The metabolic fate of 2,4-dichlorophenoxyacetic acid (2,4-D) n-butyl ester in rats has not been extensively studied. Upon subcutaneous administration of 100 mg/kg dose of 2,4-D butyl ester to four male Wistar rats, urine samples were analyzed by three analytical techniques for the presence of the butyl ester and metabolites. 2,4-D butylester was rapidly hydrolyzed in the body to form 2,4-D acid. 95% of the administered dose was excreted into the urine as the free acid within 48 hr of injection while only a small fraction (5%) was excreted over an additional 48 hr. No amino acid conjugates or the parent 2,4-D butyl ester could be detected in the urine of treated rats. A minor metabolite (< or = 2% of dose) was detected by GC-MS analysis of urine samples. This compound appears to be a side chain metabolite of the 2,4-D butyl ester. Some chemical properties of the metabolite were characterized, and a 2,4-D hydroxyethyl ester structure proposed. The mechanism of formation of this minor metabolite remains unknown.
Plants hydrolyze 2,4-D esters to 2,4-D, which is the active herbicide. ... Further metabolism ... occurs through three mechanisms, namely, side chain degradation, hydroxylation of the aromatic ring, and conjugation with plant constituents. /2,4-D esters/
HERBICIDAL ACTIVITY OF ESTERS, NITRILES, AMINES (&, OF COURSE, SALTS) APPEARS SIMILAR IF NOT IDENTICAL TO PARENT ACID. THIS IS APPARENTLY DUE TO PRESENCE OF HYDROLYTIC ENZYMES IN PLANTS & IN SOIL MICROORGANISMS THAT CONVERT THESE DERIVATIVES TO PARENT ACID. /2,4-D ESTER/
来源:Hazardous Substances Data Bank (HSDB)
毒理性
致癌性证据
A4;不可归类为人类致癌物。/2,4-D/
A4; Not classifiable as a human carcinogen. /2,4-D/
Classification of carcinogenicity: 1) evidence in humans: limited; overall summary evaluation of carcinogenic risk to humans is Group 2B: The agent is possibly carcinogenic to humans. /SRP: The older literature indicated that these compounds were carcinogenic. It was discovered that this was due to contamination, including dioxin./ /Chlorophenoxy herbicides; From table/
Occupational hepatotoxin - Secondary hepatotoxins: the potential for toxic effect in the occupational setting is based on cases of poisoning by human ingestion or animal experimentation.
IARC Carcinogen - Class 3: Chemicals are not classifiable by the International Agency for Research on Cancer.
ACGIH Carcinogen - Not Classifiable.
来源:Haz-Map, Information on Hazardous Chemicals and Occupational Diseases
Cutthroat trout (Salmo clarki) were treated with six different paired mixtures of dicamba, picloram, 2,4-D butyl ester, 2,4-D isooctyl ester, and 2,4-D propylene glycol butyl ether ester. Except for 2,4-D isooctyl ester, the LC50's resulting from mixtures of 2,4-D esters and picloram were lower than LC50's of those herbicides tested individually. Dicamba and 2,4-D isooctyl ester were the least toxic individually and mixtures of dicamba or 2,4-D isooctyl ester with the other herbicides tested did not result in increased toxicity. Results reflect the importance of using combination exposures in determining the biological significance of the simultaneous occurrence of more than one herbicide in surface waters.
2,4-D BUTYL ESTER ADMIN ORALLY TO RABBITS AT 150 OR 490 MG/KG WAS FOUND IN HIGHEST AMOUNTS IN BLOOD, KIDNEYS, LIVER, SPLEEN, LUNG, HEART, AND URINE DURING FIRST 24 HR AFTER ADMIN.
Leaves absorb nonpolar (ester) forms most readily. ... The esters of 2,4-D tend to resist washing from plants and are rapidly converted to the acid by the plants. ... Following foliar absorption, 2,4-D translocates within the phloem, probably moving with food material. Following root absorption, it may move upward in the transpiration stream. Translocation is influenced by the growth status of the plant. Accumulation of the herbicide occurs principally at the meristematic regions of shoots and roots. /2,4-D/
AFTER SC INJECTION OF 2,4-D & ITS BUTYL & ISOOCTYL ESTERS INTO MICE @ 100 MG/KG, ESTERS WERE ELIM RAPIDLY, & ONLY 5-10% OF THE 2,4-D REMAINED AFTER 1 DAY. ... 2,4-D WAS ELIM IN MILK OF COWS MAINTAINED IN PASTURES TREATED WITH 2,4-D OR ITS BUTYL OR ISOOCTYL ESTER.
来源:Hazardous Substances Data Bank (HSDB)
吸收、分配和排泄
从血浆中消失的相对速率:丁酯 > 异辛酯 > 2,4-D。
/RELATIVE/ RATES OF DISAPPEARANCE FROM PLASMA OF 2,4-D OR ITS BUTYL & ISOOCTYL ESTERS FOLLOWING SINGLE SC INJECTIONS OF 100 MG/KG BODY WT OF COMPOUNDS TO FEMALE C57BL/6 MICE WERE: BUTYL ESTER > ISOOCTYL ESTER > 2,4-D.
1.周国泰,化学危险品安全技术全书,化学工业出版社,1997 2.国家环保局有毒化学品管理办公室、北京化工研究院合编,化学品毒性法规环境数据手册,中国环境科学出版社.1992 3.Canadian Centre for Occupational Health and Safety,CHEMINFO Database.1998 4.Canadian Centre for Occupational Health and Safety, RTECS Database, 1989