Effect of the particle size and surface area on Escherichia coli attachment to mineral particles in fresh water

Abstract

The objective of this study was to assess the effects of the particle size and specific surface area (SSA) on the attachment of Escherichia coli to sediment particles. To exclude the effect of different sediment mineral compositions, pure minerals were used, and three typical suspended sediment (<62 μm) components, quartz, K-feldspar and calcite, were separated into four groups with different grain size distributions. Equilibrium attachment experiments covering common E. coli concentrations in surface water were conducted for each group. The results show that the finer fractions of each pure mineral had the greatest attachment capacity. Different mineral properties were measured, as well as an author-defined parameter (SSA_a), which was calculated by integrating the particle size distribution and only reflected the microscopic surface areas accessible to E. coli cells (∼1 μm) while excluding the effects of nanoscopic pores (5–10 nm). Pearson correlation and partial correlation analyses suggested that the partition coefficient (K_d) was positively correlated with the clay content (CC) and SSA_a (P < 0.01). Stepwise multiple regression analysis suggested that SSA_a was the dominant factor (P < 0.01) and was a better explanatory variable than CC. Moreover, in addition to SSA_a, the zeta potential and SSA also partially explained the results (P < 0.05).

Keywords:

• Escherichia coli
• attachment
• partition coefficient
• particle size
• surface area

Acknowledgments

We sincerely appreciate the comments and helpful suggestions from professor Danxun Li of Tsinghua University, China.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China (grant number 51509136) and the Tianjin Municipal Natural Science Foundation (grant number 15JCZDJC41100).