Toxic fluorinated compounds as by-products of certain BF3-catalysed industrial processes

Bedford, Colin T.; Blair, D.; Stevenson, David S.

doi:10.1038/267335a0

Cited by 13 publications

(4 citation statements)

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“…The factors that lead to the preservation of aragonite are impermeability of the shales or clays [27,76–78], impregnation with oil [62], or separation between bituminous layers [79]. The chances of aragonite preservation increase in rapid burial, e.g., by density currents or in storm beds [80–83]. The formation of hardground may inhibit burrowers that provide oxygen to the sediment (causing pH reduction), thus stopping the dissolution in the taphonomically active zone (TAZ) [80].…”

Section: Discussionmentioning

confidence: 99%

From pristine aragonite to blocky calcite: Exceptional preservation and diagenesis of cephalopod nacre in porous Cretaceous limestones

et al. 2018

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Aragonite (along with calcite) is one of the most common polymorphs of the crystalline calcium carbonate that forms the skeletal structures of organisms, but it has relatively low preservation potential. Under ambient conditions and in the presence of water, aragonite transforms into calcite, the stable polymorph. Aragonite is also more soluble therefore, in water-permeable siliceous limestones (opokas) that are typical of Upper Cretaceous deposits of Poland and Ukraine, the primary aragonitic skeletons are either entirely dissolved and found as moulds and casts or transformed into secondary calcite, whereas the primary calcitic shells remain well preserved. Contrary to the common notion of the lack of aragonite in such porous carbonate deposits, we show that relics of aragonite can be preserved as a nacreous lining on cephalopod moulds or as thin, lenticular structures entrapped in neomorphic calcite. Based on the observed intermediate steps of aragonite alteration, we propose an extended model of nacre diagenesis. Among the originally aragonitic biota, only nautilids and ammonites have retained relics of pristine skeletons. Such selective preservation of only some aragonitic structures (nacre but not the prismatic aragonitic layers) points to the role of microstructural and biochemical differences between cephalopod shell layers that may set a threshold for the dissolution, dissolution/precipitation or preservation of original biomineral structures.

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Section: Discussionmentioning

confidence: 99%

From pristine aragonite to blocky calcite: Exceptional preservation and diagenesis of cephalopod nacre in porous Cretaceous limestones

et al. 2018

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“…The EGBE used in this study was manufactured using boron trifluoride (BF3) as a catalyst, a process which has not been used for the past 15 years. EGBE so produced is known to contain a number of impurities not found in current production material (16); these include crown ethers, which have been shown to produce testicular atrophy with degeneration of the germinal epithelium (17), and fluoroethanol.…”

Section: Repeated Oral Administrationmentioning

confidence: 99%

Acute and subchronic toxicity of ethylene glycol monobutyl ether.

Tyler¹

1984

Environ Health Perspect

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The available information on the acute and subchronic toxicity of ethylene glycol monobutyl ether is reviewed. Data from animal studies have been examined from the standpoint of dose-response relationships and the sensitivity of various animal species, including man, to the effects of this chemical. In view of recent findings with other chemically related glycol ethers, particular attention has been given to possible adverse effects on blood and testicular tissue. In evaluating the hazard that this chemical may pose to man, consideration has been given to likely routes of exposure and its irritant properties. It is concluded that the available information continues to support the current ACGIH TWA8-TLV of 25 ppm with a STEL of 75 ppm.

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“…Archaeolithophyllum red algae, Tubiphytes ) and cements (e.g. radiaxial; Wendt 1977 ; Wray 1977 ; Stanley and Hardie 1998 ). Low-Mg calcite components (e.g.…”

Section: Discussionmentioning

confidence: 99%

Late Pennsylvanian carbonate platform facies and coral reef: new insights from southern China (Guizhou Province)

Maillet

Huang

et al. 2020

Facies

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The Pennsylvanian is characterized by intense paleoenvironmental changes related to glacio-eustatic sea-level fluctuations and major tectonic events, which affected the evolution of biocommunities. Most known Pennsylvanian tropical reefs and mounds are predominantly composed of calcareous algae (e.g. phylloid algae, Archaeolithophyllum), calcareous sponges, fenestrate bryozoans, Tubiphytes, and microbialites. However, in Houchang (southern China), the Late Pennsylvanian carbonate platform records a large coral reef lacking any analogs in age (Gzhelian), size (80–100 m thick) and composition (high biodiversity). The large coral reef developed at the border of the Luodian intraplatform basin. The intraplatform basin is characterized by the deposition of green algal grainstone, coated grain grainstone and bioclastic packstone, grainstone, floatstone and rudstone in shallow-waters. In the deep-water shelf, lithofacies are composed of burrowed bioclastic wackestone, microbioclastic peloidal packstone, grainstone, and fine-grained burrowed wackestone and packstone. In this context, the coral reef developed on a deep-shelf margin, in a moderate to low energy depositional environment, below the FWWB. The scarcity of Pennsylvanian coral reefs suggests global unfavorable conditions, which can be attributed to a complex pattern of several environmental factors, including seawater chemistry (aragonite seas), paleoclimatic cooling related to continental glaciation, and the biological competition with the more opportunistic and adaptive phylloid algal community that occupied similar platform margin paleoenvironments. The existence of the large Bianping coral reef in southern China, as well as a few additional examples of Pennsylvanian coralliferous bioconstructions, provides evidence that coral communities were able to endure the Late Paleozoic fluctuating paleoenvironmental conditions in specific settings. One of such settings appears to have been the deep shelf margin, where low light levels decreased competition with the phylloid algal community.

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Toxic fluorinated compounds as by-products of certain BF3-catalysed industrial processes

Cited by 13 publications

References 1 publication

From pristine aragonite to blocky calcite: Exceptional preservation and diagenesis of cephalopod nacre in porous Cretaceous limestones

From pristine aragonite to blocky calcite: Exceptional preservation and diagenesis of cephalopod nacre in porous Cretaceous limestones

Acute and subchronic toxicity of ethylene glycol monobutyl ether.

Late Pennsylvanian carbonate platform facies and coral reef: new insights from southern China (Guizhou Province)

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