Vegetable fields in and around urban areas in the Kurdistan region of Iraq may have higher than background concentrations of potentially toxic elements (PTEs) from contamination sources including municipal waste disposal and waste water used for irrigation. The purpose of this study was to assess PTE concentrations in soils and the edible parts of field-grown vegetables to quantify potential health risks to the local population. In this survey, 174 soils and 26 different vegetable and fruit types were sampled from 15 areas around Sulaymaniyah and Halabja cities. Sampling was undertaken from fields in urban, periurban and rural locations including sites close to areas of waste disposal.The soils are calcareous (pH 7.67 -8.21) and classified as silty loam, sandy or silty clay with organic matter content between 6.62 and 11.4%. Concentrations of PTEs were typically higher in waste disposal areas compared with urban, peri-urban and rural areas. Pollution load indices (PLI) suggested that agricultural soils near waste disposal sites were contaminated with some trace elements. Potentially toxic element concentrations in vegetables were highly variable. Higher total concentrations of PTEs were measured in vegetables from the waste areas with decreasing concentrations in urban, peri-urban and rural areas. Risks to human health were assessed using hazard quotients (HQ). Vegetable consumption poses no risk for adults whereas children might be exposed to Ni, As and Cd. Although HQs suggest elevated risk for children from consumption of some vegetables, these risks are likely to be lower when realistic dietary consumption levels are considered.

Land snails are crucial consumers in the terrestrial environment and beneficial significant bioindicators to evaluate the chemical impact in the ecosystem, especially on urban lands. The present study aimed to investigate the concentration of heavy metals such as As, Cr, Ni, Pb, and Zn in urban soil and study whether Eobania vermiculata acts as a bioindicator for heavy metal contamination in an urban area. Thirty soil and snail samples in triplicate from each sampling site were taken from the urban areas of Suliamani. After a microwave-assisted digestion procedure, every sample was analyzed by inductively coupled plasma-optical emission spectrometry. Results showed that the concentration of chromium (Cr) in each snail sample was significantly high. The maximum Cr concentration (15.87 mg kg−1) was recorded in the snail sample collected from Ali Kamal Park, which was adjacent to a very crowded traffic road. The As concentration in snail samples ranged from 0.08 to 1.004 mg kg−1, and it was below the permissible limits. However, the concentrations of heavy metals in urban soil locations were below their background measurements, except for nickel (Ni) which was above the permissible limits. The safest site in the study area was Chaviland 1, while the most contaminated site was the Ha-wary Shar Park. The snails bioaccumulated metals in their tissues in the following order, Cr > Zn > Ni, and this bioaccumulation occurred more on the main road locations, which represented potentially contaminated places due to anthropogenic activities. Moreover, there was no correlation among the heavy metals within the soil samples when compared to the similar metals in the snail samples, due to the low concentration of heavy metals in soil, excluding Ni, from where the snail samples were collected. Consequently, the land snail, E. vermiculata, is an appropriate sentinel organism for some metals, mainly for Cr, and the bioindicator monitoring with this snail should be extended to mixtures of heavy metals, since such relationships frequently occur in soil.

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