Tracking biological pollution sources using PCR-DGGE technology at Ta-An Beach

Area of Science:

• Environmental microbiology
• Water quality assessment
• Molecular biology techniques

Background:

• Taiwan's environmental authority defines ocean quality standard A (E. coli < 1,000 CFU/100 mL) for swimming safety.
• Ta-An Beach frequently exceeds this standard, with 51% of records showing high E. coli levels.
• Conventional methods struggle to pinpoint pollution sources like sewage and livestock wastewater.

Purpose of the Study:

• To identify the primary source of biological contamination at Ta-An Beach.
• To evaluate the effectiveness of PCR-DGGE for microbial source tracking in recreational waters.

Main Methods:

• Utilized Polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis (PCR-DGGE) to create microbial "fingerprints" of water samples.
• Compared microbial community composition between beach water and potential pollution sources (livestock wastewater).
• Applied linear regression analysis to quantify the relationship between E. coli levels and potential sources.

Main Results:

• PCR-DGGE analysis revealed high similarity between Ta-An Beach's microbial communities and upstream piggery wastewater.
• Linear regression showed a significant positive correlation (R² = 0.4102–0.7387) between livestock farm and beach E. coli levels, with piggery impact being more pronounced.
• Piggery wastewater was confirmed as the major pollution source impacting Ta-An Beach.

Conclusions:

• PCR-DGGE is a stable and reliable method for identifying microbial pollution sources in beach water.
• The study successfully pinpointed piggery wastewater as the main contaminant at Ta-An Beach.
• This approach can be applied to rapidly identify pollution sources at other recreational water sites.