In the early twentieth century, herbicides were developed to control weeds selectively and became the most beneficial chemical as plant growth controller (Burke and Bell, 2014). According to the report of the United States Department of Agriculture (USDA) in May 2014, The total quantity of pesticides for 21 crops analyzed increased from 196 million pounds of pesticide active ingredients in 1960 to 632 million pounds in 1981. The herbicide usage in the U.S. received 18 percent of the pounds in 1960, while it was 76 percent in 2008 (Jorge Fernandez et al., 2014). Herbicides are one of the common-used pesticide groups all over the world. They are used for prevention from pests and getting more and healthy agricultural products. Pendimethalin (N-(1-ethylpropyl)-3,4- dimethyl-2,6-dinitrobenzenamine) is a synthetic, selective dinitroaniline herbicide primarily used to control grasses and certain broadleaf weeds (Ramasahayam, 2014). The oral LD50 value is 1250 mg kg−۱ in male rats, while dermal LD50 value is greater than 5000 mg kg−۱ in rabbits, which means pendimethalin is slightly toxic by oral exposure and nontoxic by skin exposure (US-EPA, 1997). The oral Reference Dose (RfD) for pendimethalin was last revised on 06.03.1988 and it is reported as 4E-2 mg/kg/day. Critical health effects of pendimethalin are increasing in serum alkaline phosphatase and liver weight, and hepatic lesions (IRIS, Pendimethalin, 2017). Tolerable daily intake (TDI) of this widely used herbicide is 0.02 mg/L (WHO, 2003a,b). Pendimethalin has low acute toxicity, but causes thyroid follicular cell adenomas in male and female rats and it has classified as “suggestive evidence of carcinogenic potential” a possible human carcinogen (group C) (US-EPA, 1997, 2014). However, overall cancer incidence did not increase with increasing lifetime pendimethalin use and there was no clear evidence of an association between pendimethalin and cancer (Hou et al., 2006). The support for human carcinogenicity of pendimethalin is missing. It is classified as ‘probably not carcinogenic’, although it has not been assessed under IRIS. It is still widely used herbicide worldwide, although there are reports of the pendimethalin genotoxicity (USGS, 2015). There are studies reporting that it increases the micronucleus frequency and causes chromosomal damage. When considering the relationship between genotoxicity and cancer, the risk assessment of pendimethalin should be considered. A genotoxicity study has shown that 489 mg kg−۱ pendimethalin significantly increased the chromosomal aberrations in mouse bone marrow and induced the micronucleus (MN) frequency in plant cell and mouse bone marrow polychromatic erythrocytes (Dimitrov et al., 2006). Another genotoxicity study has shown that pendimethalin decreased the root bundle length, increased the mitotic index and the percentage of chromosome aberrations dose-dependent manner in maize and onion (Promkaev et al., 2010). Pendimethalin has been reported to be a contaminant for the environment, and it has been found highly toxic for fish and aquatic invertebrates (Singh and Singh, 2014).