Surface water quality monitoring in Sulaymaniyah Governorate, Iraq: polycyclic aromatic hydrocarbons, major anions, physicochemical parameters, and seasonal trends.

Polycyclic aromatic hydrocarbons (PAHs) are persistent organic pollutants (POPs) that pose a severe threat to aquatic ecosystems worldwide. This study presents a comprehensive assessment of PAH contamination in selected interconnected freshwater systems in the Sulaymaniyah Governorate, Iraq, based on the winter and spring 2025 samples collected from eight shoreline sites. ∑PAH concentrations were notably high across all sampling sites, ranging from 37.61 to 217.30 µg L-1 throughout the sampling campaigns. Raw sewage, massive local agriculture, municipal waste, and various toxic industrial effluents flow into the deteriorated Tanjaro River. The maximum recorded concentrations for PAHs exceeded established international water quality guidelines by several orders of magnitude, highlighting severe contamination levels in the studied waterbodies. However, the majority of detected PAH compounds currently lack established surface water quality guidelines, preventing direct regulatory comparison for those compounds. Diagnostic ratios indicated a mixed pyrogenic-petrogenic origin. Correlations between major anions and physicochemical parameters further indicated the influence of multiple anthropogenic sources on water quality. Seasonal dynamics were evident, with higher PAH burdens in winter than in spring. These findings identify severe pollution hotspots in an understudied region and highlight the urgent risks to aquatic ecosystems and communities dependent on these waters. The study underscores the need for stronger pollution control measures and establishes a critical baseline for future environmental monitoring in Iraq and similarly understudied regions.