Title Page………………..i




Table of content………v






2.1    COWPEA (Vignaunguiculata)

2.1.1    Biology of Cowpea (Vignaunguiculata)

2.1.2    Description of Cowpea (Vignaunguiculata)

2.1.3    Varieties and Cultivars

2.1.4    Origin and Distribution

2.1.5    Utilization

2.2    Heavy Metals: Sources and Effect in the Environment

2.2.1    Lead (Pb) in Soil

2.3    Heavy Metal Tolerance in Plants

2.3.1    Mechanisms of Heavy Metal Uptake by Plant

2.3.2    Factors Affecting the UptakeMechanisms

2.4    Phytoextraction of Heavy MetalsUsing Plants



3.1    Collection and Processing of Samples

3.2    Preparation of Heavy Metal Contaminants

3.3    Experimental Design and Treatment

3.4    Analysis of Lead

3.5    Determination of Bioconcentration and Translocation Factor

3.6    Statistical Analysis











Different types of heavy metals such as Cu, Zn and Ni are necessary micronutrients compulsory for a variety of functions including electron transfer reactions and as cofactors in many proteins and enzymes, on the other hand other metals like Ar, Cd and Pb are considered non-necessary. Both types of metals are toxic above certain concentrations. They inactivate metal-sensitive enzymes consequential in growth retardation and the worst in case of death of the organism. The metals found in our environment come from natural weathering process of earth’s crust, soil erosion, mining, industrial discharge, urban runoff, sewage effluents, air pollution fall out, pest or disease control agents. These heavy metals also originate through human activities such as application of phosphate fertilizers, military activities, metal working industries, mining and smelting (Chowdhury et al., 2015).

In recent years, public concerns relating to ecological threats caused by heavy metal (HM) have led to intensive research of new economical plants based remediation technologies. Conventional methods used for reclamation of contaminated soils, namely chemical, physical and microbiological methods, are costly to install and operate (Danhet al., 2009). The rapid increase in population coupled with fast industrialization growth causes serious environmental problems, including the production and release of considerable amounts of toxic waste materials into environment (Zhuang et al., 2007). The concentrations of the contaminants can vary from highly toxic concentrations from an inadvertent spill to barely measurable concentrations that after long-term exposure can be injurious to human health (Alexander, 1999). Mainly, heavy metals are toxic because they cause DNA damage and their carcinogenic effects in animals and humans are probably caused by their mutagenic ability (Knasmulleret al., 1998). Heavy metals are not degradable, without intervention they stay in soil for centuries. Over recent decades, the annual worldwide release of heavy metals reached 22,000 t (metric ton) for cadmium, 939,000 t for copper, 783,000 t for lead and 1,350,000 t for zinc (Singh et al., 2003).

Phytoremediation is the use of green plants to remove pollutants from the environment or render them harmless. Phytoremediation is a new technology in which plants are used to remove pollutants from water and soil. The use of metal-accumulating plants to clean environment contaminated with heavy metals is the most rapidly developing component of this environmentally friendly and cost-effective technology. The ever-increasing environmental pollution in agricultural soil caused by heavy metals due to application of sewage sludge, city refuse, and heavy metals containing fertilizers or pesticides, is becoming a major problem in modern agriculture. Phytoremediation is based on the removal of contaminants from the soil by mechanisms such as phytoextraction, phytodegradation, rhizofiltration, phytostabilization and phytovolatilization (Salt et al., 1995). In phytoextraction, plants absorb metals from soil through the root system and translocate them to harvestable shoots where they accumulate. Hyperaccumulators mostly used this process to extract metals from the contaminated site. The recoveries of the extracted metals are also possible through harvesting the plants appropriately.

The mechanisms of phytoremediation involved in heavy metal remediation are limited to up-take, adsorption, transport and translocation, sequestration into vacuoles, hyperaccumulation and in some cases, volatilization (Meagher, 2000). When present at increased concentrations, both essential (Cu, Fe, Mn, Mo, Zn) and non-essential metals (e.g., Cd, Pd, Hg) are toxic. Heavy metals cannot be metabolized; only possible strategy to apply is their extraction from contaminated soil and transfer to the smaller volume of harvestable plants for their disposal (Padmavathiamma and Li, 2007).

A number of plant species have been recognized for the rationale of phytoremediation. Assured plant species known as hyper accumulators are able to accumulate potentially phytotoxic fundamentals to concentrations 50-500 times higher than average plants (Lasat, 2002). Transgenic rice plants have been used for phytoremediation (Chowdhury et al., 2015). However many of the hyper accumulators are slow growing and have reduced biomass pro-duction thus requiring several years for decontamination of the polluted sites. Trees appear as an attractive hyper accumulator due to their extensive root system, high water uptake, rapid growth, and large biomass production (Gullneret al., 2001).The hyperaccumulation of heavy metals in some plants has been recorded by many researchers during last few decades (Barman et al., 2000) and this has emphasized the importance of further advanced research in molecular basis of phytoremediation technology. The hyperaccumulation of heavy metals is depends on the plant species, soil condition (pH, organic matter content, cation exchange capacity etc.) and types of heavy metal (Barman et al., 2001; Spinoza-Quinones et al., 2005; Xian and Shokohifard, 1989; Otteet al., 1993). In metal biology, it is experimentally proved that even some metals that are essential for the normal plants growth (such as iron and copper) may become toxic, depending on the oxidation state, complex form, dose and mode of exposure (Beyersmann and Hartwig, 2008).

Vignaunguiculatais an herbaceous, annual plant in the pea family Fabaceae. The domestication of Vignaunguiculatawas originated in West Africa. It is one of the most widely used legumes in the semiarid tropics including Asia, Africa, southern Europe and Central and South America. Hundreds of experiments have been conducted on this legume to understand its morphology, physiology, as well as to understand the effect of different stresses on this legume. However, only a scanty number of experiments have been carried out to study the Zn phytoextracting ability of V. unguiculata(Tanee and Akonye, 2009). Basaket al. 2014 in their study reported that V. unguiculataaccumulated a considerable amount of the heavy metal Zn which makes it a potential candidate as a phytoremediation plant in the remediation of Zn from contaminated soil.


The objectives of this study was to;

1.    Assess the potential of Cowpea (Vignaunguiculata) to remediate lead in soil contaminated with different concentrations of lead

2.    To examine the feasibility of Cowpea (Vignaunguiculata) as a hyperaccumulator plant for lead

3.    To determine the bioconcentration factor in Vignaunguiculata.

4.    To determine the translocation factor in Cowpea (Vignaunguiculata).



RESEARCHWAP.COM is an online repository for free project topics and research materials, articles and custom writing of research works. We’re an online resource centre that provides a vast database for students to access numerous research project topics and materials. guides and assist Postgraduate, Undergraduate and Final Year Students with well researched and quality project topics, topic ideas, research guides and project materials. We’re reliable and trustworthy, and we really understand what is called “time factor”, that is why we’ve simplified the process so that students can get their research projects ready on time. Our platform provides more educational services, such as hiring a writer, research analysis, and software for computer science research and we also seriously adhere to a timely delivery.


Please feel free to carefully review some written and captured responses from our satisfied clients.

  • "Exceptionally outstanding. Highly recommend for all who wish to have effective and excellent project defence. Easily Accessable, Affordable, Effective and effective."

    Debby Henry George, Massachusetts Institute of Technology (MIT), Cambridge, USA.
  • "I saw this website on facebook page and I did not even bother since I was in a hurry to complete my project. But I am totally amazed that when I visited the website and saw the topic I was looking for and I decided to give a try and now I have received it within an hour after ordering the material. Am grateful guys!"

    Hilary Yusuf, United States International University Africa, Nairobi, Kenya.
  • " is a website I recommend to all student and researchers within and outside the country. The web owners are doing great job and I appreciate them for that. Once again, thank you very much "" and God bless you and your business! ."

    Debby Henry George, Massachusetts Institute of Technology (MIT), Cambridge, USA.
  • "I love what you guys are doing, your material guided me well through my research. Thank you for helping me achieve academic success."

    Sampson, University of Nigeria, Nsukka.
  • " is God-sent! I got good grades in my seminar and project with the help of your service, thank you soooooo much."

    Cynthia, Akwa Ibom State University .
  • "Great User Experience, Nice flows and Superb functionalities.The app is indeed a great tech innovation for greasing the wheels of final year, research and other pedagogical related project works. A trial would definitely convince you."

    Lamilare Valentine, Kwame Nkrumah University, Kumasi, Ghana.
  • "Sorry, it was in my spam folder all along, I should have looked it up properly first. Please keep up the good work, your team is quite commited. Am grateful...I will certainly refer my friends too."

    Elizabeth, Obafemi Awolowo University
  • "Am happy the defense went well, thanks to your articles. I may not be able to express how grateful I am for all your assistance, but on my honour, I owe you guys a good number of referrals. Thank you once again."

    Ali Olanrewaju, Lagos State University.
  • "My Dear Researchwap, initially I never believed one can actually do honest business transactions with Nigerians online until i stumbled into your website. You have broken a new legacy of record as far as am concerned. Keep up the good work!"

    Willie Ekereobong, University of Port Harcourt.
  • "WOW, SO IT'S TRUE??!! I can't believe I got this quality work for just 3k...I thought it was scam ooo. I wouldn't mind if it goes for over 5k, its worth it. Thank you!"

    Theressa, Igbinedion University.
  • "I did not see my project topic on your website so I decided to call your customer care number, the attention I got was epic! I got help from the beginning to the end of my project in just 3 days, they even taught me how to defend my project and I got a 'B' at the end. Thank you so much, infact, I owe my graduating well today to you guys...."

    Joseph, Abia state Polytechnic.
  • "My friend told me about ResearchWap website, I doubted her until I saw her receive her full project in less than 15 miniutes, I tried mine too and got it same, right now, am telling everyone in my school about, no one has to suffer any more writing their project. Thank you for making life easy for me and my fellow students... Keep up the good work"

    Christiana, Landmark University .
  • "I wish I knew you guys when I wrote my first degree project, it took so much time and effort then. Now, with just a click of a button, I got my complete project in less than 15 minutes. You guys are too amazing!."

    Musa, Federal University of Technology Minna
  • "I was scared at first when I saw your website but I decided to risk my last 3k and surprisingly I got my complete project in my email box instantly. This is so nice!!!."

    Ali Obafemi, Ibrahim Badamasi Babangida University, Niger State.
  • To contribute to our success story, send us a feedback or please kindly call 2348037664978.
    Then your comment and contact will be published here also with your consent.

    Thank you for choosing