Water Quality Assessment in River and Aquatic Ecosystems

Water quality assessment in riverine and broader aquatic ecosystems integrates physical, chemical and biological indicators to characterise the suitability of water for human use, ecological integrity and regulatory compliance. Core approaches include the use of composite indices, mechanistic modelling and multivariate statistics to interpret parameters such as nutrient loads, dissolved oxygen dynamics, heavy-metal concentrations and microbial contaminants. Advances in sensor networks, remote sensing and data analytics have enhanced spatio-temporal resolution, enabling near-real-time monitoring of episodic pollution events and long-term trends. Interdisciplinary frameworks now link water-quality data with watershed management, land-use patterns and climate variability, highlighting the global significance of maintaining water security, biodiversity and public health. Practical applications range from identifying non-point pollution hotspots to guiding adaptive river restoration and improving drinking-water provision in urban and rural settings.

Research from Nature Portfolio

Recent studies have refined the application of the Water Quality Index in large freshwater systems, demonstrating interannual deterioration linked to nutrient enrichment and seasonal hydrodynamics. Analyses of long-term monitoring at a major lake have shown that dilution by high water levels mitigates total nitrogen concentrations, while low-water periods coincide with poorer water quality. These findings underscore the importance of integrating hydrological regime shifts into routine index-based assessments and inform adaptive management strategies for nutrient control during critical seasonal windows.

Water Quality Assessment in River and Aquatic Ecosystems publication trend

The graph below shows the total number of articles in water quality assessment in river and aquatic ecosystems across all publications each year (not limited to Nature Index journals).

Technical terms

Water Quality Index (WQI): Composite score aggregating multiple water-quality parameters into a single value to indicate overall status.

Biochemical Oxygen Demand (BOD): Amount of dissolved oxygen consumed by microbial decomposition of organic matter over a set period.

Chemical Oxygen Demand (COD): Measure of oxygen required to chemically oxidise organic and inorganic constituents in water.

Dissolved Oxygen (DO): Concentration of free oxygen molecules dissolved in water, essential for aquatic life.

Non-point source pollution: Diffuse contamination arising from widespread land-use activities, such as agricultural runoff or urban stormwater.

References

1. Spatial association of surface water quality and human cancer in China. npj Clean Water (2023).
2. Water quality assessment based on the water quality index method in Lake Poyang: The largest freshwater lake in China. Scientific Reports (2017).
3. Alteration of Water Pollution Level with the Seasonal Changes in Mean Daily Discharge in Three Main Rivers around Dhaka City, Bangladesh. Environments (2015).
4. Combined Multivariate Statistical Techniques, Water Pollution Index (WPI) and Daniel Trend Test Methods to Evaluate Temporal and Spatial Variations and Trends of Water Quality at Shanchong River in the Northwest Basin of Lake Fuxian, China. PLOS ONE (2015).