Synthesis of low and high chlorinated toxaphene and comparison of their toxicity by zebrafish (Danio rerio) embryo test

Abstract

Toxaphene, also known as camphechlor, is a persistent organochlorine pesticide of complex composition. It is technically produced by photochlorination of camphene with elemental chlorine gas under ultraviolet irradiation. In the present work, a novel, laboratory-scale synthesis using sulfuryl chloride as a chlorinating reagent is described. This approach allowed the degree of chlorination of the resulting mixtures to be arbitrarily adjusted by varying the reaction conditions. Both the compositions and the chlorine contents of the low- and high-chlorinated mixtures acquired using this method were similar to those of environmentally altered toxaphene and technical toxaphene, respectively. For comparison of these mixtures regarding toxicity, they were subjected to the zebrafish (Danio rerio) embryo test. Median effective concentrations (EC50s) were calculated based on the presence of lethal and nonlethal embryonic malformations. Surprisingly, low-chlorinated toxaphene, comprising compounds that also are present in environmentally transformed toxaphene, exhibited a twofold-higher toxicity (according to the EC50 for nonlethal effects) toward the test organisms compared with high-chlorinated toxaphene, the composition of which resembled that of the technical product. Although the effective concentrations in the embryo test were much higher than those in aquatic ecosystems burdened with toxaphene, the present results lead to the assumption that toxaphene is becoming more toxic during transformation in the environment. A decrease in the total amount of toxaphene during environmental breakdown would then be compensated for, at least in part, by the higher toxicity of weathered toxaphene in sediments, soils, and biota of contaminated ecosystems.

Biomarker assessment of toxicity with miniaturised bioassays: diclofenac as a case study

“…Danio rerio embryos (wild type) were purchased from ZF BioLabs (Tres Cantos, Madrid) 4 h post fertilization and were carried in synthetic water: 11.80 mg l -1 of CaCl 2 Á2H 2 O, 4.92 mg l -1 of MgSO 4 Á7H 2 O, 2.52 mg l -1 of NaHCO 3 and 1.10 mg l -1 of KCl (Kapp et al 2006), at a temperature of 26 ± 1°C for 1 h to Rey Juan Carlos University. Embryos, in the beginning of the gastrula period, were exposed immediately after arrival in the laboratory for 90 min (n = 8 for every concentration).…”

Activated Carbons Obtained from Orange Peels, Coffee Grounds, and Sunflower Husks—Comparison of Physicochemical Properties and Activity in the Alpha-Pinene Isomerization Process

“…Both of these compounds are mainly used in cosmetics [ 56 ] and perfumery [ 57 ]. In addition, camphene is used as the raw material in obtaining insecticides [ 58 ] and as a pyrogen to produce nano/macroporous polycaprolactone [ 59 ]. However, the most common application of this compound is the production of synthetic camphor [ 57 ].…”

Influence of the Titanium Content in the Ti-MCM-41 Catalyst on the Course of the α-Pinene Isomerization Process

“…An interesting historical aspect is that in the middle of the 19th century, a related product-camphine (a mixture of turpentine dissolved in oil with some camphor)-was used as fuel for lamps [28], but due to its explosiveness and quick burning, its use was abandoned. Currently, camphene is mainly used as an intermediate in light organic synthesis, inter alia, in the production of toxaphene (an insecticide) [29]. In addition, in the reaction of camphene with acetic acid, isobornyl acetate is formed, which is an intermediate in the production of synthetic camphor [30].…”