OBJECTIVE:

To evaluate the water quality of two beaches in Soure, Pará State, Brazil, during a climatic anomaly in 2024, focusing on bacteriological, viral, physicochemical, and metal analyses, considering the influence of oceanic waters on the Pará coastal zone.

MATERIALS AND METHODS:

Pesqueiro and Barra Velha beaches were selected due to their tourism relevance. Sampling was carried out in July and September, corresponding to the high and low tourist seasons, respectively. Samples underwent physicochemical and microbiological analyses, as well as detection of the viral marker crAssphage, and a metagenomic approach to characterize both viral and bacterial diversity.

RESULTS:

In July, both sites showed thermotolerant bacterial levels within legal limits, while in September, values exceeded the permitted thresholds. Sulfate and chloride concentrations were significantly higher than the reference limit (≤ 250.0 mg/L) in all samples. Dissolved oxygen levels were higher in July and extremely low in September, when turbidity was also greater. Metagenomic analysis revealed a broad microbial diversity, with bacterial dominance. The most prevalent viral families were Kyanoviridae, Autographiviridae, and Straboviridae. Among bacteria, Vibrionaceae and Paracoccaceae were predominant at Pesqueiro and Barra Velha beaches, respectively.

CONCLUSION:

The findings demonstrate the influence of seasonal and anthropogenic factors on water quality in the region, highlighting the need to intensify environmental research in the Amazon, given its ecological complexity and increasing pressure from large-scale developments.