Modelling the effect of season, sex, and body size on the three-spined stickleback, Gasterosteus aculeatus, cellular innate immunomarkers: A proposition of laboratory reference ranges

Innate immunomarkers reflect both environmental contamination and fish health status, providing useful information in environmental risk assessment studies. Nevertheless, the lack of knowledge about the effect of confounding factors can lead to data misinterpretation and false diagnoses. The aim of this study was to evaluate the impact of three confounding factors (season, sex and body size) on three-spined stickleback innate immunomarkers in laboratory conditions. Results shown strong seasonal variations in stickleback innate immunomarkers, with higher immune capacities in late winter-early spring and a disturbance during the spawning period in late spring-summer. Sex and body size had a season dependant effect on almost all tested immunomarkers. Reference ranges were established in laboratory-controlled conditions (i.e. laboratory reference ranges) and compared with data obtained from in vivo chemical expositions. The predictive power of the statistical model depended on the immunomarker, but the control data of the in vivo experiments, realized in same laboratory conditions, were globally well include in the laboratory reference ranges. Moreover, some statistical effects of the in vivo exposures were correlated with an augmentation of values outside the reference ranges, indicating a possible harmful effect for the organisms. As confounding factors influence is a major limit to integrate immunomarkers in biomonitoring programs, modelling their influence on studied parameter may help to better evaluated environmental contaminations.

Endosulfan induces cell dysfunction through cycle arrest resulting from DNA damage and DNA damage response signaling pathways

Our previous study showed that endosulfan increases the risk of cardiovascular disease. To identify toxic mechanism of endosulfan, we conducted an animal study for which 32 male Wistar rats were randomly and equally divided into four groups: Control group (corn oil only) and three treatment groups (1, 5 and 10mgkg^-1·d^-1). The results showed that exposure to endosulfan resulted in injury of cardiac tissue with impaired mitochondria integrity and elevated 8-OHdG expression in myocardial cells. Moreover, endosulfan increased the expressions of Fas, FasL, Caspase-8, Cleaved Caspase-8, Caspase-3 and Cleaved Caspase-3 in cardiac tissue. In vitro, human umbilical vein endothelial cells (HUVECs) were treated with different concentrations of endosulfan (1, 6 and 12μgmL^-1) for 24h. An inhibitor for Ataxia Telangiectasia Mutated Protein (ATM) (Ku-55933, 10μM) was added in 12μgmL^-1 group for 2h before exposure to endosulfan. Results showed that endosulfan induced DNA damage and activated DNA damage response signaling pathway (ATM/Chk2 and ATR/Chk1) and consequent cell cycle checkpoint. Furthermore, endosulfan promoted the cell apoptosis through death receptor pathway resulting from oxidative stress. The results provide a new insight for mechanism of endosulfan-induced cardiovascular toxicity which will be helpful in future prevention of cardiovascular diseases induced by endosulfan.

Endosulfan affects uterine development and functional differentiation by disrupting Wnt7a and β-catenin expression in rats

Neonatal exposure to a low dose of endosulfan may disrupt the expression of Wnt7a and β-catenin during uterine development leading to the failure of uterine functional differentiation during implantation. New-born female Wistar rats were treated with vehicle, endosulfan (600 μg/kg/d, E600) or diethylstilbestrol (0.2 μg/kg/d, DES) on postnatal days (PNDs) 1, 3, 5 and 7. Subsequently, uterine histomorphology and the protein expression of Wnt7a and β-catenin were evaluated on PND8, PND21 and gestational day (GD) 5 (pre-implantation period). In the E600 rats, Wnt7a and β-catenin protein expression was increased in the epithelium on PND8, and Wnt7a expression was decreased in the endometrial glands on PND21. On GD5, the number of uterine glands was decreased in the E600-and DES-treated rats. In addition, Wnt7a expression was decreased in all uterine compartments, and β-catenin expression was increased in the luminal and glandular epithelia of the E600-and DES-treated rats. Disruption of Wnt7a and β-catenin uterine expression in the prepubertal and adult females altered the uterine preparation for embryo implantation, which could be associated with the subfertility triggered by endosulfan.

Pesticide residues in human breast milk: risk assessment for infants from Punjab, India

Punjab state in India is an agrarian society, where agriculture is the lifeline of farming community. To keep pace with increasing demands of food for growing population the indiscriminate use of pesticides has led to the contamination of environment and food commodities in this region. Analysis of human breast milk samples (n=53) for pesticide residues revealed the presence of β-, γ-HCH, p,p' DDD, p,p' DDE, p,p' DDT and endrin with mean concentration of 97.9, 101.7, 239.8, 1574.1, 100.3 and 90.7 ng g(-1) lipid wt., respectively. In addition, occurrence of β-endosulfan, endosulfan sulphate, cypermethrin and chlorpyrifos in this study have also been reported for the first time in human breast milk in Punjab, India. With increase in parity, HCH and DDT residue burden in donor's milk decreased. Although levels of HCH and DDT residues in breast milk samples have decreased significantly, yet estimated daily intake values for DDT are higher than the FAO/WHO permissible tolerable daily intake values for few infants.

Endosulfan and flutamide, alone and in combination, target ovarian growth in juvenile catfish, Clarias batrachus

Juvenile Catfish(es), Clarias batrachus of 50 days post hatch (dph) were exposed to endosulfan (2.5 parts per billion [ppb]) and flutamide (33 ppb), alone and in combination for 50 days to access their impact on ovarian development. The doses used in this study were nominal considering pervious reports. Sampling was done at 100 dph to perform histology and measurement of various transcripts, estradiol-17β and aromatase activity. In general, treatments enhanced expression of ovary-specific transcription factors, steroidogenic enzymes steroidogenic acute regulatory protein and aromatases while transcripts of tryptophan hydroxylase2 (tph2) and catfish gonadotropin-releasing hormone declined in the brain of all treated groups with maximum reduction in the endosulfan group. Significant reduction of tph2 immunoreactivity in the forebrain/telencephalon-preoptic area endorsed our results. Increased number of pre-vitellogenic and less immature oocytes in the treated groups indicated hastened ovarian growth. Elevated ovarian aromatase activity and plasma estradiol-17β levels were noticed in the treated groups with maximum being in the endosulfan group. These data together demonstrate that the exposure of endosulfan causes synchronous precocious ovarian development better than flutamide, alone or in combination. Our results suggest that both endosulfan and flutamide alter ovarian growth by triggering precocious development in catfish.

Pesticide risk assessment in flower greenhouses in Argentina: the importance of manipulating concentrated products

An evaluation of the Potential Dermal Exposure of workers to endosulfan and procymidone at the mix/load and application stages was done in small floricultural production units in Argentina. Seven experiments were performed with different operators under typical greenhouse conditions, based on the whole body dosimetry methodology. These results indicate that the mean Potential Dermal Exposure of the application step was 45.0 ± 55.0 mL h(-1) with the highest proportion on torso, head, arms and hands. When the mix/load and application stages were compared, the first was found to contribute the most to the total exposure. Also, the Margin of Safety for the different operations was calculated, and a pesticide surrogate was developed and used to make comparative evaluations of hand exposure for different groups of operators. These results emphasize the importance of the mix/load stage in the exposure process.

Pesticide use patterns among small-scale farmers: a case study from Phitsanulok, Thailand

In this study, 130 small-scale farmers were surveyed regarding pesticide use patterns in rural Phitsanulok, northern Thailand using a structured questionnaire administered via personal interviews and an observational checklist of farmer pesticide storage practices. The survey was conducted during December 2007-January 2008. The results indicate pesticides are readily available and widely used in crop production. This includes the use of endosulfan which has been banned by the Thai government since 2004. Overall, pesticide use was inappropriate. Farmers did not wear suitable personal protection, apply pesticides in an appropriate fashion, or discard the waste safely. They frequently relied on commercial advertisements for the best pesticide to use. Pesticide use patterns among small-scale farmers in Thailand need improvement. Educational interventions are essential for promoting safety during all phases of pesticide handling. Public policies should be developed to encourage farmers to change their pest management methods from chemical based to methods that are healthier and more environmentally friendly.

Effects of the agricultural pesticides atrazine, chlorothalonil, and endosulfan on South Florida microbial assemblages

One of the most impacted watersheds in the US in terms of pesticide usage is South Florida, which drains through a series of canals into the Florida Everglades and Florida Bay. Single species responses to pesticide exposure are well documented; however, little is known about community level responses to pesticides, especially at lower trophic levels. Microbial assemblages at two sites along the C-111 canal in the Dade County agricultural area in October 1999 (wet season, limited pesticide application) and in February 2000 (dry season, heavy pesticide application) were colonized onto artificial substrates, transported to the laboratory and exposed to atrazine (20 and 200 microg/l), chlorothalonil (2 and 20 microg/l), or endosulfan (1 and 10 microg/l). Structural and functional responses were measured at 24 h and 168 h post-dose. Regardless of site, season or exposure time, the highest atrazine dose (200 microg/l) significantly reduced chlorophyll a, phototrophic carbon assimilation and bacterial biomass, but stimulated heterotrophic bacterial productivity. Chlorophyll a was also significantly reduced by 20 microg/l atrazine (October only). The lowest endosulfan dose (1 microg/l) significantly increased phototrophic carbon assimilation. The highest chlorothalonil dose (20 microg/l) stimulated heterotrophic bacterial productivity (October only). An overall decrease in the number of protist taxa was observed with all pesticide treatments. Atrazine significantly decreased the relative abundance of chlorophytes and chrysophytes and increased the number of diatom and heterotrophic protist taxa. Chlorothalonil significantly increased the relative abundance of diatoms and chlorophytes, while chrysophytes and heterotrophic protists decreased. Endosulfan also significantly reduced diatom abundance, as well as decreasing the number of chrysophyte, cryptophyte and dinoflagellate taxa. Although previous agricultural pesticide exposure was greater at site C than at site E, the microbial assemblages at site C did not exhibit increased resistance to a subsequent dose of the pesticides.

Developmental, behavioral, and reproductive effects experienced by Japanese medaka (Oryzias latipes) in response to short-term exposure to endosulfan

Japanese medaka (Oryzias latipes) were exposed to concentrations of 0.01, 0.10, and 1.0 microg/L of the pesticide endosulfan for 24h beginning either 4-6h postfertilization or 4-6h posthatch to determine effects on hatching time, growth, mobility, foraging ability, and reproduction. Eggs exposed to endosulfan took longer to hatch, and the resulting fry were smaller at 1 week of age and had decreased mobility at 2 weeks of age. Upon reaching sexual maturity, these individuals also produced fewer eggs, and these eggs took significantly longer to hatch. Medaka exposed to endosulfan shortly after hatching did not differ in early mobility or foraging ability. Interestingly, upon reaching sexual maturity, these individuals produced more eggs than did unexposed females. The observed effects were not dose-dependent, with medaka exposed to intermediate concentrations of endosulfan (0.10 microg/L) exhibiting the greatest response. These results suggest that short-term exposure to environmentally relevant concentrations of a common pesticide may have long-term effects on growth, behavior, and reproduction in fish.

Feed utilisation and growth in juveniles of Labeo rohita under the stress of endosulfan

The objective of the present study is to evaluate the nutrition and growth of Labeo rohita under the sublethal stress of endosulfan. It has been observed that the feed utilisation and growth were inferior in the fish under the stress of the toxicant. It was more so in the test fish under the influence of higher sublethal concentration. The food conversion ratio was higher suggesting that the nutrients are wasted.

A pulse of endosulfan-contaminated sediment affects macroinvertebrates in artificial streams

The toxicity of the organochlorine pesticide endosulfan to macroinvertebrate communities was tested using a system of 24 artificial streams. Macroinvertebrate communities in the streams were exposed to a range of endosulfan concentrations for a 12-h period and then monitored for 96 h. Endosulfan was prebound to fine river sediment and applied to the streams as a contaminated sediment slurry. This did not cause changes in the structure of benthic communities; however, significant changes (P<0.05) in the abundance of several macroinvertebrate taxa in drift were detected in the streams receiving the highest (6.14 microg/L) dose. Increased drift may have implications for recolonization processes in lowland rivers, and, as such, pulses of contaminated sediment are likely to result in significant effects on macroinvertebrate populations and communities. This study highlights the utility of artificial stream systems for detecting sublethal effects and the need for population and community-level endpoints to be included in such studies.

Endosulfan exposure disrupts pheromonal systems in the red-spotted newt: a mechanism for subtle effects of environmental chemicals

Because chemicals introduced into the environment by humans can affect both long-term survivorship and reproduction of amphibians, discovering the specific mechanisms through which these chemicals act may facilitate the development of plans for amphibian conservation. We investigated the amphibian pheromonal system as a potential target of common environmental chemicals. By treating female red-spotted newts, Notophthalmus viridescens, to a commonly used insecticide, endosulfan, we found that the pheromonal system is highly susceptible to low-concentration exposure. The impairment of the pheromonal system directly led to disrupted mate choice and lowered mating success. There were no other notable physiologic or behavioral changes demonstrated by the animals at the insecticide concentrations administered. Our findings suggest that the amphibian pheromonal system is one of the systems subject to subtle negative effects of environmental chemicals.

Exposure to endosulfan in farmers: two case studies

BACKGROUND

Endosulfan is not a restricted use organochlorine insecticide and is currently under re-registration review. In 1993, one confirmed case and one possible case of endosulfan poisoning in agricultural workers occurred in two southeastern states.

METHODS

Two cases of suspected endosulfan poisoning were investigated utilizing record reviews, blood samples, a site visit, and clothing analysis.

RESULTS

Case 1 was fatal; Case 2 resulted in permanent neurological impairment. Additionally, Case 1 mixed and applied two less toxic pesticides, acephate and maleic hydrazide to tobacco plants. Both farm owners had ample opportunity for endosulfan exposure while mixing concentrated endosulfan with water and applying the solution to tobacco with boom sprayers pulled by tractors.

CONCLUSIONS

Estimates of the absorbed dose of endosulfan were not available because methods to determine actual personal exposure that would be found in fat or tissue samples were not used. Health and safety issues associated with endosulfan require a closer examination. A cooperative multi-disciplinary approach to providing timely accurate education is needed to prevent pesticide poisonings.

Spray deposition of two insecticides into surface waters in a South African orchard area

Drift from pesticide spray application can result in contamination of nontarget environments such as surface waters. Azinphos-methyl (AZI) and endosulfan (END) deposition in containers of water was studied in fruit orchards in the Western Cape, South Africa. Additionally, attention was given to the contamination in farm streams, as well as to the resulting contamination of the subsequent main channel (Lourens River) approx. 25 km downstream of the tributary stream inlets. Spray deposit decreased with increasing distance downwind and ranged from 4.7 mg m(-2) within the target area to 0.2 mg m(-2) at 15 m downwind (AZI). Measured in-stream concentrations of both pesticides compared well with theoretical values calculated from deposition data for the respective distances. Furthermore, they were in the range of values predicted by an exposure assessment based on 95th-percentile values for basic drift deposition (German Federal Biological Research Centre for Agriculture and Forestry [BBA] and USEPA). Pesticide deposition in the tributaries was followed by a measurable increase of contamination in the Lourens River. Mortality of midges (Chironomus spp.) exposed for 24 h to samples obtained from the AZI trials decreased with decreasing concentrations (estimated LC50 from field samples = 10 microg L(-1) AZI; lethal distance: LD50 = 13 m). Mortality in the tributary samples averaged 11% (0.5-1.7 microg L(-1) AZI), while no mortality was discernible in the Lourens River samples (0.041 microg L(-1)). The sublethal endpoint failure to form tubes from the glass beads provided was significantly increased at all sites in comparison with the control (analysis of variance [ANOVA], Fisher's protected least significant difference [PLSD], p < 0.01).

Risk assessment in a third-world reality: an endosulfan case history

The author describes the chain of frustrated attempts to regulate the use of the toxic pesticide endosulfan in the Philippines in the face of opposition from its internationally powerful manufacturer. Risk assessment, although purportedly a science-based system to protect public health and the environment, has failed to do so, particularly in vulnerable third-world countries. The precautionary principle, based on preventing risk rather than assessing established risk, holds hope for resolution of the problem.

Acute carbamate and organochlorine toxicity causing convulsions in an agricultural pilot: a case report

Agricultural pilots are involved in a particularly hazardous occupation with a high occupational mortality rate. They face many risks, not least of which is exposure to the agricultural chemicals that they spray. Many accidents and illnesses have been reported previously in the literature, attributable to the acute and chronic effects of chemical exposure, most notably the organophosphate family of insecticides. There are few reports of post-crash exposure to carbamate and organochlorine insecticides. This report documents the case of a professional agricultural pilot who, following an emergency landing, was soaked with Methomyl (a carbamate) and Endosulfan (an organochlorine) leaking from his aircraft. He developed cholinergic symptoms within an hour of the accident, which settled spontaneously, but suffered a tonic-clonic seizure some 6 h later while in the hospital. The seizure was attributed to exposure to the organochlorine, however, subsequent EEG recordings demonstrated a non-specific epileptiform focus in the frontal lobes. The pilot made a full recovery and has remained seizure-free without treatment. The pathophysiology of carbamate and organochlorine poisoning is reviewed, and the differential diagnoses of seizures in this pilot discussed. The difficulty facing a licensing authority in determining the aeromedical disposition of a pilot who has suffered a provoked seizure is also highlighted.

Lack of synergy by mixtures of weakly estrogenic hydroxylated polychlorinated biphenyls and pesticides

We examined the estrogenicity of binary mixtures of the hydroxylated polychlorinated biphenyls (OHPCBs) 2,4,6-trichloro-4'-biphenylol (2,4,6-TCB-4'-OH) and 2,3,4,5-tetrachloro-4'-biphenylol and the pesticides endosulfan and dieldrin. The OHPCBs and pesticides were tested in both the MCF-7 focus assay and a competitive estrogen-receptor binding assay. Although the individual OHPCBs were estrogenic in both assays, there was no synergy when they were combined at various concentrations as equimolar mixtures. Of the pesticides, only endosulfan was estrogenic. Its weak estrogenicity was seen only in the MCF-7 focus assay at the highest concentration tested--10 microM. There was no synergy of the equimolar mixture of pesticides. To determine whether OHPCBs might respond synergistically when combined with the natural estrogen 17-beta-estradiol (E2), we tested various concentrations of 2,4,6-TCB-4'-OH in the MCF-7 focus assay in combination with physiologically relevant concentrations of E2. There was no synergy between 2,4,6-TCB-4'-OH and E2. Pretreatment for 3 or 7 days with 2,4,6-TCB-4'-OH had no effect on subsequent foci induced by a concentration of 2,4,6-TCB-4'-OH and E2. Although our results showing no synergy between the pesticides or the OHPCBs are in contrast to a recent report that binary mixtures of these same compounds produce synergistic responses in estrogen-sensitive assays, they are in agreement with the results from other assays showing a lack of synergy. Considering all results, it appears that synergy of these weakly estrogenic compounds acting through the estrogen receptor is unlikely.

Impact of endosulfan on cytoplasmic and mitochondrial liver malate dehydrogenase from the freshwater catfish (Clarias batrachus)

The impact of a sublethal concentration of an organochlorine pesticide endosulfan on the activity, specific activity, electrophoretic patterns and kinetic properties of crude and purified forms of cytoplasmic malate dehydrogenase (cMDH) and mitochondrial malate dehydrogenase (mMDH) was evaluated in the liver of the freshwater catfish, Clarias batrachus. The endosulfan reduced significantly the activity and the specific activity of cMDH and mMDH, but had no effect on total cytoplasmic and mitochondrial protein contents. The inhibition produced by endosulfan was of mixed non-competitive-uncompetitive type (KiE > KiES) and of mixed competitive-non-competitive type (KiE < KiES) for crude cMDH and mMDH, respectively. The PAGE shows five distinct isoforms (C1 to C5) of cMDH and two isoforms (M1 and M2) of mMDH. The C5-isoform of liver cMDH is predominant and it corresponds to M2-isoform of mMDH. There are no endosulfan-associated differences in the relative charges of crude cMDH and mMDH as well as their purified isoforms, C5-cMDH and M2-mMDH. The relative molecular weights of the purified isoforms are not affected by endosulfan. The purified C5-cMDH and M2-mMDH of endosulfan-treated liver in vivo showed simple non-competitive (KiE = KiES) type of inhibition; whereas in vitro it was of uncompetitive (KiES) and mixed competitive-non-competitive (Ki < KiES) type for the two respective isoforms. G-1-P acts as an uncompetitive (KiES) inhibitor of C5-cMDH and mixed competitive-non-competitive (KiE < KiES) inhibitor of M2-mMDH of the control fish. The inhibitory pattern of G-1-P is modulated by endosulfan in case of C5-cMDH; whereas there is no alteration in case of M2-mMDH. Summarizing, it can be stated that endosulfan exerts an inhibitory effect on crude cMDH and mMDH in vivo, and their purified isoforms (C5-cMDH and M2-mMDH) in vivo as well as in vitro. The impact of endosulfan is mediated through enzyme-substrate-endosulfan (ES-END) complexing for cMDH and enzyme-endosulfan (E-END) complexing for mMDH.

Effects of endosulfan and amitraz on feedlot performance, carcass yield and meat quality characteristics of Nubian goats

The pesticides endosulfan and amitraz were fed to 2 groups of Nubian goats (3 goats/group) at 5 mg/kg/d for 36 d to assess their effects on feedlot performance, carcass yield and meat quality. Growth rates, weight gains and feed conversion efficiencies were depressed insignificantly. The endosulfan-dosed group had significantly lower dressing-out percentage and both groups had significant depletions of omental and mesenteric fats. Significant reductions were also seen on body and cavity fats, the latter being severely reduced suggesting more mobilization of cavity fat than body fat. The fat-free body was homogenous with variations in the muscle/bone ratio reflected on carcass cuts. Meat quality was unaffected. Fat was the only chemical component of endosulfan-dosed total lean significantly reduced. In all parameters the effects of endosulfan were more pronounced than those of amitraz.

The pesticides endosulfan, toxaphene, and dieldrin have estrogenic effects on human estrogen-sensitive cells

Estrogenic pesticides such as DDT and chlordecone generate deleterious reproductive effects. An "in culture" bioassay was used to assess the estrogenicity of several pesticides. The E-screen test uses human breast estrogen-sensitive MCF7 cells and compares the cell yield achieved after 6 days of culture in medium supplemented with 5% charcoal-dextran stripped human serum in the presence (positive control) or absence (negative control) of estradiol and with diverse concentrations of xenobiotics suspected of being estrogenic. Among the organochlorine pesticides tested, toxaphene, dieldrin, and endosulfan had estrogenic properties comparable to those of DDT and chlordecone; the latter are known to be estrogenic in rodent models. The E-screen test also revealed that estrogenic chemicals may act cumulatively; when mixed together they induce estrogenic responses at concentrations lower than those required when each compound is administered alone.

Tissue ATPase activity and recovery in the freshwater crab Oziotelphusa senex senex exposed to a sublethal concentration of endosulfan for varying periods of time

1. Na(+)-K+ and Mg(2+)-tissue ATPases of the freshwater crab Oziotelphusa senex senex showed increasing inhibition when exposed to a sublethal concentration (1.86 mg/l = 0.1 of LC50) of endosulfan for 1-30 days. 2. Na(+)-K(+)-ATPase activity in all tissues (thoracic nerve mass, gill, hepatopancreas and claw muscle) was higher than Mg(2+)-ATPase activity. 3. After 30 days exposure tissue Mg(2+)-ATPase was less affected than Na(+)-K(+)-ATPase. 4. Crabs exposed to endosulfan and then returned to uncontaminated water showed greater recovery of Mg(2+)-ATPase than Na(+)-K(+)-ATPase with 90-95% recovery after 1 day exposure and 60-65% recovery after 30 days exposure. 5. Changes in behaviour of the crabs were noted after 7 days exposure to endosulfan with progressive loss of coordination, decreased activity and increased exudation of mucus.