**5. Future research**

**a**

As mg/kg

0

As mg/kg

0.00

**4. Discussion**

**Figure 11.** Comparison of (b) soil extractable of As with (a) total soil concentrations in Libya

0.01

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**b**

2

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868 Environmental Risk Assessment of Soil Contamination

East South West

East South West

Total As mean concentrations in ESR are nearly 4.8 and 4.1 times higher than in SSR and WSR, respectively. Total As loads in ESR may be related to the soil parent material, which is comprised of subsequently covered Lower Palaeozoic rocks. This may be the reason why the clay agricultural soils of ESR have the highest background levels of As. This is in agreement with [8], who reported higher concentrations of trace elements in Eastern Libyan soil than in other areas. In the present study, the trace elements present in Eastern Libyan soil (Co, Zn, Cu,

