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PubMed2002

Effects of atrazine and cyanazine on chlorpyrifos toxicity in Chironomus tentans (Diptera: Chironomidae).

Toxicities of two triazine herbicides (atrazine and cyanazine) and an organophosphate insecticide (chlorpyrifos) were evaluated individually and with each herbicide in binary combination with chlorpyrifos using fourth-instar larvae of the aquatic midge, Chironomus tentans. Chlorpyrifos at 0.25 microg/L resulted in an effect in less than 10% of midges in 48-h acute toxicity bioassays. Neither atrazine nor cyanazine alone at relatively high concentrations (up to 1,000 microg/L) caused significant acute toxicity to C. tentans. However, atrazine and cyanazine caused significant synergistic effects on the toxicity of chlorpyrifos when midges were exposed to mixtures of atrazine or cyanazine (10, 100, 1,000 microg/L) with chlorpyrifos (0.25 microg/L). At fixed concentrations (200 microg/L) of the herbicides, toxicity of chlorpyrifos was enhanced by 1.8- and 2.2-fold by atrazine and cyanazine, respectively, at the 50% effective concentration levels. Although atrazine and cyanazine are not effective inhibitors of acetylcholinesterase (AChE) in vitro, the synergism of the two triazine herbicides with chlorpyrifos was associated with increased in vivo inhibition of AChE in midges. We observed a positive correlation between the degree of inhibition of AChE and the concentration of atrazine or cyanazine in the presence of a fixed concentration of chlorpyrifos. It is possible that these herbicides may affect cytochrome P450 enzymes to confer synergistic effects on the toxicity of chlorpyrifos.

Acetylcholinesterase↗
PubMedDate not supplied

Runoff and drainage losses of atrazine, metribuzin, and metolachlor in three water management systems.

Rainfall can transport herbicides from agricultural land to surface waters, where they become an environmental concern. Tile drainage can benefit crop production by removing excess soil water but tile drainage may also aggravate herbicide and nutrient movement into surface waters. Water management of tile drains after planting may reduce tile drainage and thereby reduce herbicide losses to surface water. To test this hypothesis we calculated the loss of three herbicides from a field with three water management systems: free drainage (D), controlled drainage (CD), and controlled drainage with subsurface irrigation (CDS). The effect of water management systems on the dissipation of atrazine (6-chloro-N2-ethyl-N4-isopropyl-1,3,5-triazine-2,4-diamine), metribuzin [4-amino-6-(1,1-dimethylethyl)-3-(methylthio)-1,2,4-triazine-5(4H)-one), and metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide] in soil was also monitored. Less herbicide was lost by surface runoff from the D and CD treatments than from CDS. The CDS treatment increased surface runoff, which transported more herbicide than that from D or CD treatments. In one year, the time for metribuzin residue to dissipate to half its initial value was shorter for CDS (33 d) than for D (43 d) and CD (46 d). The half-life of atrazine and metolachlor were not affected by water management. Controlled drainage with subsurface irrigation may increase herbicide loss through increased surface runoff when excessive rain is received soon after herbicide application. However, increasing soil water content in CDS may decrease herbicide persistence, resulting in less residual herbicide available for aqueous transport.

Acetamides↗
PubMedDate not supplied

Retention and runoff losses of atrazine and metribuzin in soil.

Minimizing herbicide runoff and mobility in the soil and thus potential contamination of water resources is a national concern. Metribuzin [4-amino-6-(1,1-dimethylethyl)-3-(methylthio)-1,2,4-triazin-5(4H)-one] and atrazine [2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine] dynamics in surface soils and in runoff waters were studied on six 0.2-ha sugarcane (Saccharum spp.) plots of a Commerce silt loam (fine-silty, mixed, superactive, nonacid, thermic Fluvaquentic Endoaquept) during three growing seasons under different best management practices. Metribuzin was applied in the spring as a postemergence herbicide and atrazine was applied following winter harvest. Both herbicides were applied on top of the sugarcane rows as 0.6- or 0.9-m band width application, or broadcast application, where the entire area was treated. Maximum effluent concentrations were measured from the broadcast treatment and ranged from 600 to 1100 microg L(-1) for atrazine and 250 to 450 microg L(-1) for metribuzin. Atrazine runoff losses were highest for the broadcast treatment (2.8-11% of that applied) and lowest for the 0.6-m band treatment (1.9-7.6%), with a similar trend for metribuzin losses. Measured extractable herbicides from the surface soil exhibited a sharp decrease with time and were well described with a simple first-order decay model. For atrazine, estimates for the decay rate (lambda) were higher than for metribuzin. Results based on laboratory adsorption-desorption (kinetic-batch) measurements were consistent with field observations. The distribution coefficients (Kd) for atrazine exhibited stronger retention over time in comparison with metribuzin on the Commerce soil. Moreover, discrepancies between adsorption isotherm and desorption indicated slower release and that hysteresis was more pronounced for atrazine compared with metribuzin.

Atrazine↗
PubMedDate not supplied

Studies on mobility and degradation pathways of terbuthylazine using lysimeters on a field scale.

Terbuthylazine [N2-tert-butyl-6-chloro-N4-ethyl-1,3,5-triazine-2,4-diamine] degradation pathways in agricultural soils were evaluated by following the appearance and mobility of its main transformation products: dealkylated and hydroxylated derivatives. Three experimental degradation studies in open field were performed in different hydraulic conditions: constant hydraulic head on topsoil, achieved to simulate the highest-risk situation for the aquifer, intermittent artificial precipitation to simulate a medium-risk situation; and natural precipitation to reproduce the lowest-risk condition. Concentrations of terbuthylazine transformation products derived from dealkylation and hydroxylation reactions were measured in leachates and soil samples collected during the three experiments. Desethylterbuthylazine (DET) and deethylterbuthylazine-2-hydroxide [DETH; 4-amino-6-terbutylamino-(1,3,5)-triazine-2-OH] were found to be the highest-leaching compounds and therefore can be considered as potential pollutants for aquifer contamination.

Agriculture↗
PubMed2006

Persistence of the sulfonylurea herbicides thifensulfuron-methyl, ethametsulfuron-methyl, and metsulfuron-methyl in farm dugouts (ponds).

Sulfonylurea herbicides are applied at relatively low rates (3 to 40 g ha(-1)) to control weeds in a variety of crops across the Canadian prairies. Because of their high phytotoxicity and the likelihood of their transport in surface runoff, there is concern about their possible impact to aquatic ecosystems. Little is known, however, about their persistence and behavior in aquatic ecosystems. To assess persistence in aquatic ecosystems, three prairie farm dugouts (ponds) were fortified with either thifensulfuron-methyl {methyl 3-[[[[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)amino]carbonyl]amino]sulfonyl]-2-thiophenecarboxylate}, ethametsulfuron-methyl {methyl 2-[[[[[4-ethoxy-6-(methylamino)-1,3,5-triazin-2-yl]amino]carbonyl]amino]sulfonyl]benzoate} or metsulfuron-methyl {methyl 2-[[[[(4-methoxy-6-methyl-1,3,5-triazinyl)amino]carbonyl]amino]sulfonyl]benzoate}. The decreasing order of persistence of environmentally relevant concentrations (1 to 4.6 microg L(-1)) of these herbicides in dugout water over the June to October period was metsulfuron-methyl>ethametsulfuron-methyl>thifensulfuron-methyl. The corresponding dissipation half-lives (DT(50)) of 84, 30, and 16 d, respectively, are in the same relative order as the recropping intervals for these herbicides. Thifensulfuron-methyl showed a biphasic dissipation with slower dissipation during the winter months. In contrast, the dissipation of metsulfuron-methyl, the sulfonylurea herbicide with the longest DT(50), was somewhat enhanced under winter conditions. One of the major routes of sulfonylurea herbicide dissipation was removal from the water column when dugout water was lost during hydrological discharge. The relatively long persistence of these herbicides in water indicates that partitioning into sediments was minimal, the sulfonylurea and methyl ester linkages in these compounds were resistant to hydrolysis in weakly alkaline waters, and that microbial and photolytic degradation in dugout waters were slow.

Agriculture↗
PubMed2006

Wastewater dissolved organic matter: characteristics and sorptive capabilities.

An evaluation of the mobility of organic pollutants with wastewater dissolved organic matter (DOM) is essential to better understanding their fate and toxicity to the environment. In this study, DOM from two wastewater treatment plants (in Lachish and Netanya, Israel) were fractionated to hydrophobic-acid (HoA) and hydrophobic-neutral (HoN) fractions. The fractions were characterised and their sorptive capabilities for s-triazine herbicides and polycyclic aromatic hydrocarbons (PAHs) were studied. For all sorbates, binding to the HoN fractions was much higher than to HoA fractions. The high binding coefficients obtained for the studied triazines by the HoN fractions suggested that their sorption is governed by hydrophobic-like interactions rather than H-bonding. The binding coefficients of PAHs measured for the HoN fractions were within the range reported for humic acids and much higher than for the HoA fraction, suggesting that the HoN fraction plays an important role in the overall sorption of these compounds by DOM. Higher sorption coefficients were measured for the Netanya DOM sample containing a higher level of hydrophobic fractions (HoA + HoN) than the Lachish DOM, suggesting that the sorption of hydrophobic organic compounds by DOM is governed by the relative content of these structural substances.

Humic Substances↗
PubMed2000

The library of p-nitrophenyl esters of oligopeptides as a model to study the anticancer drug-peptide conjugates activated during tumor angiogenesis.

An indexed library of oligopeptide p-nitrophenyl esters immobilized via methoxy-1,3,5-triazine scaffold on the cellulose support, was synthesized by the step by step procedure and by segment coupling, involving 2-chloro-4,6-dimethoxy-1,3,5-triazine as a condensing reagent. The substrate specificity towards homogenate supernatant of mouse lung cancer LL2 cells has been studied.

Animals↗
PubMed2004

Bioavailability of bound residue derived from 14C-labeled chlorsulfuron in soil and its mechanism of phytotoxicity.

The bioavailability of bound residue (BR) derived from 14C-labeled chlorsulfuron in soil and effect of the main components of the BR on growth of rape (brassica napus) and rice (Oryza sativa L.) were investigated. The results showed that the BR with the concentration of 0.28 and 0.56 nmol/g air-dried soil, which was calculated by special radioactivity of 14C-labeled chlorsulfuron parent compound, resulted in significant depression effect on growth of rape seedling. It was assured that the main components (2-amino-4-methoxyl-6-methyl-1,3,5-triazine, 2-amino-4-hydroxyl-6-methyl-1,3,5-triazine, and 2-chloro-benzenesul-fonamide) of the BR did not inhibit the growth of rape and rice. LC-MS analysis demonstrated that the parent compound previously bound to the soil matrix could be again released and transformed into methanol-extractable residue during the course of rape growth. It was concluded that the molecular leading to the phytotoxicity to rape and rice in the BR is still the parent compound.

Biological Availability↗
PubMed1991

Synthesis of certain 2-aminoadamantane derivatives as potential antimicrobial agents.

1-(2-Adamantyl-3-(5-arylhydrazono-6-methyl-4-oxopyrimidin -2-yl)guanidines, 2-(2-adamantylamino)-4-amino-s-triazine and its 6-chloromethyl derivative were prepared by cyclization of 1-(2-adamantyl)biguanide.HCl with ethyl 2-arylhydrazono-3-oxobutyrates, ethyl formate and ethyl chloroacetate, respectively. 1-(2-damantyl)-3-(4,5-dioxo-2-imidazolidinylidene)guanidine was used as intermediate for the synthesis of amides, hydrazide and azomethine derivatives of alkyl 2-(2-adamantylamino)-4-amino-s-triazine-6-carboxylates. The antimicrobial testing of the prepared compounds proved that an azomethine derivative was the most active. It showed a marked bacteriostatic effect against Staphylococcus aureus and Bacillus subtilis.

Adamantane↗
PubMed1990

[Synthesis of N2-aryl-triazinoylamoxicillins and N2-phenyl-N4-alkyl (aryl)-triazinoylamoxicillins and their antibacterial activity].

Sixteen derivatives of BL-P1908 were synthesized by reaction of 2-aryl-1, 2, 4-triazine -3, 5-dione -6-carboxylic acid, or 2-phenyl-4-alkyl (aryl) -1, 2, 4-triazine-3, 5-dione-6-carboxylic acid with amoxicillin. All of them are new compounds. Their chemical structures were determined by elemental analysis, IR and 1HNMR. Preliminary tests showed that all compounds have marked activities against standard G(+) and G(-) bacteria and five of them have certain characteristic of broad spectrum, but they have no activities against resistant strains S. aureus S1, E coli C1 and P. aeruginosa PS1 isolated from clinic.

Amoxicillin↗
PubMed1989

QSARs and pesticides design.

A multivariate analysis of phytotoxicity and measured ecotoxicity data of a set of 30 herbicidal triazines was carried out. Results indicate that it is feasible to design triazines that combine limited ecotoxicity with high herbicidal potency.

Animals↗
PubMed1986

Pentamethylmelamine: review of an aqueous analog of hexamethylmelamine.

The s-triazine derivatives have shown preclinical antitumor activity against several histologic types. The most widely used compound of this class in the clinic, hexamethylmelamine, has been largely restricted to oral use because of its low solubility and lack of stability in solutions suitable for parenteral administration. New analogs were sought which were soluble and stable and retained antitumor activity. Pentamethylmelamine (PMM), the monodemethylated derivative, showed these promising characteristics. Preclinical toxicology studies of PMM in mice, dogs, and monkeys showed toxic manifestations that involved the hematopoietic, lymphatic, renal, male reproductive, gastrointestinal, and nervous systems; these changes were both infusion-rate- and dose-dependent. Clinical phase I trials of PMM were performed using a variety of infusion durations and frequency schedules. The dose-limiting toxic effect common to all of these trials was protracted nausea and vomiting. In addition, some studies reported dose-limiting central nervous system manifestations in the form of agitation, drowsiness, somnolence, and even coma. Mild to moderate hematologic changes were noted. Because of the severity and frequency of the gastrointestinal and central nervous system toxic effects observed in the completed trials, no new clinical trials of PMM sponsored by the National Cancer Institute are planned. However, the interest in finding a clinically useful parenteral triazine continues.

Altretamine↗
PubMed1977

[Antitumor action of new 2,4-diethyleneimino-6-amino-sym.-triazina derivatives].

In experiments of mice and rats with transplantable tumors (sarcoma 37, sarcoma 45, ascites Ehrlich tumor, etc) the authors studied the antitumor activity of a number of new water-soluble derivatives of 2,4-diethylenimino-6-amino-sym.-triazine differing only in the substituting radical associated with sym.-triazine cycle. All substances under study showed marked antitumor activity. The effect of the structure of the compounds concerned and their physico-chemical properties for antitumor activity are discussed.

Animals↗
PubMed1981

5-Methyltetrahydrofolate transport by hepatoma cells and methotrexate-resistant sublines in culture.

The properties of the folate transport system in H35 hepatoma cells have been studied by measuring the transport of (+)-5-methyltetrahydrofolate. Using initial rates of uptake, it has been demonstrated that the uptake is saturable, carrier mediated, and shared by methotrexate. The accumulation of (+)-5-methyltetrahydrofolate is concentrative, demonstrating the presence of an active transport process. A previous study suggested that methotrexate-resistant sublines (H35R) acquired methotrexate insensitivity because of an impaired capacity for transport. This postulate was substantiated in the present investigation by several observations. The initial uptake and steady-state level of (+)-5-methyltetrahydrofolate were markedly reduced in the resistant sublines as was the case with methotrexate. Triazinate (2-(chloro-4-[4,6-diamino-2,2-dimethyl-S-triazine-1(2H)-ylphenoxyl])-N,N-dimethyl-m-toluamide . ethanesulfonic acid) an inhibitor of dihydrofolate reductase which enters the cells by a pathway independent of the folate coenzyme, was equally toxic to H35 cells and to an H35 subline resistant to 0.3 microM methotrexate. Resistant sublines that are insensitive to methotrexate up to 1 microM display a transport defect but have normal levels of dihydrofolate reductase. Sublines resistant to higher levels of methotrexate showed not only defective transport but also commensurate increases in dihydrofolate reductase. Attempts to demonstrate carried-dependent transport of (+)-5-methyltetrahydrofolate or methotrexate in resistant sublines were negative, suggesting the lack of a functional carrier. These properties were readily demonstrated in H35 cells and included temperature dependence, competition for uptake with analogs, and transstimulation.

Animals↗
PubMed1980

Comparison of gas and liquid chromatography for determination of anilazine in potatoes and tomatoes.

Anilazine (2,4-dichloro-6-(2-chloroanilino)-1,3,5-triazine), a triazine fungicide, is extracted from potatoes or tomatoes with acetonitrile. An aliquot of the filtered extract is partitioned between methylene chloride and water. The organic phase is concentrated and passed through a 3% deactivated Florisil column for cleanup. The eluted anilazine is then concentrated and determined by liquid chromatography (LC) on LiChrosorb RP-8 column with a mobile phase of acetonitrile--water (55 + 45) and detection at 275 nm, the absorption maximum of anilazine. Twenty-five nanograms produces a 5 cm peak under the conditions used. Detection limit is about 0.02 ppm in both vegetables. A comparison is made with gas chromatography, using either an electron capture (EC) or nitrogen--phosphorus alkali-flame ionization (NP) detector. Separations are carried out on a 4% SE-30 + 6% SP-2401 column at 195 degrees C at 40 mL/min. Detection limits for all systems studied are about 0.02--0.05 ppm in the samples studied. Recoveries over a concentration range of 0.2--10.0 ppm are greater than 80% with the extraction procedure employed and LC determination.

Aniline Compounds↗
PubMed1994

[Pesticide pollution of groundwater and drinking water by the processes of artificial groundwater enrichment or coastal filtration: underrated sources of contamination].

The research objective of this study is to monitor the degree of pesticide pollution in public drinking waters and to characterise the pathways by which these substances get into potable waters. Public drinking waters, raw waters, ground waters, and surface waters in an area with intensive agriculture were analysed for pesticides and nitrate during the years 1987-1992. The monitoring reveals that only potable waters of water works using the process of artificial ground water recharge are polluted by pesticides. The very influence of surface water on the degree of pesticide contamination can be shown up to the wells. Wells that are influenced by bank filtration or infiltration contain significantly (P < 0.001) higher amounts and a greater number of substances than pure ground water wells. Most often triazines and phenylureas are analysed. Among the tested water works the artificial ground water recharge is the main factor for the input of pesticides into the aquifer and the drinking water. Percolation experiments, and parallel seasonal changes of pesticides and nitrate in raw and infiltration water document a high mobility during the subsoil passage and an easy vulnerability of the aquifer. There is no correlation between pesticides and nitrate. So nitrates are not suited as an indicator for pesticide pollution. Almost all tested surface waters, including channels, contain pesticides in highly varying concentrations during the whole year and are thus always a possible source for an input into the recharged ground water. In addition to agricultural runoffs a remarkable contamination of rivers with the herbicide diuron caused by municipal waste waters can be observed in the summer. Because of insufficient elimination of herbicides like triazines and phenylureas during bank filtration or infiltration and because of the high loads of surface waters with pesticides a minimisation of pesticide losses within the whole catchment area, especially of runoffs into surface waters, and the abstention from the use of slowly degradable herbicides in cities, on railways or in private gardens are inevitable. At the present time, however, a protection of ground and public drinking water from pesticide contamination can only be achieved by treating surface or ground waters with activated carbon.

Analysis of Variance↗
PubMed1993

[Synthesis of 11-aryl-7,8,9,10-tetrahydro-1,2,3-triazino-(4',5':4,5)-thienol- -(2,3-b)-quinolines with antianaphylactic action].

Title compounds of structure B with an oxo function in position 4 of the triazine ring were synthesized by reaction of the aminocarboxamides A with sodium nitrite in acetic acid. Aminocarbonitriles of structure H yielded with sodium nitrite in acetic acid and hydrochloric acid the 4-chloro derivatives I. These compounds gave with N-nucleophiles, methoxide or thiourea the substances J. Tetracyclic compounds with a hydroxyethyl or a piperidinoethyl residue in position 3 in the triazine ring (E, G) were also prepared. Some of the investigated compounds showed an antianaphylactic activity.

Anaphylaxis↗
PubMed1995

Synthesis and biological activity of 1,2,4-triazinotriazinone derivatives.

The synthesis of 1,2,4-triazines bearing a 1,2,4-triazinone moiety and of 1,2,4-triazolo[4,3-b]-1,2,4-triazonones have been achieved by reaction of 1,6-dihydro-3-hydrazino-6-spiro- (9-fluorenyl)-1,2,4-triazin-5(4H)-one with various oxo- and halo-compounds. Structures of the products have been deduced by elemental analysis and spectral data. Significant anti-HIV and anticancer activities were observed in vitro for some members of the series.

Antineoplastic Agents↗