Linking bioavailability and toxicity changes of complex chemicals mixture to support decision making for remediation endpoint of contaminated soils.
Sci Total Environ
; 650(Pt 2): 2150-2163, 2019 Feb 10.
Article
em En
| MEDLINE
| ID: mdl-30290356
ABSTRACT
A six-month laboratory scale study was carried out to investigate the effect of biochar and compost amendments on complex chemical mixtures of tar, heavy metals and metalloids in two genuine contaminated soils. An integrated approach, where organic and inorganic contaminants bioavailability and distribution changes, along with a range of microbiological indicators and ecotoxicological bioassays, was used to provide multiple lines of evidence to support the risk characterisation and assess the remediation end-point. Both compost and biochar amendment (pâ¯=â¯0.005) as well as incubation time (pâ¯=â¯0.001) significantly affected the total and bioavailable concentrations of the total petroleum hydrocarbons (TPH) in the two soils. Specifically, TPH concentration decreased by 46% and 30% in Soil 1 and Soil 2 amended with compost. These decreases were accompanied by a reduction of 78% (Soil 1) and 6% (Soil 2) of the bioavailable hydrocarbons and the most significant decrease was observed for the medium to long chain aliphatic compounds (EC16-35) and medium molecular weight aromatic compounds (EC16-21). Compost amendment enhanced the degradation of both the aliphatic and aromatic fractions in the two soils, while biochar contributed to lock the hydrocarbons in the contaminated soils. Neither compost nor biochar affected the distribution and behaviour of the heavy metals (HM) and metalloids in the different soil phases, suggesting that the co-presence of heavy metals and metalloids posed a low risk. Strong negative correlations were observed between the bioavailable hydrocarbon fractions and the ecotoxicological assays suggesting that when bioavailable concentrations decreased, the toxicity also decreased. This study showed that adopting a combined diagnostic approach can significantly help to identify optimal remediation strategies and contribute to change the over-conservative nature of the current risk assessments thus reducing the costs associated with remediation endpoint.
Palavras-chave
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Poluentes do Solo
/
Alcatrões
/
Compostagem
/
Carvão Vegetal
/
Recuperação e Remediação Ambiental
Tipo de estudo:
Etiology_studies
/
Risk_factors_studies
País/Região como assunto:
Europa
Idioma:
En
Revista:
Sci Total Environ
Ano de publicação:
2019
Tipo de documento:
Article
País de afiliação:
Reino Unido