Microcystins risk assessment in lakes from space: Implications for SDG 6.1 evaluation

Area of Science:

• Environmental Science
• Water Quality Monitoring
• Remote Sensing Applications

Background:

• Cyanobacterial blooms produce Microcystins (MCs), posing risks to drinking water safety and hindering progress towards UN Sustainable Development Goal 6.1.
• Routine monitoring of algal toxins in lake water remains infrequent and inadequately evaluated.
• Large lakes in densely populated regions are critical water sources requiring robust safety assessments.

Purpose of the Study:

• To develop a remote sensing-based scheme for assessing human health risks from Microcystins (MCs) in large lakes.
• To map the spatial and temporal dynamics of MCs risk in eastern China's lakes using satellite data.
• To evaluate the feasibility of setting drinking water intakes based on MCs risk assessment.

Main Methods:

• Utilized Sentinel-3 OLCI satellite data from 2016-2021 for monitoring.
• Developed a remote sensing scheme to identify and quantify human health risks associated with MCs.
• Analyzed data from 100 large lakes (>25 km²) in eastern China.

Main Results:

• Mapped the spatial and temporal distribution of MCs risk across eastern China's lakes.
• Detected high MCs risk in 80 out of 100 studied lakes at least once.
• Found that 70.93% of total lake areas experienced high human health risks at a frequency of only 1%.

Conclusions:

• Satellite remote sensing offers a powerful tool for monitoring algal toxins and assessing drinking water safety.
• Most large lakes in eastern China present a low overall risk from MCs, suggesting safe drinking water intakes are feasible.
• Findings provide crucial data for SDG 6.1 reporting, especially for lakes lacking routine monitoring programs.