What question did this study set out to answer?

This study evaluates the soil fertility status and heavy metal contamination levels in Sulaymaniyah.

April 3, 2026Open Access

Assessment of Soil Fertility and Heavy Metal Contamination: Nutrient Analysis and Health Risk Evaluation in Sulaymaniyah Governorate, Northern Iraq

Key Points

This study evaluates the soil fertility status and heavy metal contamination levels in Sulaymaniyah.
Soil samples were collected from ten sites at a depth of 0-15 cm.
Essential nutrients and heavy metals were analyzed using ICP-OES.
Contamination factors, ecological risk indices, and soil quality indices were calculated.
Human health risks were assessed through estimated daily intake and hazard quotients.
Elevated heavy metal concentrations were found, notably Zn (up to 103.88 mg/kg) and Pb (114.02 mg/kg).
Nutrient analysis showed adequate levels of K, Mg, and Mn but excessive Ca and Mo in some sites.
Most sites were classified with environmental concern based on CCME-SoQI values.
Health risk assessments indicated low risks for soil ingestion, though Pb and Co posed relatively higher risks.

Abstract

Soil quality plays a critical role in environmental sustainability, agricultural productivity, and human health. This study aimed to evaluate soil fertility status, heavy metal contamination, and associated non-carcinogenic health risks in ten selected sites in Sulaymaniyah province, Iraq. Soil samples (0-15 cm) were collected and analyzed for essential nutrients (K, Mg, Mn, Ca, and Mo) and heavy metals (Zn, Pb, Cd, Cu, and Co) using standard analytical methods, including ICP-OES. Soil quality was evaluated using contamination factor (Cf), potential ecological risk index (RI), and the Canadian Council of Ministers of the Environment soil quality index (CCME-SoQI). Human health risks were assessed through estimated daily intake (EDI), hazard quotient (HQ), and hazard index (HI). The results indicated elevated concentrations of Zn (up to 103.88 mg/kg), Pb (114.02 mg/kg), Cd (3.26 mg/kg), and Cu (191.30 mg/kg) at certain sites, exceeding WHO permissible limits, particularly at sites S7 and S9. Nutrient analysis indicated adequate levels of K (45.8-179.00 mg.kg⁻¹), Mg (177.7-253.7 mg.kg⁻¹), and Mn (22.3-43.4 mg.kg⁻¹), while Ca (up to 8246.7 mg.kg⁻¹) and Mo (up to 0.469 mg.kg⁻¹) were excessively high in several locations. CCME-SoQI values ranged from 36.68 to 78.03, classifying most sites as having environmental concern. Health risk assessment revealed that HQ and HI values were low and limited, with HI (0.028 to 0.080), indicating no risk through soil ingestion, although Pb and Co contributed relatively higher risk values. Overall, the results highlight localized heavy metal contamination and nutrient imbalance, emphasizing the need for continuous monitoring and sustainable soil management strategies.

Mark Helpful

Bookmark

Relay

View Full Paper