Evaluation of Ricinus communis L. for the Phytoremediation of Polluted Soil with Organochlorine Pesticides.

Sandra Regina Rissato,João Roberto Fernandes,Marli Gerenutti,Mário Sergio Galhiane,Marcos Vinícius De Almeida,Renata Ribeiro,Homero Marques Gomes

doi:10.1155/2015/549863

Abstract

Phytoremediation is an attractive alternative to conventional treatments of soil due to advantages such as low cost, large application areas, and the possibility of in situ treatment. This study presents the assessment of phytoremediation processes conducted under controlled experimental conditions to evaluate the ability of Ricinus communis L., tropical plant species, to promote the degradation of 15 persistent organic pollutants (POPs), in a 66-day period. The contaminants tested were hexachlorocyclohexane (HCH), DDT, heptachlor, aldrin, and others. Measurements made in rhizosphere soil indicate that the roots of the studied species reduce the concentration of pesticides. Results obtained during this study indicated that the higher the hydrophobicity of the organic compound and its molecular interaction with soil or root matrix the greater its tendency to concentrate in root tissues and the research showed the following trend: HCHs < diclofop-methyl < chlorpyrifos < methoxychlor < heptachlor epoxide < endrin < o,p′-DDE < heptachlor < dieldrin < aldrin < o,p′-DDT < p,p′-DDT by increasing order of log K ow values. The experimental results confirm the importance of vegetation in removing pollutants, obtaining remediation from 25% to 70%, and demonstrated that Ricinus communis L. can be used for the phytoremediation of such compounds.

Highlights

Persistent organic pollutants (POPs) are relatively inert, and their high stability is related to aromatic ring, carbonchlorine bond, and other chemical arrangements
The limit of detection (LOD) of individual target molecules was determined by the concentration of analysis in a sample that produced a peak with a signal-to-noise ratio (S/N) of 3
The limit of quantification (LOQ) for all the target molecules was based on the GC/ECD performance and background noise levels under laboratory conditions

Summary

Introduction

Persistent organic pollutants (POPs) are relatively inert, and their high stability is related to aromatic ring, carbonchlorine bond, and other chemical arrangements. These compounds are widely studied due to their high toxicity, low biodegradability, and biosolubility in fat tissue [1] Some of these compounds may persist for 15 to 20 years in soil and part of these are entrained by rain (leaching) into water courses, which receives these compounds by industrial effluents, sewage, sediment, and air and by direct contamination during use [2]. Compounds such as organochlorines accumulate along the food chain, and much remains in the environment and can contaminate water and food making them unsuitable for consumption [3] They represent the most persistent organic pollutants (POPs) prioritized by United Nations Environmental Programme (UNEP) and banned or restricted by the Stockholm Convention in May 2001 [4]. In Brazil, organochlorine pesticides were used to control pests and increase food production

Methods

Results

Conclusion