TSANANGURAYI TONGESAYI
ASSISTANT PROFESSOR OF CHEMISTRY DEPARTMENT OF CHEMISTRY, MEDICAL TECHNOLOGY AND PHYSICS
	Education: Ph.D. West Virginia University MSc. University of Zimbabwe BSc. University of Zimbabwe Office:  Edison - 149A Phone:  (732) 263-5627 OfficeHours:  Fri 10:00 - 12:00 noon Fri 1:00 - 3:00pm E-mail:  ttongesa@monmouth.edu

CURRENT RESEARCH INTERESTS

Environmental toxicology: Focus is on the biogeochemistry of chemical species particularly heavy metals and metalloids; pesticides; and inorganic nutrients as influenced by both natural and anthropogenic induced environmental conditions. Specifically, I look at the fate, speciation, mobility and bioavailability of these chemical species in the environment. Toxicity of a chemical substance is a function of dose and chemical form (speciation). Some of the factors I consider when dealing with biogeochemistry and toxicity include pH, ionic strength, natural organic matter, mineral oxide sorption sites, metal-metal interactions, temperature, light, anions, particulates and engineered nanoparticles.

Analytical Method development: Focus is on developing analytical methods to detect and quantify nano-levels of toxic chemical species in environmental samples; and methods to remove the toxicants from drinking water and wastewater. Because of the increase in knowledge about the toxicity of both synthetic and natural chemicals substances, quality standards, particularly in food and drinking water, are increasingly becoming more stringent. This development poses both analytical and engineering challenges; first there is a need to develop methods that will detect and quantify levels that match the standards and secondly, efficient technological methods to remove contaminants from drinking water, for example, will need to be developed in order to meet the standards.

A. Current Projects

Fate and mobility of Roxarsone: Roxarsone is an arsenic-containing pesticide that is used as a poultry-feed additive to promote growth by controlling coccidial intestinal parasites. Most of the ROX ingested by chickens is excreted unchanged in the manure bedding, and poultry litter (PL) collected from a typical 42-day feeding period contains from 30 to 50 mg Kg-1 of total arsenic. ROX has been shown to be stable in fresh poultry litter but is converted to As(V) and As(III) among other products when the PL is composted. The management of PL is a challenging environmental problem and the practice of amending soils with arsenic-containing PL and the use of uncovered windrows for PL storage could be causing arsenic contamination of surface and ground water. The recent reduction in the maximum contaminant level for arsenic in drinking water from 50 ppb to 10 ppb, and the resultant political debate have focused public attention on this element. The new arsenic contaminant level has a significant impact in the management of PL and the watersheds where PL is applied.

Publications:

1. Tsanangurayi Tongesayi. Mechanism for the release of inorganic arsenic from roxarsone, 3-nitro-4-hydroxyphenylarsonic, by cyclic voltammetry at a gold electrode. Analytical Chemistry: An Indian Journal, 2010 9.
2. Tongesayi, Tsanangurayi ; Byam, Eric J.; Grafton, Andrea. Electrochemical analysis of roxarsone, 3-nitro-4-hydroxyphenylarsonic, using palladium, gold, and platinum electrodes . From Abstracts of Papers, 238th ACS National Meeting, Washington, DC, United States, August 16-20, 2009, ENVR-160., Database: CAPLUS .

Conference presentations:

1. Tsanangurayi Tongesayi; E. J. Byam , Andrea Grafton. Electrochemical analysis of roxarsone, 3-nitro-4-hydroxyphenylarsonic, using palladium, gold and platinum electrodes. 238th ACS National Meeting, Washington, DC, USA, August 16-20, 2009. NOTE: The same paper was presented at the Sci-Mix and General Sessions. Only a few outstanding papers are selected for the Sci-Mix session. We were very happy that our paper made it to the Sci-Mix session).

My laboratory is currently working on the Fate of Roxarsone, 3-nitro-4-hydroxyphenylarsonic, in simulated gastrointestinal solution. I started the project with Mark Stranieri, an undergraduate chemistry major, last summer (2010). Mark left my group after summer and another student, Julia Elscheid, is continuing with the project.

Mobility of Nutrients: The mobility of nutrients, especially inorganic phosphates and nitrates in various watersheds has attracted intense research effort mainly because of the association of these nutrients with eutrophication, i.e. excessive algal blooms. Eutrophication results in a reduced amount of dissolved oxygen (DO), a condition which in the deterioration of the quality of the water. The reduction in water quality may result in the death of aquatic organisms. High levels of nutrients and the resultant reduced DO and poor water quality can influence the biogeochemical cycling of chemical species in the aquatic environment. A typical example is the biomethylation of Hg +2 to methylmercury, CH3-Hg +, the most toxic and bioavailable form of Hg which is enhanced in aquatic systems with high nutrient levels and low DO. Algal blooms may also reduce accessibility of waterways which are used for recreational activities. Nutrients can come from various sources such as domestic effluent, industrial effluent and fertilizers applied to agricultural fields, golf courses, and suburban lawns.

Publications:

1. T. Tongesayi, E. J. Byam, Sarah B. Keysper and M. J. Crounce. Sorption and desorption properties of phosphate on Fe 2O 3: Effect of fulvic acid and pH. Environmental Chemistry, 2008, 5, 161-168.

Conference Presentations:

1. Tsanangurayi Tongesayi, E. J. Byam, Sarah B. Keysper and M. J. Crounce. Sorption and desorption properties of phosphate on Fe 2O 3: Effect of fulvic acid and pH. The 4 th International Conference on Environmental Science and Technology, Houston, Texas, USA, July 28-31, 2008.
2. Tsanangurayi Tongesayi; E. J. Byam ; Sarah B. Keysper; M. J. Crounce. Mechanism of the sorption and desorption of phosphate on Fe 2O 3: Effect of fulvic acid and pH. Eastern Analytical Symposium and Exposition, Somerset, New Jersey, USA, Nov. 17-20, 2008) .

Environmental Impact of Biosolids: The main objectives are to (i) develop new methods to estimate oral bioavailability for use in human health risk assessment, (ii) to evaluate the potential threat posed by the use of biosolids as an amendment for agricultural soils by determining the total metal content and speciation of selected heavy metals in New Jersey biosolids, (iii) develop better technologies to remove metals and metalloids from wastewater without sedimenting them with the sludge, and (iv) develop methods to suppress the phytoavailability of toxic metals and metalloids in biosolid-amended soils.

Because of world-wide population growth, industrialization and urbanization, many cities across the world are faced with the daunting task of dealing with increased volumes sewage sludge and waste in general. In most situations, wastewater treatment plants receive domestic effluent combined with storm water and industrial effluent, which significantly increase the concentration of heavy metals and metalloids among other chemical contaminants prior to treatment. The lack of enough space for waste disposal, prohibitive costs of incineration and landfilling are some of the major reasons why many municipal authorities encourage the use of the sewage sludge as a fertilizer or soil conditioner. Metals(loids) do not degrade but accumulate in the environment. The non-degradability of metals and metalloids brings into question the sustainability of the practice of applying sewage sludge on land as fertilizer or soil conditioner. There is a significant threat of contaminating natural water sources and agricultural produce, with serious consequences to human health. Biosolid-amended soils can also directly affect children during playing activities and adults during farming activities. Accumulation of metals(loids) in the soil/sediment can result in the saturation of sorption sites, and this can then lead to increased mobility and bioavailability of chemical species in the environment.

Publications:

1. Peer-reviewed abstract: Tongesayi, Tsanangurayi; Dasilva, Patricia; Dilger, Katharine; Hollingsworth, Tristan. Levels of selected heavy metals in New Jersey sanitary biosolids that are used as fertilizer. From Abstracts of Papers, 240th ACS National Meeting, Boston, MA, United States, August 22-26, 2010, ENVR-211. Language: English, Database: CAPLUS.
2. Submitted manuscript (2011): Tsanangurayi Tongesayi; Patricia DaSilva; Katharine Dilger; Tristan Hollingsworth; Melissa Mooney. Speciation and cysteine-simplified physiological-based extraction technique (SBET) bioaccesibility of heavy metals in biosolids.

Conference Presentations:

1. Tsanangurayi Tongesayi; Dasilva, Patricia; Dilger, Katharine; Hollingsworth, Tristan; Mooney, Melissa. Levels of selected heavy metals in New Jersey sanitary biosolids that are applied on land as fertilizer. 240th ACS National Meeting, Boston, MA August 22-26, 2010. The same paper was presented at the Sci-Mix and General Sessions. Only a few outstanding papers are selected for the Sci-Mix session. We were extremely happy that our paper made it to the Sci-Mix session.
2. Tsanangurayi Tongesayi; Patricia Dasilva; Katharine Dilger; Tristan Hollingsworth; Mooney, Melissa; Clara Abbey; Muhammad Ali; Julia Elscheid. Heavy metals in New Jersey sanitary biosolids that are applied on land as fertilizer: Bioaccessibility and Phytoavailability. Eastern Analytical Symposium and Exposition, Somerset, New Jersey, USA, Nov. 15-18, 2010.)

Sediments Quality: The use of the dredged sediments for land reclamation and beach restoration potentially exposes humans to toxic chemicals if the sediments are contaminated. In addition to known health effects of certain chemicals, there is growing evidence of a link between human diseases later in life and fetal exposure to chemicals. It is, therefore, imperative to monitor the quality of sediments whose application can lead to be inadvertent ingestion by humans during normal daily activities. My laboratory has been assessing the quality of Deal Lake sediments and will extend the work to other fresh water sediments in NJ.

Publications:

1. Submitted Manuscript (2011): Tsanangurayi Tongesayi, Ester Booth; Sade Stevens; Eric Winter. Total levels and equilibrium-based phyto- and bioaccessibility of heavy metals as tools to assess sediment quality in recreational waterways.

Conference Presentations:

1. Tsanangurayi Tongesayi, Ester Booth; Sade Stevens; Eric Winter Total levels, phytoavailability and bioaccessibility of selected heavy metals in sediments from Deal Lake, New Jersey” (paper number: 214) ACS 241 st National Meeting National Meeting, Anaheim, California March 27-31 , 2011. (Accepted)

Method development: My laboratory, in collaboration with Dr. Ronald Smart's laboratory at West Virginia University, has developed a method for the detection and quantitation of sub-nanomolar levels of arsenic in water samples without sample pre-treatment.

Tsanangurayi Tongesayi and Ronald B. Smart. Electrochemical detection of As(III) in the presence of dissolved organic matter (DOM) by adsorptive Square-Wave Cathodic Stripping Voltammetry (Ad-SWCSV). Electroanalysis 20, 2008, #4, 434-437.

My laboratory is currently developing a novel method to remove arsenic, and other metals(loids) from drinking water using thiol-containing molecules bound on a polymer support. I started the project with two of my students, Clara Abbey and Muhammad Ali in the summer of 2010. Clara graduated and is currently in Medical School. Muhammad will be continuing with the project.

B. Future Projects:

• I have recruited two more students, Aracelis Lantigua and Nicole Palemo, to start working on the speciation of chromium under natural environmental conditions starting this spring (2011). There is a lot of concern regarding the presence of hexavalent chromium, Cr (VI), in drinking water, so the project will be specifically looking at the redox cycling of chromium between Cr(VI) and Cr(III). Cr(VI) is a known carcinogen.

• Starting summer 2011, my laboratory will be working on the preparation and characterization of magnetic iron oxide nanoparticles (MNP) with respect to their redox, catalytic and adsorption properties. An understanding of these properties can (i) help promote the efficient and sustainable utilization of the MNP, (ii) development of novel applications of the nanoparticles, especially in environmental separations and remediation, (iii) advance an understanding of the role of MNP in speciation and mobility of heavy metals(loids) in the environment. The project involves travelling to the Cornell Nanoscience and Technology Facility at Cornell University and at the Particle Characterization Laboratory at Penn State University’s Material Research Institute which are part of NSF’s National Nanotechnology Infrastructure Network (NNIN) laboratories. These two centers fall under the NNIN and provide cutting-edge facilities and services for nanotechnology research. The purpose of visits to the NNIN laboratories is to prepare and characterize nanoparticles, which will then be used for experiments in my laboratory at Monmouth University. This is a long-term project and is by no means expected to be completed by the end of the summer period.

INVITED PRESENTATIONS

1.  Tsanangurayi Tongesayi, Title of Conference: Factors Affecting Climate Change and International Governmental Regulatory Responsibility, Oxford Round Table, Lincoln College, University of Oxford, UK. March 27-April 1, 2011.
   Title of Presentation: Sustainability and the African Environment: The Role of Multinational Corporations.
2. Tsanangurayi Tongesayi *. “ Global Warming: The Reality”, OXFORD ROUND TABLE: THE COPENHAGEN PROTOCOL, UK, March 21-26, 2010.

SELECTED PRESENTATIONS AT SCHOLARLY/PROFESSIONAL MEETINGS