Search

The organophosphorus (OP) and carbamate (CB) insecticides are responsible for inhibition of the Acetylcholinesterase (AChE) enzyme. The AChE activity, therefore, has been demonstrated to be a potent biomarker for these insecticides in terrestrial and aquatic environments. The objective of this study was to investigate the response of AChE in the brain of four-week old fingerlings of silver perch, Bidyanus bidyanus exposed to OP and CB insecticides. The fish fingeling were exposed to three OPs and one CB insecticide as individual and their binary mixtures for 48 h. The OP insecticides with oxon (PO) as well as thion (PS) group gets oxidized to oxon analogs in biological systems. The 50% AChE inhibition (48 h EC50) in fingerling exposed to chlorpyrifos (CPF) and triazophos (TRZ) was evident at 2.3 and 6.7 µg/L, respectively. The toxicological interaction of three OPs and one CB insecticide was evaluated using the toxic unit method. A strong synergism was observed for binary combination of CPF with profenofos (PRF), and CPF with TAZ. In contrast, the mixture of TAZ with PRF and carbofuran (CBF) with CPF and PRF showed antagonistic behavior. Although OP and CB insecticides can break down rapidly in the environment, this study suggests that non-target aquatic biota may be exposed to mixtures of ChE-inhibiting insecticides for a period of several months, in agricultural regions where insecticides are applied for extended periods of the year. And at environmentally relevant concentrations such mixtures may lead to deleterious effects in non-target organisms.

Carbaryl is the representative of carbamate insecticide. As an acetylcholinesterase inhibitor, it poses potential threat to humans and other non-target organisms. Agrobacterium sp. XWY-2, which could grow with carbaryl as the sole carbon source, was isolated and characterized. The carH gene, encoding a carbaryl hydrolase, was cloned from strain XWY-2 and expressed in Escherichia coli BL21 (DE3). CarH was able to hydrolyze carbamate pesticides including carbaryl, carbofuran, isoprocarb, propoxur and fenobucarb efficiently, while it hydrolyzed oxamyl and aldicarb poorly. The optimal pH of CarH was 8.0 and the optimal temperature was 30 ℃. The apparent Km and kcat values of CarH for carbaryl were 38.01 ± 2.81 μM and 0.33 ± 0.01 s−1, respectively. The point mutation experiment demonstrated that His341, His343, His346, His416 and D437 are the key sites for CarH to hydrolyze carbaryl.

The transformation of carbosulfan (CSN) in apples was investigated during oven-drying, microwave drying, and sun-drying. CSN transformed primarily into carbofuran (COA) during these drying processes. The conversion kinetics of CSN and COA was fitted by curve regression and mainly conformed to quadratic models (R2 = 0.70–0.97). Oven-drying promoted the transformation of CSN into COA. Microwave drying resulted in the highest scavenging capacity against CSN and COA (41%–100%). Moreover, a transformation mechanism was proposed on the basis of density functional theory (DFT) calculation. The COA originated from a series of chemical reactions involving hydroxyl substitution, cleavage, and oxidation; this result was further confirmed on the basis of molecular electrostatic potential (MEP) and molecular orbital theory. Furthermore, the toxicity and stability of CSN and COA were evaluated with the T.E.S.T. program. COA was less toxic than CSN to aquatic organisms but more toxic than CSN to rats. Therefore, COA production should be avoided during drying. Microwave drying was found to be the optimum choice for drying apples.

This study investigated the levels of highly toxic pesticides (HTPs) in 6554 vegetable and fruit samples from 31 regions of China, along with the associated risk of dietary exposure for the population between 2014 and 2017. 18 HTPs were detected in 325 (4.96%) samples, and the levels of HTPs in 103 (1.57%) samples were found to be higher than the maximum residue limits (MRLs) of China. The rate of detection of HTPs in six types of vegetables and fruits, in a decreasing order, was found to be as follows: eggplant (8.84%) >grape (5.58%) >tomato (5.43%) >cucumber (5.43%) >pear (3.12%) >apple (2.30%). The level of contamination of HTPs was found to be higher in vegetables compared with fruits. The vegetable and fruit samples with the highest percentages of HTPs exceeding MRLs were found in eggplants from Guangxi (20%) and grapes from Inner Mongolia (12.5%), respectively. Both, the average target hazard quotient (THQ) of a single highly toxic pesticide (HTP) and the average hazard index (HI) of the mixture of HTPs for adults and children from vegetables and fruits from the 31 regions were found to be less than one. Omethoate, carbofuran, ethoprophos, triazophos, and phorate were identified as the major contributors to the average HI for vegetables, and carbofuran, ethoprophos, omethoate, phorate, and phosphamidon were identified as the primary contributors to the average HI for fruits. The results of this study revealed that HTPs in vegetables and fruits did not cause any significant chronic risk of dietary exposure. The detection of HTPs exceeding MRLs in some of the samples implied that appropriate management guidelines for HTPs should be implemented to protect the health of the consumers.

The toxicity of the insecticide carbofuran and herbicide diuron (individually and in mixture) to the invertebrates Paramecium caudatum and Ceriodaphnia silvestrii was evaluated. Acute and chronic toxicity tests were carried out with the diuron and carbofuran active ingredients and their commercial products, Diuron Nortox® 500 SC and Furadan® 350 SC, respectively. Individual toxicity tests showed that C. silvestrii was more sensitive to both carbofuran and diuron than P. caudatum. In single exposures, both pesticides caused adverse effects to C. silvestrii in environmentally relevant concentrations (48 h EC50 = 0.001 mg L−1 and 8 d LOEC = 0.00038 mg L−1 for formulated carbofuran; 8 d LOEC

Microorganisms' role in pesticide degradation has been studied widely. Insitu treatments of effluents containing pesticides such as biological beds (biobeds) are efficient biological systems where biomixture (mixture of substrates) and microorganisms are the keys in pesticide treatment; however, microbial activity has been studied poorly, and its potential beyond biobeds has not been widely explored. In this study, the capacity of microbial consortium and bacteria-pure strains isolated from a biomixture (soil-straw; 1:1, v/v) used to treat agricultural effluents under real conditions were evaluated during a bioremediation process of five pesticides commonly used Yucatan Mexico. Atrazine, carbofuran, and glyphosate had the highest degradations (>90%) using the microbial consortium; 2,4-D and diazinon were the most persistent (DT50 = 8.64 and 6.63 days). From the 21 identified bacteria species in the microbial consortium, Pseudomonas nitroreducens was the most abundant (52%) according to identified sequences. For the pure strains evaluation 2,4-D (DT50 = 9.87 days), carbofuran (DT50 = 8.27 days), diazinon (DT50 = 8.80 days) and glyphosate (DT50 = 8.59 days) were less persistent in the presence of the mixed consortium (Ochrobactrum sp. DGG-1-3, Ochrobactrum sp. Ge-14, Ochrobactrum sp. B18 and Pseudomonas citronellolis strain ADA-23B). Time, pesticide, and strain type were significant (P

A novel carbofuran-degrading strain CFD-1 was isolated and preliminarily identified as Sphingbium sp. This strain was able to utilize carbofuran as the sole carbon source for growth. The carbofuran hydrolase gene cehA was cloned from strain CFD-1 and expressed in Escherichia coli. CehA could hydrolyze carbamate pesticides including carbofuran and carbaryl efficiently, while it showed poor hydrolysis ability against isoprocarb, propoxur, oxamyl and aldicarb. CehA displayed maximal enzymatic activity at 40 °C and pH 7.0. The apparent Km and Kcat values of CehA for carbofuran were 133.22 ± 5.70 μM and 9.48 ± 0.89 s-1, respectively. The site-directed mutation experiment showed that His313, His315, His453 and His495 played important roles in the hydrolysis of carbofuran by CehA. Furthermore, the sequence of cehA is highly conserved among different carbofuran-degrading strains, and there are mobile elements around cehA, indicating that it may be transferred horizontally between different strains.

Estuarine environments gather pollution from large regions including urban and industrial zones. The monitoring of environmental quality in these areas constitutes a real requirement for global sustainable development. Therefore, the aim of this study was to characterize the physicochemical and kinetic parameters of brain acetylcholinesterase (AChE) in the species Centropomus undecimalis, Diapterus auratus and Diapterus rhombeus and to assess the effects (in vitro) of pesticides and metal ions on their respective activities in order to investigate them as potential biomarkers. Physicochemical properties such as thermostability, optimal pH and temperature, as well as kinetic parameters were investigated. AChE was pointed as the predominant cholinesterase (ChE) in the brains of the species under study. The highest optimum pH value was observed for C. undecimalis (8.0), and the lowest for D. rhombeus and D. auratus, with 7.2 and 7.0, respectively. The optimal temperature was 35 °C for the three species. The AChEs of the three species presented moderate thermostability, since they retained 61%, 72% and 67% of the activity up to 45 °C (C. undecimalis, D. auratus and D. rhombeus, respectively). The carbamate carbofuran showed to be the strongest inhibitor even at very low concentrations (IC50: 0.182, 0.174 and 0.203 μmol/L - C. undecimalis, D. auratus and D. rhombeus, respectively), followed by dichlorvos and carbaryl. According to the findings, the AChE of these species may be proposed as in vitro biomarker of exposure to carbofuran and dichlorvos (all three species) and carbaryl (D. auratus and D. Rhombeus), as well as for exceeding limit concentrations of Hg2+ (D. rhombeus) and As3+ (D. auratus) in biomonitoring programs located or not at estuarine environments.

The present study examined the impacts of carbofuran on endocrinology of the catfish, Clarias gariepinus, for the first time and evaluated cortisol (CRT), triiodothyronine (T3), thyroxin (T4), 17β-estradiol (E2) and testosterone (TST) and the oxidative stress markers including SOD, CAT, GSTs, GSH. The toxic effects on the metabolic enzymes, G6PDH and LDH, in addition to lipid peroxidation (LPO) and DNA damage as biomarkers in Nile catfish, to sublethal exposures of carbofuran (0.16 and 0.49mg/L, for 35 days) were studied. Statistically significant differences between selected parameters between control and carbofuran-treated fish were recorded. Carbofuran caused a significant (p0.05) increase in CRT and T3 levels; the mean levels of T4, TST, E2 exhibited significant decreases (p0.05) in carbofuran-treated fish. Toxicity of carbofuran on liver, kidney, gills, gonads and muscles after 35 days of exposure was found. Glycogen levels showed a highly significant decrease in liver and gills (p0.001), a significant decrease (p0.05) in kidney and muscles, and insignificant changes (p0.05) in gonads of treated fish. The two metabolic enzymes G6PDH and LDH in all tissues exhibited significant decreases (p0.05) in treated fish. SOD, CAT, GSH and GST levels showed significant decreases (p0.05) in all tissues of fish after exposure to carbofuran. LPO levels increased significantly (p0.05) in all tissues except gonads after 5 weeks of exposure to carbofuran. There was a significant (p0.05) increase in DNA fragmentation percentage in treated fish. Our results provide a clear evidence on the response of C. gariepinus to sublethal doses of carbofuran and allow us to consider catfish as a good bioindicator to reflect the endocrine disrupting impacts of carbofuran, and reflect the potential of this pesticide to cause disturbance in antioxidant defense system as well as metabolism and induction of lipid peroxidation (LPO) and DNA damage in contaminated ecosystems.

Effects of carbofuran commercial formulation on oxidative stress parameters were studied in carps (Cyprinus carpio) exposed to 50µg/L for 7 and 30 days under rice field and laboratory conditions. Thiobarbituric acid reactive substance (TBARS) levels were increased in the brain of fish after 7 and 30 days under rice field and laboratory conditions. In the liver and muscle, TBARS levels increased after 7 and 30 days under laboratory conditions, whereas in rice field the levels increased only after 30 days. Protein carbonyl content in the liver increased after 7 and 30 days under both experimental conditions. Acetylcholinesterase (AChE) activity was decreased in the brain and muscle after 7 and 30 days under both experimental conditions evaluated. The superoxide dismutase (SOD) activity increased in the liver after 7 and 30 days under rice field condition, whereas under laboratory condition this enzyme increased only after 30 days. The catalase (CAT) activity in the liver decreased after 30 days under rice field condition, whereas no changes were observed under laboratory conditions. In rice field, glutathione S-transferase (GST) decreased after 7 days but increased after 30 days, whereas no change was observed in fish exposed to carbofuran under laboratory conditions. These results suggest that environmental relevant carbofuran concentrations may cause oxidative stress, affecting biochemical and enzymatic parameters on carps. Some parameters could be used as biomarkers to carbofuran exposure.

To establish the use of Metaphire posthuma as a sensitive test model for ecotoxicological studies, acute toxicity testing of carbaryl, carbofuran, cypermethrin and fenvalerate on Eisenia fetida and Metaphire posthuma were carried out. Two different types of bioassays, contact filter paper toxicity and soil toxicity bioassays were used to determine LC 50 values for these insecticides. Among the tested chemicals, carbofuran was the most toxic to both the earthworm species. In paper contact method, 72 h-LC 50 values of carbofuran in M. posthuma and E. fetida were found to be 0.08 μg/cm 2 and 1.55 μg/cm 2 respectively while in soil test, 14-d LC 50 values were 0.49 mg/kg and 21.15 mg/kg respectively. On comparing the toxicity data of these chemicals for both the earthworm species, M. posthuma was found to be more sensitive than E. fetida. Based on the acute toxicity data, the order of toxicity of insecticides in both the test procedures was carbofuran>cypermethrin>carbaryl>fenvalerate for M. posthuma whereas for E. fetida it was carbofuran>carbaryl>fenvalerate>cypermethrin. Morphological changes also appeared in the organisms exposed to these chemicals which were more pronounced in M. posthuma at lower concentrations than E. fetida in both the test procedures. The results of the present study advocates the use of M. posthuma for ecotoxicity studies, being a more sensitive and reliable model than E. fetida. Based on the data on partial atomic charges, structural features and spectroscopic studies on carbaryl and carbofuran, a possible mechanism of toxicity of carbamate insecticides in earthworm was proposed.

International audience; The effects of carbofuran toxicity on a genetically modified bacterial strain E. coli DPD2794 were enhanced using a new bioluminescent protocol which consisted of three consecutive steps: incubation, washing and luminescence reading. Specifically, in the first step, several concentrations of carbofuran aqueous solutions were incubated with different bacterial suspensions at recorded optical densities for different lengths of time. Thereafter, the resulting bacterial/toxicant mixtures were centrifuged and the aged cellular supernatant replaced with fresh medium. In the final step, the carbofuran- induced bioluminescence to the exposed E. coli DPD2794 bacteria was shown to provide a faster and higher intensity when recorded at a higher temperature at30 °C which is not usually used in the literature. It was found that the incubation time and the replacement of aged cellular medium were essential factors to distinguish different concentrations of carbofuran in the bioluminescent assays. From our results, the optimum incubation time for a “light ON” bioluminescence detection of the effect of carbofuran was 6 h. Thanks to the replacement of the aged cellular medium, a group of additional peaks starting around 30 min were observed and we used the corresponding areas under the curve (AUC) at different contents of carbofuran to produce the calibration curve. Based on the new protocol, a carbofuran concentration of 0.5 pg/mL can be easily determined in a microtiter plate bioluminescent assay, while a non-wash protocol provides an unexplainable order of curve evolutionswhich does not allow the user to determine the concentration.

The use of fungal bioaugmentation represents a promising way to improve the performance of biomixtures for the elimination of pesticides. The ligninolyitc fungus Trametes versicolor was employed for the removal of three carbamates (aldicarb, ALD; methomyl, MTM; and methiocarb, MTC) in defined liquid medium; in this matrix ALD and MTM showed similar half-lives (14d), nonetheless MTC exhibited a faster removal, with a half-life of 6.5d. Then the fungus was employed in the bioaugmentation of an optimized biomixture to remove the aforementioned carbamates plus carbofuran (CFN). Bioaugmented and non-bioaugmented systems removed over 99% ALD and MTM after 8d of treatment, nonetheless a slight initial delay in the removal was observed in the bioaugmented biomixtures (removal after 3d: ALD 87%/97%; MTM 86%/99%, in bioaugmented/non-bioaugmented systems). The elimination of the other carbamates was slower, but independent of the presence of the fungus: >98% for MTM after 35d and >99.5% for CFN after 22d. Though the bioaugmentation did not improve the removal capacity of the biomixture, it favored a lower production of transformation products at the first stages of the treatment, and in both cases, a marked decrease in the toxicity of the matrix was swiftly achieved along the process (from 435 to 448 TU to values

The objective of this study was to investigate the acute effects of the pesticide carbofuran on the sea bass (Dicentrarchus labrax) using parameters at different levels of biological organisation (swimming behaviour and several biomarkers) and possible relationships between alterations found in different effect criteria. In a bioassay, sea bass juveniles were individually exposed to different doses of carbofuran (31, 63, 125 and 250 μg/L) for 96 h. At the end of the bioassay, the swimming performance and 11 biomarkers were determined. Biomarkers were: hepatosomatic index (HSI), lipid peroxidation (LPO), reduced glutathione and the activities of the enzymes ethoxyresorufin O-deethylase (EROD), glutathione S-transferases, superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, brain acetylcholinesterase (AChE) and muscle cholinesterases (ChE). After 96 h of exposure, carbofuran induced a decrease of the swimming velocity and inhibition of EROD activity at all concentrations tested, and inhibition of muscle ChE and brain AChE activities at 250 μg/L. No relevant alterations in any of the other tested parameters were found. These results show that carbofuran induced adverse effects on fish by interfering with neurofunction, capability of detoxication and swimming velocity. In addition, positive and significant correlations between the swimming velocity and (i) brain AChE activity, (ii) muscle ChE activity and (iii) EROD activity suggest that the inhibition of these enzymes may somehow be related to the behavioural changes observed. Since these functions are determinant for the survival and performance of the fish in the wild, the findings of the present study suggest that adverse effects may occur in populations exposed to carbofuran if a sufficient number of animals is affected.

A total of 23 pesticides from different chemical groups in 160 different domestic vegetables collected from four major big supermarkets located in Al-Qassim region, Saudi Arabia, were identified by gas chromatography with mass spectrometry (GC-MS). Residues were found in 89 of the 160 samples and 53 samples were above the maximum residue levels (MRLs). The most frequently found pesticides were carbaryl followed by biphenyl and then carbofuran. Cabbage was the most positive and violated MLRs (16 and 11 samples), followed by carrot and green pepper (12 and 7 samples), cucumber (12 and 6 samples), egg-plant (12 and 5 samples), squash (11 and 7 samples), lettuce (11 and 6 samples) and tomato (11 and 4 samples). The highest concentrations were found in lettuce (ethiofencarb, 7.648), followed by tomato (tolclofos-methyl, 7.312 mg/kg), cabbage (chlropyrifos, 6.207 mg/kg), carrot (heptanophos, 3.267 mg/kg), green pepper (carbaryl, 2.228 mg/kg) and egg-plant (carbaryl, 1.917 mg/kg). These findings pointed to the following recommendation: the need for a monitoring program for pesticide residues in vegetables cultivated under greenhouse conditions at the national level to protect consumers' health.

To determine the potential risk of pesticides frequently used in Indonesia, a new toxicity test was developed using the indigenous freshwater shrimp Caridina laevis, which is representative of tropical ecosystems. The test species could easily be maintained in the laboratory. Acute toxicity tests with different insecticides, fungicides, and herbicides assessing adult survival after 24 and 96 h of static exposure showed low control mortality (

Direct lethal and sublethal effects of pesticides on farmland birds' populations are recurring questions and largely debated. In this context, we conducted an innovative study combining radiotelemetry, farmer surveys, residue analyses on carcasses and modelling to assess the unintentional effects of pesticides on terrestrial birds. We chose the grey partridge Perdix perdix as a case study because this typical bird of European cereal ecosystems is highly exposed to pesticides. In this paper we focused on acute and short-term impacts of pesticides on adult mortality during spring and summer in a one-substance approach (multiple exposure were not studied here) but for a large variety of active substances (a.s.) actually used in cultivated farmland of Northern France. The fate and the location of 529 partridges were monitored twice a day from early March to late August 2010 and 2011 on 12 sites (14,500 ha). Their daily potential exposure to 183 a.s. was determined by overlapping birds' habitat use and daily pesticide application data. Based on this procedure, we calculated mortality rates within 10 days following a potential exposure for 157 different a.s.. 5 a.s. were associated with a “10-day mortality rate” higher than 10% but a single one (thiacloprid) is reported to be highly toxic to birds. We recorded 261 mortalities among which 94 carcasses were in suitable condition for residue analyses. We detected at least one a.s in 39.4% of carcasses. However, only 2 mortality cases were attributed to poisoning (carbofuran). Furthermore, modelling results showed that these lethal pesticide-related poisonings decreased the population growth rate by less than 1%. In conclusion, we did not point out important direct acute and short-term effects of pesticides currently used by farmers during the breeding season on the grey partridge. This is discussed with regards to the complexity of potential effects in operational conditions.

The interactions of carbon nanotubes with pesticides, such as carbofuran, classical contaminants (e.g., pesticides, polyaromatic hydrocarbons, heavy metals, and dyes) and emerging contaminants, including endocrine disruptors, are critical components of the environmental risks of this important class of carbon-based nanomaterials. In this work, we studied the modulation of acute carbofuran toxicity to the freshwater fish Nile tilapia (Oreochromis niloticus) by nitric acid treated multiwalled carbon nanotubes, termed HNO3-MWCNT. Nitric acid oxidation is a common chemical method employed for the purification, functionalisation and aqueous dispersion of carbon nanotubes. HNO3-MWCNT were not toxic to Nile tilapia at concentrations ranging from 0.1 to 3.0 mg/L for exposure times of up to 96 h. After 24, 48, 72 and 96 h, the LC50 values of carbofuran were 4.0, 3.2, 3.0 and 2.4 mg/mL, respectively. To evaluate the influence of carbofuran-nanotube interactions on ecotoxicity, we exposed the Nile tilapia to different concentrations of carbofuran mixed together with a non-toxic concentration of HNO3-MWCNT (1.0 mg/L). After 24, 48, 72, and 96 h of exposure, the LC50 values of carbofuran plus nanotubes were 3.7, 1.6, 0.7 and 0.5 mg/L, respectively. These results demonstrate that HNO3-MWCNT potentiate the acute toxicity of carbofuran, leading to a more than five-fold increase in the LC50 values. Furthermore, the exposure of Nile tilapia to carbofuran plus nanotubes led to decreases in both oxygen consumption and swimming capacity compared to the control. These findings indicate that carbon nanotubes could act as pesticide carriers affecting fish survival, metabolism and behaviour.

Newly hatched fathead minnow (Pimephales promelas) larvae were exposed for 4 days to two pesticides and ambient receiving waters to simulate conditions in the Sacramento River, California, during the striped bass spawning season which coincides with pesticide use in adjacent rice culture. Carbofuran and molinate were tested at two concentrations: a higher level approximating one-half the LC50 and a level much lower that is similar to that seen in the receiving waters of Colusa Basin Drain. Physiological measurements were made immediately after the exposures and again after a 10-day recovery period in noncontaminated waters. These included growth rate, swimming capacity, response to a mild electric shock, upper and lower lethal temperatures, and activity of acetylcholinesterase in whole-body homogenates. The higher concentrations of carbofuran and molinate caused reductions in swimming capacity, an increased sensitivity to the electric shock, and a reduction in upper lethal temperature. Acetylcholinesterase was reduced in those larvae exposed to the higher levels of carbofuran. In general, the lower levels of pesticide exposure caused no measureable effects nor did exposure to water from Colusa Basin Drain.

The present work aimed to evaluate the toxic effects of two sublethal concentrations of carbofuran pesticide (0.16 and 0.49mg/L, for 35 days) on hematological and blood biochemical parameters of catfish, Clarias gariepinus, and to evaluate the genotoxic potential of carbofuran on the erythrocytes of C. gariepinus for the first time by micronucleus and erythrocyte alteration assays. The results revealed a significant (p0.05) decrease in red blood cells (RBCs) count, haemoglobin (Hb) concentration, haematocrit (Hct) and the mean corpuscular haemoglobin concentration (MCHC) levels, but the mean corpuscular volume (MCV) and the mean corpuscular haemoglobin (MCH) levels were increased. White blood cells (WBCs) count, neutrophils, eosinophils, basophils and monocytes were increased significantly (p0.05), while the lymphocytes were decreased. Also, carbofuran exposure caused a significant (p0.05) increase in aspartic aminotransferase (AST) and alanine aminotransferase (ALT) and a significant (p0.05) decrease in alkaline phosphatase (ALP) activity. The results obtained showed a significant (p0.05) increase in plasma glucose, total lipids, urea and creatinin levels, but the total protein, albumin concentration and globulin levels were decreased (p0.05) significantly and consequently A/G ratio also decreased. Carbofuran caused many genotoxic and morphological alterations in erythrocytes such as formation of micronuclei (MN), echinocytes, acanthocytes, tear like drop cells, microcytes and erythrocytes with vacuolated cytoplasm and pale nucleus. The exposed groups have shown significant variations in frequencies of MN and altered erythrocytes in comparison to control group, and these frequencies increased significantly (p0.05) with the increase of carbofuran concentration. Therefore, current results present a clear evidence of the response of C. gariepinus to carbofuran and allow us to consider that C. gariepinus as a good bioindicator to reflect the toxicity and the genotoxic potential of carbofuran that might be released into the aquatic ecosystems.

Blood plasma cholinesterase (ChE) activity is a sensitive biomarker of exposure to organophosphorus (OP) and carbamate (CB) insecticides in vertebrates. Several studies indicate that more than one ChE form may be present in blood of birds. In this study the predominant ChE activity (acetylcholinesterase – AChE– or butyrylcholinesterase – BChE–), the range of ChE activity as well as ChE age-dependent changes in non-exposed individuals of White stork ( Ciconia ciconia ) have been established. The in vitro sensitivity of ChE to OP and CB insecticides such as paraoxon-methyl, carbofuran and carbaryl was also investigated. Plasma ChE was characterised using three substrates (acetylthiocholine iodide, propionylthiocholine iodide, and S-butyrylthiocholine iodide) and three ChE inhibitors (eserine sulphate, BW284C51 and iso-OMPA). The results indicated that propionylthiocholine was the preferred substrate by plasma cholinesterase followed by acetylcholine and butyrylcholine and the predominant enzymatic activity in plasma of White storks was BChE. Normal plasma BChE activity in White stork was 0.32±0.01 μmol/min/ml for adults and 0.28±0.03 μmol/min/ml for juveniles. So, the age had no significant effect on the range of BChE activity. The study on the in vitro inhibitory potential of tested anticholinesterase pesticides on plasma ChE activity revealed that paraoxon-methyl is the most potent inhibitor followed by carbofuran and finally by carbaryl. The percentage of in vitro plasma ChE inhibition was observed to be similar between adults and juveniles.

Studies were conducted in the laboratory to determine the influence of sublethal doses of pesticides on the respiration of earthworms. Three different lumbricids were exposed to different concentrations of terbuthylazine and carbofuran for up to 12 weeks by allowing them to feed on contaminated plant material. After different exposure periods the CO2 output of the worms was determined by gas chromatography. High terbuthylazine concentrations generally increased CO2 production, whereas the low concentration tended to decrease it, especially in two of the three species studied. Low carbofuran concentration increased the CO2 expired in all the species; the high dose negatively affected the respiration in Lumbricus terrestris and L. rubellus after 3 weeks and in Eisenia andrei after 4 weeks of exposure.

The effects of exchangeable cations (H+ and Na+), autoclaving, organic matter, cationic and anionic surfactants, and temperature on the adsorption of carbofuran on two different types of soils were studied. The adsorption isotherms for all effects/treatments were in close agreement with the Freundlich equation and yielded S-shaped isotherms. The amount of carbofuran adsorbed in all cases was higher in Jhansi red loam soil than in Pilibhit sandy loam soil and was related to organic matter content, clay content, CaCO3 content, surface area, and cation-exchange capacity of the soils. The adsorption on soils from both sites follows the order H soil--Na soil--natural soil at 25 degrees C--autoclaved soil--soil from which organic matter had been removed--cationic surfactant--anionic surfactant--natural soil at 50 degrees C and was in accordance with Freundlich constant K values and distribution coefficient Kd values. The adsorptive capacity of carbofuran for organic matter and clay content for both the Jhansi and the Pilibhit soils was also evaluated by calculating Kom and Kc values, and it was found that the carbofuran adsorption was better correlated with clay content than with organic matter content of soils. On the basis of adsorption isotherms, various thermodynamic parameters such as the thermodynamic equilibrium constant Ko, standard free energy (delta G zero) changes standard ethalpy (delta H zero) changes, and standard entropy (delta S zero) changes have been calculated in order to predict the nature of isotherms.

This work intends to implement the use of native soil nematode communities in ecotoxicological tests using a model pesticide and two geographically nematode communities (Mediterranean and sub-tropical) in order to obtain new perspectives on the evaluation of the toxic potential of chemical substances. The environmental condition of the nematode communities was described using a trait-based approach (grouping the organisms according to their feeding traits) and a traditional taxonomic method (identification to family level). Effects on total nematode abundance, number of families and abundance of nematode feeding groups as well as potential shifts in both trophic and family structure were assessed. Agricultural soils from Curitiba (Brazil) and Coimbra (Portugal) were sampled and the corresponding nematode communities were extracted. Part of the collected soil was defaunated and spiked with four doses of a carbofuran commercial formulation. Afterwards each of the replicates was inoculated with a nematode suspension containing ≈200 or 300 nematodes. After 14 and 28 d of exposure the nematodes were extracted, counted and identified at family level and separately classified according to their feeding traits. The patterns of nematode responses revealed a decrease in the total abundance and a reduction in the number of families. Despite the similar effects observed for both communities, statistically significant toxic effects were only found within the Portuguese community. The total nematode abundance was significantly reduced at the highest carbofuran concentrations and significant shifts in the family structure were detected. However, the trophic structure, i.e., the contribution of each feeding group for the overall community structure, did not significantly change along the contamination gradient. Results showed that using such a trait-based approach may increase the ecological relevance of toxicity data, by establishing communalities in the response to a chemical from two different taxonomic communities, although with potential loss of information on biodiversity of the communities. We would like to thank FTC for funding, Arlei Macedo (UFPR, Brazil) for the methodological and bibliographic support, Cintia Niva (Embrapa Florestas, Brazil) for helping in the soil sampling and Carla Maleita (IMAR-CMA, Portugal) for the logistic support and for facilitating the soil sampling in Portugal. published

The aim of present study was to assess pesticide residues in vegetables in the Hyderabad region of Pakistan. The concentrations of six pesticides were determined by gas chromatography coupled with mass selective detector (GC-MSD) in locally produced vegetables purchased from wholesale markets. A total of 200 samples of eight vegetables viz. cauliflower, green chilli, eggplant, tomato, peas, bitter gourd, spinach and apple gourd were analyzed for pesticide residues. The results indicated that almost all samples were contained pesticides, only 39% contained pesticide residues at or below maximum residue limits (MRLs), and 61% contained pesticide residues above MRLs. From the six analyzed pesticides, carbofuran and chlorpyrifos were found above to MRLs with concentrations ranging from 0.01-0.39 and 0.05-0.96 mg/kg, respectively. The results provided important information on the current pesticide contamination status of some commonly used vegetables and pointed an urgent need to control the use of some excessively applied and potentially persistent pesticides, such as carbofuran and chlorpyrifos.

Sublethal effects of cypermethrin and carbofuran on hematological parameters and their complete recovery were studied in Labeo rohita as a function of exposure time. Exposure of Labeo rohita to sublethal levels of cypermethrin and carbofuran resulted in significantly (P0.05) lower values for erythrocyte count (RBC), hemoglobin content (Hb), and hematocrit compared with the control group. In contrast, there was a significant increase (P0.05) in leukocyte count (TLC) in the pesticide-treated group. Mean cell volume (MCV) and mean cell hemoglobin (MCH) increased in response to both pesticides during the study. The rate of recovery or extrapolation time between Days 0 and 28 of the recovery period revealed that RBC completely recovered from cypermethrin toxicity on Days 80, 86.6, and 90 and TLC recovered on Days 60, 62.7, and 63.3 in fish exposed to 0.16, 0.40, and 0.80 microL/L cypermethrin, respectively. In the case of carbofuran toxicity, the complete recovery for RBC was on Days 100, 101.5, and 102, and for TLC, on Days 77, 77.6, and 79.3 in fish exposed to 0.06, 0.15, and 0.30 mg/L carbofuran, respectively. TLC recovered faster than RBC. RBC and TLC of fish exposed to carbofuran took more time to complete recovery than RBC and TLC in fish exposed to cypermethrin.

Juvenile goldfish (Carassius auratus) were exposed to three widely used pesticides; carbofuran, diuron, and nicosulfuron. Acetylcholinesterase (AChE) activity and molecular forms of AChE were first characterized in brain and skeletal muscle of unexposed fish. Skeletal muscle had higher AChE activity than brain (306 and 215 nmol/min/mg protein, respectively). In brain, four molecular forms of AChE were found: A12, G4, G2, and G1. In the muscle, three molecular forms were found A12, A8, and G2. AChE activity was then evaluated in both tissues of fish exposed to different concentration of pesticides (5, 50, and 500 microg/L) for 6, 12, 24, and 48 h. In brain, AChE activity was significantly inhibited during all the periods of exposure in response to 50 microg/L (19-28%) and 500 microg/L (85-87%) carbofuran. Such effect was observed in the muscle only at 500 microg/L (86-92%). Carbofuran had no effect on the distribution of molecular forms. Significant inhibitions (9-12%) of brain AChE activity were also observed in response to diuron and nicosulfuron at 500 microg/L during all periods of exposure and for 50 microg/L nicosulfuron after 24 and 48 h. This study pointed out short-term effects of exposure to sublethal concentrations of the three pesticides, ranging among different chemical families, on brain and muscle AChE in goldfish.

The differential inhibition of acetylcholinesterase (AChE) by organophosphate (OP) and carbamate (C) is followed by the distinct duration of exposure effect on common carp AChE. Hence, in the present study in vivo exposure period effect and in vitro concentration-response of chlorfenvinphos, chlorpyrifos diazinon, and carbofuran were investigated on Cyprinus carpio L. AChE. Individuals of 1-year-old carp were exposed for 96 h to different concentrations of insecticides, after which AChE activity was measured in the brain. The highest concentrations of carbofuran (2.44 mg x L(-1)), chlorfenvinphos (2.9 mg x L(-1)), and diazinon (2.5 mg x L(-1)) killed all the test animals after only 4 h, although there was no statistically significant difference from the control group's brain AChE activity. The lowest concentration significantly inhibited brain AChE after 96 h. Chlorfenvinphos was the most potent inhibitor in vivo and chlorpyrifos the least active inhibitor after 96 h of exposure time. In vitro experimentation with the same pesticide indicated that several concentrations inhibited 50% of the AChE activity (I50), ranging from 4.1x10(-7) to 8.12x10(-4) M in both single inhibitory action and joint inhibitory effect. The results suggest that in biomonitoring programs carp brain AChE can be a good diagnostic tool for chronic OP nd C pollution.

Assessment of the influence of carbofuran on the nontarget cyanobacterium Anabaena doliolum revealed that this sheathless heterocystous form of cyanobacteria was more sensitive to the insecticide carbofuran. Anabaena doliolum was initially able to utilize low concentrations of carbofuran, whereas higher concentrations and the subsequent formation of hydrolytic breakdown products were toxic. Growth inhibition reached more than 50% by treatment with 80 and 100 ppm of the insecticide. Nitrogenase activity of the cyanobacterium was reduced by 38% after 48 h by treatment with 100 ppm carbofuran with no observed change in heterocyst frequency. Toxicity of the insecticide was the highest at pH 4-6 (46-59%) and the lowest at pH 7-10 (12-27%) due to the persistence of carbofuran and the resulting alkaline-catalyzed hydrolysis associated with the water regime of the rice fields. Doubling the initial population level of the cyanobacterium reduced the toxicity of the insecticide.

The possible contamination of groundwater by the insecticide carbofuran was assessed with the behavior assessment model (BAM) and groundwater pollution-potential model (GWP). Dissipation coefficients of this insecticide in two subtropical soils at different moisture contents and soil temperatures were studied by determining the degradation and adsorption of the herbicide in soils. Movement of carbofuran was studied by leaching the insecticide in a soil column in the laboratory. Under 40% field capacity and at 25 degrees C, more than 80% of carbofuran residue was found in both Luchu clay and Yuanlin silty clay loam after incubation for 63 days. The results indicate that the higher the moisture content in the soil, the less the carbofuran residue under the soil moisture below the field capacity. Carbofuran tends to dissipate more easily in Yuanlin soil than in Luchu soil. The distribution coefficient (Kd) with r2 of 0.69 and 0.92 for Luchu and Yuanlin soils, respectively, was found using the first-order kinetics law. In leaching experiment, carbofuran exhibited easier movement in Luchu than in Yuanlin soil.

There is now much information on the presence of pesticides in surface waters, but very little about their actual effects on aquatic life. This paper reports on the transient concentrations of a carbamate insecticide carbofuran, which were observed in a head-water stream draining treated farmland, and describes the resulting effects on a bioassay organism. One month after an application of 3 kg carbofuran/ha as broadcast granules to an oilseed rape crop, carbofuran concentrations of up to 26 micrograms/liter were measured in a nearby headwater stream after heavy rainfall. The majority of the carbofuran was translocated via field drains (where concentrations up to 264 micrograms/liter were detected), although the possibility of some surface runoff cannot be ruled out. Peak carbofuran concentrations only persisted for about 24 hr after the rainfall event, although measurable levels could be detected for at least 4 days. An in situ bioassay of streamwater which monitored the feeding rate of the gammarid amphipod crustacean Gammarus pulex showed that feeding stopped completely during the rainfall event, and was rapidly followed by death of all the caged organisms. Subsequent laboratory studies of toxicity showed that the peak concentrations of carbofuran had exceeded the G. pulex 24-hr LC50 of 21 micrograms/liter, and that concentrations as low as 4 micrograms/liter could reduce feeding rate. These findings are discussed with reference to regulatory risk evaluation procedures.

To investigate whether results of laboratory toxicity tests with earthworms are capable of being used to predict effects in the field, a literature study was carried out. Benomyl, its metabolite carbendazim, carbofuran, and carbaryl were chosen as model substances. From data on the behavior of these pesticides in soil, it can be concluded that shortly after application most of the dosage will be in the top 2.5-cm soil layer. Soil concentrations can be estimated from field dosages used. Estimated field soil concentrations that affected earthworm populations were in agreement with effect levels determined in laboratory studies. In the field, species living in the surface layers (e.g., juveniles of many species) or coming to the soil surface to feed (e.g., Lumbricus terrestris) are most affected, since they experience a high degree of exposure. Evidently, species having long generation times need a relatively long time to recover. Both the distribution of the pesticide and the behavior of earthworms in soil affect earthworm exposure. Insight into these aspects may provide tools to predict both short- and long-term effects of pesticides on earthworm populations in field soils.

In vitro inhibition of goat cerebellar acetylcholinesterase by pure and commerical anticholinesterase pesticides clearly indicates a remarkably high inhibitory effect of commerical carbamate and organophosphate pesticides containing a lower percentage of the respective active ingredients comparable to that of the known anticholinesterase agents such as DFP and physostigmine. It may be presumed that injudicious use of commercial formulations conduce severe toxicity in the nontarget mammalian species, namely, goat, and this response of the brain acetylcholinesterase may be utilized as a reliable bioindicator of pesticidal contamination of the terrestrial environment.

Adsorption and movement of carbofuran (a systemic nematicide) were studied using two Indian soils (clay loam and silt loam) of alluvial origin. Equilibrium adsorption coefficient ( K ) values measured using a batch-slurry technique follows the order clay loam >silt loam soil. The distribution coefficients ( K d ) for both the soils in batch adsorption as well as in columns were also calculated. Carbofuran movement in soil columns during water infiltration in both airdried and water-saturated columns was estimated. The order was as anticipated from K and K d values. A larger amount of water was needed for leaching the carbofuran to 152 cm in clay loam soil than in silt loam soil. Carbofuran appears to increase in drier soils and in finer textured soils.

Carbofuran (Curater 5G) behavior was studied in two drained cornfield soils, clay and loamyclay, for 2 successive years. Different dissipations were observed in each soil for the same time period (8 weeks in 1985, 9 weeks in 1986). The authors found drained water from organic matter-rich soil to possess a higher carbofuran content, with 7.1–13.7 and 2.5–5.0% of the applied dose for clay and loamy-clay soils, respectively. The major part of these percentages arose from the drained waters associated with rainfall occurring during the first 2–3 weeks after application. Laboratory experiments confirmed the influence of the soil structure and its properties on carbofuran adsorption, and consequently on carbofuran leaching under field conditions.

The adsorption thermodynamics of carbofuran has been studied on antimony (V) silicate cation exchanger at 30 and 50 degrees C. The adsorption isotherms of carbofuran have been found to follow the Freundlich adsorption model and yield "S" class isotherms. The order of adsorption of carbofuran is in accordance with the partial molal free-energy changes in the exchanger. The thermodynamic equilibrium constant (K0), standard free energy (delta G degrees), enthalpy (delta H degrees), and entropy (delta S degrees) changes have also been calculated for predicting the nature of adsorption.

The effect of safe application rate (SAR) concentrations of fenitrothion 50% EC—an organophosphate and carbofuran 3% G—a carbamate on the gonads (ovaries/testes) of Channa punctatus was studied for 120 days (mid-April through mid-August) extending over the preparatory, prespawning, and spawning phases of annual reproductive cycle. The studies have revealed that the levels of total proteins, RNA, total lipids, and ascorbic acid decreased, while those of the cholesterol and the phospholipids increased following exposure to the two biocides. Furthermore, it was observed that in both treatments the decline in the levels of total proteins, RNA, total lipids, and ascorbic acid was relatively more marked in the testes than in the ovaries. On the contrary, increase in the levels of cholesterol was relatively more in the ovaries, while increase in the levels of phospholipids was more in the testes in both treatments. The results suggest that the decrease/increase in the levels of the above-mentioned biochemical parameters was more in the fenitrothion treatment than in the carbofuran treatment and, therefore, may be considered relatively more toxic to this species.

The long-term toxic effects of continuous exposure for 6 months, from January to June, to a safe dose (4.5 ppm) of a commercial carbamate pesticide, carbofuran, on the histophysiology of thyroid in adult and young (yearling) Channa punctatus, are described in this investigation. In both the experimental groups, thyroid histology exhibited various abnormalities, including hypertrophy, hyperplasia and degeneration of follicular epithelial cells, and reduction in colloid content. Apart from this, in young experimentals, fibrosis of thyroid components, formation of cystic cellular masses, and rupture of blood vessels resulting in hemorrhage can also be seen and suggest direct action of this pesticide on the thyroid. On the other hand, in both treated groups, retardation of thyroid function was also evidenced by significantly reduced thyroidal radioiodine (/sup 131/I) uptake and CR (conversion ratio of PB/sup 131/I in blood serum in relation to total serum /sup 131/I uptake) values. Apparently, these histopathological and physiological changes were markedly pronounced in young experimentals, suggesting greater susceptibility of this group to chronic toxicity of carbofuran than that of adults. Thus, on the basis of these results, it can be inferred that carbofuran pesticide, which is washed into water systems in small quantities, induces adverse histophysiological alterationsmore » in thyroid, in an age- and size-dependent manner, possibly by acting directly on thyroid and/or through the hypothalamo-pituitary-thyroid axis, in this species.« less

The effects of safe concentrations of carbofuran 3% G (5 ppm) and fenitrothion 30% E.C. (1.5 ppm) on ovarian recrudescence of Channa punctatus during the maturing, prespawning, and spawning phases (mid-April through mid-August) of the annual reproduction cycle were studied. The results reveal that, compared to carbofuran treatment, fenitrothion was more effective not only in lowering ovarian weights, but also in retarding the growth of previtellogenic (stage I) oocytes into vitellogenic (stage II) and yolky (stage III) oocytes. In addition, more previtellogenic and vitellogenic oocytes underwent atresia in fenitrothion-treated fish and only atretic oocytes were observed in the ovaries of these fish after 120 days of exposure. The fenitrothion treatment also caused a significant decline in the diameter of stage III oocytes, and in the number of nucleoli in stage I oocytes.

The effects of safe concentrations of fenitrothion 50% E.C., an organophosphate, and carbofuran 3% G, a carbamate, on testicular recrudescence of Channa punctatus during the maturing, prespawning, and spawning phases (15th April through 12th August, 1980) of the annual reproductive cycle have been studied. The results reveal that compared to the carbofuran treatment, the fenitrothion treatment was more effective in lowering testicular weights. Furthermore, the carbofuran treatment delayed the formation of spermatids and sperm, since their occurrence in the testes was observed at 90 days of exposure, but at 60 days of exposure in the control fish. The fenitrothion treatment not only delayed the formation of spermatids, but also arrested the formation of sperm, since most of the spermatids had undergone necrosis. The exposure for 120 days to safe concentrations of carbofuran/fenitrothion also resulted in the necrosis of spermatogonia and spermatocytes, which led to their gradual loss. As such, the lobules completely devoid of the spermatogenetic stages were observed in the testes of the treated fish. The occurrence of such empty lobules, however, was relatively greater in the fenitrothion-treated fish. The formation of the collagenous capsules around the necrotic germ cells was also observed in the treated fish testes. The interstitial (Leydig) cells were in the involuted condition in the treated fish testes, but active in the control fish.

The adsorption of carbofuran on hydrogen, sodium, and calcium saturated soils has been studied at 25 and 50 degrees C. The adsorption data for all types of soils is in close agreement with Freundlich isotherms and yielded S-class isotherms. The maximum adsorption was observed in acid saturated soil. Therefore, it has been in accordance with the partial molal free energy changes (F) and Kd values. The adsorption has been lower at higher temperatures. The thermodynamic constant (KO), standard free energies (delta G degree), enthalpies (delta H degree), and entropy changes (delta S degree) have been calculated for predicting the nature of adsorption.

The acute toxicities of 13 granular anticholinesterase insecticides were compared with their technical grade active ingredients by administering single oral doses of chemical to adult Northern bobwhites ( Colinus virginianus ) and evaluating resultant LD 50 values and doseresponse curves. Similar tests with ringed turtledoves ( Streptopelia risoria ) were conducted with five of the granular formulations to check for interspecific differences. The test chemicals were Amaze 15G (isofenphos), Counter 15G (terbufos), Dasanit 15G (fensulfothion), Diazinon 14G (diazinon), Di-Syston 15G (disulfoton), Dyfonate 20G (fonofos), Furadan 10G (carbofuran), Lorsban 15G (chlorpyrifos), Nemacur 15G (fenamiphos), Parathion 10G (parathion), Tattoo 10G (bendiocarb), Temik 15G (aldicarb), and Thimet 15G (phorate). Information is also presented on dose-response relations and their use in hazard assessment, granule size and hazard, response patterns, and toxic signs. The general conclusions were: (1) The organophosphates (fenamiphos and fensulfothion) and the carbamate (aldicarb) were the most toxic of the insecticides tested. (2) The granular formulation and its technical grade active ingredient were of equivalent toxicity, or the granular was significantly less toxic. (3) The dose-response curve enhances hazard assessment. (4) Ingestion of a single granule of Temik 15G was shown to be life threatening to bobwhite-sized birds, and ingestion of fewer than five granules could be lethal to sparrow-sized birds for Dasanit 15G, Diazinon 14G, Dyfonate 20G, Furadan 15G, and Nemacur 15G. (5) It is therefore suggested that the hazard associated with granular insecticides may be more dependent on which species (cf. size and feeding behavior) inhabit a treated area than on the actual application rate.

The adsorption of carbofuran on sandy clay loam and silt loam soils has been studied at 30 and 50 degrees C. Adsorption data for both soils are in close agreement with the Freundlich isotherms and yield "S" class isotherms. The order of adsorption of carbofuran is in accordance with the partial molal free energy changes and conforms to the mobility of carbofuran in different soils. The thermodynamic constant (K0) and standard free energy (delta G degrees), enthalpy (delta H degrees), and entropy changes (delta S degrees) have also been calculated for predicting the nature of adsorption.

Fingerlings of Labeo rohita, Catla catla, and Cirrhinus mrigala were exposed to selected doses of four commonly used pesticides carbofuran, DDT, dimethoate, and Meta-Systox for a period up to 30 days to determine relative toxicological effects, LC50 values for 96 hr, maximum acceptable tolerant concentration, and application factor. The use of early life history tests has been emphasized for toxicological assessments.