Widespread occurrence of polyhalogenated aromatic ethers in the marine atmosphere

Methyl ethers of halogenated phenols have been identified in marine air samples from the North and South Hemispheres. The compounds are tribromoanisole, pentachloroanisole and tetrachlorohydroquinone dimethyl ether. The concentrations of these compounds are in the pg m−3 range, and they are among the more abundant high-molecular weight halocarbons in the remote marine troposphere. A probable source of these compounds is the microbial methylation of the biocide pentachlorophenol and tribromophenol of either pollutant or natural origin

Phthalate esters, PCB and DDT residues in the gulf of mexico atmosphere

Phthalate ester plasticizers, di-2-ethylhexyl phthalate (DEHP) and di- n- butyl phthalate (DBF), were measured in the atmosphere of the Gulf of Mexico. Significant amounts of the phthalate esters were found both in the vapor phase and associated with particulate matter. PCB and DDT residues measured on the same samples were found primarily in the vapor phase. The levels of the phthalate esters and chlorinated compounds are one to two orders of magnitude lower than those reported for continental and urban air

Organic compounds of environmental concern in the Gulf of Mexico: a review

An overview of the data available on the distribution of volatile organic compounds (VOC), high molecular weight hydrocarbons (HMWHC) and synthetic organochlorine compounds in sediments, water and organisms from the Gulf of Mexico is presented. VOC contain many environmentally important substances and are widespread contaminants in Gulf of Mexico coastal and nearshore waters. VOC, compounds with volatilities between those of ∼ n-C 5 and n-C 15, are highest near chemical plants, oil platforms and other industrial or urban centers. VOC detected include aromatics, chlorinated and brominated compounds, and alkanes. VOC concentrations and distributions are controlled initially by the dynamics of local sources but are ultimately determined by exchange with the atmosphere. The major sources of HMWHC in the Gulf of Mexico are biological production, natural seepage, petroleum production, shipping activities, coastal and riverine runoff, and atmospheric exchange and fallout with the dominant sources being very location-dependent. The more pristine areas are offshore from Florida and Southern Texas, whereas the coasts of upper Texas, Louisiana, and Alabama show the highest levels of contamination. The organochlorine compounds most commonly found in organisms are DDT metabolites, PCB and occasionally dieldrin. There is some evidence that estuarine biota contain higher levels of certain residues than pelagic organisms. Organochlorine residues in sediments are believed to originate from contamination by industry or agricultural activities. The highest levels detected to date are associated with Mississippi Delta sediments

Novel approaches to a study of the fundamental organic chemistry of coal. Final report, September 1, 1977-September 1, 1979

The studies are preliminary in nature, and the following conclusions are tentative. (1) The results with mixed carboxylic-sulfonic anhydrides seem to indicate an increase in polymerization of the coal molecular structure, when based on the results of pyrolysis/gas chromatographic analyses. The mixed anhydrides are such powerful acylating reagents that they should be capable of causing profound and dramatic structural modifications of coal and the results suggest sub-optimal reaction conditions. The results may also be due to the presence of only a small number of ether linkages connecting large molecular units together. Possibly, at elevated pressures and larger concentrations of mixed anhydride, a greater extent of depolymerization would occur, coupled perhaps with acylation. (2) The Nimz lignin degradation reaction has now been fully implemented and good conditions have been found for lignite reaction. The products from this degradation were basically hydrocarbon in nature. Thus, in the absence of monolignols, we postulate that such phenolic linkages of the type found in lignin are not found to a large degree in Texas lignites. (3) Our recently developed technique of analyzing methylene to methyl ratios by IR spectroscopy represents a useful method for characterization of both soluble and insoluble coal-derived products. The technique is less expensive than mass spectroscopy and not limited by solubility as in the case of NMR spectroscopy. (4) From the measurements of the acidic hydrogen content of the lignites studies, we have formed a postulate as to the involvement of heteroatoms (especially oxygen) in the lignite structure. We feel that heteroatoms in Texas lignites are involved mainly in carbonyl, low molecular weight alkoxy and/or heterocyclic units. (5) Conditions for depolymerizing and solubilizing lignites by use of t-butyllithium have been developed and utilized successfully