China
Africa
Explore chapters and articles related to this topic
Outdoor Air Pollution
Published in William J. Rea, Kalpana D. Patel, Reversibility of Chronic Disease and Hypersensitivity, Volume 4, 2017
William J. Rea, Kalpana D. Patel
Clinically healthy mongrel dogs from Tlaxcala and SWMC were studied. The selection of the two different cities was based on their concentrations of air pollutants and similar altitudes above sea level. Metropolitan Mexico City extends over 2000 km2 and is located in an elevated valley, 2250 m above sea level. It is a megacity with 20 million residents and the associated production of air pollutants from automobiles, leakage of petroleum gas, and industrial activity. The climate is mild with year-round sunshine, light winds, and temperature inversions. Each of these factors contributes to create an environment in which complex photochemical reactions produce oxidant chemicals and other toxic compounds. Air quality data are provided by an automated surface network of 33 monitoring stations in and around MC; hourly, near-surface measurements are made of monitored pollutants, including ozone, PM10, SO2, NO2, CO, and Pb. Mexico City's main pollutants are PM and ozone, with levels exceeding U.S. National Ambient Air Quality Standards (NAAQS) most of the year. The maximal concentrations of ozone precursors appear downwind of the emission zones toward the southern urban area, southwest and southeast MC.329 According to Fast and Zhong,330 the highest particle concentrations occur regularly in the vicinity of the peak ozone concentrations during the afternoon. Ozone concentrations as high as 0.48 ppm have been measured during severe air pollution331; the SWMC atmosphere is characterized by average maximal ozone daily concentrations of 0.250 ppm. An average of 4 ± 1 hours/day with ozone >0.08 ppm is recorded in SWMC year-round (83.9% of days).329 NO2 concentrations do not usually exceed the annual arithmetic mean of 0.053 ppm (4.6% of days), whereas SO2 levels exceed the 24-hour primary standard of 0.14 ppm in the winter months. Both PM10 and PM2.5 exceed their respective annual arithmetic means above the standards (annual NAAQS PM10 78 μg/m3 and PM2.5 21.6 μg/m3 vs. standards of 50 μg/m3 and 15 μg/m3, respectively).332,333 Other pollutants detected in SWMC include volatile organic compounds (VOC) such as linear and cyclic saturated and unsaturated HC; aromatic HC; aldehydes; ketones; esters; and acids and their halogenated derivatives.334 Formaldehyde and acetaldehyde ambient values are in the range of 5.9–110 ppbv and 2–66.7 ppbv, respectively.335 Mutagenic PM336; alkane HC331; benzene337; various metals such as vanadium, manganese, and chromium338; and peroxyacetyl nitrate333 are also detected. Lichens absorb their nutrients from the atmosphere and can be used as sensitive monitors of airborne metals339; Parmotrema arnoldii accumulates lead, copper, and zinc in SWMC.334 In addition, 500 metric tons of canine fecal materials are deposited daily on MC streets.340 There is clearly a total environmental pollutant load that can be transferred to a total body pollutant load and that can cause and disturb the chemically sensitive patient.
Chemical composition of essential oil and oleoresins of Zingiber officinale and toxicity of extracts/essential oil against diamondback moth (Plutella xylostella)
Published in Toxin Reviews, 2020
G. D. Kiran Babu, Shudh Kirti Dolma, Mohit Sharma, S. G. Eswara Reddy
The oleoresins extracted from ginger rhizomes by acetone and ethanol varied composition. The undistilled dried ginger rhizomes extracted by acetone (AF) and ethanol (EF) contains similar composition viz., zingiberene (19.4% and 19.1%), [6]-gingerol (9.6% each), β-sesquiphellandrene (9.1% and 9.4%), (E,E)-α-farnesene (6.6% and 6.3%), ar-curcumene (5.1% and 6.3%), β-bisabolene (4.5% and 4.6%), trans-[6]-shogaol (3.5% to 5.6%), and geranial (3% and 2.5%, respectively) as major constituents except in that the acetone extract also possessed 4-hydroxy-4-methyl-2-pentanone (8.6%) as other major compound (Table 2). On contrary, this hydroxyl ketone detected in low concentrations in the oleoresins extracted from de-oiled cake by acetone (1.5% in ADD and 1% in ADW), and by ethanol (0.4% in EDW) which could be due to its degradation during HD, where very harsh conditions such as high water content and temperature prevails. The degradation of this compound may contribute to the formation of components such as peroxyacetyl nitrate, acetone, formaldehyde, etc. (Sleiman et al. 2013). It is interesting to note that the absolute ethanol unable to extract this compound from the dried rhizomes may be due to its solvent polarity. The presence of small amount (0.4%) of this compound in the oleoresin extracted from wet de-oiled cake by ethanol (EDW) can be attributed to high polarity of solvent mixture (ethanol + water) than the absolute ethanol. Moderate levels of neral, γ-amorphene, (E)-nerolidol, zingerone, α-bisabolol, etc., were detected in the oleoresins produced from undistilled rhizomes (AF and EF). On contrary, Singh et al. (2008) reported the composition of ethanol extracted oleoresin abundant in eugenol (49.8%), gingerone (14.5%), trans-[6]-shogaol (5.9%), etc. This is the first study of its kind wherein the chemical composition and insecticidal properties of ginger oleoresins extracted from the solid-spent obtained after hydro-distillation is being reported. The dried de-oiled cake (solid-spent) were dominated by zingiberene (16.3% and 21.2%), [6]-paradol (11.2% and 8.5%), β-sesquiphellandrene (9.7% and 9.9%), etc., in their oleoresins produced by acetone (ADD) and absolute ethanol (EDD), respectively. Ethanol extract produced from wet de-oiled cake (EDW) possessed unique composition viz., 54.7% bis (2-ethylhexyl) phthalate, which was devoid in rest of the oleoresins. The ethanolic oleoresin composition reported by Singh et al. (2008) was also found devoid of the same. The other major constituents of EDW were trans-[6]-shogaol, zingiberene, β-sesquiphellandrene, etc., However, ADW was found to be dominated by trans-[6]-shogaol (17.1%), zingiberene (10.6%), [6]-paradol (5.2%), etc. It is interesting to note that only the wet de-oiled cake produced by acetone (ADW) and ethanol (EDW) possessed appreciable amounts of 2,3-butanediol [S-(R*,R*)], whereas the same was absent in all the other oleoresins and EO. Similarly, 2,3-butanediol [R-(R*,R*)] was also dominated in the ADW (4.5%) and EDW (1.6%) and small quantities were detected in EF (0.4%) and ADD (0.2%).