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10 Old Grimsbury Rd, Banbury OX16 3HG, UK

7LFS1029 Research Methods

Brief Description:

You are required to prepare a project proposal for your Project.


Title of the study

Study on the impacts of heavy metals on agricultural crops.

  1. Introduction and rationale
    1. Background

Ensuring food security is an essential challenge for long-term global growth and development (Rosegrant et al, 2005; Capone et al., 2014). The adverse effects of unforeseen heavy metal contamination of soils have threatened crop growth and quality due to its non-biodegradable nature (Meena et al, 2020; Qin et al., 2021). Rapid urbanisation, changing land use (Cohen, 2006) and industrialisation with extraordinarily large populations are the main causes of this problem (Rai et al., 2019). Pollutants have a direct impact on the quality and growth of crops (Shindell et al., 2012). Crops depend on healthy soils, which can be significantly affected by heavy metals from sources such as sewage sludge, industries, processing of textiles, e-waste, (Rai et al, 2019) soil erosion and agricultural runoff (Rajendiran et al., 2015). Arsenic, lead, cadmium, and mercury are hazardous non-essential deleterious heavy metals listed in the top 20 list of harmful compounds (Stojsavljević et al., 2022) by the United States Environmental Protection Agency and the Agency for Toxic Compounds and Disease Registry (ATSDR, 2012). Metals like copper, iron, and zinc are necessary because they function as cytochromes and enzymes in physiological pathways (Hawkesford et al., 2012). The presence of high levels of these essential and non-essential heavy metals has negative impact on physiology of plants, such as low biomass accumulation, chlorosis, photosynthesis inhibition, (Asati et al, 2016) water imbalance, senescence, and ultimately plant death (Gill, 2014). These accumulated heavy metals can be transmitted through the food chain (Gall et al, 2015) and cause negative effects on human health, such as cancers, weakened immunological mechanisms, and malnutrition (Priyadarshanee et al., 2022). Therefore, it is very important to prevent the transfer of heavy metals into the soil-plant system. This may be accomplished by developing and deploying ecologically safe, fast, and economically viable heavy metal remediation methods in the soil-crop system (Boregowda et al., 2022).

  1. 2 Rationale

A better understanding of the different types, sources, causes, mechanisms of transmission of heavy metals, and risks associated with the accumulation of heavy metals in the food chain is necessary to reveal the exact roots and ramifications of the problem. This is a prerequisite for developing effective remediation technologies to address this problem. Even though rapid population growth and industrialisation are the primary causes of this global problem (Yaylalı-Abanuz, 2011; Li et al., 2019). The secondary causes are different in both developing and developed countries. So a general strategy and policy will not be enough to control heavy metal pollution of all kinds worldwide.

Another point is that the basic stress tolerance to metals, the mechanisms and fate of metals in plants are similar, but each plant species may differ in this. So a detailed study of the individual crop species, the parts in which the metals accumulate and the metal concentrations recorded is therefore essential in order to develop specific remedial measures.

Various heavy metals shows toxic effects mediated by different mechanisms (Munir et al., 2022). However, these mechanisms have not been fully illustrated and summarised, indicating the need for further investigation and review. Existing remedies rely on reducing heavy metal concentrations on the crops to prevent adverse effects (Chibuike and Obiora, 2014). But any progress in this field requires a thorough overview of all possible sources, allowable concentrations and transport pathways of the different types of heavy metals on the various crop species.

  1. Aim and objectives

Aim of the study     

To study the different types, sources, causes and effects of heavy metals in crops. And to identify different possible approaches to manage the risk factors associated with heavy metal pollution on agriculture.

The objectives of the study are:

1. To assess the causes of heavy metal pollution on crops

2. To identify different types of heavy metals and their sources

3. To illustrate the transport pathways of heavy metals from their source to crops.

3. To examine in detail the effects of heavy metal pollution on crops.

4. To discuss the various risks associated with heavy metal contamination of crops.

5. To identify possible approaches for the management of heavy metal contamination on agricultural crops.

6. To analyse latest case studies with particular attention to developing countries to describe how a particular heavy metal contamination affects a particular crop and how it is managed.


  1. Overview

This section describes the methodology used to thoroughly review the literature on “the impacts of heavy metals on agricultural crops.” It aims to collect and synthesize current research findings to examine the many types, origins, causes, and consequences of heavy metal build up on diverse agricultural crops. The methodology included different tasks and meetings with the supervisor for guidelines.  The information gathered will be utilised to help construct the systematic review and identify gaps in previous research tasks.

Task 1: Literature review

1.1       Developing Research Questions

The research question for the present investigation is: “What are the impacts of heavy metals on agricultural crops?”

1.2       Search Strategy

The search approach involves identifying relevant databases, selecting acceptable search terms and phrases, and formulating search queries. Science Direct, Google Scholar and Scopus were among the databases searched. The search queries included keywords linked to heavy metals and agricultural crops, heavy metal pollution, metal toxicity, and agricultural consequences, among other things.

1.3       Criteria for Study Selection

The following were the inclusion criteria:

  • Research articles published between 2000 and 2023 in full-access, peer-reviewed journals.
  • Studies concentrating on the effects of heavy metals on agricultural crops.
  • Studies including empirical data or conclusions as well as case studies.
  • Studies that have been published in English.

The exclusion criteria were as follows:

  • Studies with limited content on the subject.
  • Studies published before the year 2000.
  • Studies that did not specifically analyse the impacts of heavy metals on agricultural crops.
  • Studies published in languages other than English

Task 2: Analysing the risks associated with the study and submission of risk assessment form.

Biased information encountered during this literature review study is overcome by adopting a rigorous selection process for choosing relevant and reliable sources. Multiple sources are cross-referenced to ensure the accuracy of the collected data. Critical evaluation of the methodology and validity of the studies is done to ensure the reliability of the information gathered. The risk of misinterpreting or inaccurately identifying the risk factors can be overcome with the help of a supervisor.

Task 3: Data Extraction Process

A standardized data collection format was designed and contains the following data:

  • Study characteristics including author, year, title and country.
  • Methodology employed
  • Heavy metals investigated (including type, concentration, source, and analysis method)
  • Crop studied (including type, species, family, cultivated area and sample size)
  • Cause and impacts on crops (physiology and biochemical)
  • Risk factors reported
  • Management strategies adopted 

Task 4: Data Analysis and interpretation

A systematic review is performed on articles from publications that have addressed heavy metal contamination on agricultural crops. Selected publications, including case studies, were evaluated, and the data collection form were analysed and interpreted to reach a good conclusion that is relevant to the objectives of the research.

Task 5: Generation of secondary data

Generation of the findings from the reviewed literature to provide a systematic overview of the topic and thereby interpret the implications.

3. Project management

3.1 Schedule

Gantt chart

Conduct background reading           
Writing literature review            
Conduct discussion           
Preparation of Project Proposal           
Data collection           
Data analysis           
Discuss conclusion           
Submission of draft work           
Conduct final discussion           
Preparation of thesis           
Final submission of thesis           

3.2 Milestones

S/NMilestones achievedTarget dates
1Selection of research topic and define the objectives03/04/2023
2Literature search, reviewing and documentation.25/04/2023
3Project proposal documentation06/06/2023
4Data collection, analysis, and interpretation30/09/2023
5Finalizing the draft of thesis24/11/2023
6Final submission02/01/2024

3.3 Deliverables

An overview of the project goals and anticipated results for a systematic review of research on the impact of heavy metals on crops is shown in the table below.

S/NObjectivesOutcomeExpected date
1Explore relevant papersComprehensive list of relevant sources03/04/2023
2Explain the selection criteriaClearly established guidelines25/04/2023
3Examine the accuracy and reliabilityExamination of methodology and reliability01/05/2023
4Data extractionSummarization of findings30/07/2023
5Review and integrate the collected dataFinding correlations in data30/08/2023
6Analyze heavy metals’ types, sources, and overall effects in agricultural crops.Analysis of the various heavy metal impacts on crops30/09/2023
7Determine knowledge gapsIdentifying topics that need further research24/10/2023
8Specify suggestions for further studies.Recommendations for mitigating measures30/12/2023
9Develop a review reportA comprehensive paper that summarises the study’s goals, procedures, findings, and conclusions.02/01/2024


  1. Asati, A., Pichhode, M., & Nikhil, K. (2016). Effect of heavy metals on plants: an overview. International Journal of Application or Innovation in Engineering & Management5(3), 56-66.
  2. ATSDR, F. O. (2012). Toxicological profile for cadmium. Atlanta, GA.
  3. Boregowda, N., Jogigowda, S. C., Bhavya, G., Sunilkumar, C. R., Geetha, N., Udikeri, S. S., & Jogaiah, S. (2022). Recent advances in nanoremediation: Carving sustainable solution to clean-up polluted agriculture soils. Environmental Pollution297, 118728.
  4. Capone, R., Bilali, H. E., Debs, P., Cardone, G., & Driouech, N. (2014). Food system sustainability and food security: connecting the dots. Journal of Food Security2(1), 13-22.
  5. Chibuike, G. U., & Obiora, S. C. (2014). Heavy metal polluted soils: effect on plants and bioremediation methods. Applied and environmental soil science2014.
  6. Cohen, B. (2006). Urbanization in developing countries: Current trends, future projections, and key challenges for sustainability. Technology in society28(1-2), 63-80.
  7. Gall, J. E., Boyd, R. S., & Rajakaruna, N. (2015). Transfer of heavy metals through terrestrial food webs: a review. Environmental monitoring and assessment187, 1-21.
  8. Gill, M. (2014). Heavy metal stress in plants: a review. Int J Adv Res2(6), 1043-1055.
  9. Hawkesford, M., Horst, W., Kichey, T., Lambers, H., Schjoerring, J., Møller, I. S., & White, P. (2012). Marschner’s mineral nutrition of higher plants. Functions of macronutrients. Academic Press, London, 135-189.
  10. Li, C., Zhou, K., Qin, W., Tian, C., Qi, M., Yan, X., & Han, W. (2019). A review on heavy metals contamination in soil: effects, sources, and remediation techniques. Soil and Sediment Contamination: An International Journal28(4), 380-394.
  11. Meena, V., Dotaniya, M. L., Saha, J. K., Das, H., & Patra, A. K. (2020). Impact of lead contamination on agroecosystem and human health. Lead in Plants and the Environment, 67-82.
  12. Munir, N., Jahangeer, M., Bouyahya, A., El Omari, N., Ghchime, R., Balahbib, A., & Shariati, M. A. (2022). Heavy metal contamination of natural foods is a serious health issue: a review. Sustainability14(1), 161.
  13. Priyadarshanee, M., Mahto, U., & Das, S. (2022). Mechanism of toxicity and adverse health effects of environmental pollutants. In Microbial biodegradation and bioremediation (pp. 33-53). Elsevier.
  14. Qin, G., Niu, Z., Yu, J., Li, Z., Ma, J., & Xiang, P. (2021). Soil heavy metal pollution and food safety in China: Effects, sources and removing technology. Chemosphere267, 129205.
  15. Rai, P. K., Lee, S. S., Zhang, M., Tsang, Y. F., & Kim, K. H. (2019). Heavy metals in food crops: Health risks, fate, mechanisms, and management. Environment international125, 365-385.
  16. Rajendiran, S., Dotaniya, M. L., Coumar, M. V., Panwar, N. R., & Saha, J. K. (2015). Heavy metal polluted soils in India: status and countermeasures. JNKVV Res J49(3), 320-337.
  17. Rosegrant, M. W., Cline, S. A., Li, W., Sulser, T. B., & Valmonte-Santos, R. (2005). Looking ahead: long-term prospects for Africa’s agricultural development and food security (Vol. 41). Intl Food Policy Res Inst.
  18. Shindell, D., Kuylenstierna, J. C., Vignati, E., van Dingenen, R., Amann, M., Klimont, Z., & Fowler, D. (2012). Simultaneously mitigating near-term climate change and improving human health and food security. Science335(6065), 183-189.
  19. Stojsavljević, A., Perović, M., Nešić, A., Miković, Ž. & Manojlović, D. (2022). Levels of non-essential trace metals and their impact on placental health: a review. Environmental Science and Pollution Research29(29), 43662-43674.
  20. Yaylalı-Abanuz, G. (2011). Heavy metal contamination of surface soil around Gebze industrial area, Turkey. Microchemical Journal99(1), 82-92.

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