Pollution, spatial distribution, and health risks assessment of nutrient concentration in surface water resources of Maroon-Jarahi Basin in southwestern Iran.

Nowadays, the introduction of nutrients caused by human activities is considered an environmental issue and a significant problem in river basins and coastal ecosystems. In this study, the concentration of nutrients ( NO 3 - and PO 4 3 - ) in the surface water sources of the Maroon-Jarahi watershed in the southwest of Iran was determined, and the pollution status and health risk assessment were done. The average concentration of nitrate and phosphate in Ludab, Maroon, Zard, Allah, Jarahi rivers, and Shadegan wetland were obtained at 2.25-0.59, 4.59-1.84, 4.07-2.02, 5.40-2.81, 11.51-4.67, 21.63 and 6.20 (mg/l), respectively. A comparison of the results with the World Health Organization (WHO) limit showed that nitrate was lower than in all stations, but phosphate was higher than the limit in some stations of the Maroon, Allah, Jarahi rivers, and Shadegan wetland. Calculation of linear regression analysis showed significant positive relationships between nitrate and phosphate in all surface water sources (except Ludab) and based on the N/P ratio, nitrogen was estimated as the limiting factor in phytoplankton growth (N/P < 16). The evaluation of the status of the Nutrient pollution index (NPI) was observed as: Shadegan > Jarahi > Allah > Maroon > Zard > Ludab that the Jarahi River and Shadegan wetland were in the medium pollution class (1 < NPI ≤ 3) and other waterbodies were in the non-polluted to low pollution state (NPI < 1). Calculation of the chronic daily intake (CDI) showed that water body nutrients cause more non-carcinogenic health risks through the oral route than dermal exposure, and according to HI, children's health is more at risk than adults. Findings showed that surface water resources especially downstream of the Maroon-Jarahi watershed are at eutrophication risk, and to control the nearby human activities and as a result increase the nutrients in these water resources, measures should be taken.

Optimization of geographical space of ecosystem service areas and land-use planning, Iran.

This study provides a framework for optimizing ecosystem service zones based on landscape patterns. Ecosystem service zoning is a tool for making more informed land-use decisions and integrating ecosystem services into land development strategies. Accordingly, a meta-heuristic algorithm (simulated annealing-genetic hybrid) was applied to optimize zones of three ecosystem services, including aesthetic value, recreation value, and noise pollution reduction service. The goal was to select ecosystem service zones in terms of area, percentage of landscape, shape, and number of patches in two land-use types, including the built-up and green cover. The results indicated that optimum zones based on green infrastructure comprised more extent and average suitability than human infrastructure. The western and southern parts of the target area showed the highest values of ecosystem services for the two land-use classes. The convergence curve of the objective functions indicated the good performance of the employed algorithm in optimizing ecosystem service zones. Overall, the results indicated that optimizing ecosystem service zones based on landscape patterns improved the land-use management framework in the study area. Moreover, the used algorithm allowed for integrating different parameters into ecosystem services zone configurations.