Review of highway runoff characteristics: comparative analysis and universal implications

Area of Science:

• Environmental Science
• Water Quality Management
• Highway Runoff Studies

Background:

• Highway runoff is a significant source of aquatic pollution.
• Characterization studies globally reveal trends and pollutant behaviors.
• Variability in water quality data necessitates synthesis and interpretation.

Purpose of the Study:

• To synthesize global highway runoff characterization studies.
• To analyze historical trends, first flush effects, and pollutant forms (dissolved vs. particulate).
• To identify reliable surrogate water quality parameters for monitoring.

Main Methods:

• Comprehensive literature review of highway runoff studies across continents.
• Synthesis of data on pollutant concentrations, forms, and temporal variations.
• Statistical analysis to identify correlations between water quality parameters.

Main Results:

• Global highway runoff quality parameters exhibit variability within expected ranges.
• Lead (Pb) concentrations have decreased significantly due to leaded gasoline phase-out.
• Pollutants, including metals and phosphorus, exist in both dissolved and particulate forms.
• Strong correlations exist between Total Suspended Solids (TSS), Total Dissolved Solids (TDS), Total Organic Carbon (TOC), and iron (Fe) with numerous other parameters.

Conclusions:

• Highway runoff quality is variable but generally within expected ranges.
• Regulatory actions, like phasing out leaded gasoline, effectively reduce specific pollutant levels.
• Understanding pollutant partitioning and first flush dynamics is crucial for effective stormwater management.
• TSS, TDS, TOC, and Fe can serve as effective surrogate parameters for monitoring highway runoff quality.