## 3 Results and Discussion
### Pesticide Residues in Water Samples
\begin{table}
\begin{tabular}{c c c c c} \hline
**No.** & **Compound** & **Total Samples Tested** & **Contaminated Samples** & **Range (\(\mathrm{\SIUnitSymbolMicro\text{Hz}}\) L\({}^{-1}\))** \\ \hline
1 & \(\alpha\)-BHC & 30 & 0 & nd \({}^{*}\) \\
2 & \(\beta\)-BHC & 30 & 0 & nd \\
3 & \(\gamma\)-BHC & 30 & 16 & nd–0.023 \\
4 & \(\delta\)-BHC & 30 & 0 & nd \\
5 & Heptachlor & 30 & 17 & nd–0.108 \\
6 & Aldrin & 30 & 14 & nd–0.014 \\
7 & Heptachlor epoxide & 30 & 0 & nd \\
8 & \(\gamma\)-Chlordane & 30 & 0 & nd \\
9 & \(\alpha\)-Chlordane & 30 & 0 & nd \\
10 & Endosulfan I & 30 & 2 & nd–0.005 \\
11 & 4,4\({}^{\prime}\)-DDE & 30 & 5 & nd–0.020 \\
12 & Dieldrin & 30 & 11 & nd–0.013 \\
13 & Endrin & 30 & 0 & nd \\
14 & Endosulfan II & 30 & 0 & nd \\
15 & 4,4\({}^{\prime}\)-DDD & 30 & 0 & nd \\
16 & Endrin aldehyde & 30 & 2 & 0.030 \\
17 & Endrin ketone & 30 & 0 & nd \\
18 & 4,4\({}^{\prime}\)-DDT & 30 & 0 & nd \\
19 & Endosulfan sulfate & 30 & 1 & 0.009 \\
20 & Methoxychlor & 30 & 0 & nd \\ \hline \end{tabular} nd \({}^{*}\): Not detected.  
\end{table} 
Table 4: Summary of selected pesticides contamination in surface water samples of Charsadda area. Figure 3: Representative Chromatogram and peaks identification of pesticides in surface water samples from Charsadda area: (1) \(\gamma\)-BHC, (2) heptachlor, (3) aldrin, (4) \(\alpha\)-chlordane, (5) endosulfan I, (6) 4,4\({}^{\prime}\)-DDE, (7) dieldrin, (8) endosulfan II, (9) Endrin aldehyde, (10) Endosulfan sulfate. reported pesticide contamination in the surface water samples of China, with maximum concentrations of 0.003, 0.006, 0.003 and 0.012 \(\upmu\)g L\({}^{-1}\) for \(\upalpha\)-BHC, \(\upbeta\)-BHC, \(\upgamma\)-BHC, and heptachlor, respectively [46]. [PERSON] et al. (2013) identified pesticide contamination in surface water samples of Lake Chaohu, China, with maximum concentrations of 0.003 \(\upmu\)g L\({}^{-1}\) (\(\upalpha\)-BHC), 0.009 \(\upmu\)g L\({}^{-1}\) (\(\upbeta\)-BHC), 0.003 \(\upmu\)g L\({}^{-1}\) (\(\upgamma\)-BHC), 0.001 \(\upmu\)g L\({}^{-1}\) (heptachlor) and 0.001 \(\upmu\)g L\({}^{-1}\) (aldrin) [8]. However, [PERSON] et al. (2003) reported pesticide contamination in surface water samples of Northern Greece with maximum concentrations of 0.031, 0.096, 0.081, 0.189, 0.020 and 0.101 \(\upmu\)g L\({}^{-1}\) for \(\upalpha\)-BHC, \(\upbeta\)-BHC, \(\upgamma\)-BHC, \(\updelta\)-BHC, heptachlor and aldrin, respectively [19]. Lindane (\(\upgamma\)-BHC) has been used to treat food crops, forestry products, seeds and soil, and to treat pets and livestock. It was applied largely to cotton, coffee, cocoa, sugar can and other crops. BHC isomers can undergo long-range transport and can be deposited into aquatic systems, where they can bioaccumulate in the food chain. Heptachlor has been used to kill soil insects and fermites, to control grasshoppers, cotton insects and some crop pests, particularly those infecting corn. Aldrin and dieldrin are strongly related to each other. They were counted for a number of cases that produced the mortality of many wild life species, because following the application of aldrin in the fields, it rapidly changes to dieldrin [47]. The pesticides endosulfan I, 4,4\({}^{\prime}\)-DDE, endrin aldehyde and endosulfan sulfate were detected only in 2, 5, 2 and 1 surface water samples, with maximum concentrations of 0.005, 0.020, 0.030 and 0.009 \(\upmu\)g L\({}^{-1}\) in the Charsadda area, respectively. The Australian guideline values for the pesticides endosulfan I, 4,4\({}^{\prime}\)-DDE, 4,4\({}^{\prime}\)-DDT, methoxychlor and endosulfan sulfate are 0.05, 0.06, 0.06, 0.2 and 0.5 \(\upmu\)g L\({}^{-1}\), respectively. The endosulfan I was more dominant than the other endosulfans. The 4,4-DDE is the byproduct of DDT degradation and is more stable in the environment. None of the other pesticides in this study were detected in any of the surface water samples collected from the Charsadda area. [PERSON] et al.