Unraveling the spatiotemporal heterogeneity of odorous compounds and their associated parameters in drinking water reservoirs: A systematic review.

Aesthetic parameters have become integral to drinking water reservoir management, yet the pronounced spatiotemporal heterogeneity of odorants challenges effective control. Current knowledge gaps include comprehensive characterization of seasonal/spatial odorant patterns and their associated factors, hindering evidence-based mitigation strategies. To address these gaps, we systematically analyzed 1005 observations from 22 reservoirs worldwide, quantifying spatiotemporal dynamics of four typical odorants-2-methylisoborneol (2-MIB), geosmin (GSM), β-ionone and β-cyclocitral-alongside key environmental parameters, while elucidating critical factor interactions. Results showed odorant concentrations peaked in spring and autumn, followed by summer and winter. 2-MIB and GSM maximized in transition zones whereas β-ionone and β-cyclocitral peaked in lacustrine zones; all odorants minimized near dams. Mixed-effects modeling identified chlorophyll-a (Chla), temperature, dissolved oxygen, pH, total nitrogen, total phosphorus as critical predictors with odorant-specific effect magnitudes. Linear regressions revealed consistent spring-autumn patterns but divergent summer-winter trends, with significant factor-odorant relationships increasing progressively from riverine (n = 4) to lacustrine zones (n = 7). Structural equation modeling demonstrated interconnected temperature-Chla-nutrient networks exerting compound-specific effects on odorant formation. Based on these insights, we propose an integrated "Monitor-Predict-Control" framework, which translates the identified seasonal and spatial patterns into concrete, actionable strategies for proactive reservoir odorant management.