understood, increasing the need of evaluating its impact on plants, especially in restoration areas (Gianessi 2013).
Adulation or Adulteration? Representing Chemical Dyes in the Victorian Media
Published in Ambix, 2019
Despite the initial reluctance by chemists to discredit the new dyes, these beautiful substances transmuted from black and dirty waste by the marvel of science soon began to be seen as problematic, complex, dangerous, and unnatural. As was often the case, Punch led the charge to undermine the credibility and reputation of science’s latest miracle, declaring in 1868 that it now knew: what killed Hercules. The shirt of Nessus was not imbued with the poisoned blood of the Centaur. Of course Deianeira, before she sent it to her husband, washed it out. No doubt the garment was one which had been dyed brilliant red with chloroxy-nitric acid, dinitroaniline, or some or other of those splendid but deleterious compounds of aniline which in coloured socks are blistering the feet and ankles of the British public.38Founded in 1841, Punch had a weekly circulation of 60,000 by 1860. Throughout the nineteenth century, the satirical magazine covered science, technology, and medicine as extensively as any Victorian periodical, placing science in its social and political context and revealing its benefits, dangers, genius, absurdity, and usefulness. Contributors with scientific or medical backgrounds were regulars among the journal’s anonymous commentators on science. While Punch has long been mined for material and viewed as an important nineteenth-century source, it is only in recent years that historians have realised the extent to which Punch and other periodicals acted as producers, as well as a disseminators, of knowledge.39
Tree uptake of excess nutrients and herbicides in a maize-olive tree cultivation system
Published in Journal of Environmental Science and Health, Part A, 2018
George Pavlidis, Vassilios A. Tsihrintzis, Helen Karasali, Dimitrios Alexakis
The two examined herbicides belong to different chemical groups. Pendimethalin belongs to dinitroaniline herbicides and nicosulfuron to sulfonylureas. Consequently, they have different modes of action and physicochemical and environmental fate properties. The physicochemical properties of the herbicides analysed in the present study (solubility, soil-binding characteristics, persistence, etc.) constitute a fundamental component of managing the risk for off-site movement after application.[12]