Oxidative ring cleavage of low chlorinated biphenyl derivatives by fungi leads to the formation of chlorinated lactone derivatives

The yeast Trichosporon mucoides and the filamentous fungus Paecilomyces lilacinus as biphenyl oxidizing organisms are able to oxidize chlorinated biphenyl derivatives. Initial oxidation of derivatives chlorinated at C4 position started at the non-halogenated ring and went on up to ring cleavage. The products formed were mono- and dihydroxylated 4-chlorobiphenyls, muconic acid derivatives 2-hydroxy-4-(4-chlorophenyl)-muconic acid and 2-hydroxy-5-(4-chlorophenyl)-muconic acid as well as the corresponding lactones 4-(4-chlorophenyl)-2-pyrone-6-carboxylic acid and 3-(4-chlorophenyl)-2-pyrone-6-carboxylic acid. Altogether T. mucoides formed 12 products and P. lilacinus accumulated five products. Whereas the rate of the first oxidation step at 4-chlorobiphenyl seems to be diminished by the decreased bioavailability of the compound, no considerable differences were observed between the degradation of 4-chloro-4'-hydroxybiphenyl and 4-hydroxybiphenyl. Twofold chlorinated biphenyl derivatives did not serve as substrates for oxidation by either organism with the exception of 2,2'-dichlorobiphenyl, transformed by the yeast Trichosporon mucoides to two monohydroxylated derivatives. The results show, that soil fungi may contribute to the aerobic degradation of low chlorinated biphenyls accumulating from anaerobic dehalogenation of PCB by bacteria.     

Improving ready biodegradability testing of fatty amine derivatives

This study assesses the biodegradation potential of a number of fatty amine derivatives in tests following the OECD guidelines for ready biodegradability. A number of methods are used to reduce toxicity and improve the bioavailability of the fatty amine derivatives in these tests. Alkyl-1,3-diaminopropanes and octadecyltrimethylammonium chloride are toxic to microorganisms at concentrations used in OECD ready biodegradability tests. The concentration of these fatty amine derivatives in the aqueous phase can be reduced by reacting humic, or lignosulphonic acids with the derivatives or through the addition of silica gel to the test bottles. Using these non-biodegradable substances, ready biodegradability test results were obtained with tallow-1,3-diaminopropane and octadecyltrimethylammonium chloride. Demonstration of the ready biodegradability of the water-insoluble dioctadecylamine under the prescribed standard conditions is almost impossible due to the limited bioavailability of this compound. However, ready biodegradability results were achieved by using very low initial test substance concentrations and by introducing an organic phase. The contents of the bottles used to assess the biodegradability of dioctadecylamine were always mixed. False negative biodegradability results obtained with the fatty amine derivatives studied are the result of toxic effects and/or limited bioavailability. The aids investigated therefore improve ready biodegradability testing.     

Diphenylamine and derivatives in the environment: a review

Diphenylamine (DPA) is a compound from the third European Union (EU) list of priority pollutants. It was assigned by the EU to Germany to assess and control its environmental risks. DPA and derivatives are most commonly used as stabilizers in nitrocellulose-containing explosives and propellants, in the perfumery, and as antioxidants in the rubber and elastomer industry. DPA is also widely used to prevent post-harvest deterioration of apple and pear crops. DPA is a parent compound of many derivatives, which are used for the production of dyes, pharmaceuticals, photography chemicals and further small-scale applications. Diphenylamines are still produced worldwide by the chemical industries. First reports showed that DPA was found in soil and groundwater. Some ecotoxicological studies demonstrated the potential hazard of various diphenylamines to the aquatic environment and to bacteria and animals. Studies on the biodegradability of DPA and its derivatives are very sparse. Therefore, further investigation is required to determine the complete dimension of the potential environmental hazard and to introduce possible (bio)remediation techniques for sites that are contaminated with this class of compounds. This is the first detailed review on DPA and some derivatives summarizing their environmental relevance as it is published in the literature so far and this review will recommend conducting further research in the future.     

Human health effects of selected pesticides, chloroaniline derivatives

The health effects of two pesticides, chlordimeform and propanil, are discussed. Chlordimeform and 2-methyl-4-chloroaniline, a major metabolite of chlordimeform, cause severe hemorrhagic cystitis in humans. In cats, however, only a mild effect on the bladder was noted. The herbicide propanil has produced chloracne in humans, and along with 3,4-dichloroaniline, hyperkeratosis in rabbits. The contaminants 3,4,3',4'-tetrachloroazobenzene and 3,4,3',4'-tetrachloroazoxybenzene are responsible for the chloracnegenic characteristics of propanil, 3,4-dichloroaniline, and methazole.     

Chemical ionisation mass spectra of urea derivatives of diisocyanates

The mass spectrometric behaviour of 9-(N-methylaminomethyl)-anthracene derivatives of diisocyanates and the commercial prepolymer of hexamethylenediisocyanate, N,N′2-tris(6-isocyanatohexyl)imidodicarbonic diamide, was studied. Both positive and negative ion chemical ionisation mass spectra with methane as the reagent gas were investigated and the positive ion spectra were found to be the most informative. They all showed quasimolecular ions, (M+1)⁺, as well as fragments useful for identification purposes.     

Human health effects of selected pesticides,chloroaniline derivatives.

Abstract

The health effects of two pesticides, chlordimeform and propanil, are discussed. Chlordimeform and 2‐methyl‐4‐chloroaniline, a major metabolite of chlordimeform, cause severe hemorrhagic cystitis in humans. In cats, however, only a mild effect on the bladder was noted. The herbicide propanil has produced chloracne in humans, and along with 3,4‐dichloroaniline, hyperkeratosis in rabbits. The contaminants 3,4,3’,4'‐tetrachloroazobenzene and 3,4,3’,4'‐tetrachloroazoxybenzene are responsible for the chloracnegenic characteristics of propanil, 3,4‐dichloroaniline, and methazole.     

Iophenoxic acid derivatives as markers of oral baits to wildlife

The bait-marker iophenoxic acid (IPA) and its derivatives are increasingly used for evaluating and optimizing the cost-effectiveness of baiting campaigns on wildlife, particularly on game species such as the wild boar. We aimed to determine whether concentrations of the three main IPA derivatives ethyl, methyl and propyl-IPA measured on thoracic liquid extracts (TLE) of hunted wild boars may be representative of two exposure doses, 40 and 200 mg, from 20 to 217 days after ingestion. Then we developed a method of detection of the three IPA derivatives by LC/ESI-MS-MS in muscle and liver to evaluate the suitability of these two other tissues for monitoring the marked bait consumption and for measuring available residues in the meat of marked animals. Three semi-captive wild boars received 40 mg of each IPA derivative, three received 200 mg, and three, as controls, did not receive IPA. Blood serum was sampled 20, 197 or 217 days after IPA exposure according to animals and to the derivative. Wild boars were shot by gun after the different times of serum sampling times, and TLE, muscle and liver were sampled. Our results suggest that TLE is not a relevant tissue for quantitatively expressing IPA exposure. Due to interference, no analytical method was validated on TLE containing digestive material. On the other hand, quantifications in the muscle and particularly in the liver could discriminate wild boars that had ingested the two IPA doses from 20 days until 7 months after exposure, especially for the two long term markers ethyl and propyl-IPA. So IPA quantifications in the liver sampled on hunted animals appear to be a reliable tool for monitoring bait consumption in the field at a large scale. Nevertheless, whatever the ingested dose, ethyl- and propyl-IPA concentrations measured in the muscle and the liver of tested animals until 217 days after exposure, remained higher than 0.01 mg/kg, the Maximal Residue Limit (MRL) is recommended for molecules for which no toxicological data are available. Based on the range of IPA residues available in these two tissues, implications for humans consuming marked animals are discussed.     

Sulfonated derivatives of naphthalene in water samples of an Italian river

Naphthalenesulfonates were found in water samples of the Italian river Bormida. Samples were collected at increasing distances from the point of emission of pollutants, and their analyses showed that these compounds can persist in river water and that they can propagate for considerable distances.     

Gladius and its derivatives as potential biosorbents for marine diesel oil

The demand for low cost and effective materials to remove contaminants such as residues of oil spills has encouraged studies on new biosorbents produced from wastes. Considering the overgeneration of fishing residues and the necessity to provide an alternative purpose for such materials, this study aimed to evaluate squid gladius and its derivatives (β-chitin and chitosan) as sorbents to remove marine diesel oil (MDO) from fresh and artificial seawater. It was also executed an attempted to improve their performances through a high-intensity ultrasound treatment (UT-gladius and UT-β-chitin). All sorbents removed MDO at both salinities. Contact surface area, salinity, and water retention seemed to play a key role in the outcomes. UT-β-chitin’s performance was significantly superior to β-chitin’s and chitosan’s in MDO removal at salinity 0, as well as at salinity 30, where gladius and UT-gladius also excelled. Ultrasound treatment improved the oil removal performance of UT-β-chitin by increasing its contact surface area. This is the first report on the efficiency of gladius and UT-β-chitin for such purpose, and brought up huge possibilities and new questions that can lead to the achievement of biosorbents of great efficiency.     

Structure-activity relationships of larvicidal monoterpenes and derivatives against Aedes aegypti Linn

In the search for larvicidal compounds against Aedes aegypti L. (Diptera: Culicidae), a collection of monoterpenes were selected and evaluated. R- and S-limonene exhibited the highest larvicidal potency (LC₅₀ = 27 and 30 ppm, respectively), followed by γ-terpinene (LC₅₀ = 56 ppm) and RS-carvone (LC₅₀ = 118 ppm). Structural characteristics which may contribute to the understanding of the larvicidal activity of monoterpenes were empirically identified. The presence of heteroatoms in the basic hydrocarbon structure decreases larvicidal potency. Conjugated and exo double bonds appear to increase larvicidal potency. Replacement of double bonds by more reactive epoxides decreases the larvicidal potency. The presence of hydroxyls in the cyclic structure resulted in decreased potency, probably due to increased polarity indicanting that lipophilicity seems to play an important role in increasing the larvicidal potency in this set of compounds.     

Computer-based QSARs for predicting mixture toxicity of benzene and its derivatives

During the past decades, the Quantitative structure-activity relationships (QSARs) have been proven to be reliable tools when little or no empirical data are available in medicinal chemistry, biochemistry, toxicology, and environmental sciences. However, only few studies that quantitatively predict mixtures toxicity have been reported. In this study, the QASR models for the binary mixtures toxicity of 12 benzene and its derivatives, including eight non-polar-narcotic compounds and four polar narcotic compounds were developed, without reference to exact toxicity mechanisms of single compounds. All parameters for the QSAR studies were defined on the basis of quantum mechanical calculations and these parameters were selected by the stepwise procedure. The results of this study provided a simple means of predicting the binary mixtures toxicity from the chemical structure.     

Sorption of naphthalene derivatives to soils from a long-term field experiment

The influence of long-term farming practices on the soil's behaviour to adsorb hydrophobic organic compounds (HOCs) over long times was investigated. Adsorption of five naphthalene derivatives (naphthalene, 1-naphthol, 1-naphthylamine, 1-hydroxy-2-naphthoic acid, 1,4-naphthoquinone) was examined on soils with varying amounts and origins of soil organic matter obtained after amendment with different organic materials over more than 40 years. Soil organic matter, pore sizes and aggregate stability were significantly altered influencing the adsorption behaviour of the soils. Samples of soil amended with peat having an organic carbon content of 3.4% sorbed naphthalene derivatives stronger than the soil treated with sewage sludge (2.6% C(org)). All other treatments, calcium nitrate, plots without nitrogen fertilizers, grassland, animal manure, green manure and the fallowed soil sorbed less and no significant difference was found between them although the organic carbon content ranged from 1.0% to 2.6%. Thus, a decrease of the carbon content of a soil does not necessarily imply a reduction of sorption capacities for hydrophobic compounds such as naphthalene derivatives. Furthermore, the importance of protonation of HOCs for the adsorption on soil surfaces was shown. Different polarities of electronic structures of HOCs distinctly influence their adsorption behaviour.     

Toxicity of prednisolone, dexamethasone and their photochemical derivatives on aquatic organisms

Light exposure of aqueous suspensions of prednisolone and dexamethasone causes their partial phototransformation. The photoproducts, isolated by chromatographic techniques, have been identified by spectroscopic means. Prednisolone, dexamethasone and their photoproducts have been tested to evaluate their acute and chronic toxic effects on some freshwater chain organisms. The rotifer Brachionus calyciflorus and the crustaceans Thamnocephalus platyurus and Daphnia magna were chosen to perform acute toxicity tests, while the alga Pseudokircheneriella subcapitata (formerly known as Selenastrum capricornutum) and the crustacean Ceriodaphnia dubia to perform chronic tests. The photochemical derivatives are more toxic than the parent compounds. Generally low acute toxicity was found. Chronic exposure to this class of pharmaceuticals caused inhibition of growth population on the freshwater crustacean C. dubia while the alga P. subcapitata seems to be less affected by the presence of these drugs.     

Distribution of14C-TNT and derivatives in different biochemical compartments ofPhaseolus vulgaris

¹⁴C-TNT was used to quantify the uptake rate and metabolic turnover of TNT inPhaseolus vulgaris. Seventeen plants were analysed by a special cell fractionation method with polar and nonpolar solvents and enzymes. We obtained three cytoplasmic fractions and five cell wall derived fractions. The recovery rate was 72% as measured by liquid scintillation counting.¹⁴C partitioned almost in equal amounts with approximately 50% in the cytoplasm and in the cell wall. The majority of the TNT-metabolites are present in the cytoplasm as was shown by GC/ ECD and thin layer chromatography. The¹⁴C in the cell wall is bound probably resulting in long-term immobilisation of these metabolites. We conclude that plants may also be a model for nitroaromatic turnover and immobilisation in soil components.     

The effect of thymol and its derivatives on reactions generating reactive oxygen species

The effects of thymol (TOH), thymoquinone (TQ) and dithymoquinone (TQ2) on the reactions generating reactive oxygen species (ROS) such as superoxide anion radical (O2*-), hydroxyl radical (HO*) and singlet oxygen (1O2) were tested using the chemiluminescence (CL) and spectrophotometry methods. All tested compounds acted as scavengers of various ROS. The rate constant of 1O2-dimols quenching by thymol was calculated.     

Gas chromatographic determination of phenolic compounds in water,as their pentafluorobenzoyl derivatives

A sensitive gas chromatographic method for the determination of phenolic compounds in water samples has been developed. The phenols are converted by means of pentafluorobenzoyl chloride to the corresponding acyl derivatives. The procedure, specific for phenolic compounds, is compared with pentafluorobenzylation and was found to be faster and simpler. The method has been applied to industrial waste water.     

Monitoring of pyrrolizidine alkaloids in beehive products and derivatives on the Belgian market

Pyrrolizidine alkaloids (PAs) and related N-oxides (PANOs) are secondary plant metabolites thought to be found in approximately 3% of the flowering plants worldwide and exhibiting hepatotoxic properties to humans. As a consequence, beehive products are prone to be contaminated with those compounds by bees foraging PA-producing plants. Downstream contamination can also occur through food items containing honey. Analytical methods based on UHPLC separation and MS/MS detection were developed with a focus on very low LOQs and validated for the analysis of 16 PAs and 14 PANOs in honey, honey-based candies and snacks, as well as beehive product–based food supplements. A maximum level of 182 ng/g of PAs was detected in a Mediterranean honey, and high levels of heliotrine-type compounds were reported for the first time. An extensive sampling of honeys harvested in Belgium was performed (N = 374), the concentration levels were more limited with a maximum of 60 ng/g, and the contamination pattern was dominated by senecionine-type PAs. The PA levels in honey-based candies and snacks were very low, with respective maxima of 7.61 ng/g and 0.36 ng/g. Seventy-five percent among the pre-dosed food supplements based on beehive products were contaminated, with a maximum of 43 ng/g. The highest level was detected in a bee-collected pollen sample (1672 ng/g). The analytical results were consistent with the previously reported data for beehive products and confirmed that PA/PANO contamination in these food commodities is recurrent.