Overview
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Key numbers
The worker extracted the full PDF text with layout preservation twice and compared extraction hashes before commit. The following lines are copied from numeric/table-bearing regions of the PDF and retain the source units and wording where legible:
- matrix also shows positive correlation between the possible metal pairs at 95% level of confi-
- the afternoon the temperature can soar to as high as 30˚C (86˚F), while the relative humidity drops under 10%
- tion and analysis. The various sample locations and their respective office codes are listed in Table 1.
- Table 1. Sampling site characteristics including geographic coordinates (decimal degrees), elevation, site classification and
- deviations and bar charts. Table 2 shows indoor settled dust loading (g/m2) for all the sample locations during
- tled dust were fairly uniform (4.475 - 6.533 g/m2) throughout all the sampling sites as depicted in Table 2. Dust
- unintentional hand to mouth contact or by inhalation of dust (19). However, the overall mean of dust loading
- showing the relationship (at 0.05 level of significance) between the metals under study is depicted in Table 3,
- while Table 4 shows Comparison of heavy metal concentration (mg/kg) in dust samples found in the present
- Table 2. Indoor dust loading within the University of Agriculture Makurdi.
- Table 3. Correlation matrix for heavy metal concentrations.
- Table 4. Heavy metal concentrations (mg/kg) in comparison with reported studies.
- area ranges from 0.2372 - 0.7152 mg/kg. The highest concentration was recorded at the College of Engineering
- Fe ranges from 293.6 - 884.9, with the highest value recorded at the College of Science (SC) while the lowest
- ment ranges from 4.265 - 68.55 mg/kg, with the highest value recorded at the College of Sciences (SC) while
- in the range of 4.239 - 42.53 mg/kg as shown in Figure 5. Zn concentration was highest at the College of Agri-
- The Pearson correlation matrix for heavy metal concentration in studied samples as shown in Table 3 indicates
- positive correlation between all the possible pairs of heavy metals at 95% confidence level. High positive corre-
- Table 4 shows the comparison between the concentrations of heavy metals in indoor settled harmattan dust from
Methods (brief)
- kurdi were collected between November, 2014 to March, 2015 (five months) using the wipe sam-
- pling methodology. Gravimetric measurement of the dust samples from all the sample locations
- this study. AAS analysis of the dust samples shows that heavy metal concentrations (mg/kg dry
- wipe samples were collected according to the American Society for Testing and Material, ASTM E1728 proto-
- pling sites. Before weighing, the samples were equilibrated in desiccators at 20˚C - 30˚C in a humidity con-
- trolled room for 24 h (16). This was to prevent any possible error in the mass of samples as a result of available
- study area. Outdoor settled dust samples were also collected from the vicinities of sampled College buildings
- the nine Colleges of the University) were selected at random for this study. A total of 210 wipe samples of in-
- door settled dust were collected from office desks (900 cm2) and ceiling fan blades (100 cm2 each) not pre-
- viously rusted. While a total of 30 samples of outdoor settled dust was collected from three locations A, B and C
- within the vicinities of the sampled College buildings during the same period to serve as control. In each College
- building sampled, one field blank tissue paper was exposed to all handling procedures used for the samples with
- mediately following completion of sampling, all wipe samples were transported back to the laboratory for diges-
- tion and analysis. The various sample locations and their respective office codes are listed in Table 1.
- College Building Sample Code Coordinate Coordinate
- ance. Dust loading for each sample location was obtained using the following mathematical expression:
- After digestion, the contents in the beaker, upon cooling was then transferred quantitatively into a 50 mL volu-
- and stored in polypropylene bottles prior to heavy metals analysis. 0.5 g of dust samples from each of the control
Implications
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