Dodd, Matt

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https://hdl.handle.net/10613/12761

Matt Dodd is an environmental analytical chemist with research interests in metal speciation and bioaccessibility, air quality monitoring, soil toxicity testing, persistent organic pollutants, microplastics, and contaminated sites assessment and remediation. He has conducted research and served as project scientist for numerous environmental projects in Canada, China and Ghana. He has also supervised or provided scientific advice on environmental remediation of contaminated sites in the Canadian Arctic including the DEW Line. Dodd is a member of Bioaccessibility Research Canada, a board member of the Vancouver Island chapter of the Air and Waste Management Association, and has participated in the Northern Contaminants Program. Dodd joined Royal Roads University in 1995 as a research associate with the Centre for Economic Development and Applied Research (CEDAR) and moved to the School of Environment and Sustainability in 2006. Prior to this he was a research associate with the Environmental Sciences Group at Royal Roads Military College and taught briefly at Grenfell College, Memorial University of Newfoundland. He has also developed and delivered short courses on environmental assessment to various agencies, successfully incorporating practical experiences from the numerous projects on which he has worked. Dodd holds a PhD in environmental analytical chemistry from the University of British Columbia (1988) and a Bachelor of Science, First Class Honours from the Kwame Nkrumah University of Science and Technology in Ghana (1981).

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Distribution, bioaccessibility and human health risks of toxic metals in peri-urban topsoils of the Kumasi Metropolis
(Scientific African, 2021) Konwuruk, Niib; Sheringham Borquaye, Lawrence; Darko, Godfred; Dodd, Matt
The occurrence of heavy metals in urban soils is of great environmental concern due to the unwanted health effect associated with their excessive exposure. The study assessed levels of heavy metals (As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Sn, V, and Zn) in peri-urban communities of the Kumasi metropolis and evaluated sources and potential health risk associated with exposure to these metals. Soil samples collected from topsoils at a depth of 0–10 cm were subjected to x-ray fluorescence (XRF) spectroscopy analysis for total metal quantification. The XRF results were then confirmed by inductively coupled plasma mass spectrometry. Soil pH, conductivity, and total organic carbon were determined using standard procedures. The mean concentrations (mg/kg) of metals were As (10.11), Cd (12.91), Cr (77.97), Cu (20.20), Fe (23031), Pb (18.60), Mn (158.68), Ni (29.33), Sn (8.83), V (78.21) and Zn (49.27). The pH and electrical conductivity were in a range of 6.5 - 8.5 and 153 - 8990 μS/cm respectively. The mean total organic carbon was 8.85%. Pollution indicators such as enrichment factor, contamination factor, and pollution load index all showed that soil in the study area is of low degree of contamination. The potential ecological risk index projected a low-risk effect. In contrast, the hazard index and carcinogenic risk index indicated no significant human health risk associated with exposure to the metals presently. However, to regulate bioaccumulation effects, constant monitoring is essential.
Gastric bioaccessibility and human health risks associated with soil metal exposure via ingestion at an E-waste recycling site in Kumasi, Ghana
(Environmental Geochemistry and Health, 2020) Amponsah, Lydia O.; Dodd, Matt; Darko, Godfred
Over 1000 people make a living by processing electronic and electrical waste (E-waste) and scrap metals for the recovery of valuable metals and integrated circuits at Dagomba Line, Kumasi, Ghana. These processing include activities such as dismantling, open burning and open dumping of e-waste which can potentially release toxic metals into the environment and thus impact the health of recyclers and nearby residents. This study investigated the distribution of toxic metals (As, Cd, Cr, Cu, Hg, Ni, Pb, Sb, and Zn) in surface soils at the e-waste recycling sites and determined the associated human health risk via ingestion incorporating bioaccessibility measurements. Metal concentrations in the activity sites were highly elevated, significantly higher than those in the surrounding area and exceeded international soil quality guidelines such as the Canadian soil quality guidelines for residential use and the Dutch Intervention Value. Bioaccessibility was high for Pb (70.8%), Cd (64.1%), Cu (62.3%) and Ni (53.6%) which could be credited to the existence of oxidized species as a result of the e-waste burning. Non-carcinogenic effects were unacceptably high (hazard indices > 1) at 14 out of 31 sites and the cancer risk for arsenic for adult workers was greater than 1 × 10−5 at five of the sampling sites.
Heavy metal content and potential health risk of geophagic white clay from the Kumasi Metropolis in Ghana
(Toxicology Reports, 2016) Nkansah, Marian Asantewah; Korankyea, Mavis; Darko, Godfred; Dodd, Matt
Geophagia is the craving for non-food substances and commonly practiced among pregnant women and children. Consumption of geophagic clay samples can have serious implications on the health of the consumers as a result of the presence of toxic metals such as Pb, As, Hg and Cd. This study sought to determine the levels of heavy metals in the studied geophagic clay samples and to determine the potential risks of heavy metals as cumulative carcinogenic and non-carcinogenic risks to the health of the consumers via oral (ingestion) and dermal exposure routes. A total of thirty (30) white clay samples were analysed using Niton Thermo scientific XRF Analyser (Mobile Test S, NDTr-XL3t-86956, com 24). The clay samples were found to contain essential elements such as Ca, Fe, K and Zn as well as toxic metals such as As and Pb. There were isolated cases of the presence of Hg and all samples had Cd levels below detection. Health risk indices such as hazard quotient and cancer risk were calculated and the results indicated that consumers are likely to suffer from cancer through ingestion of geophagic clay. Bioaccessibility studies were done on zinc and it did not indicate any potential toxicity due to zincs essential nature. The levels of heavy metals in some of the geophagic clay consumed by some residents in the Kumasi were high compared to the Permitted Maximum Tolerable Daily Intake (PMTDI) by (WHO/FAO) and may pose potential health threat over time.
Distribution and ecological risks of toxic metals in the topsoils in the Kumasi metropolis, Ghana
(Cogent Environmental Science, 2017) Darko, Godfred; Dodd, Matt; Nkansah, Marian Asantewah; Aduse-Poku, Yaw; Ansah, Eugene; Wemegah, David Dotse; Borquaye, Lawrence Sheringham
The distribution, and ecological risks due to toxic metals in topsoils of an urban commercial centre of Kumasi metropolis were determined. Concentrations of heavy metals in the samples were initially screened using field portable X-ray fluorescence spectrometer prior to confirmation on an inductively coupled plasmamass spectrometer. The results from the two instruments correlated well with high linearity (R2 > 0.70). Concentrations of metals were in the order: Fe (45246.15 mg/ kg) > Mn (347.86 mg/kg) > Zn (176.40 mg/kg) > V (173.10 mg/kg) > Cr (125.12 mg/ kg) > Pb (53.47 mg/kg) > Ni (43.16 mg/kg) > Cu (39.85 mg/kg) > As (4.59 mg/ kg) > Sn (3.69 mg/kg) > Cd (0.46 mg/kg) > Hg (0.28 mg/kg). Multivariate and geostatistical analyses exploring various hazard indices such as geo-accumulation, contamination, pollution load and ecological risks all suggest contamination of the topsoils with toxic metals and that the contamination due to Pb, Cu, Ni, Cr and Zn is mainly derived from anthropogenic origins whereas, As, Hg, Mn, V, Sn and Cd contaminations are attributable mainly to geological and atmospheric depositions.
Assessment of pollution levels, potential ecological risk and human health risk of heavy metals/metalloids in dust around fuel filling stations from the Kumasi Metropolis, Ghana
(Cogent Environmental Science, 2017) Nkansah, Marian Asantewah; Darko, Godfred; Dodd, Matt; Opoku, Francis; Essuman, Thomas Bentum; Antwi-Boasiako, Joshua
The aim of this study was to evaluate the levels of selected heavy metals/ metalloids in filling station dust from the Kumasi Metropolis, Ghana. A total of forty (40) dust samples were analysed for Fe, Ti, Zn, Zr, Mn, Sr, Ba, Cr, Pd, Ni, Cu, As and Mo using X-ray Fluorescence technique. Mean concentrations of Ba, As, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Sr, Ti, Zn and Zr were 92.26, 6.20, 70.41, 50.18, 466.22, 163.68, 4.63, 44.05, 46.93, 106.69, 327.51, 280.32 and 182.05 mg/kg, respectively. The pollution index (PI) and geo-accumulation (Igeo) index values were in the order of Ba < Mn < Sr < Zr < Cu < Cr < Ni < Mo < As < Zn < Pb < Fe < Ti. The pollution load index had a mean of 2.20, signifying moderate pollution. Higher PI and Igeo value for Pb, Fe and Ti indicated high pollution. The PCA analysis identified anthropogenic inputs and natural origin as the main sources of pollution in filling station dust. The potential ecological risk index decreased as follows: As > Pb > Ni > Cu > Cr > Zn > Mn > Ba. The contribution of hazard quotient via ingestion for most of the heavy metals/metalloids were high with 11.83% for adults and 88.17% for children. For health risk assessment, non-carcinogenic values were below the threshold values, except hazard index via ingestion. The main exposure pathway for both children and adults was ingestion, followed by dermal contact and inhalation.

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