Polycyclic aromatic hydrocarbons in biochar amended soils: Long-term experiments in Brazilian tropical areas

Michele Fabri de Resende; Taila Figueredo Brasil; Beata Emoke Madari; Annibal Duarte Pereira Netto; Etelvino Henrique Novotny

doi:10.1016/j.chemosphere.2018.02.139

Polycyclic aromatic hydrocarbons in biochar amended soils: Long-term experiments in Brazilian tropical areas

Chemosphere. 2018 Jun:200:641-648. doi: 10.1016/j.chemosphere.2018.02.139. Epub 2018 Feb 23.

Authors

Michele Fabri de Resende¹, Taila Figueredo Brasil², Beata Emoke Madari³, Annibal Duarte Pereira Netto⁴, Etelvino Henrique Novotny⁵

Affiliations

¹ Programa de Pós-Graduação em Química, Instituto de Química, Universidade Federal Fluminense, Outeiro de São João Batista, s/n, 24020-141, Niterói, RJ, Brazil; Laboratório de Química Analítica Fundamental e Aplicada, Departamento de Química Analítica, Instituto de Química, Universidade Federal Fluminense, Outeiro de São João Batista, s/n, 24020-141, Niterói, RJ, Brazil; Embrapa Soils, Rua Jardim Botânico, 1024, 22460-000, Rio de Janeiro, RJ, Brazil.
² Laboratório de Química Analítica Fundamental e Aplicada, Departamento de Química Analítica, Instituto de Química, Universidade Federal Fluminense, Outeiro de São João Batista, s/n, 24020-141, Niterói, RJ, Brazil.
³ Embrapa Rice & Beans, Rodovia GO-462, Km 12, Santo Antônio de Goiás, GO, Brazil.
⁴ Programa de Pós-Graduação em Química, Instituto de Química, Universidade Federal Fluminense, Outeiro de São João Batista, s/n, 24020-141, Niterói, RJ, Brazil; Laboratório de Química Analítica Fundamental e Aplicada, Departamento de Química Analítica, Instituto de Química, Universidade Federal Fluminense, Outeiro de São João Batista, s/n, 24020-141, Niterói, RJ, Brazil.
⁵ Embrapa Soils, Rua Jardim Botânico, 1024, 22460-000, Rio de Janeiro, RJ, Brazil. Electronic address: etelvino.novotny@embrapa.br.

PMID: 29518648
DOI: 10.1016/j.chemosphere.2018.02.139

Abstract

The interest in charcoal for agricultural use (biochar) has sharply increased in recent years. However, biochar can contain groups of compounds such as polycyclic aromatic hydrocarbons (PAHs) that are considered persistent pollutants, and are formed concomitantly with biochar during its production by pyrolysis. Soil samples were collected in three experimental areas at different intervals (1, 3, 5 or 6 years) after the application of 16 Mg ha^-1 of biochar. The total concentrations of PAHs; benzo[a]pyrene; and the estimated total cancer risk in biochar treated plots were larger than found in the control ones, but they decreased over time, equaling the control values after three years in the high C content soil (11.2 g C kg^-1 soil), or after six years in the low C content soil (6.8 g C kg^-1 soil). Nevertheless, the sum of PAH concentrations found in the biochar amended plots, in the range of 15.80-39.40 ng g^-1, were around two orders of magnitude below the limits of prevention established by Brazilian legislation (8100 ng g^-1) and some European regulations for soils (3000 ng g^-1) and also lower than the observed in previous studies about biochar amended soils. Our results indicate that, under the conditions evaluated, the application of biochar to soil in the studied proportion (16 Mg ha^-1, every six years) is safe concerning soil contamination by PAHs.

Keywords: Black carbon; Charcoal; Factor analysis; PAH; Pyrogenic carbon; Soil contamination.

MeSH terms

Agriculture
Brazil
Charcoal / chemistry*
Environmental Pollution
Polycyclic Aromatic Hydrocarbons / chemistry*
Soil / chemistry
Soil Pollutants / chemistry*
Time Factors

Substances

Polycyclic Aromatic Hydrocarbons
Soil
Soil Pollutants
biochar
Charcoal