A COMPOSITE POLLUTION INDEX (CPI) FOR INTEGRATED ENVIRONMENTAL RISK ASSESSMENT IN THE ARAL SEA REGION: METHODOLOGY AND DISTRICT-LEVEL APPLICATION TO KARAKALPAKSTAN AND KHOREZM, UZBEKISTAN (2010–2025)

Abstract

The desiccation of the Aral Sea has produced one of the most severe anthropogenic environmental catastrophes of the modern era, exposing populations of Karakalpakstan and Khorezm (Uzbekistan) to combined air, water and soil pollution. Existing assessments rely on single-medium indices that obscure the cumulative ecological burden. Objective. To develop and validate a district-level Composite Pollution Index (CPI) integrating atmospheric, hydrospheric and pedospheric pollution into a single, policy-relevant metric. Methods. CPI was constructed as the unweighted mean of three normalised sub-indices: US EPA AQI for PM2.5/PM10, CCME WQI, and a Håkanson–Müller soil quality index. It was applied to 25 administrative units of Karakalpakstan and Khorezm using monitoring data for 2010–2025. Results. CPI ranged from 0.31 to 0.64. Moynak was the sole 'critical' district (CPI = 0.64). Regional mean CPI rose by 15.8 % between 2010 and 2025, with post-2017 acceleration. CPI correlated with five major disease groups at r_s = 0.70–0.82. Conclusions. The CPI is parsimonious, district-resolved and suitable for routine environmentalhealth surveillance and policy targeting in arid degraded basins