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Percutaneous Absorption in Humans
Published in Francis N. Marzulli, Howard I. Maibach, Dermatotoxicology Methods: The Laboratory Worker’s Vade Mecum, 2019
Ronald C. Wester, Howard I. Maibach
There are two components to skin washing in the recovery of chemicals. The first component is the physical rubbing and removal from the skin surface. The second component is the solvent action of soap and water. Glyphosate is a water-soluble compound. Its removal from skin with water alone or soap and water is the same (Wester et al., 1990). In contrast, alachlor is lipid soluble. Therefore, more alachlor can be removed from skin with soap and water, than with water alone (Fig. 3) (Wester et al., 1992). Alachlor partitions into powdered human stratum corneum from its commercial vehicle, Lasso (Bucks et al., 1985). However, the addition of soap reverses the partitioning. Some compounds such as chlordane require multiple successive washings with soap and water applications for removal from skin.
Agrochemicals: A Brief Overview
Published in Dongyou Liu, Handbook of Foodborne Diseases, 2018
Alachlor, together with other chloroacetalinides such as acetochlor and metolachlor, is used to control herbal grasses and broad-leaf weeds in a number of crops, primarily corn. Compounds of this class display moderate to low acute toxicity, with oral LD50 in rat ranging from about 600 mg/kg to 2800 mg/kg. Subchronic and chronic toxicity studies have identified the liver and kidney as principal target organs (51). Though these compounds are not considered to be genotoxic (51,52), they have been shown to induce tumors at various sites in rats, leading to their classification as probable human carcinogens (Group B2 of IARC) and restriction or ban of alachlor in some countries. Mechanistic studies suggest that tumors induced by alachlor in rats may be species specific, and may not be relevant to humans (51,52). Investigations in workers involved in the manufacturing of alachlor have not identified increased mortality or cancer incidence (53).
Percutaneous Absorption of Chemicals From Water During Swimming and Bathing
Published in Rhoda G. M. Wang, James B. Knaak, Howard I. Maibach, Health Risk Assessment, 2017
Ronald C. Wester, Howard I. Maibach
Table 6 shows in vitro absorption of alachlor. Lasso® emulsifiable concentrate diluted with water 1:20, 1:40, or 1:80 was placed on human skin at two concentrations (0.5 or 1.0 ml over 5.7 cm2 skin surface area). The data in Table 7 show that with increasing water dilution, the percentage of dose absorbed increased significantly (p < 0.01). If the mass (microgram) of alachlor diffusing into the plasma receptor fluid is compared for theoretical (dilution reduces mass) and actual levels, the skin absorption increases by many times (although overall percentage efficiency remains low compared to total dose applied). It appears that the thermodynamic forces determining alachlor skin absorption change with water dilution (at least in an in vitro system using human skin).4 However, recent in vivo studies with alachlor failed to confirm increased absorption with increased dilution. The in vitro results are thus probably due to the in vitro methodology.6
Ultra-preconcentration of common herbicides in aqueous samples using solid phase extraction combined with dispersive liquid–liquid microextraction followed by HPLC–UV
Published in Toxin Reviews, 2021
Toraj Ahmadi-Jouibari, Negar Noori, Kiomars Sharafi, Nazir Fattahi
The proposed SPE–DLLME–HPLC–UV methodology was applied to the determination of herbicides in several water samples. River water was collected from Gharaso River (Kermanshah, Iran), tap water was collected from Kermanshah (Iran) and well water samples were collected from Mahidasht and Miandarband (Kermanshah, Iran). The results for river and tap waters showed that they were free of herbicides contamination. In the well water samples, 2,4-D and alachlor were detected and they were confirmed by spiking herbicides into the well water samples. The concentration of 2,4-D and alachlor in the well water samples are shown in Table 2. The accuracy of the method was verified by the analysis of the samples spiked with different levels of herbicides. The resulted relative recoveries (Table 2) are between 88.4 and 108.0%, which indicates that matrix had little effect on the extraction efficiency. Figure 2 shows the obtained chromatograms of well water and spiked well water at the concentration level of 0.50 µg L–1 for 2,4-D and alachlor, and 1.00 µg L–1 for atrazine.
Compound pesticide controlled release system based on the mixture of poly(butylene succinate) and PLA
Published in Journal of Microencapsulation, 2018
Ya Wang, Chaonan Li, Yuxiang Wang, Ying Zhang, Xiaogang Li
Today, pesticides have made great contributions to mankind and received a variety of controversies as well (Jeyaratnam 1990). In spite of their environmentally harmful side, the fact that they provide a great degree of protection against agricultural pests and allow for tremendous increases in crop yield should not be ignored (Bartlewicz et al. 2016). Controlled release formulation of the pesticide has been widely developed and utilised in agriculture to optimise its efficacy and minimise environmental pollution. Because of their prominent characteristics (1) overcomes and defers the drug fastness, (2) expands controlling spectrum, and (3) reduces pesticide cost and alleviates toxicity (Johnson and Pepperman 1996, Popp et al. 2013). Given such advantages, controlled release drug delivery system never fails to fascinate researchers, particularly, the microcapsules and microspheres. Besides, controlled release formulation of pesticide includes hollow fibre, inclusion compounds, adsorbate, foam and so on. Li prepared a novel lignin-based avermectin microsphere through self-assembly. The enhanced photo-protection possessed a great application prospect for efficient pesticide utilisation. Microspheres of alachlor were prepared using ethylcellulose, according to the solvent evaporation method. Ethylcellulose microspheres retarded the release of alachlor in different degrees (Fernandez-Urrusuno et al. 2000, Li et al. 2017). The microsphere which was especially discussed is deemed to be an important research orientation in the field of pesticide formulation.
Evaluation of genotoxicity induced by herbicide pendimethalin in fresh water fish Clarias batrachus (linn.) and possible role of oxidative stress in induced DNA damage
Published in Drug and Chemical Toxicology, 2022
Priyanka Gupta, Sushant Kumar Verma
In the present study concentration and time dependent increase in LPO was observed in liver tissue of pendimethalin exposed fishes. This increase was maximum after 30 days of exposure at all test concentrations after which a linear decrease was noted in a similar fashion to that of observed DNA damage. Similar increase in LPO was reported in fishes exposed to alachlor (Peebua et al.2007) and butachlor (Farombi et al. 2008). The increased level of LPO in liver tissue of exposed fish is due to increased production of ROS which in turn may be due to metabolism of the herbicide as liver is the main site of detoxification. The increased ROS directly damages membranes and contributes to DNA damage (Mutlu-Turkoglu et al. 2003).