# Evaluation of Green Tea Leaves as an In Situ Capping Material for the Remediation of Lindane-Contaminated Sediments

## TL;DR

Green tea leaves are used to create a sustainable material that effectively reduces lindane pollution in river sediments.

## Contribution

A novel in situ capping material using green tea polyphenols is developed for lindane remediation.

## Key findings

- The GT ISCM formulation effectively immobilizes and degrades lindane in contaminated sediments.
- The material prevents the formation of harmful byproducts during lindane degradation.
- The ISCM shows high removal efficiency of lindane under simulated field conditions.

## Abstract

Organochlorine pesticides (OCPs), such as lindane, persist
as toxic
pollutants in river sediments, necessitating operative and effective
remediation. An alkaline green tea (GT)/Fe2+ system shows
promise for chemical reductive degradation of lindane through sustained
polyphenol release. This study developed a novel in situ capping material
(ISCM) composed of tea leaves, bentonite, sodium alginate, and pyrite.
The GT ISCM exhibits strong water absorption, swelling, extended polyphenol
release, and a stable reducing environment. Using the Taguchi method
(L9 orthogonal array), the ISCM formulation was systematically optimized,
and Analysis of Variance identified the optimal composition as 10
g bentonite, 0.5 g tea leaves, 0.25 g pyrite, and 0.1 g sodium alginate.
Utilizing tea polyphenols as reducing agents, it immobilized lindane
and promoted its degradation while preventing the formation of 1,3,4,5,6-pentachlorocyclohexene
and trichlorobenzene, byproducts produced during alkaline hydrolysis.
Under simulated field conditions, the ISCM significantly reduced lindane
release from contaminated sediments into the aqueous phase, demonstrating
high removal efficiencies. These findings underscore the potential
of GT ISCM as a sustainable strategy for stabilizing and degrading
lindane in contaminated sediments, providing a green alternative for
OCP remediation.