Farmers use pesticide (herbicides, insecticides, fungicides, molluscicides, rodenticides, acaricides and nematicides) for the protection of crop . Chlorinated aromatic compounds (CACs) have been widely used in industrial, agricultural and domestic products such as pesticides, soil fumigants, disinfectants, toilet deodorants, solvents, and also used as precursors for the production of dyes [2, 3].
As a result of worldwide extensive use, CACs are widespread and released as environmental pollutants in coastal marine sediments, freshwater lake sediments, sewage sludge, waste water, groundwater, rivers and estuaries, and soils [4–6]. Due to their persistence, toxicity, and bioaccumulation potential, CACs are subject to regulation in most of the developed countries . The main environmental impact of pesticide is caused by their mobilization and transport from agriculture fields to pollute soils, sediment, water and also percolating through the soil and reaching the ground water [8–11].
Pentachloronitrobenzene (PCNB) is an important group of organochlorine fungicide which has been widely used either for seed dressing or for soil treatment to control a wide range of phytopathogenic fungi in crops [12, 13]. Hexachlorobenzene (HCB) is also used as a fungicide and is a side product of industrial emission related to the manufacture of chlorinated solvents and pesticides [14–16]. Both organochlorine fungicide (PCNB and HCB) are widespread and found in every environmental compartment i.e. soil, water, and air [17, 18]. Lipophilic nature of these compounds results in their bioaccumulation at different trophic levels via the food chain, thereby increasing risk to different living beings [19, 20]. The accumulation of organochlorine pesticide is due to their resistance to both biotic and abiotic degradation in environmental condition . Public concern has prompted the need for removal of these contaminants from the environment. Therefore, there has been an increase in effort to remove PCNB, HCB and their possible intermediates from the environment either by abiological or biological means during the past decades. The biotransformation products of PCNB include pentachloroaniline (PeCA), tetrachloroaniline (TeCA), trichloroaniline (TCA), dichloroaniline (DCA), chloroaniline (CA), pentachlorophenol (PCP), pentachlorothiophenol, pentachlorothioanisole and pentachloromethyl-phenyl sulfoxide [22–25]. The biotransformation products of HCB are pentachlorobenzene (PeCB), tetrachlorobenzene (TeCB), trichlorobenzene (TCB), dichlorobenzene (DCB), pentachlorophenol (PCP), tetrachlorohydroquinone (TeCH) and dichlorohydroquinone (DiCH) [14–16]. Some of these polychlorinated and their nitro or amino derivatives metabolites such as PeCB, TeCB, TCB, DCB, PeCA, TeCA, TCA, DCA and CA can be determined by gas chromatography coupled with electron capture detector (GC-ECD) [26–29]. However, it is difficult to identify some of chlorophenolics and chloroquinolics intermediates such as PCP, tetrachlorophenol (TeCP), trichlorophenol (TCP), dichlorophenol (DCP) and TeCH, DiCH by GC due to their relative polarity, low vapour pressure, chemical reactivity, causing adsorption and tailing of the chromatographic peaks [30, 31]. Therefore, for determination of these CACs and chemically different nature (polar/ionic) of the putative intermediates, there is a need to develop simple, quick extraction and analytical method. In the present study we report a high performance liquid chromatography (HPLC) method for determination of PCNB, HCB and their possible metabolites.