Effects of Matricaria chamomilla L. on lipid peroxidation,antioxidant enzyme systems,and key liver enzymes in CCl4-treated rats

In this study, we investigated the effects of Matricaria chamomilla L. extract (MCE) on lipid peroxidation, antioxidant enzyme systems, and several liver enzymes in carbon tetrachloride (CCl₄)-treated rats. Rats were divided into five groups. The first group (control group) was fed on standard feed. The rats in the other groups (CCl₄, MCE50, MCE100, and MCE200) were injected intraperitoneally with 0.8?mL?kg^?1 CCl₄. Moreover, rats in the MCE50, MCE100, and MCE200 groups were gavaged with 50?mg?kg^?1, 100?mg?kg^?1, and 200?mg?kg^?1 MCE, respectively. Serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels, whole blood malondialdehyde (MDA) and glutathione (GSH) levels, and erythrocyte superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) activity levels were measured after 14 days of exposure. ALT and AST in the CCl₄ group increased significantly in comparison to the control group (p?4, MCE50, MCE100, and MCE200 groups at different significance levels. In conclusion, the findings suggest that, depending on the dose administered, MCE decreases CCl₄-induced damage and consequent oxidative stress in rats; it affects the antioxidant system positively.     

Residues of 14C‐γ‐HCH in paddy after dusting,and the fate of γ‐HCH during refining process of rice bran oil

Paddy (rice) plants were dusted with 10% HCH containing ¹⁴C‐Γ‐HCH, at the rate of 2.5 kg a.i./ha and ¹⁴C‐residues were determined in different fractions of rice. Rice bran (0.187 ppm) had more of ¹⁴C‐residues than grain (0.026 ppm) and husk (0.042 ppm). The rice bran oil contained 0.129 ppm HCH residues. While degumming, dewaxing, alkali refining and bleaching had no effect, deodorisation alone eliminated 99.5% of added ¹⁴C‐residues in rice bran the oil during refining process.     

Concentrations of Hchs and Ddts in the Tissues of River Dolphins,Platanista Gangetica,From the River Ganges,India

Abstract

Concentrations of HCH and DDT organochlorine insecticide residues were measured in blubber, muscle and oil samples from three specimens of river dolphins, Platanista gangetica, from the River Ganges, India. Concentrations of HCH and DDT ranged from 94 to 289 ng g^?1 and from 1324 to 9388 ng g^?1 on wet wt. basis respectively. Comparisons are made with other aquatic mammals and other studies on river dolphins. P. gangetica appears to exhibit similar patterns of accumulation with age and with ß-HCH and p-p′-DDE being accumulated to higher levels than other HCH isomers and parent DDT and its other metabolites, respectively. These organochlorines may pose a health risk to river dolphin populations that are already showing evidence of environmental stress. Further studies are recommended.     

Potential hepatoprotective effects of vitamin E and Nigella sativa oil on hepatotoxicity induced by chronic exposure to malathion in human and male albino rats

Malathion is an organophosphorus (OP) insecticide and has a wide range of use in agriculture, veterinary medicine, and public health. Malathion and other OP insecticides produce hepatotoxic effects. The objective of the present study was to investigate the protective effects of Nigella sativa oil and α-tocopherol (vitamin E) on the hepatotoxicity induced by malathion on workers involved in the formulation of pesticides, chronically exposed to malathion, and in male albino rats orally administrated malathion. This study was conducted on both human and experimental animals, the human study was conducted on 30 control subjects working as administrators and 45 subjects working in formulation of pesticides and exposed to malathion (≥3 years), all were males with age ranges from 30 to 60 years. The 45 males working in pesticides formulation were classified into three groups; (1) 15 workers exposed to pesticides (2) 15 workers exposed to pesticides and received vitamin (E), in a dose of 10 mg kg?1 day^?1 orally for 60 days, and (3) 15 workers exposed to pesticides and received 100 mg kg^?1 day^?1 of N. sativa oil for 60 days. The animal experiment was conducted on 40 adult male albino rats weighing 150–200 g. They were divided into four groups (10 rats in each group). First group served as the control group, the second group received malathion in a dose of 50 mg kg^?1 orally per day for 60 days, the third group received malathion (in the same dose and route of administration) and vitamin E in a dose of 10 mg kg^?1 day^?1 orally for 60 days, and the fourth group received malathion (in the same dose and route of administration) and N. sativa oil in a dose of 100 mg kg^?1 day^?1 orally for 60 days. Liver function tests (alanine aminotransferase [ALT], aspartate aminotransferase [AST], serum alkaline phosphatase [ALP], albumin, globulin, albumin/globulin ratio, and total proteins), antioxidant enzymes (catalase (CAT), superoxide dismutase (SOD), and total glutathione peroxidase (GPx)), and lipid peroxidation [MDA] were analyzed in both human and animal experiments. The results of both human and animal study revealed that, exposure to malathion produced significant increases in AST, ALT, and lipid peroxidation. There were significant decrease in albumin, albumin/globulin ratio, total protein, and antioxidant enzymes. There was no significant change in ALP. In addition exposed workers showed significant decreases in serum globulin. Nigella sativa oil or vitamin E administration showed significant improvement of liver function tests, lipid peroxidation, and antioxidant enzymes impairment induced by malathion. Thus, dietary supplement, N. sativa oil, or vitamin E may represent a potential therapeutic agent in reducing malathion-induced hepatotoxicity.     

Seed pre-soaking with 24-epibrassinolide reduces the imidacloprid pesticide residues in green pods of Brassica juncea L.

The effect of 24-epibrassinolide seed soaking on imidacloprid residues in green pods and mature seeds of Brassica juncea L. plants was investigated. The activities of the antioxidative enzymes glutathione-S-transferase, glutathione peroxidase, glutathione reductase, ascorbate peroxidase and guaiacol peroxidase, and the content of glutathione were determined. Imidacloprid residues in green pods were analyzed and quantified by gas chromatography-mass spectrometry, revealing that 24-epibrassinolide treatment resulted in a decrease of residues by almost 30%. In mature seeds, no pesticide residues were detected. Activities of all the antioxidative enzymes and glutathione content were found to be high in plants grown in soil amended with 300 mg imidacloprid kg^?1 soil, but pre-soaking with 100 nmol L^?1 24-epibrassinolide further enhanced the activities of all these enzymes and the glutathione content.     

Distribution of Organo-Chlorine Pesticides (DDT and HCH) Between Plant and Soil System

This paper reports a study of the distribution of organo-chlorine pesticides (DDT and HCH) between rice plants and the soil system by spraying before the heading stage at four different dosage levels – control, normal dosage (15 kg ha^–1 of 6% HCH and 7.5 kg ha^–1 of 25% DDT), double dosage and four times dosage. Soil and plant samples were taken respectively at the 1st h, 3rd, 10th, 20th, and 40th day after spraying and at the harvest time. The results indicate that less than 5% of HCH and 15% of DDT were absorbed by the surface of rice leaves for normal dosage. Most of both pesticides moved into the soil in solution after spraying. Compared with DDT, HCH was degraded and run off more easily. HCH residues in the surface soil layer (1–3 cm) were already below 6.4 g kg^–1 at the mature stage, lower than Chinese Environmental Quality Standard for Agricultural Soils: HCH <0.05 mg kg^–1. However DDT residues in the surface soil layer remained 172 g kg^–1, higher than the national standard: DDT <0.05 mg kg^–1. According to the test f OCP residues in rice seeds, it can be concluded that the OCP sprayed onto the surface of rice leaves can move into rice plants and accumulate in the seeds at the mature stage. HCH residues in rice seeds of the double and four times dosage treatments, and DDT residues in all treatments, exceeded the Chinese National Food Standard (HCH <0.10 mg kg^–1, DDT <0.20 mg kg^–1).     

Effect of a popular Middle Eastern food (Falafel) on rat liver

The aim of this study was to evaluate the effect of short-term consumption of oil and frying oil extracted from falafel patties, and then to study the long-term effect of consumption of falafel patties on rat liver gross morphology and serum liver enzymes. The frying oil quality was assessed using thiobarbituric acid reaction on rat liver homogenate. Frying oil and oil extracted from falafel patties were administered to male Wistar albino rats via gavage for 5 days. Blood samples were collected and the activities of alkaline phosphatase (ALP), aspartate aminotransferase, alanine aminotransferase (ALT), and bilirubin levels were determined. Livers were weighed and gross morphology was assessed. For the long-term effect of falafel consumption, rats were fed falafel patties for 30 days, and then blood samples were collected and assayed for the above-mentioned parameters. Short-term consumption of falafel extracts and frying oil did not cause any significant difference in the liver function tests and liver gross morphology. Whereas, long-term consumption of falafel patties caused a significant increase in ALP, ALT, bilirubin level and increased liver weight/body weight ratio denoting hepatotoxicity. This indicates that consumption of large amounts of falafel on daily basis might lead to hepatotoxicity.     

Stable isotope study of sedimentary carbon utilization by Capitella spp.: effects of two carbon sources and geochemical conditions during their diagenesis

Two experiments were conducted to determine the effect of the type of sediment organic matter and geochemical conditions during diagenesis on the stable carbon isotope ratio ¹³C of the deposit-feeding polychaete worms Capitella spp. Laboratory experiments showed ¹³C values of-13.5 to-13.9%. for worms grown on fresh and aged kelp, Macrocystis pyrifera. Field experiments on worms in the Santa Barbara Channel, California (USA), in 1986 revealed more negative ¹³C values (to-19%.) when oil and kelp were added to sediments. The more negative values suggest the incorporation of oil carbon into worm tissues, supporting previous indications of the importance of hydrocarbons in food webs near oil seeps.     

Biochemical assessment of lead,phenol, and benzene-contaminated water on the heart and blood of Albino rats

A study was performed to evaluate the effect of contaminated water on the tissues of Rattus novergicus (albino rats). Test rats were given water contaminated with lead (0.015 µg L^?1 tap water), phenol (0.05 mL L^?1 tap water), and benzene (0.05 mL L^?1 tap water), while control rats were given tap water over a period of 65 days after which the activity of selected enzymes of the heart and serum was assayed, and hematological parameters and serum lipid profiles were also determined. Generally, a significant (p < 0.05) drop in the activity of the enzymes was observed in the heart of test rats relative to the control rats. However, the serum activities increased significantly in the test group compared to the control group (p < 0.05). The concentrations of serum cholesterol, low-density lipoprotein (LDL), and triglycerides of the test rats were found to be significantly higher than those of the control rats (p < 0.05). Concentrations of hemoglobin, red blood cell count, and packed cell volume of test rats were observed to be significantly lower than those of the control rats (p < 0.05). The experimental results indicated that consumption of water contaminated with lead, phenol, and benzene may damage the heart, increase the risk of atherosclerosis as reflected by the serum lipid profile, and anemia as suggested by abnormal hematological properties.     

Protective efficacy of Mucuna pruriens extract on Epichlorohydrin induced toxicity in epididymis of albino rats

The protective effects of seeds of Mucuna pruriens on epichlorohydrin (ECH)-induced toxicity in epididymis and epididymal sperms of rats were studied. Different doses of ECH and M. pruriens (75 and 100 mg kg^?1, respectively) were administered daily, orally for 70 days. Group I animals served as control. Group II and III rats received ECH (75 or 100 mg kg^?1 body weight, respectively) alone. The group IV and V rats received a combination of both ECH and the seed extract of M. pruriens at 75 or 100 mg kg^?1 body weight. Group VI rats was administered only the extract of M. pruriens 100 mg kg^?1 body weight. At the end of the experiment (71st day), rats were sacrificed and sperm collected from epididymis were used for the assessment of sperm count, sperm viability, and sperm motility. Administration of ECH produced a reduction in epididymal sperm count, sperm viability, and sperm motility. The activities of catalase, superoxide dismutase, and glutathione peroxidase were decreased, while lipid peroxidation was increased. ECH produced a decrease in the levels of protein, acid phosphatase, sialic acids, and increased the level of alkaline phosphatase, and cholesterol. The administration of M. pruriens to ECH-treated rats resulted in a protective effect.     

Screening of phthalic acid esters in raw materials,premixes and feed additives

Phthalates are animal carcinogens and may cause death or tissue deformities. Samples of feedstuffs collected in 2005 and 2006 from industrial feed manufacturers in the Czech Republic were analysed for contamination with phthalic acid esters (PAEs), specifically di-2-ethylhexyl phthalate (DEHP) and di-n-butyl phthalate (DBP). Samples of feed additives, premixes and raw materials were collected (year 2005, n = 26). For soybean oil, the total volume of phthalates measured (DBP + DEHP) reached a level of 131.42 mg kg⁻¹; for rapeseed oil, fish meal and animal fats, the levels measured were 15.00, 7.96 and 58.87 mg kg⁻¹, respectively. The lowest level of DBP + DEHP was found in corn (2.03 mg kg⁻¹). Since phthalates were detected, samples of feed additives (n = 28) and raw materials (n = 28) were collected again in 2006. The highest levels of DBP + DEHP were found in raw materials containing fat. Phthalate levels in rapeseed oil samples ranged from 1.38 to 32.40 mg kg⁻¹ DBP + DEHP. For feed additives, contamination levels in vitamins and amino acids ranged from 0.06 to 3.15 and 1.76 to 4.52 mg kg⁻¹ DBP + DEHP, respectively. Here, we show that the levels of PAEs found in cereals such as wheat, barley and corn may be regarded as being alarmingly high, because cereals make up the largest proportion of compound feed of farm animals.     

Effects of zinc oxide nanoparticles on growth and antioxidant enzymes of Capsicum chinense

Abstract

The effects of suspensions of zinc oxide nanoparticles at concentrations between 100 and 500?mg L^?1 on germination of Capsicum chinense seeds and vigor of plants were evaluated using a randomized complete design with four replications, resulting in increased germination and improved development of lengths of plumule and radicle. The activities of peroxidase, catalase and ascorbate peroxidase were determined, showing that at all concentrations the activities of the former two enzymes were increased, whereas the activity of the latter was reduced at 500?mg L^?1. Pretreatments of seeds with ZnO nanoparticles can improve germination and development of seedlings and the activities of antioxidant enzymes.     

Gender-based comparative toxicity of di-ethyl phthalate in Wistar rats

In recent years, the exposure of humans to phthalate esters through environmental contamination has increased. One among them is di-ethyl phthalate (DEP), which is used as a plastisizer for cellulose ester plastic films and sheets, solid rocket propellants, molded and extruded articles, as a component in insecticide sprays and various other substances, as well as in industrial applications. Release into the environment occurs primarily as a result of production and manufacturing of DEP and during the use and disposal of products containing DEP. Therefore, a study was undertaken to evaluate gender-specific toxicity of DEP in Wistar rats. Rats of both sexes, weighing 125–130?g, were administered 50?ppm (w/v) DEP in water ad libitum for a period of 180 days and were given normal diet. Control animals received normal diet and water ad libitum. During the treatment, rats were weighed every week and water consumption per day was measured. After the completion of treatment, liver weight?:?body weight^?1 ratio, liver weight, body weight^?1, liver and serum enzymes, and other biochemical parameters of liver and serum were assessed. It was observed that there was no significant change in body weight^?1, liver weight, liver weight?: body weight^?1 ratio, and water consumption in both sexes. There were significant increases in liver acid phosphatase (ACP) activity and kidney glutathione levels, and nonsignificant changes in liver alkaline phosphatase (ALP), aspartate aminotransferase (AST), alanine aminotransferase (ALT), succinate dehydrogenase (SDH), and lactate dehydrogenase (LDH) activities in DEP-treated male rats, whereas in DEP-treated female rats the liver showed significant decrease in ALP and SDH and nonsignificant changes in AST, ALT, and LDH activities. Serum ACP and LDH levels in DEP-treated male rats were significantly decreased, and in the case of DEP-treated female rats, only serum LDH levels were significantly decreased. There was no significant change in serum ALP, AST, and SDH levels in DEP-treated male and female rats as compared to control rats. Histology of the livers of both male and female rats showed loss of hepatic architecture, degenerative changes in hepatocytes, and vacuolation in hepatocytes in both the centrilobular and periportal areas. It can be concluded from this study that prolonged exposure to DEP at 50?ppm levels can be harmful to animals and humans. This is evident from the present study as certain significant changes in enzyme activities in the liver, serum, and histological alterations in liver were observed.     

Determination of cytotoxic,genotoxic, and oxidative damage from deltamethrin on primary hepatocyte culture of Lake Van fish,Alburnus tarichi

ABSTRACT

Deltamethrin is a widely used pyrethroits worldwide. Although the chemical is used to combat insects, it has effects on other non-target organisms. Deltamethrin is extensively used in agriculture, animal husbandry, and domestic areas in the Lake Van basin. The aim of this study was to determine the cytotoxic, genotoxic, and oxidative damage from deltamethrin on the primary hepatocyte culture of Lake Van fish (Alburnus tarichi). In this study, the toxic effects of different concentrations (0.01, 0.1, 1, and 10?µM) of deltamethrin in the primary hepatocyte culture of Lake Van fish were investigated via liver enzymes aspartase aminotransferase (AST) and alanine aminotransferase (ALT), and the total antioxidant status (TAS), total oxidant status (TOS), lipid peroxidation (MDA), and DNA damage (8-OHdG).

Deltamethrin caused an increase in the AST and ALT levels dependent on the dosage and time. The TAS and TOS levels increased at the end of 24?h and there was no difference at the end of 48?h. Deltamethrin did not affect the MDA level, but increased the 8-OHdG (P?<?0.05). In conclusion, it can be said that high doses of deltamethrin (1 and 10?µM) have a toxic effect on the primary hepatocyte culture of Lake Van fish.     

Demonstration,using Desulfobacter sp., of two pools of acetate with different biological availabilities in marine pore water

Desulfobacter sp. (Strain 3ac10), an acetate-utilizing sulphatereducing bacteria, was added to sterile marine pore water spiked with ¹⁴C-acetate, and changes in both the natural acetate pool and the added ¹⁴C-acetate were measured over time. Initially, both the added ¹⁴C-acetate and the chemically measured acetate were rapidly mineralized, but then the rate of removal decreased and a significant amount (approximately 20%) of both ¹⁴C-acetate and chemically measured acetate remained unmetabolised. In a replicate experiment, approximately 50% of the acetate was not metabolised. Kinetic analysis of the data indicated that there were two pools of acetate in the original pore water, a biologically available pool (which is rapidly metabolised) and a recalcitrant pool (which is only very slowly metabolised). Addition of ¹⁴C-acetate after the biologically available acetate had been removed resulted in rapid removal of the added acetate but no change in the recalcitrant acetate pool. The implications of this data to radiolabelled techniques of measuring in situ acetate turnover are discussed.     

Chronic mixture toxicity study of Clophen A60 and diethyl phthalate in male rats

Chemical mixtures are an important area of research as individuals are exposed to low doses of persistent chemical agents known as environmental pollutants throughout their life time. Polychlorinated biphenyls (PCBs) and diethyl phthalate (DEP) are ubiquitous environmental pollutants that could be present in the same environmental compartment; hence organisms may get simultaneously exposed to both. Therefore, a study was undertaken to see whether PCB and DEP together show interactive chronic mixture toxicity in male Wistar rats. Healthy male Wistar rats weighing 70–100?g were randomly assigned to four groups of six each. Control rats were fed on normal diet and water ad libitum. Oil control rats were maintained on a normal diet mixed with corn oil. Rats were given Clophen A60 (PCB) and DEP dissolved individually in corn oil mixed with the diet at 50?mg?kg^?1 of the diet/day, as well as a mixture in corn oil mixed with the diet both at 50?mg?kg^?1 of the diet/day. After 150 days of treatment animals were sacrificed and enzymes and other biochemical parameters in the serum and liver were assessed. Liver weight to body weight ratio showed a significant increase in Clophen A60 and in Clophen A60?+?DEP treated rats. In the DEP, Clophen A60 and Clophen A60?+?DEP treated groups there was significant increase in liver and serum alanine aminotransferase (ALT) and acid phosphatase (ACP) activity. Aspartate aminotransferase (AST) was significantly increased in the liver and serum of DEP treated rats only. Cholesterol levels were significantly increased only in the serum and the liver of DEP treated rats. Triglyceride levels were significantly increased in the serum of treated rats and only in the liver of Clophen A60 and Clophen A60?+?DEP treated rats. Liver glycogen levels were significantly increased in DEP and Clophen A60?+?DEP treated rats. In all treated animals, there was a significant decrease in liver glutathione reductase (GR). Histology of liver showed severe vacuolations, fatty degeneration and loss of hepatic architecture in Clophen A60 and Clophen A60?+?DEP treated rats, whereas in DEP treated rats only loss of hepatic architecture and granular deposits in the hepatocytes was predominant with mild vacuolations of centrilobular and periportal area. It is evident from this study of mixture toxicity of Clophen A60 and DEP that there is no significantly enhanced toxicity due to the interaction of these two compounds. On the other hand, to some extent there is alleviation in toxicity as evidenced by enzyme ACP and AST levels in the liver. The hepatocellular damage and biliary congestion caused by these two compounds, which can be confirmed by significantly increased liver weights and elevated serum and liver enzyme levels as well as histology, was almost the same between individual and mixture treated group.     

芹菜素对丙烯腈引起大鼠精子脂质过氧化和DNA损伤的影响

分析芹菜素(apigenin,AP)对丙烯腈(acrylonitrile,ACN)引起的大鼠精子脂质过氧化和DNA损伤的影响,并探讨其可能的机制。将50只SPF级SD成年雄性大鼠随机分为阴性对照组(玉米油)、ACN组(50 mg·kg~(-1)ACN)、低AP组(50 mg·kg~(-1)ACN+234 mg·kg~(-1)AP)、高AP组(50 mg·kg~(-1)ACN+468 mg·kg~(-1)AP)、N-乙酰半胱氨酸(N-acetylcysteine,NAC)组(50 mg·kg~(-1)ACN+300mg·kg~(-1)NAC),以5 m L·(kg bw)~(-1)灌胃染毒,1次·d~(-1),6 d·周~(-1),连续13周。检测大鼠精子活性氧(ROS)、丙二醛(MDA)含量、超氧化物歧化酶(SOD)活性以及精子DNA损伤情况。结果发现,ACN组、低AP组、高AP组、NAC组精子ROS、MDA含量显著升高,SOD活力显著降低,精子尾部DNA含量百分比、尾长、尾距、Olive尾距均显著增高于对照组(均P0.05);而低AP组、高AP组、NAC组精子ROS、MDA含量、SOD活性和精子DNA损伤情况与ACN组相比差异均无统计学意义(P0.05)。提示ACN可引起大鼠精子脂质过氧化和DNA损伤,而AP、NAC对其无干预作用。     

The effect of Kuwait crude oil and a solvent emulsifier on the metabolism of the marine lichen Lichina pygmaea

As lichens are sensitive monitors of environmental pollution and are known to be affected by marine pollutants, a study was made of the effect of Kuwait crude oil and a solvent emulsifier (BP 1002) on the metabolism of the marine lichen Lichina pygmaea (Lightf.) C. Ag. Photosynthesis in the presence of NaH¹⁴CO₃ enabled an investigation to be made of the effect of these pollutants on the total ¹⁴C-fixation and the pattern of ¹⁴C-fixation. Oil was shown to be substantially less inhibitory than the emulsifier to the total ¹⁴C fixed. The emulsifier, but not the oil, induced loss of labelled material from the lichen. No change was observed in the influence of oil or undiluted emulsifier after ageing. Combination of the emulsifier with either oil or sea water resulted in a decreased inhibitory effect, which was further reduced on ageing the mixture. It was concluded that the inhibitory component of the emulsifier was the surfactant and not the solvent.     

Biodegradation and phytotoxicity assessment of phenanthrene by biosurfactant-producing Bacillus pumilus 1529 bacteria

ABSTRACT

Phenanthrene is a toxic and mutagenic pollutant that can cause severe environmental and human health issues. The bioremediation of these polyaromatic hydrocarbons (PAHs) is possible with a biosurfactant by enhancing hydrophobicity. In this study, the production of a biosurfactant by Bacillus pumilus 1529 and its effects on the phenanthrene biodegradation pathway were examined. Biosurfactant production was determined using hemolytic activity, emulsification index, and surface tension. For phenanthrene metabolite detection, samples at 0, 7, 14, and 21 incubation days were analysed by gas chromatography-mass (GC-mass) spectrometry. The results showed that Bacillus pumilus 1529 can reduce surface tension to 22.83?±?1.1?mN?m^?1. Furthermore, the GC-mass spectrometry analysis showed that 1-hydroxy-2-naphthoic acid, benzaldehyde, o-phthalic acid, and phenylacetic acid were notable phenanthrene metabolites produced during phenanthrene biodegradation. Biodegraded phenanthrene and its metabolites have a less toxic effect on the germination of safflower seeds than non-biodegraded phenanthrene. The IC50 of phenanthrene on seed germination after biodegradation was increased to approximately 113?mg?L^?1. In general, biodegradation aided by biosurfactant producing bacteria contributed to turning the toxic phenanthrene into less harmful metabolites with lower phytotoxicity effects, indicating that its application in the bioremediation of PAHs is promising.     

Phytotoxicity to and uptake of TNT by rice

The contamination of the environment by explosives is a worldwide problem resulting in part from 2,4,6-trinitrotoluene (TNT) production. In situ phytoremediation is an appropriate, alternative, cost-effective technology to detoxify extended contamination of surface soil. The ability of rice (Oriza sativa) to both tolerate and assimilate ¹⁴C-labeled TNT was investigated over a 40-day exposure period. The germination rate decreased at 500 mg/kg TNT whereas root and shoot length increased significantly at high TNT concentrations, from 150 to 500 mg/kg. Rice took up TNT residues from soil and accumulated most in roots. Less than 25% of radioactivity taken up was translocated to aerial parts. Above 200 mg/kg TNT, the concentration of TNT residues in roots reached a maximum of approximately 0.7 mg/g. No TNT was found in plant extracts, good evidence for rapid metabolism of TNT. More than 60% of ¹⁴C activity was found as unextractable residues in roots. It was concluded that TNT metabolized and subsequently sequestered by roots could not be translocated to aerial parts.