Rainwater geochemistry inside the Barcarena power station at the mouth of the Tocantins River

ABSTRACT

Most of South America lacks studies on rainwater composition. The present study evaluates rainwater composition and bulk deposition inside Barcarena power station, located at the mouth of the Tocantins River with Amazon River in Brazil. In 2012, 24-h rainwater samples were collected inside the ELETRONORTE power plant (n = 93), and pH, EC, cations and anions were analyzed. In order of abundance, the rainwater ions were Na⁺ > Cl⁻ > SO₄⁻² > Ca⁺² > K⁺ > F⁻ > Mg⁺² > NH₄⁺-N > NO₃⁻-N. pH values ranged from 4.5 to 6.9, with 17 events with pH <5.6 and 5 events with pH < 5.0. Sodium and Cl⁻ were the dominant ions with sea salt as main contribution. Acidity, enrichment factors and principal component analysis (PCA) indicate that F⁻, SO₄⁻² and NO₃⁻-N in the rainwater came from anthropogenic sources. Fluoride correlated strongly (>0.85) with Ca⁺² and Mg⁺², likely originated from same source in the aluminum production chain. Potassium originated from a mixture of anthropogenic and natural sources, with a good correlation (>0.70) with NO₃⁻-N and NH₄⁺-N, indicating biomass burning and fertilizer origins. In 2012, Barcarena total bulk deposition ranged from 14,070 to 17,890 mg m⁻² y⁻¹ with significant contributions of SO4⁻² (2,385 to 2,851 mg m⁻² y⁻¹), F⁻ (419 to 479 mg m⁻² y⁻¹) and NO₃⁻-N (128 to 280 mg m⁻² y⁻¹). EC values (4 to 254 µS cm⁻¹) indicated a medium site pollution severity (> 175 µS cm⁻¹), which increased the risk of damage to electrical components.

Highlights

• Chemical characterization of Barcarena, PA/Brazil rainwater in 2012 events.

• Apportionment sources of ionic rainwater content evaluated by acidity fraction, enrichment factors and principal component analysis.

• Anthropic fluoride, sulfate and nitrate local deposition values were compared with other regional data.

• Maintenance procedure recommendations under identified atmospheric deposition.

GRAPHICAL ABSTRACT

KEYWORDS:

• Rainwater and pollution
• enrichment factor
• major ions
• power plant
• principal component analysis

Acknowledgement

Appreciation is extended to all employees of the Vila do Conde Power Station in Barcarena and especially to José Maria Aquino da Luz, Higino Rodrigues Cardoso and Augusto Sérgio Mourão Noronha. Finally, the authors are grateful to their colleagues of the Centro de Tecnologia da Eletronorte Eletrobras.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Darilena Monteiro Porfírio http://orcid.org/0000-0003-3320-0255

Lucilena Rebêlo Monteiro http://orcid.org/0000-0002-4457-4925

Marcondes Lima da Costa http://orcid.org/0000-0002-0134-0432

Additional information

Funding

The authors thank the financial support provided by Agencia Nacional de Energia Elétrica – ANEEL to the project “Desenvolvimento de Tecnologia para Avaliação de Desempenho de Isoladores e Áreas de Alta Agressividade contrato” #4500078262 from 2013 to 2016, PROPESP/UFPA and National Council for Scientific and Technological Development - CNPq (Grant number 305015/2016-8).