A new method for assessment of sediment-associated contamination risks using multivariate statistical approach.

Area of Science:

• Environmental Science
• Marine Chemistry
• Ecotoxicology

Background:

• Sediment contamination by heavy metals poses significant ecological risks.
• Existing methods for assessing sediment quality require refinement for accurate risk prediction.

Purpose of the Study:

• To develop and propose two novel sediment quality indices: the modified hazard quotient (mHQ) and the ecological contamination index (ECI).
• To predict potential ecological risks associated with heavy metal contamination in sediments.
• To evaluate the effectiveness of these new indices against existing methods.

Main Methods:

• Assimilation of heavy metal concentration data from sequential extraction method (SEM).
• Integration of metal toxicity factors into new index calculations.
• Application of the developed indices to heavy metal speciation data (Cd, Cr, Cu, Ni, Pb) from Equatorial Atlantic coastal ecosystems.
• Utilized principal component analysis (PCA) and factor analysis to identify pollution sources.

Main Results:

• The developed mHQ and ECI indices demonstrated reliability and precision in assessing sediment contamination.
• Evaluation indicated that sediments in most studied ecosystems were considerably to highly contaminated.
• Results showed close agreement between the proposed indices and existing pollution indices.
• PCA and factor analysis identified anthropogenic sources as the primary contributors to heavy metal pollution, particularly Cd and Pb.

Conclusions:

• The newly developed mHQ and ECI indices are effective tools for predicting sediment-associated adverse ecological effects.
• The proposed indices align well with established pollution indices, validating their utility.
• Significant anthropogenic contamination by cadmium and lead was confirmed in the studied benthic sediments.