Application of compost assisted by Fe3O4 nanoparticles in di (2-ethylhexyl) phthalate-contaminated soil remediation: Biostimulation strategy, Soil responses, and RSM/CCD Optimization

Laleh Ghafghazi; Lobat Taghavi; Behnam Rasekh; Hadi Farahani; Amir Hessam Hassani

doi:10.1016/j.scitotenv.2023.168029

Application of compost assisted by Fe₃O₄ nanoparticles in di (2-ethylhexyl) phthalate-contaminated soil remediation: Biostimulation strategy, Soil responses, and RSM/CCD Optimization

Sci Total Environ. 2024 Jan 15:908:168029. doi: 10.1016/j.scitotenv.2023.168029. Epub 2023 Oct 26.

Authors

Laleh Ghafghazi¹, Lobat Taghavi², Behnam Rasekh³, Hadi Farahani⁴, Amir Hessam Hassani⁵

Affiliations

¹ Department of Environmental Science and Forest, Faculty of Natural Resources and Environment, Science and Research Branch, Islamic Azad University (SRBIAU), P. O. Box 14515-775, Tehran, Iran.
² Department of Environmental Science and Forest, Faculty of Natural Resources and Environment, Science and Research Branch, Islamic Azad University (SRBIAU), P. O. Box 14515-775, Tehran, Iran. Electronic address: l.taghavi@srbiau.ac.ir.
³ Environment & Biotechnology Division, Research Institute of Petroleum Industry (RIPI), P. O. Box: 14665-137, Tehran, Iran.
⁴ Research Institute of Petroleum Industry (RIPI), P. O. Box 1485733111, Tehran, Iran.
⁵ Department of Environmental Engineering, Faculty of Natural Resources and Environment, Science and Research Branch, Islamic Azad University, Tehran, Iran.

PMID: 37898188
DOI: 10.1016/j.scitotenv.2023.168029

Abstract

Globally, contamination of agricultural soils by phthalate esters (PAEs) caused by direct consumption of plastic mulch films has been confirmed. The most widely used plasticizer is di (2-ethylhexyl) phthalate (DEHP), which is a more recalcitrant endocrine-disrupting chemical (EDC). Because of its low solubility and hydrophobicity, it remains in the soil longer, causes bioaccumulation in agricultural products, and has negative repercussions for food safety. In this study, the performance of kitchen organic waste compost assisted by Fe₃O₄ nanoparticles in DEHP removal efficiency (%) and soil C:N ratio (two responses) was optimized using Response Surface Methodology (RSM) based on Central Composite Design (CCD) in Design-Expert software (11.0.3.0). Under optimum conditions, a DEHP concentration of 10 mg·kg^-1 (dw soil), a retention time of 35 days, an NPs dose of 0.99 g·kg^-1 (media), a removal efficiency of 91.6 %, and a soil C:N ratio of 10.5 with a desirability of 0.963 were determined. A quadratic model (P-value <0.0001, adjusted R² = 0.974 (Y₁), 0.943 (Y₂)) was used to predict the variables and their interactions. The agricultural soil responses in the treatments amended by compost and Fe₃O₄ NPs (SCN) showed a significant increase in SOM, TC, TN, AP, K, and Fe nutrients when compared to the control (P < 0.05). After 35 days, in the SC1N3 treatment (DEHP concentration = 10 mg·kg^-1, NPs dose =1.2 g·kg^-1), with higher DEHP removal efficiency (89.57 %), the C:N:P ratio was equal to 100: 9.75:0.69, and the total microbial colony count was 3.6 × 10⁹ CFU/ml at pH 7.45. The study found that compost nutrients and Fe-based nanoparticle micronutrients can enhance DEHP degradation by stimulating the soil's native microflora. As a result, the synergistic potential of compost and Fe₃O₄ nanoparticles can be considered a promising, cost-effective, and agri-environmentally friendly approach in the "assisted bioremediation" strategy of DEHP-contaminated soils.

Keywords: Agricultural soil health; Assisted bioremediation; Endocrine-disrupting chemical; Kitchen organic waste compost; Plastic mulch films.

MeSH terms

Biodegradation, Environmental
Composting*
Diethylhexyl Phthalate* / metabolism
Phthalic Acids*
Soil
Soil Pollutants* / metabolism

Substances

phthalic acid
Soil
Diethylhexyl Phthalate
Phthalic Acids
Soil Pollutants