**4. Bioconcentration Factor (BCF) of heavy metals in plants**

**Chromium**: BCF for Cr was generally low across seasons and site. In the two study areas, the BCF of Cr ranged between 0.00 to 0.03 in the dry season, while in the wet season it varied between 0.00 and 0.07. *Combretummucronatum* was observed to have the highest BF value (Fig. 7and 8).

**Copper**: BCF for Cu (Fig. 7 and 8) was generally higher in the wet season than in the dry season, with *Combretum mucronatum* having the highest value of 6.16. *Ipomoea ascarafolia* was observed to have the highest BF in the dry season. Across seasons and sites, other plant species that had BCF >1.0, were: *Gardenia rubescens*, *Senna singuena*, *Gymnema sylvestris*, *Capparis polymopha*, *Guiera senegalensis*, *Englerina gracilinus*, *Senna siberiana*, *Combretum nigricans*, *Dicrostachys cinerea*, *Crateva religiosa*, *Stylosanthes arectalea* and *Terminalia mollis* (Fig. 7 and 8).

**Nickel**: Highest BCF of Ni was observed in *Combretumnigricans* (1.61) and *Capparis polymo‐ pha (*syn*. C. tomentosa)* (0.61). Most plants show a higher BF during the wet season in compar‐ ison to the dry season (Fig. 7 and 8).

**Iron**: BCF of Fe was generally low, with the highest value of 0.07 observed in *Sennasiberiana*, across seasons and sites (Fig. 7 and 8 ).

**Manganese**: For Manganese, BCF was generally low (<1.0) (Fig. 9) across seasons and sites. In the wet season, *Combretum nigricans* was observed to show a high BF of 0.53 and 0.41 of Mn in two different replicate plots. *Guiera senegalensis* was observed to accumulate Mn to a BF of 0.38. *Boscia senegalensis* was observed to have a BF of 0.62 during the dry season (Fig. 7 and 8).

**Zinc**: For Zinc, BCF was also generally low (<1.0) (Fig. 9) across seasons and sites.The highest BCF of Zn were observed in Ipomoea ascarafolia (0.70), Capparis polymopha (syn. C. tomen‐ tosa) (0.59), Guiera senegalensis (0.41) and Combretum nigricans (0.50) (Fig. 7 and 8).

**Cadmium**: *Sennaoccidentalis* and *Ipomoea ascarafolia* were observed to have considerably high BCF of 20.69 and 13.45 respectively. Most of the other plants were observed to have recorded higher BF in the wet season than the dry season. Across sites and seasons, other species that had BCF >1.0, were *Leptadenia hastata*, *Capparis polymopha*, *Senna siberiana* and *Ziziphus abyssinica* (Fig. 9)

Table 5 presents a summary of the most frequently accumulated metal in all species encoun‐ tered at the sampling locations. Eighteen plant species were found to bioaccumulate metals (BCF >1) in their above ground part to varying degrees. Cu was the most frequently accumu‐ lated, being found to occur in all of the 18 species (100%) across sites and seasons. This was followed by Cd in 6 species (33.33%) and Ni in only one (05.6%) species.

3

**4. Bioconcentration Factor (BCF) of heavy metals in plants**

7and 8).

(Fig. 9)

ison to the dry season (Fig. 7 and 8).

710 Environmental Risk Assessment of Soil Contamination

across seasons and sites (Fig. 7 and 8 ).

**Chromium**: BCF for Cr was generally low across seasons and site. In the two study areas, the BCF of Cr ranged between 0.00 to 0.03 in the dry season, while in the wet season it varied between 0.00 and 0.07. *Combretummucronatum* was observed to have the highest BF value (Fig.

**Copper**: BCF for Cu (Fig. 7 and 8) was generally higher in the wet season than in the dry season, with *Combretum mucronatum* having the highest value of 6.16. *Ipomoea ascarafolia* was observed to have the highest BF in the dry season. Across seasons and sites, other plant species that had BCF >1.0, were: *Gardenia rubescens*, *Senna singuena*, *Gymnema sylvestris*, *Capparis polymopha*, *Guiera senegalensis*, *Englerina gracilinus*, *Senna siberiana*, *Combretum nigricans*, *Dicrostachys*

**Nickel**: Highest BCF of Ni was observed in *Combretumnigricans* (1.61) and *Capparis polymo‐ pha (*syn*. C. tomentosa)* (0.61). Most plants show a higher BF during the wet season in compar‐

**Iron**: BCF of Fe was generally low, with the highest value of 0.07 observed in *Sennasiberiana*,

**Manganese**: For Manganese, BCF was generally low (<1.0) (Fig. 9) across seasons and sites. In the wet season, *Combretum nigricans* was observed to show a high BF of 0.53 and 0.41 of Mn in two different replicate plots. *Guiera senegalensis* was observed to accumulate Mn to a BF of 0.38. *Boscia senegalensis* was observed to have a BF of 0.62 during the dry season (Fig. 7 and 8).

**Zinc**: For Zinc, BCF was also generally low (<1.0) (Fig. 9) across seasons and sites.The highest BCF of Zn were observed in Ipomoea ascarafolia (0.70), Capparis polymopha (syn. C. tomen‐

**Cadmium**: *Sennaoccidentalis* and *Ipomoea ascarafolia* were observed to have considerably high BCF of 20.69 and 13.45 respectively. Most of the other plants were observed to have recorded higher BF in the wet season than the dry season. Across sites and seasons, other species that had BCF >1.0, were *Leptadenia hastata*, *Capparis polymopha*, *Senna siberiana* and *Ziziphus abyssinica*

Table 5 presents a summary of the most frequently accumulated metal in all species encoun‐ tered at the sampling locations. Eighteen plant species were found to bioaccumulate metals (BCF >1) in their above ground part to varying degrees. Cu was the most frequently accumu‐ lated, being found to occur in all of the 18 species (100%) across sites and seasons. This was

followed by Cd in 6 species (33.33%) and Ni in only one (05.6%) species.

tosa) (0.59), Guiera senegalensis (0.41) and Combretum nigricans (0.50) (Fig. 7 and 8).

*cinerea*, *Crateva religiosa*, *Stylosanthes arectalea* and *Terminalia mollis* (Fig. 7 and 8).

**Fig 7: Bioconcentration of (a) Cr, Cu and Ni, (b) Fe, Mn and Zn in plants collected from Zobe dam catchment and the environs of Katsina Steel Rolling Mill during the Dry Season Figure 7.** Bioconcentration of (a) Cr, Cu and Ni, (b) Fe, Mn and Zn in plants collected from Zobe dam catchment and the environs of Katsina Steel Rolling Mill during the Dry Season

15

**Fig 8: Bioconcentration of (a) Cu and Ni, (b) Fe and Cr, and (c) Mn and Zn in plants collected from Zobe dam catchment and the environs of Katsina Steel Rolling Mill during the Wet Season Figure 8.** Bioconcentration of (a) Cu and Ni, (b) Fe and Cr, and (c) Mn and Zn in plants collected from Zobe dam catch‐ ment and the environs of Katsina Steel Rolling Mill during the Wet Season

16

Heavy Metal Deposition in Soils and Plants Impacted by Anthropogenic Modification of Two Sites in the Sudan… http://dx.doi.org/10.5772/57299 713

**Fig 9: Bioconcentration of Cd in plants collected from Zobe dam catchment and the Figure 9.** Bioconcentration of Cd in plants collected from Zobe dam catchment and the environs of Katsina Steel Roll‐ ing Mill during the Wet and Dry Seasons

**environs of Katsina Steel Rolling Mill during the Wet and Dry Seasons**

17

16

**during the Wet Season** 

Senna Leptadenia hastata

Ipomea Gardenia Senna Gymnema

ment and the environs of Katsina Steel Rolling Mill during the Wet Season

sylvestris

Combretum…

Capparis

Coldenia Guiera Englerina Cadaba

Zobe 1 Zobe 2 Zobe 3 KTSRM 1 KTSRM2 KTSRM3

farinosa

gralicinus

senegalensis

procumbens

polymopha

sinquena

rubescens

ascarafolia

occidentalis

0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00

0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07

0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 Senna Leptadenia hastata

Ipomea Gardenia Senna Gymnema

sylvestris

Combretum…

Capparis

Coldenia Guiera Englerina Cadaba

Zobe 1 Zobe 2 Zobe 3 KTSRM 1 KTSRM2 KTSRM3

c

Senna Combretum

Capparis Dicrostachys cinerea

Creteva

religiosa

Stylosanthes…

Combretum

Boscia Cadaba Terminalia mollis

Guiera Combretum

nigricans

Fe Cr

senegalensis

farinosa

senegalensis

nigricans

polymopha

nigricans

sieberiana

farinosa

gralicinus

senegalensis

procumbens

polymopha

sinquena

rubescens

ascarafolia

occidentalis

Senna Leptadenia hastata

Ipomea Gardenia Senna Gymnema

sylvestris

Combretum…

Capparis

Coldenia Guiera Englerina Cadaba

Zobe 1 Zobe 2 Zobe 3 KTSRM 1 KTSRM2 KTSRM3

b

Senna Combretum

Capparis Dicrostachys cinerea

Creteva

religiosa

Stylosanthes…

Combretum

Boscia Cadaba Terminalia mollis

Guiera Combretum

nigricans

Cu Ni

senegalensis

farinosa

senegalensis

nigricans

polymopha

nigricans

sieberiana

a

farinosa

gralicinus

senegalensis

procumbens

polymopha

sinquena

rubescens

ascarafolia

712 Environmental Risk Assessment of Soil Contamination

occidentalis

**Fig 8: Bioconcentration of (a) Cu and Ni, (b) Fe and Cr, and (c) Mn and Zn in plants collected from Zobe dam catchment and the environs of Katsina Steel Rolling Mill** 

**Figure 8.** Bioconcentration of (a) Cu and Ni, (b) Fe and Cr, and (c) Mn and Zn in plants collected from Zobe dam catch‐

Senna Combretum

Capparis Dicrostachys cinerea

Creteva

religiosa

Stylosanthes…

Combretum

Boscia Cadaba Terminalia mollis

Guiera Combretum

nigricans

Mn Zn

senegalensis

farinosa

senegalensis

nigricans

polymopha

nigricans

sieberiana


**Table 5.** Seasonal occurrence of plant species with potential for phytoextraction (BCF) of Cu; Ni and Cd in the catchment of Zobe Dam and the environs of Katsina Steel Rolling Mill.
