The study area is the city of Zintan, in northwestern Libya, which has grown over the past 30 years. Its current population is roughly 30,000. Although the city is in part commercial, most of the population engages in agriculture and primarily grows cereal crops (wheat and barley). The demand of the growing city for agricultural products has increased, intensifying the use of fertilizers, pesticides, and insecticides. Consequently, concentrations of potentially toxic elements (PTE) in the soil have increased. To assess the soil quality (to provide a snapshot of the condition of the soil), systematic sampling was undertaken across a grid of about 2 km × 2 km. The main objective was to determine the chemical and mineral composition of the area of interest, keeping in mind the geological footprint of the terrain. The geologic framework itself is not conducive to elevated concentrations of elements like U, Th, Mo, As, Hg, Pb, and Cr. Therefore, metal concentrations greater than the amounts in the Earth’s crust are most likely of anthropogenic origin. A total of 143 samples were collected and chemical analyses were performed using a Thermo Fisher Scientific Niton XL3t GOLDD+ XRF analyzer for the following elements: Mo, Zr, Sr, U, Rb, Th, Pb, Au, Se, As, Hg, Zn, W, Cu, Ni, Co, Fe, Mn, Cr, V, Ti, Sc, Ca, K, S, Ba, Cs, Te, Sb, Sn, Cd, Pd, and Ag. This paper provides examples of elevated concentrations, potentially harmful to the environment, such as those of the following: sulfur of unknown origin (two to three times higher than the Earth’s crust average); arsenic, given that there are no related natural phenomena (all the samples measured displayed concentrations higher than those found in the Earth’s crust); mercury (concentrations much higher than permissible levels); cesium (additional investigations required to determine the origin); molybdenum; and uranium likely resulting from the use of superphosphates (concentrations nearly always significantly higher than those in the Earth’s crust).

Global population is growing rapidly. As a result, increasingly large areas are being settled and farmed. This devastates soils and causes pollution by heavy metals and other components. Heavy metals in the environment originate from both natural and anthropogenic sources. Natural sources generally include rock weathering and the propagation of heavy metals, such as Cr and Ni, from ultrabasic rocks. These are natural processes that generally do not threaten human health. Anthropogenic sources include industry and inappropriate disposal of waste in the environment. In such cases concentrations of heavy metals can be harmful to people and other living beings. Al Zintan is a city located in northwestern Libya, on a plateau mainly built up of Cretaceous sediments. Since the 1980?s, nomadic population has rapidly been settling this area. As a result, a former part of the desert was transformed and is used for farming. Soil sampling at Al Zintan was conducted in 2017, across a 2?2 km grid. A total of 143 samples were collected from depths of about 30 cm. The samples weighed 2 to 2.5 kg and generally comprised sand with a clay component. A Niton Xl3t goldd+ instrument was used for chemical analyses, based on which GIS heavy-metal distribution maps were generated. The distribution of Cr, Ni, Cu and Zn is discussed on the paper.