Phytotoxic Effects Of Heavy Metals-Enriched Water Irrigation On Food Crops Using A Closed Hydroponic System

The issues of food and water security have conventionally been addressed independently, and to date, their nexus has emerged to be the most intricate global agenda. Today, wastewater irrigation has emerged to be a widespread strategy to fulfil the pressing need of non-conventional water resources. T...

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Main Author:	Chow, Yuh Nien
Format:	Thesis
Language:	English
Published:	2019
Subjects:	T Technology
Online Access:	http://eprints.usm.my/47855/1/Phytotoxic%20Effects%20Of%20Heavy%20Metals-Enriched%20Water%20Irrigation%20On%20Food%20Crops%20Using%20A%20Closed%20Hydroponic%20System.pdf
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spelling	my-usm-ep.478552021-11-17T03:42:10Z Phytotoxic Effects Of Heavy Metals-Enriched Water Irrigation On Food Crops Using A Closed Hydroponic System 2019-10-01 Chow, Yuh Nien T Technology TA1-2040 Engineering (General). Civil engineering (General) The issues of food and water security have conventionally been addressed independently, and to date, their nexus has emerged to be the most intricate global agenda. Today, wastewater irrigation has emerged to be a widespread strategy to fulfil the pressing need of non-conventional water resources. These discharges carry toxic elements, exceeding the maximum allowable limits, suggesting the possible risks to food crops and food chain. Heavy metals are the most carcinogenic, teratogenic and mutagenic constituents, accumulating in the irrigation water. Trivalent chromium [Cr (III)], lead [Pb (II)] and nickel [Ni (II)] are the most insidious pollutants, ascribed to their complex electronic chemistry, non-biodegradability, solubility and mobility. This study aimed to investigate the complex interconnection of metals-enriched water irrigation on Vigna radiata, Ipomoea aquatica and Brassica chinensis in relation to the physical growth; physiological characteristics: photosynthetic pigments, proline, antioxidative response [guaiacol peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX)], antioxidant capacities and morphological characteristics. The toxicity implications were evaluated using in vitro bioassays. Metals-enriched water irrigation adversely induced significant concentration- and duration-dependent reductions in the elongation of roots and shoots; with Cr (III) exerted the highest inhibition in Vigna radiata and Brassica chinensis, denoted the reduction of 68.04% and 75.69% for root and shoot. Ipomoea aquatica was specifically sensitive to Ni (II), with the highest root and shoot inhibition of 83.78% and 87.33%. Chlorophyll-a, chlorophyll-b, and carotenoid contents were significantly reduced, up to 83.92%, 75.86%, and 63%. Profound lipid peroxidation (170.30%) and rising proline content (201.08%) were complementary with the pronounced alterations for POD, APX and CAT activities. The marked suppressions of antioxidant activities above the threshold levels of 0.50 mM Pb (II), 0.20 mM Cr (III) and 0.05 mM Ni (II) in the plant models indicated that the antioxidant defense machinery could no longer protect the plant systems against the oxidative damages. These disturbances corroborated with the xylem and phloem distortion, and stomata disruption. Significant cytotoxic effect with 50% reduction in HepG2 cell viability was noted at 0.20 mM Pb (II), 0.40 mM Ni (II) and 1.20 mM Cr (III). Genotoxic effects on DNA tail moment and tail damage were observed at the lowest concentration of 0.04 μg/mL. Conclusively, the oxidative stress-related health threats associated with the deteriorating effects on the food crops could be exacerbated by a wide scale unregulated metals-polluted wastewater irrigation practice, and place alarming threats to the sustainability of water-food nexus. 2019-10 Thesis http://eprints.usm.my/47855/ http://eprints.usm.my/47855/1/Phytotoxic%20Effects%20Of%20Heavy%20Metals-Enriched%20Water%20Irrigation%20On%20Food%20Crops%20Using%20A%20Closed%20Hydroponic%20System.pdf application/pdf en public phd doctoral Universiti Sains Malaysia Pusat Penyelidikan Kejuruteraan Sungai Dan Saliran Bandar (REDAC)
institution	Universiti Sains Malaysia
collection	USM Institutional Repository
language	English
topic	T Technology T Technology
spellingShingle	T Technology T Technology Chow, Yuh Nien Phytotoxic Effects Of Heavy Metals-Enriched Water Irrigation On Food Crops Using A Closed Hydroponic System
description	The issues of food and water security have conventionally been addressed independently, and to date, their nexus has emerged to be the most intricate global agenda. Today, wastewater irrigation has emerged to be a widespread strategy to fulfil the pressing need of non-conventional water resources. These discharges carry toxic elements, exceeding the maximum allowable limits, suggesting the possible risks to food crops and food chain. Heavy metals are the most carcinogenic, teratogenic and mutagenic constituents, accumulating in the irrigation water. Trivalent chromium [Cr (III)], lead [Pb (II)] and nickel [Ni (II)] are the most insidious pollutants, ascribed to their complex electronic chemistry, non-biodegradability, solubility and mobility. This study aimed to investigate the complex interconnection of metals-enriched water irrigation on Vigna radiata, Ipomoea aquatica and Brassica chinensis in relation to the physical growth; physiological characteristics: photosynthetic pigments, proline, antioxidative response [guaiacol peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX)], antioxidant capacities and morphological characteristics. The toxicity implications were evaluated using in vitro bioassays. Metals-enriched water irrigation adversely induced significant concentration- and duration-dependent reductions in the elongation of roots and shoots; with Cr (III) exerted the highest inhibition in Vigna radiata and Brassica chinensis, denoted the reduction of 68.04% and 75.69% for root and shoot. Ipomoea aquatica was specifically sensitive to Ni (II), with the highest root and shoot inhibition of 83.78% and 87.33%. Chlorophyll-a, chlorophyll-b, and carotenoid contents were significantly reduced, up to 83.92%, 75.86%, and 63%. Profound lipid peroxidation (170.30%) and rising proline content (201.08%) were complementary with the pronounced alterations for POD, APX and CAT activities. The marked suppressions of antioxidant activities above the threshold levels of 0.50 mM Pb (II), 0.20 mM Cr (III) and 0.05 mM Ni (II) in the plant models indicated that the antioxidant defense machinery could no longer protect the plant systems against the oxidative damages. These disturbances corroborated with the xylem and phloem distortion, and stomata disruption. Significant cytotoxic effect with 50% reduction in HepG2 cell viability was noted at 0.20 mM Pb (II), 0.40 mM Ni (II) and 1.20 mM Cr (III). Genotoxic effects on DNA tail moment and tail damage were observed at the lowest concentration of 0.04 μg/mL. Conclusively, the oxidative stress-related health threats associated with the deteriorating effects on the food crops could be exacerbated by a wide scale unregulated metals-polluted wastewater irrigation practice, and place alarming threats to the sustainability of water-food nexus.
format	Thesis
qualification_name	Doctor of Philosophy (PhD.)
qualification_level	Doctorate
author	Chow, Yuh Nien
author_facet	Chow, Yuh Nien
author_sort	Chow, Yuh Nien
title	Phytotoxic Effects Of Heavy Metals-Enriched Water Irrigation On Food Crops Using A Closed Hydroponic System
title_short	Phytotoxic Effects Of Heavy Metals-Enriched Water Irrigation On Food Crops Using A Closed Hydroponic System
title_full	Phytotoxic Effects Of Heavy Metals-Enriched Water Irrigation On Food Crops Using A Closed Hydroponic System
title_fullStr	Phytotoxic Effects Of Heavy Metals-Enriched Water Irrigation On Food Crops Using A Closed Hydroponic System
title_full_unstemmed	Phytotoxic Effects Of Heavy Metals-Enriched Water Irrigation On Food Crops Using A Closed Hydroponic System
title_sort	phytotoxic effects of heavy metals-enriched water irrigation on food crops using a closed hydroponic system
granting_institution	Universiti Sains Malaysia
granting_department	Pusat Penyelidikan Kejuruteraan Sungai Dan Saliran Bandar (REDAC)
publishDate	2019
url	http://eprints.usm.my/47855/1/Phytotoxic%20Effects%20Of%20Heavy%20Metals-Enriched%20Water%20Irrigation%20On%20Food%20Crops%20Using%20A%20Closed%20Hydroponic%20System.pdf
_version_	1747821841682006016

Phytotoxic Effects Of Heavy Metals-Enriched Water Irrigation On Food Crops Using A Closed Hydroponic System

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