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Home > Application of Biochar in Reducing the Levels of Pesticide Residues in Contaminated Soils and Food Crops. a Strategy to Minimize the Health Risk

Application of Biochar in Reducing the Levels of Pesticide Residues in Contaminated Soils and Food Crops. a Strategy to Minimize the Health Risk

Thesis Info

Access Option

External Link

Author

Neelum Ali

Program

PhD

Institute

University of Peshawar

Institute Type

Public

City

Peshawar

Province

KPK

Country

Pakistan

Thesis Completing Year

2018

Thesis Completion Status

Completed

Language

English

Link

http://prr.hec.gov.pk/jspui/bitstream/123456789/11151/1/Neelum%20Ali%20thesis.pdf

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676728110025

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Organochloride pesticides (OCPs) also known as ―endocrine disrupting‖ chemicals are one of the persistent group of contaminants in soil that has gained worldwide concerns over the past few decades. They can transferred into the vegetables grown on the contaminated soils and eventually entered the food chain. The associated risk to human health makes the remediation of pesticide-contaminated soil a crucial undertaking. This research work is divided into different parts and several experiments were conducted to achieve the proposed objectives. The first study was carried out to evaluate the concentrations of OCPs in soils and vegetables grown in selected sites of Khyber Pakhtunkhwa (KP), Pakistan. The soil and selected vegetable species including Spinacia oleracea, Raphanus sativus, Brassica rapa, Lactuca sativa, Allium cepa and Allium sativum were collected from six districts (Peshawar, Charsadda, Nowshera, Mardan, Swabi and Swat), and were analysed for selected OCPs. Results showed that the concentrations of the selected OCPs exceeded their respective maximum residue limits (MRLs) in most of the soil samples and showed great variation from site to site. In case of the studied vegetables, the most contaminated observed was Lactuca sativa (28.9 μg kg-1), followed by Raphanus sativus (26.6 μg kg-1), Spinacia oleracea (25.8 μg kg-1), Allium cepa (16.3 μg kg-1), Brassica rapa (15.6 μg kg-1), and Allium sativum (14.7 μg kg-1). Analysis of health risk revealed that incremental lifetime cancer risks (ILCR) associated with dietary exposure of Σ30OCP through vegetables consumption by adults and children were below the acceptable risk level (10-6), indicating no cancer risk to the consumers. Moreover, exposure to the endocrine disruptor and probable carcinogen heptachlor epoxide (in children only) contributes toward non-cancer risk (HQ>1) from ingestion of selected vegetables. The presence of the banned OCPs in soils and vegetables in xvi the study area indicates that these legacy chemicals are still being used illegally for agricultural purposes which may be a cause for concern. Similarly, the second study was focused on the remediation of OCP-contaminated soils, as most of the OCPs are known to be possible/suspected endocrine disruptors and carcinogenic in nature and may severely affect humans or other living biota. Therefore, a 65-d incubation experiment was conducted to investigate the efficacy of biochars on the accessibility of OCPs, and also to evaluate their influence on soil microbial community. Results indicated that despite greater persistence of OCPs in soil, the application of selected biochars significantly (p<0.01) reduced the accessibility of åOCPs in contaminated soil as compared to the control soil during 65-days incubation period. Moreover, the findings from total phospholipid acid (PLFA) and Illumina next-generation sequencing revealed that the incorporation of biochar have altered the soil microbial community structure over time. Higher abundances of Proteobacteria, Firmicutes, Gemmatimonadetes, and Actinobacteria, were found in the biochar amendments. This recommends that biochar amendment (3%) could be advantageous for sustaining soil microbial communities and may thus likely influence the eco-toxicological processes and potential accumulation of OCPs. The third study was conducted to evaluate the effects of biochar (BC), biochar-based organic fertilizer (OF) and their combination (BCOF) on the bioaccessibility and accumulation of endocrine disruptive pesticides (EDPs) into leafy vegetables (Lactuca sativa and Spinacia oleracea) grown in a contaminated soil. The results revealed that application of BCOF and OF significantly (p<0.05) decreased bioaccessible concentrations of åEDPs in leafy vegetables by 23 and 44%, respectively, BC was particularly effective and decreased åEDPs bio-accessible concentrations by 60%, as compared to control. Biomass production, however, xvii increased the most for the BCOF amendments, (with a 70% increase in crop production compared to the control soil). Moreover, the incremental lifetime cancer risk (ILCR) values for selected EDPs were significantly (p<0.01) reduced in the amended soil as compared to control. These findings suggest that OF, BCOF and BC could be useful soil amendments to minimize the EDPs bioaccessibility in a degraded soil and their subsequent exposure to humans through vegetable consumption. Likewise, to investigate the effects of different biochars on the bioaccessible fractions of OCPs in a contaminated soil and their subsequent bioaccumulation into vegetable crops a fourth study was conducted. Four different biochars, derived from sewage sludge, soybean straw, rice straw and peanut shells were applied to a pesticide-contaminated soil at 2%, and the resulting impacts were measured. The results indicated that following biochar additions, the bioaccessible fractions of OCPs in soil and their accumulation in vegetable crops significantly (p<0.01) reduced, as compared to control. Risk assessment showed that biochar amendments markedly (p<0.01) decreased the hazard quotient (HQ) indices and the incremental lifetime cancer (ILCR) values for OCPs associated with the consumption of vegetable crops. From the results of the present studies it is concluded that the application of biochar could play a promising role in enhancing microbial abundance, reducing accessibility, restricting bioaccumulation of organochlorine pesticides in vegetables and decreasing their associated human health risk.
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۔مابعد جدید کےنظریہ کا اصل مقولہ

 

 مابعد جدید کےنظریہ کا اصل مقولہ

 احمد سہیل

میرے تقریبا آدھی صدی کے ادبی سفر میں میرا زیادہ تر وقت ادبی نطرئیے کی تنقید اور اس کی تفھیم اور تشریح میں گذرے۔ اس حوالے سے میں  نے چار کتابیں  ' جدید تھیٹر' ، ساختیات'، تنقیدی تحریرین اور  ' تنقیدی مخاطبہ' کے  نام سے چار کتابیں لکھی اور   سیکرو مضامین ادب کے تنقیدی نظرئیے پر لکھے جو  اردو اور انگریزی کے   ادبی اور علمی جرائد میں شائع ہوئے۔ میں نے یہ محسوس کیا کی اردو کا  ادبی اور تنقیدی محاول ادبی تنقیدی نظرئیے میں زیادہ سنجیدہ نہیں ہے یا  شاید اس کو یہ سمھ نہیں آتا۔

 یہ خاکسار آج  مابعد جدید نظرئیے پر  اساسی اور چند  اہم نکات پر  مختصرا بات کرے گا۔ اور   یہ بھی چاہوں گا کی شفاف اور آسان زبان میں " مابعد جدیدت" کا مفہوم واضح ہو جائے۔

*** مابعد جدیدت کیا ہے؟ ***

مابعد جدیدیت ایک ادبی صنف اور اسلوب کے لیے ایک اصطلاح ہے جو 20ویں صدی کے دوسرے نصف میں ابھری۔ مابعد جدیدیت کی تعریف میں، ادب نئی خوبیوں اور خصوصیات کو اپناتا ہے جو اس سے پہلے کی دہائیوں میں نہیں تھیں۔ مابعد جدیدیت پسند مصنفین نے اپنی زندگی کے دوران دنیا میں رونما ہونے والے اہم واقعات کے گرد اپنے شدید احساسات کو تلاش کرنے کے لیے قائم کردہ ادبی کنونشنوں کو کمزور کرنے کی کوشش کی۔

ایک عام اور وسیع تر اصطلاح جس کا اطلاق ادب، فن، فلسفہ، فن تعمیر، افسانہ، اور ثقافتی اور ادبی تنقید پر ہوتا ہے۔ مابعد جدیدیت بڑی حد تک سائنسی، یا مقصدی، حقیقت کی وضاحت کی کوششوں کے مفروضہ یقین کا ردعمل ہے۔ جوہر میں، یہ ایک...

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