Toxicity of technical X-factor to weanling rats. II. A subacute oral study

Eighty male weanling rats were fed dietary levels of Technical X-factor (beta-isomer free BHC, a by-product obtained during the separation of lindane from Tech. BHC) at dosages of 10,50,250,750,1500 and 3000 ppm for 90 days. No overt signs of toxicity or mortality were observed at any of the dietary levels. However, a significant reduction in food consumption and growth was evident beyond 750 ppm. Pronounced hepatomegaly observed at 1500 and 3000 ppm was associated with histological alterations such as cellular hypertrophy, cytoplasmic vacuolisation and focal necrosis. Adrenals showed cortical hypertrophy and highly vacuolated cytoplasm. Though a significant increase in the levels of SGOT was noted at 3000 ppm dosage, no appreciable changes were observed in the levels of SGPT and SLDH. Technical X-factor appeared to possess low chronic toxicity compared to Tech. BHC as evidenced by the various parameters studied. The observed low chronic toxicity of X-factor is probably due to the absence if beta-isomer and altered composition of delta and alpha isomers.     

Toxicity op technical X‐factor∗ to weanling rats. II. A subacute oral study

Abstract

Eighty male weanling rats were fed dietary levels o£ Technical X‐factor (β ‐isomer free BHC, a by‐product obtained during the separation of lindane from Tech. BHC) at dosages of 10, 50, 250, 750, 1500 and 3000 ppm for 90 days. No overt signs of toxicity or mortality were observed at any of the dietary levels. However, a significant reduction in food consumption and growth was evident beyond 750 ppm. Pronounced hepatomegaly observed at 1500 and 3000 ppra was associated with histolo‐gical alterations such as cellular hypertrophy, cyto‐plasmic vacuolisation and focal necrosis. Adrenals showed cortical hypertrophy and highly vacuolated cytoplasm. Though a significant increase in the levels of SGOT was noted at 3000 ppra dosage, no appreciable changes were observed in the levels of SGPT and SLDH. Technical X‐factor appeared to possess low chronic toxicity compared to Tech. BHC as evidenced by the various parameters studied. The observed low chronic toxicity of X‐factor is probably due to the absence of β ‐isomer and altered composition of delta and alpha isomers.     

Toxicological properties of trialkyl phosphorothioate and dialkyl alkyl- and arylphosphonothioate esters

Impurities such as O,S,S-trimethyl phosphorodithioate (TMPD) and the S-methyl isomer of malathion (isomalathion) strongly potentiated the mammalian toxicity of malathion. In contrast, impurities present in the phosphoramidothioate insecticide acephate had an antagonizing effect on its mammalian toxicity. The potentiation of the toxicity of malathion was attributed to inhibition of mammalian liver and serum carboxylesterase. O,O,S-Trimethyl phosphorothioate (TMP), another impurity present in technical malathion and in other organophosphorus insecticides, proved to be highly toxic. Rats given a single oral dose of TMP at a level as low as 20 mg/kg died over a period of three weeks, with death occurring with non-cholinergic signs of poisoning. TMPD also caused similar delayed death in rats. O,O,O-Trimethyl phosphorothioate (TMP=S), also another impurity in technical malathion and a structural isomer of TMP, was a potent antagonist to the delayed toxicity of TMP. Examination of a number of related trialkyl phosphorothioate and dialkyl alkylphosphonothioate esters revealed several of these compounds to be highly toxic to rats.     

Seasonal variations of organochlorine insecticide residues in air from Porto Novo, South India

Air samples collected from Porto Novo (11 degrees 29' N, 79 degrees 46' E), Tamil Nadu State, South India from December, 1987 to January, 1989 were analysed to determine the seasonal variations of the levels of organochlorine insecticides such as HCH (BHC) and DDT. Both these insecticides showed higher levels from August to January, although this trend was more marked in HCH than DDT, reflecting the application of HCH largely, and probably small quantities of DDT during the flowering season of rice. The alpha-HCH was detected as a dominant isomer for all seasons monitored followed by gamma-HCH. Among DDT compounds, p,p'-DDT was the highest except in dry season (January to April) when p,p-DDE showed higher percentage. The levels and percentage composition of these insecticides recorded in the present study may aid in interpreting the role of a 'point source' area since India is one of the countries still using the persistent organochlorine pesticides in large quantities.     

Toxicity of fipronil and its enantiomers to marine and freshwater non-targets

Fipronil is a phenylpyrazole insecticide used in agricultural and domestic settings for controlling various insect pests in crops, lawns, and residential structures. Fipronil is chiral; however, it is released into the environment as a racemic mixture of two enantiomers. In this study, the acute toxicity of the (S,+) and (R,-) enantiomers and the racemic mixture of fipronil were assessed using Simulium vittatum IS-7 (black fly), Xenopus laevis (African clawed frog), Procambarus clarkii (crayfish), Palaemonetes pugio (grass shrimp), Mercenaria mercenaria (hardshell clam), and Dunaliella tertiolecta (phytoplankton). Results showed that S. vittatum IS-7 was the most sensitive freshwater species to the racemic mixture of fipronil (LC50 = 0.65 microg/L) while P. pugio was the most sensitive marine species (LC50 = 0.32 microg/L). Procambarus clarkii were significantly more sensitive to the (S,+) enantiomer while larval P. pugio were significantly more sensitive to the (R,-) enantiomer. Enantioselective toxicity was not observed in the other organisms tested. Increased mortality and minimal recovery was observed in all species tested for recovery from fipronil exposure. These results indicate that the most toxic isomer of fipronil is organism-specific and that enantioselective toxicity may be more common in crustaceans than in other aquatic organisms.     

Pesticide-induced impairment of thyroid physiology in the freshwater catfish, Heteropneustes fossilis

Effects of BHC (8 mg litre(-1)) and malathion (10 mg litre(-1)) exposure for 96 h have been studied on T(3) and T(4) concentrations in plasma, and in pharyngeal thyroid tissue preparations. Thyroid peroxidase (TPO) activity in the pharyngeal thyroid tissue, along with the extra-thyroidal conversion of T(4) into T(3) were measured in a freshwater catfish, Heteropneustes fossilis. BHC stimulated TPO activity in this fish, during both in vitro and in vivo studies. In contrast, malathion was found to stimulate TPO activity during the in vitro experiments but to inhibit it in the in vivo study. Concentrations of T(3) and T(4) increased in the thyroid gland, as well as in the plasma, in response to BHC exposure. However, in both these tissues, malathion increased T(3) concentrations and reduced T(4) concentrations. The extrathyroidal conversion of T(4) into T(3) was stimulated by malathion and inhibited by BHC.     

水泥窑共处置污染土壤的污染排放研究

以被DDT和六六六污染的土壤为研究对象,开展了利用水泥窑进行共处置的工程试验研究,分析了共处置过程对尾气排放的影响。结果表明,水泥窑共处置对农药污染物的焚毁去除率很高,DDT达到99.99991%,六六六达到99.99964%,均高于我国危险废物焚烧炉规定99.99％的焚烧效率;与空白处理相比,尾气排放中有机污染物（包括二恶英/呋喃,简称PCDD/F、多氯联苯PCB、六氯苯HCB、挥发性有机物VOC）、酸性气体和重金属的排放在共处置过程中没有显著增加,且都低于相应的规定限值。试验结果表明,水泥窑共处置固体废物不会导致污染负荷的增加。     

Interconversions and toxicity changes in hexachlorocyclohexane isomers on dispersion in water

Abstract

Studies on the transformations of hexachlorocyclohexane isomers, α‐, β‐, γ‐ and δ‐, in aqueous solution were carried out at 25 ± 1°C over a period of four weeks. Gas liquid chromatographic technique was used for analysis. The results indicated a loss as well as interconversion of all the four isomers with time. The resulting changes in toxicity of the aqueous solution were studied against Drosophila using topical application. Toxicity studies with aqueous solution of technical hexachlorocyclohexane were simultaneously carried out for comparison. Toxicity of the aqueous solutions of α‐, β‐, and δ ‐isomers showed an increase while that of the γ‐isomer decreased significantly during the four week experimental period. Aqueous solution of technical HCH was equally toxic as that of the γ‐isomer initially and did not show much decrease in its toxicity at the end. Changes in toxicity of the individual isomer solutions were considered to be due, in part, to interconversions of HCH isomers.     

Toxicity of new pyrethroid in pest insects Asciamonuste and Diaphania hyalinata,predator Solenopsis saevissima and stingless bee Tetragonisca angustula

There is increasing demand for new products for vegetable pest management. Thus, the aim of this study was to assess the toxicity of pyrethroids with acid moiety modifications to measure the insecticidal activity of these compounds on the lepidopteran vegetable pests Diaphania hyalinata (L.) (Lepidoptera: Pyralidae) and Asciamonuste (Latreille) (Lepidoptera: Pieridae) and evaluate their selectivity for the predatory ant Solenopsis saevissima (F. Smith) (Hymenoptera: Formicidae) and pollinator Tetragonisca angustula (Latreille) (Hymenoptera: Apidae: Meliponinae). Racemic mixtures of five new pyrethroids (30 µg molecule mg^?1 insect body weight) resulted in high (100%) and rapid (stable LD₅₀ after 12 h) mortality in D. hyalinata and A. monuste. In A. monuste, the trans-pyrethroid [12] isomer showed similar toxicity to permethrin. For D. hyalinata, the trans-pyrethroid [9] isomer and cis-pyrethroid [10] isomer were as toxic as permethrin. Due to their low selectivity, these new pyrethroids should be applied on the basis of ecological selectivity principles to minimize impacts on nontarget organisms S. saevissima and T. angustula.     

The joint effects of sulfonamides and their potentiator on Photobacterium phosphoreum: differences between the acute and chronic mixture toxicity mechanisms

Organisms are typically exposed to mixtures of chemicals over long periods of time; thus, chronic mixture toxicity analysis is the best way to perform risk assessment in regards to organisms. However, most studies focus on the acute mixture toxicity. To investigate the difference between chronic mixture toxicity and acute mixture toxicity, Photobacterium phosphoreum were exposed to chronic (24 h exposure) and acute (15 min exposure) toxicity of single sulfonamide (SA) and their potentiator (trimethoprim, TMP), both individually and mixtures (SA with TMP). A comparison of chronic vs. acute mixture toxicity revealed the presence of an interesting phenomenon, that is, that the joint effects vary with the duration of exposure; the acute mixture toxicity was antagonistic, whereas the chronic mixture toxicity was synergistic. Based on the approach of Quantitative Structure Activity Relationships (QSARs) and molecular docking, this phenomenon was proved to be caused by the presence of two points of dissimilarity between the acute and chronic mixture toxicity mechanism: (1) the receptor protein of SAs in acute toxicity was Luc, while in chronic toxicity it was Dhps, and (2) there is a difference between actual concentration of binding-Luc in acute toxicity and individual binding-Dhps in chronic toxicity. This deep insight into the difference between chronic and acute mixture toxicity will benefit environmental science, medical science, and other disciplines. The existence of these differences poses a challenge for the assessment of routine combinations in medicine, risk assessment, and mixture pollutant control, in which, previously, only a synergistic effect has been observed between SA and their potentiator.     

S絮凝剂急性和亚慢性毒性研究

对原水处理剂Ｓ絮凝剂进行了大鼠急性毒性和９０ｄ喂养试验。Ｓ絮凝剂大鼠经口半数致死量雄性为８７１０ｍｇ／ｋｇ，Ｂ．Ｗ．，雌性为１０９６５ｍｇ／ｋｇＢ．Ｗ．，属实际无毒类物质。９０ｄ喂试验结果表明，剂量≥０．８％，时对大鼠生长发育，血液学、生化学及病理组织学等各项指标水见有不良影响，Ｓ絮凝剂最大无作用剂量为０．８％，相当于实际作用量的１０００倍。     

Seasonal variation of persistent organochlorine insecticide residues in Vellar River waters in Tamil Nadu, South India

Water samples collected from Vellar river and Pichavaran mangroves at Porto Novo (11 degrees 29' N, 79 degrees 46' E), Tamil Nadu State, South India, from December 1987 to January 1989 were analyzed to determine the seasonal variation of the levels of organochlorine insecticides such as HCH (BHC) and DDT. Both these insecticides showed higher levels from October to February, although this trend was more pronounced in HCH than DDT, reflecting the application of technical HCH largely and probably small quantities of DDT during the flowering season of rice. The alpha-HCH was detected as a dominant isomer for all seasons monitored followed by beta-HCH. Among DDT compounds, p,p'-DDT was the highest in river water except in the dry season when p,p'-DDD showed a higher percentage. On the other hand, in mangroves p,p'-DDE was highest during the wet season and p,p'-DDD during the dry season. Air-water partitioning data of HCH isomers and DDT compounds in Vellar river revealed that these chemicals tend to be in the water phase. These observations may aid in understanding the role of a tropical paddy area on the behavior and fate of man-made chemicals in view of worldwide contamination.     

Ionic liquids as lubricants or lubrication additives: An ecotoxicity and biodegradability assessment

This paper reports on the (eco)toxicity and biodegradability of ionic liquids considered for application as lubricants or lubrication additives. Ammonium- and pyrrolidinium-based cations combined with methylsulphate, methylsulphonate and/or (CF₃SO₂)₂N⁻ anions were investigated in tests to determine their aquatic toxicity using water fleas Daphnia magna, green algae Selenastrum capricornutum and marine bacteria (Vibrio fischeri). Additional test systems with an isolated enzyme (acetylcholinesterase) and isolated leukaemia cells from rats (IPC-81) were used to assess the biological activity of the ionic liquids. These compounds generally exhibit low acute toxicity and biological activity. Their biodegradability was screened according to OECD test procedures 301 B and 301 F. For choline and methoxy-choline ionic liquids ready biodegradability was observed within 5 or 10 d, respectively. Some of the compounds selected have a considerable potential to contribute to the development of more sustainable products and processes.     

Diphenyl diselenide attenuates hepatic and hematologic toxicity induced by chlorpyrifos acute exposure in rats

Purpose

In this study, we investigated the effect of diphenyl diselenide [(PhSe)₂] on chlorpyrifos (CPF)-induced hepatic and hematologic toxicity in rats.

Methods

Rats were pre-treated with (PhSe)₂ (5?mg/kg) via the oral route (oral gavage) once a day for 7?days. On the eighth and ninth days, rats were treated with (PhSe)₂ (5?mg/kg) 30?min prior to CPF (50?mg/kg, by subcutaneous route). The aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase activities were determined in plasma of rats. Lipid peroxidation, protein carbonyl, and non-protein thiol levels as well as catalase, superoxide dismutase, glutathione peroxidase, glutathione reductase, and gluthatione S-transferase activities were determined in livers of rats. Hematological parameters were also determined.

Results

The results showed that CPF caused hepatic oxidative damage, as demonstrated by an increase in lipid peroxidation and protein carbonyl levels which was associated with a decrease in antioxidant defenses. CPF exposure caused a reduction in the leukocyte, indicating hematologic toxicity. (PhSe)₂ was effective in attenuating these toxic effects caused by CPF exposure in rats.

Conclusions

The results indicated that (PhSe)₂ was effective in protecting the hepatic and hematologic toxicity induced by acute CPF exposure in rats.     

PCDTs in the environment

Polychlorinated dibenzothiophenes (PCDTs) are sulfur analogues of polychlorinated dibenzofurans. Recently, PCDTs have been found in stack gas and fly ash samples, pulp mill effluents, sediments and in some aquatic organisms. PCDTs have been analyzed by high resolution GC/MS and by other GC-MS techniques. Combustion is until now the major known source of PCDTs in the environment. Tri-, tetra- and pentaCDTs in concentrations approaching those of PCDTs have been analyzed in some samples from waste incineration and metal reclamation. Concentrations of PCDTs in pulp mill effluents have been found to be quite low. 2378-TeCDT was found to be the major TeCDT isomer in some pulp mill effluents. Preliminary toxicological investigations have shown that PCDTs possess some kind of dioxin type toxicity.     

Discrepancies in the acute versus chronic toxicity of compounds with a designated narcotic mechanism

In this study, it was illustrated that even for certain simple organic compounds with a designated mode of action (MOA) (i.e. narcotic toxicity) unexpected differences in acute and chronic toxicity can be observed. In a first part of the study, species sensitivity distributions (SSDs) based on either acute or chronic toxicity data of three narcotic test compounds (methanol, ethanol and 2-propanol) were constructed. The results of the acute SSDs were as expected for narcotic compounds: rather similar sensitivity and small differences in toxicity were observed among different species. On the contrary, the chronic SSDs of methanol and ethanol indicated larger interspecies variation in sensitivity. Furthermore, the chronic toxicity trend (ethanol > methanol > 2-propanol) was unexpectedly different from the acute toxicity trend (2-propanol > ethanol > methanol) and acute versus chronic extrapolation could not be successfully described for methanol and ethanol using an ACR of 10 (as suggested for narcotic compounds). In contrast to the interspecies approach in the first part of this study, the second part of the study was focused on the assessment of acute and chronic toxicity of the three test compounds in Daphnia magna, which was identified as one of the most sensitive organisms to methanol and ethanol. Here, the differences in acute and chronic toxicity trend were in accordance to the results of the SSDs. The enhancement of membrane penetration due to the small molecular size of methanol and ethanol, in combination with the higher toxicity of their respective biotransformation products were suggested as potential causes of the increased chronic toxicity. Furthermore, it was stressed that larger awareness of these irregularities in acute to chronic extrapolations of narcotic compounds is required and should receive additional attention in further environmental risk assessment procedure.     

Endocrine disruptors in freshwater streams of Hesse, Germany: changes in concentration levels in the time span from 2003 to 2005

Four small freshwater streams in the region known as Hessisches Ried in Germany were investigated with respect to the temporal and spatial concentration variations of the endocrine disruptors bisphenol A (BPA), 4-tert-octylphenol (4-tert-OP), and the technical isomer mixture of 4-nonylphenol (tech.-4-NP). Measured concentrations of the target compounds in the river water samples ranged from <20 ng/l to 1927 ng/l, <10 ng/l to 770 ng/l, and <10 ng/l to 420 ng/l for BPA, 4-tert-OP and tech.-4-NP, respectively. BPA levels were, with the exception of two samples, below the predicted no-effect concentration (PNEC) for water organisms. Tech.-4-NP concentrations showed a significant tendency of decreasing concentrations during the sampling period. This is mainly attributed to the implementation of the European Directive 2003/53/EG, which restricts both the marketing and use of nonylphenols. Results from the analysis of additionally collected water samples from sewage treatment plant (STP) effluents indicate that the STPs cannot be the only sources for tech.-4-NP found in the river water.     

Distribution and behaviour of persistent organochlorine insecticides in paddy soil and sediments in the tropical environment: a case study in South India

Paddy soil and sediment samples collected from the Vellar River watershed, Tamil Nadu state, South India from December, 1987 to January, 1989 were analysed to understand the comprehensive behaviour of organochlorine insecticides (HCH and DDT) in the tropical environment. HCH (BHC) showed higher levels in soil during wet season, reflecting the application of technical HCH largely during the flowering season of rice. On the other hand, DDT residues were low and did not show a significant seasonal trend in soil or sediment, indicating small quantities of DDT utilized at present for agricultural purposes in India. When compared to soil, the residue levels in sediments are low and the seasonal variation is less pronounced. This indicates that in tropical watersheds, the relative flux of residues into the aquatic environment is smaller than the amount volatilized to the atmosphere.     

The acute toxicity of phenol and unionized ammonia, separately and together, to the ephemeropteran Baetis rhodani (Pictet)

The acute toxicity of phenol and ammonia, singly and in combination, to larvae of the ephemeropteran, Baetis rhodani, was examined using a computerized continuous flow system in the laboratory. The 24 h LC50 values (with 95% confidence intervals) were calculated to be 29.9 (17.3-51.5) mg phenol litre(-1) and 8.2 (2.0-33.0) mg un-ionized ammonia litre(-1). When phenol and ammonia were together in low concentration (< 20 mg litre(-1) and < 3 mg litre(-1) [un-ionized], respectively), they expressed their toxicity additively, but at higher concentrations they behaved in a greater-than-additive manner. When the 24 h LC50 values were used to predict the toxicity of a coking plant effluent, containing principally ammonia and phenol, it was found that the B. rhodani larvae died quicker than expected indicating the presence of other toxic chemicals. This exemplifies the value of using direct toxicity assessments to detect the presence of unknown toxicants.