HydrologyModerate
Nakhon Sawan Headwaters
Chao Phraya
WQI 58pH 7.2NTU 45
Agricultural runoff upstream; fertilizer nitrates detected
HydrologyHeavy
Bangkok Estuary Station
Chao Phraya
WQI 34pH 6.8NTU 78
Industrial discharge + urban wastewater; mercury traces above WHO limit
HydrologyClean
Kemble Source
Thames
WQI 82pH 7.6NTU 12
Pristine chalk stream headwater; within WHO drinking limits
HydrologyModerate
Thames Barrier Monitoring
Thames
WQI 61pH 7.4NTU 38
Microplastic contamination; sewage overflow events during storms
HydrologyClean
Fouta Djallon Highlands
Niger
WQI 76pH 7.1NTU 18
Natural spring source; minimal industrial impact upstream
HydrologyToxic
Niger Delta Outflow
Niger
WQI 22pH 5.9NTU 92
Oil spill contamination; hydrocarbon levels exceed SDG 6.3 thresholds
HydrologyClean
Gangotri Glacier Source
Ganges
WQI 88pH 7.8NTU 8
Glacial meltwater; pristine source, within all WHO parameters
HydrologyToxic
Varanasi Monitoring Station
Ganges
WQI 18pH 6.2NTU 88
Coliform bacteria 400x WHO limit; ritual + industrial contamination
HydrologyClean
Nevado Mismi Source
Amazon
WQI 91pH 7.5NTU 6
Remote Andean source; pristine water chemistry
HydrologyModerate
Mouth / Atlantic Outflow
Amazon
WQI 64pH 7.3NTU 55
Deforestation-driven sediment load; mercury from illegal mining upstream