Andrew Kindness

Elemental composition and chemical characteristics of five edible nuts (almond, Brazil, pecan, macadamia and walnut) consumed in Southern Africa

The total elemental concentrations and proximate chemical composition of five different tree nuts, almond (Prunus dulcus), Brazil (Bertholletia excelsa), pecan (Carya pecan), macadamia (Macadamia integrifolia) and walnut (Juglans nigra) that are consumed in South African households were investigated. In addition, six physicochemical properties of the extracted nut oils, namely acid value, iodine value, saponification value, refractive index, density and specific gravity were evaluated. A high concentration of Se (36.1 ± 0.4 μ g g− 1) was found in the Brazil nuts only. With maximum and minimum limits being set by the almond and pecan nut samples, Cr ranging from 0.94 ± 0.14–2.02 ± 0.07 μ g g− 1 was detected in the nut samples. Generally, the order of the concentrations of the elements in all the nut samples is found to be Mg > Ca > Fe > Cu > Cr > As > Se. The concentrations of Mn and Zn showed greater variation amongst the different types of nuts. The extracted oils showed low acid values and high saponification values with the macadamia nut sample having the highest oil content (76.0 ± 0.5 g per 100 g of sample), the lowest acid value (0.42 ± 0.01 mg KOH per g of oil) and highest saponification value (193.7 ± 2.4 mg KOH per g of oil). The present findings are useful in calculating the Dietary Reference Intakes of these nutrients.

Heavy metal uptake by two edible Amaranthus herbs grown on soils contaminated with lead, mercury, cadmium, and nickel.

The uptake of an element by a plant is primarily dependent on the plant species, its inherent controls, and the soil quality. Amaranthus hybridus (green herbs) and Amaranthus dubius (red herbs) were chosen to investigate their response and ability to accumulate and tolerate varying levels of elements in their roots and shoots. Red herbs and green herbs were grown in soil pots contaminated with three mixtures of Cd(II), Ni(II), Pb(II), and Hg(II). Plants in the control treatment were grown in the absence of the heavy metals mixture. The distribution of Cd, Ni, Pb, and Hg in the plants (in roots, stems, and leaves) was determined in two stages. Stage 1, after 5 weeks of plant growth and stage 2, full grown after 10 weeks of growth. In the red herbs the Cd concentration in the leaves at stage 2 was 150 ppm and was present in higher concentrations than Ni, Hg, and Pb. At the highest contamination level, in the green herbs plant, Hg was present in the highest concentration in the root, i.e., 336 ppm at stage 1, while the level in the leaves was 7.12 ppm. Both the green and red herbs species showed an affinity for Ni and Cd with moderate to high levels detected in the leaves, respectively.

Synthesis, Characterization, and Adsorption Kinetic Studies of Ethylenediamine Modified Cellulose for Removal of Cd and Pb

Surface functionalization of cellulose using ethylenediamine was performed to improve its binding capacity for Cd and Pb. Adsorption kinetics at pH 6.0 and 25°C revealed the Langmuir model to better describe the binding phenomena based on linear regression correlation coefficient (R2) values of 0.998 and 0.986 with adsorption capacities of 0.0136 and 0.0179 mmol g−1 for Cd and Pb, respectively, using raw cellulose and 0.128 and 0.242 mmol g−1 with ethylenediamine-modified cellulose. The Freundlich model gave binding capacities of 2.32 × 10−3 and 2.08 × 10−3 mmol g−1 for Cd and Pb, with R2 values of 0.979 and 0.942, respectively.

Seaweeds Along KwaZulu-Natal Coast of South Africa—4: Elemental Uptake by Edible Seaweed Caulerpa racemosa (Sea grapes) and the Arsenic Speciation

The elemental uptake by edible seaweed Caulerpa racemosa (Sea grapes), a marine macroalgae (chlorophyta, green alga) grown richly along KwaZulu-Natal coastline. The total concentrations of seven elements, namely Mn, Fe, As, B, Ti, Zn and Hg in Caulerpa racemosa were monitored for a one-year cycle (June 2002 to May 2003) at four selected sampling sites spread over 150 km wide from North to South. The C. racemosa possess high arsenic, boron and titanium accumulating ability, but low iron uptake. A typical C. racemosa sample at Treasure Beach in the vicinity of Durban Metropolis in autumn contained Mn (5.2 ± ppm), Fe (0.21 ± 0.01 ppm), As (8.5 ± 0. ppm), B (1090 ± ppb), Ti (159 ± ppb), Zn (3.8 ± 0.1 ppb), and Hg (189 ± ppb). The general trend found at all sites was high elemental concentrations in winter and a decrease in concentrations from winter to spring and summer. C. racemosa recorded highest mercury levels (>205 ppb) during the summer season at the Zinkwasi site. The arsenic speciation in four abundant seaweeds from the beaches of Indian Ocean in the KwaZulu-Natal coast is investigated. The speciation of arsenic in two rhodophyta seaweeds, Plocamium corallorhiza and Gelidium abbottiorum, and two chlorophyta seaweeds, Ulva lactuca and Caulerpa racemosa at four sampling sites during the summer of 2003, is elucidated. Caulerpa racemosa had highest total arsenic (in ppb) reaching (8850 ± 200) at Zinkwasi, and the concentrations of the other arsenic species analysed are As (III) (194 ± 10), As(V) (568 ± 27), methylarsonic acid (494 ± 22) and dimethylarsinic acid (373 ± 12). In an indirect estimation, C. racemosa had 81 ± 2% aresenosugars.

Seaweeds along KwaZulu-Natal Coast of South Africa—3: Elemental Uptake by Ulva lactuca (Sea Lettuce)

The elemental uptake by Ulva lactuca (Sea lettuce), a marine macro-algae (chlorophyta, green alga) grown richly along KwaZulu-Natal coastline. The total elemental concentrations of seven important elements, namely manganese, iron, arsenic, boron, titanium, zinc and mercury, selected based on their abundance in U. lactuca were investigated for one year cycle (June 2002 to May 2003). The four selected sampling sites, Zinkwasi, Ballito, Treasure Beach and Park Ryrie are spread over 150 km wide along the KwaZulu-Natal coastline from North to South. The Ulva lectuca possess good manganese and arsenic accumulating ability and an excellent bio-indicator for most of the metals studied. A typical U. lectuca sample at Zinkwasi (in winter) recorded Mn (25.3 +/- 1.16 ppm), Fe (21.0 +/- 0.85 ppm), As (6.2 +/- 0.30 ppm), B (935 +/- 14 ppb), Ti (863 +/- 34 ppb), Zn (421 +/- 21 ppb), and Hg (61.3 +/- 1.2 ppb). The general trend found at all sites was high elemental concentrations in winter and a decrease in concentrations from winter to spring and summer. Iron uptake was lowest in summer and autumn at all sites. Ulva lactuca recorded highest mercury levels (>400 ppb) during the spring season at the Treasure Beach site near Durban.

Macro, minor and toxic elemental uptake and distribution in Hypoxis hemerocallidea, the African Potato : an edible medicinal plant

The elemental uptake and distribution, in various parts of the admired herbal plant, Hypoxis hemerocallidea, the ‘African potato’ and its ability to accumulate elements in response to the growth soil quality are investigated. The total and exchangeable concentrations of twelve elements in the growth soils and their distribution in the roots, potato bulb and leaves of the plants grown under four different settings were compared. The typical concentrations of the twelve selected elements, in the bulb and leaves of the plant grown in a nursery pot (site 2) were (in μ g g−1dry weight) Ca (8430 and 27075), Mg (2113 and 1566), Fe (66 and 150), Al (10 and 368), Zn (105 and 6.1), Mn (42 and 51), Cu (7.2 and 20.8), Ba (0.23 and 4.44), Co (0.20 and 0.42), As (2.05 and 24.56), Hg (0.92 and 1.82) and Cr (0.13 and 0.33). Except for Ca, Mg, Zn and Mn, the exchangeable cation concentrations in all the growth soils were low. Ca, Mg, Mn, Zn and As had bioaccumulation factors > 1. Fe, Al and Co concentrations were high in the roots with little in the rest of the plant. High concentration of arsenic (≈ 13 μ g g−1 dry weight) with bioaccumulation factors of 7 and 20 were observed in the roots and leaves of the plant respectively (site 2), but the concentration of mercury in bulb was very low (0.92 μ g g−1 dry weight).

Chemical composition of edible Macadamia nuts (Macadamia integrifolia) and impact of soil quality

The distribution of eight selected elements (As, Ca, Cr, Cu, Fe, Mg, Mn and Zn) in edible Macadamia (Macadamia integrifolia) nuts from eight sampling sites in the south east coast region of South Africa is investigated. The levels of the elements in all the Macadamia nuts are found to be in the decreasing order of Mg > Ca > Fe > Zn > Cu > Cr > As. The exception is Mn, which exhibited large variability with concentrations in nuts ranging from 10.21 ± 0.47μg g−1 to 216.4 ± 0.4 μg g−1. The impact of soil quality parameters: soil pH, cation exchange capacity, soil organic matter and elemental concentrations, as well as interactions in the soil on the elemental composition in the nuts are also studied. At the Ifafa site, south of Durban, typical elemental concentrations (in μg g−1 dry weight) in the (nuts and soil) are Mg (4920 and 4656), Ca (2169 and 6173), Fe (92 and 20200), Zn (52 and 30), Cu (20 and 49), Cr (2.0 and 69.0) and As (0.024 and 0.104). The maximum concentration of Mg in the nuts is observed to be 4956.1 ± 92.8 μg g−1, while that of As is below 0.058 ± 0.003 μg g−1. Ca and Mg levels in nuts are antagonistic. Further, when bioavailable levels of Fe, Cu and Zn in soil are low, the bioaccumulation factor for Fe in nuts is high. Although, the soil quality parameters have an influence on the elemental uptake by the Macadamia nut, the results show that uptake and distribution of metals in the nuts are primarily dependent on the plants inherent controls that ensure the physiological well-being of the plant. Macadamia nuts prove to have good control on elemental uptake and are low in the toxic metals investigated.

Elemental Uptake by Seaweed, Plocamium corallorhirza Along the KwaZulu-Natal Coast of Indian Ocean, South Africa

This study reports the elemental uptake by Plocamium corallorhiza, a Rhodophyta class of coralline alga grown richly along KwaZulu-Natal coastline. The uptake of seven important elements, namely Fe, Mn, As, B, Ti, Zn and Hg, selected based on their abundance in the samples, were investigated for a one-year cycle, from June 2002 to May 2003, at four chosen sites located along the KwaZulu-Natal coastline. The sites spread over 150 km from North to South Coast are Zinkwasi, Ballito, Treasure Beach and Park Rynie. P. corallorhiza possess good manganese and arsenic-accumulating ability and has potential to be an excellent indicator for most of the metals studied. A typical P. corallorhiza sample at Park Rynie (winter) recorded Mn (14 ppm), Fe (6.02 ppm), As (8.4 ppm), B (1580 ppb), Zn (234 ppb), Ti (751 ppb) and Hg (15.8 ppb). The general trend found at all sites was a large decrease in iron concentration in spring and summer and increase in winter. Mercury uptake was lowest in winter and autumn at all sites. The highest mercury levels in the seaweeds were recorded during spring or summer.

Elemental Distribution in Seaweed, Gelidium abbottiorum Along the KwaZulu-Natal Coastline, South Africa

The total concentrations of 7 selected metals, namely manganese, iron, zinc, titanium, boron, arsenic and mercury, were monitored for one annual cycle covering four seasons in the seaweed, Gelidium abbottiorum, at four sampling sites at Zinkwasi, Ballito, Treasure beach and Park Rynie along the South-East coastline of KwaZulu-Natal, South Africa to assess the current status of the marine environment. Inductively Coupled Plasma Optical Emission Spectrophotometry, Mercury Cold Vapour AAS, and Hydride Generation AAS were used for the determination of metal concentrations. Mn concentrations were particularly high in the G. abbottiorum species, followed by Fe, As and B concentrations which were in the 3–8 ppm range. Ti and Zn were in the 100–400 ppb range, while Hg was low and below 100 ppb. A typical sample of G. abbottiorum at Treasure beach, a site close to Durban metropolis in winter had Mn (8.6 ppm), Fe (4.6 ppm), As (5.6 ppm), B (3.0 ppm), Ti (420 ppb), Zn (167 ppb) and Hg (7.5 ppb). All metals recorded a decrease in concentrations from winter to spring with the exception of Hg. The Hg levels increased considerably from winter to spring.

Method Development for Flow Adsorption and Removal of Lead and Copper in Contaminated Water Using Electrospun Nanofibers of Chitosan Blend

This study reports column flow adsorption capacity for Pb and Cu of 56.54 mgg−1 and 5.75 mgg−1, respectively, using electrospun nanofibers (70–264 nm) of chitosan:polyacrylamide blend ratio 77:23 with glutaraldehyde cross-linking. The Freundlich isotherms gave a better fit than Langmuir. The fibers were applied in contaminated pond water and pulp wastewater, for removal of Pb and Cu, with removal efficiencies of 100% (Pb) and 98.6% (Cu) in pond water; and 97.2% (Pb) and 99.5% (Cu) in wastewater. The regeneration efficiencies (recovery %) were 64% (Pb) and 89% (Cu) in pond; 72% (Pb) and 90% (Cu) for pulp, respectively, using an adsorbent mass of 0.05 g.