Simazine (2-chloro-4,6-bis(ethylamino)-s-triazine) is a selective, herbicide that inhibits photosynthesis. It occurs as awhite crystalline solid, soluble at 5 ppm(at20–22 °C) in water and 400 ppm in methanol. The vapor pressure of simazine is 0.0000000061mmHg (at 20 °C [68°F]).
Simazine acts by inhibiting photosynthesis. It is an active ingredient in Aquazine, Cekusan, Gesatop, Primatol/S, Princep, Simades, and Simanex. This herbicide is used primarily on fruit and maize and at industrial and aquatic sites, including near swimming pools and cooling towers. It typically is found as an 80% wettable powder or a 90% granule.
S-triazine herbicide. It is easily adsorbed on the surface by soil to form a poisonous soil layer, which can kill the roots of shallow-rootedness weeds seedling. The effect on perennial or deep rooted weeds with deep roots is poor. It is used to prevent annual or biennial broadleaf and most monocotyledonous weeds which are propagated by seeds for corn, sugarcane, sorghum, tea, rubber, orchard and nursery. It has obvious inhibiting effects on perennial weeds that are propagated by rhizomes or roots. It can be used as a sterilant herbicide for forest firebreaks, railroad bed lines, courtyards, storage areas in warehouse, tank farms, woodyards and so on by increasing the dose. Suggested use: corn 30 to 60g/100m2 (summer corn 15 to 30g/100m2), sorghum 30 to 66g/100 m2, sugarcane 22.5 to 30g/100 m2, tea 22.5 to 37.5g/100 m2, rubber 45 to 67.6g/100 m2, orchard 45 to 75g/100 m2, nursery garden 1 to 2g per square meter. It is added into water for the suspension for to spray on the soil surface.
The product is obtained by the reaction between triazine cypermethrin and ethylamine in the presence of acid acceptor. If using water as the reaction medium, add materials at 0℃, then hold temperature and stir at 70℃ for 2h. If the reaction is carried out in the solvents like trichloroethylene, the reaction temperature is between 30℃ and 50℃. The consumption figures of raw materials: cyanuric chloride (96%), 1020kg/t (100% 520kg/t) ethylamine, liquid (40%) 100kg/t, trichloroethylene (industrial products) 120kg/t.
Orally - rat LD50: 971 mg / kg; orally - mice LD50: 5000 mg / kg
Skin- A rabbit 500 mg light
Toxic nitrogen oxides and chloride gases are produced by combustion; toxic reaction: emaciation and the decrease of red blood cells.
Store it in low temperature, dry and ventilated environment.
While compounds exhibiting estrogen mimicry are structurally
diverse, they share common properties such as retention in
body fat deposits (highly lipophilic), ability to cross the
placental barrier, transport in blood usually unbound to
specialized serum proteins (e.g., steroid hormone binding
globulin, SHBG/TeBG), and their affinity for the estrogenreceptor
protein. If the environmental compound impersonates
estrogen sufficiently, it associates with the estrogen-receptor
protein and either disrupts the action of the native hormone or
communicates activities similar to estrogen (i.e., antagonistic or
agonistic activities). Association between a xenoestrogen and
the estrogen receptor (ER), characterized by a wide range of
affinities, is reversible and saturable. No metabolism of the ligand occurs when it is bound to the receptor protein. In
addition to the phenotypic expression of gender, estrogens and
their mimics may influence development and physiological
processes in many organs of the body, particularly the reproductive
tract, as well as the central nervous system and skeleton.
It is obvious that fragile, biological events occurring during
ovulation, pregnancy, fetal development, and lactation could
easily be influenced by xenoestrogens with endocrine disruptor
compound (EDC) activities, which mimic naturally occurring
hormones.
With a variety of sensitive, rapid assays, xenoestrogens now
may be detected and activities assessed by ER proteins. The
range of techniques available includes both cell-free and
whole-cell-based assays:
1. Rat uterine cytosol preparations containing ERs (a cell-free
assay using radiolabeled ligand);
2. Recombinant human ER proteins produced by a bacteria,
yeast, or baculovirus-infected insect cell system (cell-free
assays using radiolabeled ligand);
3. A yeast cell system containing recombinant human ER and
a reporter gene (yeast whole-cell assay);
4. The LUMI-CELL ER transcriptional activation assay
(BG1Luc ER TA, a mammalian whole-cell assay); and
5. MCF7 cell proliferation assay (E-SCREEN assay) and modifications
of this method (mammalian whole-cell assay).
Additionally, certain investigations are focused on differential
recognition of EDCs by ER isoforms separated by highperformance
liquid chromatography.
Simazine is a combustible, white crystalline solid. Practically odorless.Its solubility in methanol is 400mg/L, its solubility in water is 5mg/L, its solubility in petroleum ether is 2mg/L and it is slightly soluble in chloroform. It has the advantages of stable chemical property, but it is easily hydrolyzed under the strong acid or alkali conditions and at higher temperatures to produce inactive hydroxyl derivatives. No corrosion. Original medicine m.p.224℃.
Xenoestrogens are used widely in a number of cosmetic products
such as plasticizers, perfume fixatives, and solvents (e.g.,
dibutyl phthalate); and industrial chemicals and pollutants
such as insecticides (e.g., methoxychlor, DDT, and DDE),
epoxy resins, polycarbonate (e.g., bisphenol A), other plastics
(e.g., butyl benzyl phthalate (BBP)), and herbicides (e.g.,
simazine). Compounds in this group exhibit a broad molecular
and structural diversity, often mimicking the activities of
naturally occurring hormones, since they are recognized by the
hormone’s cognate receptor protein. Many compounds in this
group of chemicals have been classified as environmental
EDCs, defined by the US Environmental Protection Agency
(EPA) as “an exogenous agent that interfere with synthesis,
secretion, transport, metabolism, binding action, or elimination
of natural blood-borne hormones that are present in the
body and are responsible for homeostasis, reproduction and
developmental processes.” However, not all EDCs are classified
as xenoestrogens.
Although relative binding affinities (RBAs) of a number of
compounds exhibiting xenoestrogenic activities, it should be noted that the values appearing here and
in the reports listed under Further Reading are highly dependent
on the type of ER-based assay used and the concentration
of the compound tested. In addition, caution should be exercised
in interpreting the results from assays performed in vitro
compared to effects observed in vivo. Duration of exposure and dose in vivo, which are likely influenced by the lipophilic
properties of many of the agents, should be considered in
health risk assessment.
In summary, the body of experimental and epidemiological
evidence suggesting that many substances in the environment
may disrupt human health continues to expand to cover a wide
range of exposures. Of greatest concern are the effects of
transgenerational exposure to unrecognized agents, which may
be present in foodstuffs, drinking water, and other consumables,
including medications and cosmetics. Using hormone
receptor-based technology and highly purified preparations of
EDCs as standards, there is an opportunity to improve exposure
and risk assessment for environmental estrogen mimics, as
well as the quantitative analysis of their occurrence in the
environment. However, discussions continue regarding the
relationships between assessment in vitro of xenoestrogen
activities and their effects in vivo resulting in a risk to health.
Selective preemergence systemic herbicide used to control many broad-leaved weeds
and annual grasses in deep-rooted fruit and vegetable crops.
Simazine is a preemergence herbicide used to control
broadleaf and grassy weeds. It is also used as a soil sterilant.
Principal crops involved include maize, citrus, and deciduous
fruit. Simazine is also used in aquatic weed control.
Simazine is prepared by reacting two equivalents of ethylamine
in the presence of an acid acceptor. It is stable in neutral
and slightly basic or acidic media, but is hydrolyzed by
stronger acids and bases especially at higher temperatures.
Primary exposures occur during application, not during
production, and include both inhalation and dermal components.
ChEBI: A diamino-1,3,5-triazine that is N,N'-diethyl-1,3,5-triazine-2,4-diamine substituted by a chloro group at position 6.
White to off-white crystalline powder.
Simazine is hydrolyzed by strong acids and alkalis .
Inconsistent data in the literature; oral LD50values in rats reported as 970 and 5000 mg/L,showing a wide difference; toxicity is of loworder.
Literature sources indicate that Simazine is nonflammable.
Pre-emergence herbicide, Algaecide: and ornamental crops, turf grass, orchards, and vineyards. At higher rates, it is used for non-selective weed control in industrial areas. Before 1992, simazine was used to control submerged weeds and algae in large aquariums, farm ponds, fish hatcheries, swimming pools, ornamental ponds, and cooling towers. Simazine is available in wettable powder, waterdispersible granule, liquid, and granular formulations. It may be soil-applied. Not approved for use in EU countries. A U.S. EPA restricted Use Pesticide (RUP) for all land uses because of its potential to contaminate ground water
AKTINIT S®; ALCO® Simizine; AQUAZINE®; ATLAS SIMAZINE®; BATAZINA®; BITEMOL®; CALIBER®; CDT®; CEKUSAN®; CEKUZINA-S®; FRAMED®; G 27692®; GEIGY 27692®; GESARAN®; GESATOP®; GESATOP-50®; H 1803®; HARLEQUIN®; HERBAZIN® 500 BR; HERBAZIN® 50; HERBEX®; HERBOXY®; HUNGAZIN DT®; OXON ITALIA SIM-TROL®; PREMAZINE®; PRIMATEL S®; PRIMATOL S®; PRINCEP®; PRINCEP® 80W; SIMADEX®; SIMANEX®; SIMAZINE® 80W; SIMAZAT®; SIM-TROL®; TAFAZINE®; TAFAZINE® 50-W; TANZINE®; TAPHAZINE®; TOTAZINE®; TRIAZINE A 384®; W 6658®; WEEDEX®; ZEAPUR®
A potential danger to those involved in the manufacture, formulation, and application of this preemergence herbicide. Pesticide not in use; TRI and/or IUR indicates importers or manufacturers are unlikely. Banned for use in the EU.
No tumorigenic response was
seen in mice treated orally at doses ranging from 75 to
215mg/kg. In a 2-year feeding study in rats, 100 ppm
produced mammary tumors. Sarcomas at the injection
sitewere produced in another study ofboth rats and mice.
Simazinewas fedtoratsatdoselevelsequivalent to 0,0.5,5,and
50mg/kg for 2 years.Bodyweight and hematological changes
were seen primarily at the highest dose. After 24 months at
50mg/kg, an increase in ovarian atrophy and Sertoli cell
hyperplasia were seen. Increases in mammary gland tumors
were seen in females at 50mg/kg.
Soil. The reported half-life in soil is 75 days (Alva and Singh, 1991). Under laboratory
conditions, the half-lives of simazine in a Hatzenbühl soil (pH 4.8) and Neuhofen soil (pH
6.5) at 22°C were 45 and 100 days, respectively (Burkhard and Guth, 1981).
The half-lives for simazine in soil incubated in the laboratory under aerobic conditions
ranged from 27 to 231 days (Zimdahl et al., 1970; Beynon et al., 1972; Walker, 1976,
1976a). In field soils, the disappearance half-lives were lower and ranged from 11 to 91
days (Roadhouse and Birk, 1961; Clay, 1973; Joshi and Datta, 1975; Marriage et al., 1975).
Groundwater. According to the U.S. EPA (1986) simazine has a high potential to leach
to groundwater.
Plant. Simazine is metabolized by plants to the herbicidally inactive 6-hydroxysimazine which is further degraded via dealkylation of the side chains and hydrolysis of
the amino group releasing carbon dioxide (Castelfranco et al., 1961; Humburg et al., 1989).
Photolytic. Pelizzetti et al. (1990) studied the aqueous photocatalytic degradation of
simazine and other s-triazines (ppb level) using simulated sunlight (λ >340 nm) and
titanium dioxide as a photocatalyst. Simazine rapidly degraded forming cyanuric acid,
nitrates and other intermediate compounds similar to those found for atrazine. Mineralization of cyanuric acid to carbon dioxide was not observed (Pelizzetti et al., 1990). In
aqueous solutions, simazine is converted exclusively to hydroxysimazine by UV light (λ
= 253.7 nm). The UV irradiation of methanolic solutions of simazine afforded simetone
(2-methoxy-4,6-bis(ethylamino-s-triazine). Photodegradation of simazine in methyl alcohol did not occur when irradiated at wavelengths >300 nm (Pape and Zabik, 1970).
Chemical/Physical. Emits toxic fumes of nitrogen oxides and chlorine when heated
to decomposition (Sax and Lewis, 1987). In the presence of hydroxy or perhydroxy radicals
generated from Fenton’s reagent, simazine undergoes dealkylation to give 2-chloro-4,6-
diamino-s-triazine as the major product (Kaufman and Kearney, 1970).
UN3077 Environmentally hazardous substances, solid, n.o.s., Hazard class: 9; Labels: 9-Miscellaneous hazardous material, Technical Name Required. UN2763 Triazine pesticides, solid, toxic, Hazard Class: 6.1; Labels: 6.1-Poisonous materials.
With regard to estrogen-associated toxicity, the primary
mechanism appears to be via association with the estrogen receptor proteins (ERa and ERb) and subsequent alteration in
the signal transduction pathway. While largely acting as
estrogen antagonists, some xenoestrogens (e.g., diethylstilbestrol
(DES)) may act as agonists at low doses and antagonists at
elevated doses. Furthermore, compounds such as DES are
classified as an EDC since it may promote transgenerational
effects, including development of clear cell adenocarcinoma of
the vagina in daughters of mothers administered DES as
a therapeutic.
Many studies of toxicokinetics suggest the difficulty in
extrapolating quantitative structure–activity relationships
(QSARs) of particular compounds with their influence on
biological responses (e.g., reproduction, neuroendocrine behavior).
Several compounds classified as xenoestrogens (BPA
and BBP) are reported to have estrogenic activity, although the
concentrations required in vitro for the effects and those doses
given in vivo to animal models are significantly higher than the
estimated doses observed in human exposure. The variety of ERbased
tests for assessing QSARs of diverse xenoestrogens cannot
address the effects of long-term exposure to low doses of these
compounds. In addition, factors such as age at exposure and
mixtures of compounds influence latent effects of chronic
exposure. However, QSAR models using results from ER-based
tests are used for chemical risk management and development
of regulatory practices.
Powder may form explosive mixture with air. Incompatible with strong oxidizers (chlorates, nitrates, peroxides, permanganates, perchlorates, chlorine, bromine, fluorine, etc.); contact may cause fires or explosions. Keep away from alkaline materials, strong bases, strong acids, oxoacids, epoxides.
Strong acid or alkaline hydrolysis leads to complete degradation of simazine. However,large quantities of simazine should be incinerated in a unit operating @ 850℃ equipped with off-gas scrubbing equipment. In accordance with 40CFR165, follow recommendations for the disposal of pesticides and pesticide containers. Must be disposed properly by following package label directions or by contacting your local or federal environmental control agency, or by contacting your regional EPA office.
