[Apropos of physiological and biochemical causes of the selective action of the herbicide simazin (4,6-bis(ethylamino)-2-chloro-s-triazine)].
Explore the source record for details and available documents.
Herbicides↗
SEARCH · Search PubMed
Results for “Simazine”
Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Distribution of pesticides and heavy metals in trophic chain.
Determination of triazines herbicides (atrazine and simazine) by high performance liquid chromatography (HPLC) in samples of trophic chain were worked out. Determination limits of 0.5 microg g(-1) for atrazine, 0.8 microg g(-1) for simazine with pesticides recovery of 70-77% in trophic chain samples were obtained. The content of simazine in soils was in range 1.72-57.89 microg g(-1), in grass 5-88 microg g(-1), in milk 2.32-15.29 microg g(-1), in cereals 10.98-387 microg g(-1), in eggs 30.14-59.48 microg g(-1), for fruits: 2.45-6.19 microg g(-1). The content of atrazine in soils was in range 0.69-19.59 microg g(-1), in grass 7.85-23.85 microg g(-1), in cereals 1.88-43.08 microg g(-1). Cadmium, lead and zinc were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES) in the same samples as atrazine and simazine. Determination limits for cadmium 5 x 10(-3) microg g(-1), for lead 1 x 10(-2) microg g(-1), and for zinc 0.2 x 10(-3) microg g(-1), were obtained. The content of cadmium in soil was in range 0.13-5.89 microg g(-1), in grass 114-627.72 x 10(-3) microg g(-1), in milk 8.88-61.88 x 10(-3) microg g(-1), in cereals 0.20-0.31 microg g(-1), in eggs 0.11-0.15 microg g(-1), in fruits 0.23-0.59 microg g(-1). The content of lead in soils was in range 0.57-151.50 microg g(-1), in grass 0.16-136.57 microg g(-1), in milk 1.16-3.74 microg g(-1), in cereals 1.05-5.47 microg g(-1), in eggs 5.79-55.87 microg g(-1), in fruits 21.00-87.36 microg g(-1). Zinc content in soil was in range 9.15-424.5 microg g(-1), in grass 35.20-55.87 microg g(-1), in milk 20.00-34.38 microg g(-1), in cereals 14.94-28.78 microg g(-1), in eggs 15.67-32.01 microg g(-1), in fruits 14.94-18.88 microg g(-1). Described below extraction and mineralization methods for particular trophic chains allowed to determine of atrazine, simazine, cadmium, lead and zinc with good repeatability and precision. Emphasis was focused on liquid-liquid extraction and solid-phase extraction of atrazine and simazine from analysed materials, as well as, on monitoring the content of herbicides and metals in soil and along trophic chain. Higher concentration of pesticides in samples from west region of Poland in comparison to that of east region is likely related to common applying them in Western Europe in relation to East Europe. The content of metals strongly depends on samples origin (industry area, vicinity of motorways).
Animals↗
Differential modulation of catecholamines by chlorotriazine herbicides in pheochromocytoma (PC12) cells in vitro.
Epidemiological, wildlife, and laboratory studies have pointed to the possible adverse health effects of chlorotriazine herbicide (i.e. , atrazine, simazine, and cyanazine) exposure. However, the cellular mechanism(s) of action of these compounds remains unknown. Recently, it was reported by Cooper et al. (2000, Toxicol. Sci. 53, 297-307) that atrazine disrupts ovarian function by altering hypothalamic catecholamine concentrations and subsequently the regulation of luteinizing hormone (LH) and prolactin (PRL) secretion by the pituitary. In this study, we examined the effect of three chlorotriazines on catecholamine metabolism in vitro using PC12 cells. Intracellular norepinephrine (NE) and dopamine (DA) concentrations and spontaneous NE release were measured following treatment with different concentrations of atrazine, simazine (0, 12. 5, 25, 50, 100, and 200 microM) and cyanazine (0, 25, 50, 100, and 400 microM) for 6, 12, 18, 24, and 48 h. Atrazine and simazine significantly decreased intracellular DA concentration in a concentration-dependent manner. Intracellular NE concentration was also significantly decreased by 100 and 200 microM atrazine and 200 microM simazine. Similarly, there was a dose-dependent inhibition of NE release with 100 and 200 microM concentrations of both compounds. Although 100 and 400 microM cyanazine increased intracellular NE concentration, 50, 100, and 400 microM cyanazine significantly increased NE release at 24 and 36 h. In contrast, intracellular DA concentration was decreased by cyanazine, but only at 400 microM. The GABA(A)-receptor agonist, muscimol (0, 0.01, 0.1, and 1.0 microM) had no effect on either the release or on intracellular catecholamine concentrations from 6 through 24 h of treatment. Cell viability was somewhat lower in the groups exposed to 100 and 200 microM atrazine and simazine. However, the reduction in viability was significant only in the highest dose of atrazine used (200 microM) at 24 h. Cyanazine did not have an effect on the viability at any of the doses tested, and the cells were functional, even up to 48 h of exposure. These data indicate that both atrazine and simazine inhibit the cellular synthesis of DA mediated by the tyrosine hydroxylase (TH), and NE mediated by dopamine beta-hydroxylase (DbetaH), and, as a result, there is a partial or significant inhibition of NE release. Cyanazine, on the other hand, stimulated the synthesis of intracellular NE, and not DA. Thus, chlorotriazine compounds presumably act at the enzymatic steps or sites of CA biosynthesis to modulate monoaminergic activity in PC12 cells.
Animals↗
Laboratory study on leachability of five herbicides in South Australian soils.
Norflurazon, oxadiazon, oxyfluorfen, trifluralin and simazine are herbicides widely used in the vineyards of the Barossa Valley, South Australia. The leaching behaviour of norflurazon, oxadiazon, oxyfluorfen and trifluralin was investigated on four key soils in the Barossa Valley. Leaching potential on packed soil columns and actual mobility using intact soil columns were investigated. On the packed soil columns, norflurazon was the most leachable herbicide. More of the herbicides were detected in the leachates from the sandy soils (Mountadam and Nuriootpa) than from the clayey soils (Lyndoch and Tanunda). Organic matter is generally low in soils in the Barossa region. Porosity and saturated conductivity significantly affect herbicide movement and in the sandy Mountadam and Nuriootpa soils, the water flux is greater than for the higher clay content Lyndoch and Tanunda soils. Increasing the time interval between herbicide application and the incidence of "rainfall" reduced the amounts of herbicides found in the leachates. The use of intact soil columns and including simazine for comparison showed that both norflurazon and simazine were present in the leachates. Simazine was the first herbicide to appear in leachates. Sectioning of the intact soil columns after leaching clearly demonstrated that norflurazon and simazine reached the bottom of the soil columns for all soils studied. Greater amounts of norflurazon were retained in the soil columns compared with simazine. The other herbicides were mostly retained in the initial sections of the soil columns.
Environmental Monitoring↗
A micro-immuno supported liquid membrane assay (mu-ISLMA).
A chemiluminescent (CL) based micro-immuno supported liquid membrane assay (mu-ISLMA) has been developed that enables clean up, enrichment and detection of simazine in a single miniaturised cartridge system. The mu-ISLM cartridge contains a supported liquid membrane (SLM) sandwiched between a donor and an acceptor plate (channel volumes 1.65 microL), the latter being covered by a thin layer of gold on to which anti-simazine antibodies were covalently immobilised via a self assembled monolayer (SAM) of either dithiobis(11-aminoundecane, hydrochloride) (DTAU) or beta-mercaptoethylamine (beta-MEA). The mu-ISLMA based on DTAU was characterised by both a high apparent extraction efficiency (E(app) = 136%) and high apparent enrichment factor (E(e)(app) = 544), which resulted in a very high sensitivity for simazine (LOD = 0.1 ng L(-1)). The paper discusses the influence of the different SAMs and three different anti-simazine-antibody preparations (polyclonal, affinity purified polyclonal and monoclonal) on the extraction parameters and assay sensitivity. The influence of the sample matrix (e.g. mineral water, orange juice and milk) on the simazine mu-ISLMA was also investigated.
Biosensing Techniques↗
Leaching and degradation of corn and soybean pesticides in an Oxisol of the Brazilian Cerrados.
Pesticide pollution of ground and surface water is of growing concern in tropical countries. The objective of this pilot study was to evaluate the leaching potential of eight pesticides in a Brazilian Oxisol. In a field experiment near Cuiabá, Mato Grosso, atrazine, chlorpyrifos, lambda-cyhalothrin, endosulfane alpha, metolachlor, monocrotofos, simazine, and trifluraline were applied onto a Typic Haplustox. Dissipation in the topsoil, mobility within the soil profile and leaching of pesticides were studied for a period of 28 days after application. The dissipation half-life of pesticides in the topsoil ranged from 0.9 to 14 d for trifluraline and metolachlor, respectively. Dissipation curves were described by exponential functions for polar pesticides (atrazine, metolachlor, monocrotofos, simazine) and bi-exponential ones for apolar substances (chlorpyrifos, lambda-cyhalothrin, endosulfane alpha, trifluraline). Atrazine, simazine and metolachlor were moderately leached beyond 15 cm soil depth, whereas all other compounds remained within the top 15 cm of the soil. In lysimeter percolates (at 35 cm soil depth), 0.8-2.0% of the applied amounts of atrazine, simazine, and metolachlor were measured within 28 days after application. Of the other compounds less than 0.03% of the applied amounts was detected in the soil water percolates. The relative contamination potentials of pesticides, according to the lysimeter study, were ranked as follows: metolachlor > atrazine = simazine >> monocrotofos > endsulfane alpha > chlorpyrifos > trifluraline > lambda-cyhalothrin. This order of the pesticides was also achieved by ranking them according to their effective sorption coefficient Ke, which is the ratio of Koc to field-dissipation half-life.
Acetamides↗
Effect of temperature on the disappearance of four triazine herbicides in environmental waters.
The influence of temperature on the disappearance of four s-triazine herbicides, terbuthylazine, simazine, atrazine and prometryn was studied in sea, river and groundwaters spiked with approx. 5 mg l(-1) of each during long-term laboratory incubation. Residues were analyzed by GC-NPD and confirmed by GC-MSD. No clean-up was necessary and a micro on-line method for the determination of herbicide residues was used. The results showed that temperature had little effect on the behaviour of the four herbicides in river and seawaters but strongly affected their behaviour in groundwater. Simazine was the most readily affected compound in sea, river and groundwaters, while terbuthylazine and atrazine were the most persistent in all cases, especially in riverwater. Half-lives ranged from 41 days (constant rate = 0.017 days(-1)) to 196 days (constant rate = 0.003 days(-1)) for simazine (40 degrees C) and terbuthylazine (20 degrees C), respectively, in riverwater. Only for terbuthylazine in riverwater was the remaining percentage at the end of the experiment higher than 50% (58%, 3.21 mg l(-1)). In the other cases, the remaining percentage varied from 4% (0.20 mg l(-1), 40 degrees C) to 43% (2.25 mg l(-1), 20 degrees C) for simazine and terbuthylazine, respectively, in groundwater.
Atrazine↗
Use of 15N-depleted artificial compost in bound residue studies.
Association of bound residues to soil humic matter may be accomplished by different binding mechanisms such as sequestration in hydrophobic interiors of the organic material or covalent linkage to the organic matter. The structures and chemical environments of compounds can be observed by NMR spectroscopy. We applied 15N-NMR spectroscopy to study the soil-bound residues of 15N-labeled simazine. As the 15N-isotope has a low sensitivity and natural abundance 15N-NMR experiments require long measurement times and often result in low signal-to-noise (S/N) ratios. Therefore, in addition to the use of 15N-labeled simazine, 15N-depleted compost was used to reduce the amount of background signal and enhance the sensitivity. The compost was produced from maize and wheat plants grown on sand with 15N-depleted NH4NO3 as sole nitrogen source. The plants were freeze-dried, ground and mixed with sand for composting. After a composting period of 224 days analysis of the compost revealed a 15N-content of 267 ppm as opposed to a natural abundance of 3650 ppm. Characterization of this artificial compost produced parameter values similar to those of a natural compost. The 13C-NMR-spectra of the humic and fulvic acids during different stages of maturity showed that there was a shift from single-bond functional groups to more complex double-bond and aromatic structures. Experiments with this compost showed an increased signal intensity. The improved sensitivity made it possible to obtain interpretable NMR signals in contrast to experiments with 15N-simazine on native soil where no signals were detectable. The data indicated that the bound residues of simazine are composed of metabolites resulting from N-dealkylation and triazine ring destruction. Silylation of the bound residues showed a very strong binding of the residues to the matrix as only a small fraction could be solubilized.
Chromatography, Gel↗
Removal of a synthetic organic chemical by PAC-UF systems--I: Theory and modeling.
Based on the age distributions of powdered activated carbon (PAC) in reactors, the competitive bi-solute isotherm and the pore-surface diffusion mechanism, a model was developed to predict the removal of a trace synthetic organic chemical (SOC) when PAC was applied to an ultrafiltration (UF) membrane system. Independent experiments evaluated the input parameters for the model. The pore diffusion in liquid-filled pore was the dominant internal mass transfer mechanism in a PAC particle and the surface diffusion mechanism was neglected in the model. Model prediction was compared with data from pilot plant experiments treating simazine in natural water. Due to the blending and the increasing PAC in the UF loop, a transient behavior of effluent simazine concentration was observed in the UF effluent. The model predicted successfully this periodical variation of the simazine concentration in the UF loop effluent, as well as the simazine concentration in the effluent from the PAC slurry contactor. The faithful model prediction required the modeling of the phenomenon of adsorption/desorption of an SOC on membrane itself.
Adsorption↗
Mineralization, metabolism and formation of non-extractable residues of 14C-labelled organic contaminants during pilot-scale composting of municipal biowaste.
Use of municipal biowaste for composting instead of its disposal has become a major source of concern as regards contamination by hazardous substances. To elucidate the hazard potential of compost application, municipal biowaste was amended with 14C-labelled model substances (pyrene, simazine) and incubated in a pilot-scale composting simulation system. A mass balance incorporating the mineralization, metabolism and sorption of the two model substances was established over a period of 370 days. The results are quite different for the two chemicals, reflecting their intrinsic properties: more than 60% of the applied 14C-simazine resulted in non-extractable residues (NER). Silylation experiments indicated that the formation of NER from simazine and its metabolites was due to both physical entrapment in the matrix and chemical binding. The mineralization and formation of NER represented the major pathways of disappearance for pyrene during one year of composting, accounting for 60 and 26% of initially applied 14C-activity, respectively. Mineralization occurred delayed after the thermophilic phase. As regards remobilization, release of pyrene from NER during composting could be excluded, whereas simazine, data were inconclusive in this respect.
Biodegradation, Environmental↗
The impact of two pesticides on olfactory-mediated endocrine function in mature male Atlantic salmon (Salmo salar L.) parr.
Short-term exposure of the olfactory epithelium of mature male Atlantic salmon parr to either the pesticide simazine (concentrations 1.0 and 2.0 microg l(-1)) or the pesticide atrazine (concentration 1.0 microg l(-1)) significantly reduced the olfactory response to the female priming pheromone, prostaglandin F(2alpha). In addition, the reproductive priming effect of the pheromone on the levels of expressible milt was also reduced after exposure to the individual pesticides (simazine 0.1, 0.5, 1.0 and 2.0 microg l(-1) and atrazine 0.5 and 2.0 microg l(-1)). When the olfactory epithelium was exposed to a mixture of simazine and atrazine, (concentrations of 0.5:0.5 and 1.0:1.0 microg l(-1)), there was no significant reduction in the olfactory response when compared to the single pesticides at equivalent concentrations. In addition, exposure to a mixture of simazine and atrazine had no synergistic effect on the priming response, and plasma levels of testosterone, 11-ketotestosterone and 17,20beta-dihydroxy-4-pregnen-3-one were similar in the groups of male parr exposed to the individual pesticides. Although the levels of expressible milt were reduced in all groups, there were no significant differences between the different pesticide treatments. The results of the study suggest that the two s-triazine pesticides have an additive and not a synergistic impact on olfactory-mediated endocrine function in mature male salmon parr.
Animals↗
Pesticide adsorption by granular activated carbon adsorbers. 2. Effects of pesticide and natural organic matter characteristics on pesticide breakthrough curves.
The principal objective of this study was to elucidate mechanisms by which NOM affects the adsorption of a nonpolar (simazine) and a polar (asulam) herbicide on activated carbon. Experiments were carried out in microcolumns that were continuously fed solutions containing NOM with different molecular weight (MW) distributions and intermittently solutions containing the same NOM plus simazine or asulam. The MW distributions of a groundwater NOM were altered by coagulation and ultrafiltration, which resulted in the preferential removal of high-MW, UV260-absorbing NOM. At a given NOM loading, the simazine removal efficiency was higher in the column that was preloaded with raw groundwater than in columns receiving coagulated or ultrafiltered water. In contrast, the asulam removal efficiency was similar for all three NOM solutions at a given NOM loading. Therefore, the results suggested that low-MW, UV260-absorbing NOM molecules competed directly with strongly adsorbing pesticides, such as simazine, for adsorption sites. For more weakly adsorbing pesticides, such as asulam, direct competition for adsorption sites originated not only from the strongly adsorbing, low-MW NOM, but also from more weakly adsorbing, higher-MW NOM. Consequently, the competing NOM fraction increases as the adsorbability of the SOC decreases, a result that was confirmed by adsorption data for additional pesticides of similar size. However, a smaller pesticide competed more effectively for adsorption sites than a larger pesticide of similar polarity, suggesting that the concentration of competing NOM decreases as the MW of the SOC decreases.
Adsorption↗
Analysis of herbicides: demonstration of the utility of enzyme immunoassay verification by HPLC.
Evidence has accumulated that herbicides in the environment present a significant health hazard to the population. Therefore, the levels of heavily used substances such as atrazine and simazine and their metabolites need to be regularly assessed. The objective was to develop a rapid and simple tube ELISA procedure suitable for use in field studies and non-specialized laboratories. The antisera used were polyclonal antibodies raised in sheep against atrazine or simazine amido caproic acid conjugated to bovine serum albumin. The antibodies were first used to construct a two-step competitive ELISA procedure in 96-well microtitre plates. The 96-well format was then adapted to a coated-tube enzyme immunoassay, by immobilization of hapten-gelatine conjugates on polystyrene tubes. This enabled the colour to be read using a basic spectrophotometer. Soil samples were collected from agricultural and non-agricultural sites in Poland. Atrazine and simazine were extracted by liquid extraction from soil and assayed by tube ELISA. In addition, the samples were extracted by solid-phase extraction before analysis by HPLC. The immunoassays and chemical analysis were carried out by different individuals who were unaware of each other's results, which were then compared at the end of the study. Correlation of the two methods was excellent, with R=98.7 and 81.3 for atrazine and simazine, respectively. The immunoassay yielded the same order of results without having to perform solid-phase extraction before analysis. The study has demonstrated that the simple antigen-coated tube assay provides a cost-effective and valuable screening test. Comparison with the more elaborate, heavily labour-intensive HPLC analysis demonstrated that the results obtained by the simpler enzyme-immunoassay tests were within the same order.
Atrazine↗
Possible antiestrogenic properties of chloro-s-triazines in rat uterus.
Several published reports have indicated that certain chloro-s-triazine herbicides may alter endocrine function in rats, possibly by androgen receptor binding. In direct tests of estrogenic bioactivity, oral doses of up to 300 mg/kg/d of atrazine, simazine, or the common metabolite diaminochlorotriazine (DACT) did not significantly increase uterine weight of ovariectomized Sprague-Dawley female rats. The highest dose, which was approximately 10% of the LD50 for these compounds, did cause body weight loss. When administered concomitantly with sc injections of estradiol (2 micrograms/kg), 300 mg/kg of orally administered chlorotriazines significantly reduced uterine weight in comparison to animals given estrogen alone. Neither atrazine, simazine, nor DACT, at oral doses up to 300 mg/kg/d, stimulated incorporation of [3H]thymidine into uterine DNA of immature Sprague-Dawley female rats. However, oral treatment at doses of 50 mg/kg and higher significantly reduced thymidine incorporation into uterine DNA extracted from immature rats given a single injection of 0.15 microgram estradiol. Oral doses of 300 mg/kg of atrazine, simazine, or DACT significantly reduced expression of progesterone receptor binding in cytosol fractions prepared from uteri of ovariectomized rats injected sc with 1 microgram estradiol; 50 mg/kg triazine was not effective in this case. Uterine progesterone receptor levels were not stimulated in rats given oral doses up to 300 mg/kg of these triazines without estradiol injections. These results suggest that atrazine, simazine, and DACT possess no intrinsic estrogenic activity but that they are capable of weak inhibition of estrogen-stimulated responses in the rat uterus. This inhibition may play a role in the previously observed disruptive actions of chlorotriazines on reproductive endocrine function of female rats.
Administration, Oral↗
The clastogenic potential of triazine herbicide combinations found in potable water supplies.
Pesticide contamination of drinking water supplies has increased over the past decade. A major concern is how exposure to combinations of low levels of pesticides, especially herbicides, could affect public health. Flow cytometric analysis was performed to determine the clastogenic potential of herbicide interaction on Chinese hamster ovary (CHO) cells. The cells were exposed to atrazine, simazine, cyanazine, and all possible combinations of these chemicals for 48 hr. Two concentrations were used for each sample: the U.S. EPA maximum contamination level (MCL) and the highest contamination level found in Illinois water supplies. Nuclei were isolated from the cells and analyzed by flow cytometry. The effects of clastogenicity were measured by the coefficient of variation (CV) of the G1 peak of whole cells and the change in CV of the largest chromosome in the flow karyotype. At both levels tested, atrazine caused chromosomal damage to the CHO cells. Simazine was observed to induce whole-cell clastogenicity but not flow karyotype damage. Cyanazine did not induce any measurable chromosomal damage in either analysis. Each of the herbicides, although all three were triazines, had different effects with respect to chromosome damage as measured by flow cytometry. CHO cells treated with a combination of atrazine and simazine, or atrazine and cyanazine, were observed to have whole-cell and flow karyotype damage. This damage was, however, equal to or less severe than the damage caused by either atrazine or simazine alone. No synergy was observed. When all three herbicides were combined, three of the four possible combinations gave no observable clastogenic response.
Animals↗
Herbicide transport to surface waters at field and watershed scales in a Mediterranean vineyard area.
The contamination of soil and runoff water by two herbicides, diuron [N'-(3,4-dichlorphenyl)-N,N-dimethylurea] and simazine (6-chloro-N,N'-diethyl-1,3,5-triazine-2,4-diamine), were monitored on two fields, one no-till and one tilled. Experiments were carried out in a 91.4-ha watershed in southern France during the 1997 growing season in order to understand the patterns of pesticide transport from field to watershed. The persistence of the herbicides in soil was prolonged due to the climatic conditions. At the field scale, annual herbicide loads were due to overland flow and amounted to 65.6 and 6.3 g ha(-1) of diuron for the no-till and tilled field, respectively, and to 29.6 and 1.83 g ha(-1) of simazine. Maximum herbicide concentrations exceeded 580 microg L(-1) during the first storm event after application and decreased thereafter but remained for 8 mo above 0.1 microg L(-1). At the watershed outlet, estimated annual loads amounted to 4.12 g ha(-1) of diuron and 0.56 g ha(-1) of simazine. Among them, 96% of the losses in diuron and 83% of those in simazine were caused by the fast transmission through the network of ditches of the overland flow exiting the fields. For diuron, which was sprayed over most of the vineyards, its in-stream concentrations during storm flow were close to those at the outlet of the fields. The herbicide loads in baseflow were smaller than 0.2 g ha(-1). The patterns of the loads at the field and watershed scales suggested that a major part of the herbicides leaving the fields reinfiltrated to the ground water by seepage through the ditches, and was there degraded or adsorbed.
Agriculture↗
Failure of chloro-S-triazine-derived compounds to induce estrogen receptor-mediated responses in vivo and in vitro.
The potential estrogenic activities of atrazine and simazine were investigated in vivo using the immature female Sprague-Dawley rat uterus and in vitro using the estrogen-responsive MCF-7 human breast cancer cell line and the estrogen-dependent recombinant yeast strain PL3. Animals that were dosed with 50, 150, or 300 mg/kg of atrazine or simazine alone for 3 consecutive days did not exhibit any significant increases in uterine wet weight while decreases in cytosolic progesterone receptor (PR) binding levels and uterine peroxidase activity were observed. 17 beta-estradiol (E2)-induced increases in uterine wet weight were not significantly affected by cotreatment with either chemical; however, some dose-independent decreases in E2-induced cytosolic PR binding and uterine peroxidase activity were observed. In vitro, atrazine and simazine did not affect basal or E2-induced MCF-7 cell proliferation or the formation of nuclear PR-DNA complexes as determined by gel electrophoretic mobility shift assays. In addition, these chloro-S-triazines did not display agonist activity or antagonize E2-induced luciferase activity in MCF-7 cells transiently transfected with a Gal4-human estrogen receptor chimera (Gal4-HEGO) and a Gal4-regulated luciferase reporter gene (17m5-G-Luc). Moreover, the estrogen-dependent PL3 yeast strain was not capable of growth on minimal media supplemented with atrazine or simazine in place of E2. Collectively, these results indicate that the reported estrogenic and antiestrogenic effects elicited by these chemicals are not mediated by the estrogen receptor.
Animals↗
Occurrence of organochlorines (PCBs, pesticides) and herbicides (triazines, phenylureas) in the atmosphere and in the fallout from urban and rural stations of the Paris area.
The concentrations of organochlorines (PCBs, pesticides) and herbicides (triazines, phenylureas) were determined in the atmosphere. The total fallout in the Paris area in 1992 and in 1993 was measured. Fallout was investigated at two stations, urban and rural and the gaseous phase was studied at the rural one. PCB concentrations (0.3-4.9 ng/m3) and compositions in the atmosphere and in the fallout (20-520 ng/l) varied, according to the local emission, with the temperature and the direction of wind. Compared to our first results in 1986, there were no changes of pollution levels by organochlorines in that area. Pesticide concentrations in the atmosphere and in the fallout reached maximal values after the local agricultural treatments in spring. No phenylurea was detected in any of the gaseous or liquid samples. Lindane, atrazine and simazine were the main pesticides found. Their levels in the vapour phase, expressed as ng/m3, were: lindane 0.3-6.3, atrazine < 0.03-2, simazine < 0.03-3; in the fallout, expressed as ng/l they were: lindane 5-350, atrazine 5-380, simazine 5-650. In relative terms, the Parisian area is very small. No difference in the diversity and in the abundance of the micropollutants introduced by the atmosphere was observed between the rural and the urban stations. The pollution level of atrazine was close to that found in Europe and in North America, while the organochlorine and the simazine levels were higher.
Air Pollutants↗