**4.2 Metal content**

**4. Results and discussion**

**4.1 Soil physical properties**

**Table 6.**

**88**

*Sieve analysis of the gold mine tailings sediment samples.*

Textural properties obtained from sieve analysis of the gold mine tailings sediments using classification as prescribed by [25] are presented in **Table 6**. These results reveal that fine sand (0.150–0.075 mm) and clay (0.075–0.053 mm) were the principal fractions of all sediment samples, with an average composition of 66.03% for fine sand, 23.08% clay and 10.89% silt respectively. With the larger portion of the sediments being fine sand, there is a likelihood for nutrients accu-

Geochemical properties of the sediments such as the pH, EC and carbonate content (see **Table 7**) helps in ascertaining vital information to comprehend the soils potential to withhold heavy metals [34]. The results obtained for the sediment pH measurements, showed that the study area is very strongly acidic ranging from 3.86 to 4.34. The low pH values in the study area were related with heterogeneous deposits of sulfidic residues from the mine surroundings, which resulted in low pH values that is attributed to microbial sulfide oxidation and the resultant formation

> **% Materials; Retains (gms) No. 100 No. 140 No. 200 No. 270 PAN TOTAL % Sand % Silt % Clay**

 5.68 45.51 15.84 10.25 22.72 100 67.03 10.25 22.72 5.75 46.82 13.79 10.58 23.41 100 66.01 10.58 23.41 5.40 46.52 13.61 10.62 23.85 100 65.53 10.62 23.85 5.37 45.84 14.71 11.25 22.83 100 65.92 11.25 22.83 5.42 45.93 13.93 11.81 22.91 100 65.28 11.81 22.91 5.39 47.88 13.01 11.20 22.52 100 66.28 11.20 22.52 5.42 48.23 11.87 10.78 23.70 100 65.52 10.78 23.70 5.88 46.38 13.42 10.44 23.88 100 65.68 10.44 23.88 5.94 46.82 13.00 10.32 23.92 100 65.76 10.32 23.92 5.66 44.46 16.15 10.58 23.15 100 66.27 10.58 23.15 5.86 47.20 14.22 9.88 22.84 100 67.28 9.88 22.84 5.42 45.30 15.83 11.32 22.13 100 66.55 11.32 22.13 5.38 45.92 13.68 11.84 23.18 100 64.98 11.84 23.18 5.62 46.34 13.74 10.68 23.62 100 65.70 10.68 23.62 5.48 46.82 13.81 10.31 23.58 100 66.11 10.31 23.58 5.23 46.92 14.81 10.22 22.82 100 66.96 10.22 22.82 5.98 48.22 11.62 11.69 22.49 100 65.82 11.69 22.49 5.36 48.80 11.78 11.38 22.68 100 65.94 11.38 22.68 5.92 48.24 11.34 11.75 22.75 100 65.50 11.75 22.75 5.68 47.36 13.37 10.94 22.65 100 66.41 10.94 22.65

mulation is high due to the higher surface-to-volume ratios [33].

*Trace Metals in the Environment - New Approaches and Recent Advances*

**Sample no. Sieve size (ASTM)**

The summary of the determined heavy metal concentrations within the sediments of the study area by using ICP-OES are presented in **Table 8**. The concentration of various heavy metal varies from 860.3–862.6 mg/kg for Cr; 324.9–328.4 mg/kg for Al; 200.9–203.4 mg/kg for As; 130.1–136.2 mg/kg for Fe; 121.9–125.8 mg/kg for Pb; 27.3–30.2 mg/kg for Co; 23.8–26.8 mg/kg for Ni; 7.2–9.2 mg/kg for Ti; 7.1–9.2 mg/kg for Cd; 4.0–5.6 mg/kg for Zn and 0.1–0.6 mg/kg for Cu. Chromium (Cr) was identified as the most abundant heavy metal in the sediment samples. Mean concentration of the metals were Cr: 861.5 mg/kg; Al: 326.8 mg/kg; As: 202.2 mg/kg; Fe: 134.3 mg/kg; Pb: 123.7 mg/kg; Co: 28.8 mg/kg; Ni: 25.4 mg/kg; Ti: 8.5 mg/kg; Cd: 8.3 mg/kg; Zn: 4.5 mg/kg and Cu: 0.2 mg/kg dry weights. The average order of metal concentration is Cr > Al > As > Fe > Pb > Co >


#### **Table 7.** *Geochemical properties of gold mine tailings sediments.*

Ni > Ti > Cd > Zn > Cu. The mineral composition of the sediments and mining activities that took place within this region may be attributed to the high element concentrations in the soil samples.

replaces phosphorus with As for a number of cellular functions [39]. Plants often accumulate As by root uptake from soil or by absorption of airborne As deposited on their leaves [40]. Arsenate, a dominant specie of Arsenic in soils, based on its similarity to phosphate usually compete for the same uptake carriers in the root plasmalemma of most plants. In so doing interrupts with several metabolic processes that end up inhibiting plant growth and development through arsenicinduced phytotoxicity [41, 42]. Some of the toxicity symptoms may include inhibition of seed germination, decrease in plant height, depressed tillering, reduction in root growth and some necrosis, decrease in shoot growth, lower fruit and grain yield, reductions in chlorophyll and protein contents, and in photosynthetic capacity and even death [41–46]. Due to migration and expansion of residential areas into former mining territories, the danger of human exposure to soil As has risen in the last two decades which have affected adversely the health of many [47]. Continued

*Evaluation of Trace Elemental Levels as Pollution Indicators in an Abandoned Gold Mine Dump…*

exposure to As results in several clinical manifestations such as melanosis

ogen, causing skin, lung, bladder, liver, and kidney cancers [50, 51].

which does not pose a danger to the environment [54, 55].

of the Republic of South Africa [52].

*DOI: http://dx.doi.org/10.5772/intechopen.89582*

kidney and liver disorders [61].

**91**

(hyperpigmentation), keratosis, and leukomelanosis (hypopigmentation) of which cutaneous lesions are the highest reported [48, 49]. As is also a well-known carcin-

The average concentration of Copper (Cu) being 0.2 mg/kg was within the maximum acceptable concentration of 6.6 mg/kg for agricultural soil and safe limit

animals. In humans, it aids in the production of blood hemoglobin while plants utilize it in seed production, disease resistance, and regulation of water. In high levels, Cu could cause anemia, liver and kidney damage, as well as stomach and intestinal irritation [53]. Cu typically occurs in drinking water from Cu pipes, as well as from additives intended to control algal growth. The interaction of Cu with the environment is complex, however different studies revealed that most Cu introduced into the environment rapidly becomes, stable and results in a form

Zinc is an important metal due to its enzymatic and regulatory functions in biological systems. Being a readily mobile element, Zinc (Zn) when in high doses exhibit toxic and carcinogenic effects that could result in serious hematological and neurologic complications, liver and kidney disorders, hypertension, gastrointestinal misery, loose bowels, pancreatic harm and a host of other ailments in both humans and animals [56]. On the earth crust, Zinc is found in an average concentration of 80 mg/kg in association with ores of other metals such as Pb, Cu and Cd [57]. Chromium (Cr) has an average concentration of 100 mg/kg in the earth crust and the only known ore of commercial value is chromite (FeO.Cr2O4). Contamination by Cr could result in toxicity in plants depending on its state of valency since Cr (VI) due to its being highly mobile is toxic, while Cr (III) as less mobile is less toxic. The subsequent uptake, translocation, and accumulation of Cr by plants is dependent on its speciation. Cr in its trivalent (III) and hexavalent (VI) forms are known to be of biological importance. Generally, Cr poses the greatest threat to humans, animals and plants. Decreased seed germination, reduction of growth, decreased yield, inhibition of enzymatic activities, impairment of photosynthesis, nutrient and oxidative imbalances, and mutagenesis are some of the symptoms of Cr toxicity in plants [58]. In a previous study by López-Luna et al. [59], the toxicity of Cr (VI), Cr (III), and Cr tannery sludge were compared with respect to Cr mobility in soil and toxicity in wheat, oat, and sorghum plants and findings were that Cr(VI) was more mobile in soil and caused higher toxicity on those plant seedlings, while tannery sludge was the least toxic [60]. In humans, prolonged exposure results in

As an important micronutrient, Cu is required for the growth of both plants and

In comparison to the interim sediment quality guidelines (ISQG) proposed by the Canadian Council of Ministers of the Environment [38], the elemental pollution status of the tailings (soil) were assessed **Table 8**. The heavy metals from the studied tailings sediments except for Zn and Cu all exceeded the ISQG. This implies that the sediments are toxic and could result in the introduction of sediment contaminants into the aquatic food web through predation by organisms at higher trophic levels.

In trace amounts, Arsenic is one of the priority toxic metals due to its several deteriorating effects to both plants and animals. The level of identified arsenic in the sediment is worrisome. As a non-essential element, Arsenic is not required for the growth of living organisms, though recent discovery reports a bacterium that


#### **Table 8.**

*Heavy metals concentration (mg/kg dry weight) in gold mine tailings sediments.*

### *Evaluation of Trace Elemental Levels as Pollution Indicators in an Abandoned Gold Mine Dump… DOI: http://dx.doi.org/10.5772/intechopen.89582*

replaces phosphorus with As for a number of cellular functions [39]. Plants often accumulate As by root uptake from soil or by absorption of airborne As deposited on their leaves [40]. Arsenate, a dominant specie of Arsenic in soils, based on its similarity to phosphate usually compete for the same uptake carriers in the root plasmalemma of most plants. In so doing interrupts with several metabolic processes that end up inhibiting plant growth and development through arsenicinduced phytotoxicity [41, 42]. Some of the toxicity symptoms may include inhibition of seed germination, decrease in plant height, depressed tillering, reduction in root growth and some necrosis, decrease in shoot growth, lower fruit and grain yield, reductions in chlorophyll and protein contents, and in photosynthetic capacity and even death [41–46]. Due to migration and expansion of residential areas into former mining territories, the danger of human exposure to soil As has risen in the last two decades which have affected adversely the health of many [47]. Continued exposure to As results in several clinical manifestations such as melanosis (hyperpigmentation), keratosis, and leukomelanosis (hypopigmentation) of which cutaneous lesions are the highest reported [48, 49]. As is also a well-known carcinogen, causing skin, lung, bladder, liver, and kidney cancers [50, 51].

The average concentration of Copper (Cu) being 0.2 mg/kg was within the maximum acceptable concentration of 6.6 mg/kg for agricultural soil and safe limit of the Republic of South Africa [52].

As an important micronutrient, Cu is required for the growth of both plants and animals. In humans, it aids in the production of blood hemoglobin while plants utilize it in seed production, disease resistance, and regulation of water. In high levels, Cu could cause anemia, liver and kidney damage, as well as stomach and intestinal irritation [53]. Cu typically occurs in drinking water from Cu pipes, as well as from additives intended to control algal growth. The interaction of Cu with the environment is complex, however different studies revealed that most Cu introduced into the environment rapidly becomes, stable and results in a form which does not pose a danger to the environment [54, 55].

Zinc is an important metal due to its enzymatic and regulatory functions in biological systems. Being a readily mobile element, Zinc (Zn) when in high doses exhibit toxic and carcinogenic effects that could result in serious hematological and neurologic complications, liver and kidney disorders, hypertension, gastrointestinal misery, loose bowels, pancreatic harm and a host of other ailments in both humans and animals [56]. On the earth crust, Zinc is found in an average concentration of 80 mg/kg in association with ores of other metals such as Pb, Cu and Cd [57].

Chromium (Cr) has an average concentration of 100 mg/kg in the earth crust and the only known ore of commercial value is chromite (FeO.Cr2O4). Contamination by Cr could result in toxicity in plants depending on its state of valency since Cr (VI) due to its being highly mobile is toxic, while Cr (III) as less mobile is less toxic. The subsequent uptake, translocation, and accumulation of Cr by plants is dependent on its speciation. Cr in its trivalent (III) and hexavalent (VI) forms are known to be of biological importance. Generally, Cr poses the greatest threat to humans, animals and plants. Decreased seed germination, reduction of growth, decreased yield, inhibition of enzymatic activities, impairment of photosynthesis, nutrient and oxidative imbalances, and mutagenesis are some of the symptoms of Cr toxicity in plants [58]. In a previous study by López-Luna et al. [59], the toxicity of Cr (VI), Cr (III), and Cr tannery sludge were compared with respect to Cr mobility in soil and toxicity in wheat, oat, and sorghum plants and findings were that Cr(VI) was more mobile in soil and caused higher toxicity on those plant seedlings, while tannery sludge was the least toxic [60]. In humans, prolonged exposure results in kidney and liver disorders [61].

Ni > Ti > Cd > Zn > Cu. The mineral composition of the sediments and mining activities that took place within this region may be attributed to the high element

*Trace Metals in the Environment - New Approaches and Recent Advances*

In comparison to the interim sediment quality guidelines (ISQG) proposed by the Canadian Council of Ministers of the Environment [38], the elemental pollution status of the tailings (soil) were assessed **Table 8**. The heavy metals from the studied tailings sediments except for Zn and Cu all exceeded the ISQG. This implies that the sediments are toxic and could result in the introduction of sediment contaminants into the aquatic food web through predation by organisms at higher

In trace amounts, Arsenic is one of the priority toxic metals due to its several deteriorating effects to both plants and animals. The level of identified arsenic in the sediment is worrisome. As a non-essential element, Arsenic is not required for the growth of living organisms, though recent discovery reports a bacterium that

**Station no. Cr Al As Fe Pb Co Ni Ti Cd Zn Cu** 862.6 327.4 201.7 134.1 125.6 28.4 26.1 9.0 9.2 4.7 0.6 860.4 327.9 203.4 136.2 122.9 30.2 25.3 8.3 8.8 4.0 0.1 861.3 328.0 202.9 133.7 123.1 29.5 26.4 9.2 8.1 4.1 0.2 862.4 328.4 202.4 130.1 124.7 28.8 24.7 8.1 7.9 3.9 0.2 862.1 326.5 202.1 132.5 121.9 29.6 23.8 8.7 7.2 5.6 0.3 861.5 325.7 201.7 134.9 122.1 29.3 25.1 7.9 8.3 4.3 0.1 860.6 324.9 203.0 135.3 123.5 28.7 25.7 8.5 7.5 5.2 0.1 861.1 328.1 201.9 135.1 123.2 29.2 26.3 9.0 7.9 4.9 0.3 860.7 327.9 202.6 135.9 124.1 27.5 26.8 9.2 9.0 4.2 0.1 860.3 326.3 202.1 132.7 124.8 29.1 25.2 8.1 8.5 5.1 0.1 860.6 325.4 201.7 136.0 122.3 27.3 25.7 8.3 7.1 5.3 0.1 861.0 326.7 200.9 131.8 122.5 27.9 23.9 8.7 8.7 5.0 0.2 862.1 326.1 201.2 135.9 124.9 28.7 24.3 7.6 8.3 5.5 0.6 860.5 327.9 201.4 134.1 123.1 28.3 26.0 9.1 9.1 4.5 0.1 862.5 328.2 203.0 133.7 122.7 28.0 25.8 9.2 8.3 5.0 0.2 862.3 326.3 202.6 134.9 125.8 29.1 24.6 8.3 8.5 5.3 0.3 862.4 325.9 201.5 133.5 123.7 29.5 24.2 8.0 8.1 4.1 0.1 861.9 327.4 202.3 134.2 125.1 29.7 26.5 7.2 8.0 4.8 0.4 861.6 326.1 201.9 134.9 124.3 28.1 25.7 8.4 8.5 4.4 0.5 862.0 325.6 203.1 135.7 125.3 28.4 26.3 8.7 8.8 4.6 0.1 Mean 861.5 326.8 202.2 134.3 123.7 28.8 25.4 8.5 8.3 4.5 0.2 Max 862.6 328.4 203.4 136.2 125.8 30.2 26.8 9.2 9.2 5.6 0.6 Min 860.3 324.9 200.9 130.1 121.9 27.3 23.8 7.2 7.1 3.9 0.1

concentrations in the soil samples.

trophic levels.

Bn ISQG

**Table 8.**

**90**

90 52.3 88,000 NA

13 7.24

*Heavy metals concentration (mg/kg dry weight) in gold mine tailings sediments.*

47,200 NA

20 30.2

19 NA

50 NA 4600 NA

0.3 0.7

95 124.0

45 18.7

Lead (Pb) is the largely known immobile nonessential element among the heavy metals with most of its compounds being noxious in nature. Pb on the earth crust has an average concentration of 0.1 mg/kg. There is a gradual phase out of Pb from the materials regularly used by humans due to it being a metal toxicant. Mostly via food chain, Pb penetrates human or animal metabolism. The observed Pb content within the samples was very high and have been reported globally to be very harmful to humans and other animals as a long-term exposure could result in the bioaccumulation and biomagnification that end up in serious neurological health challenges. In plants, concentrations above 5 mg/kg of Pb causes severe growth retardation, discoloration, and morphological deformities. Pb accumulates in the body organs (i.e., brain), which may lead to poisoning (plumbism) or even death. The presence of lead often affects the gastrointestinal tracts, kidneys, and central nervous system. Infants exposed to lead are likely to suffer impaired development, lower IQ, shortened attention span, hyperactivity, and mental deterioration [62]. Adults usually suffer decreased reaction time, loss of memory, nausea, insomnia, anorexia, and weakness of the joints when exposed to Pb [63]. Lead performs no known essential function in the human body, it can merely do harm after uptake from food, air, or water.

Industrial waste materials, lime, fertilizer and sewage sludge constitute the major sources of nickel into soils [64]. Till date, nickel (Ni) remains a heavy metal of environmental concern as a result of decreased soil pH, due to reduced use of soil liming in agricultural soils and mobilization arising from increased acid rain in industrialized areas [65]. With decreasing pH, Ni exhibits increased solubility and mobility, thus, soil pH is the major factor controlling its solubility, mobility and sorption, while clay content, iron- manganese mineral and soil organic matter are of secondary importance [66]. Nickel (Ni) concentrations were observed to be high which could result in toxic effects to both plants and animals due to its ability to replace other metal ions in enzymes, proteins or bind to cellular compounds [65]. Nickel (Ni) is reported to interact with at least 13 essential elements namely calcium, chromium, cobalt, copper, iodine, iron, magnesium, manganese, molybdenum, phosphorus, potassium, sodium and zinc [67]. As a result, prolong exposure of humans to oxides and sulfides of nickel is linked with possible risk to lung and nasal tumors, skin allergies, nasal sinusitis, rhinitis and dermatitis [68]. Symptoms of nickel toxicity in plants besides inhibited growth include chlorosis, stunted root growth and brown interveinal necrosis [69].

Cadmium (Cd) is being discussed on a global platform as one of the most ecotoxic metals with a tendency of adversely affecting biological activities, plant metabolism, soil health and human health. The usage of Cadmium (Cd) is widely seen in Ni/Cd batteries, as rechargeable or secondary power sources exhibiting high output, long life, low maintenance, and high tolerance to physical and electrical stress. Observed levels of Cadmium was high and of great concern because it is very biopersistent and, once absorbed by an organism, remains resident for many years. In humans, Cadmium is known to affect several enzymes. Previous research revealed that renal damage that results in proteinuria is the consequence of Cd adversely affecting enzymes responsible for reabsorption of proteins in kidney tubules [70]. A prolong exposure to this metal even at very low concentration also reduces the activity of delta-aminolevulinic acid synthetase, arylsulfatase, alcohol dehydrogenase, and lipoamide dehydrogenase, which often cause anemia, cardiovascular disorders and hypertension whereas it enhances the activity of deltaaminolevulinic acid dehydratase, pyruvate dehydrogenase, and pyruvate decarboxylase [71].

**4.3 Pollution status**

*abandoned gold mine tailings site.*

**Table 9.**

high contamination.

rioration of the study site.

**93**

The assessment of the overall contamination of the studied area was based on the contamination factor **Table 9**. The average contamination factor for single metal from this study revealed the sediments as slightly contaminated with Ni and Zn, moderately contaminated with Co and highly contaminated with Cr, As, Pb and Cd. The highest average contamination factor value was that of Cd (27.63). Overall, the degree of contamination values of the sediments from the study site indicate very

*Contamination factor (CF) and degree of contamination at various sampling station at the Blesbokspruit*

**Station no. Contamination factor of single metal Degree of contamination**

*Evaluation of Trace Elemental Levels as Pollution Indicators in an Abandoned Gold Mine Dump…*

 9.58 15.52 6.28 1.49 0.52 30.67 0.05 64.11 Very high 9.56 15.65 6.15 1.59 0.51 29.33 0.04 62.83 Very high 9.57 15.61 6.16 1.55 0.53 27.00 0.04 60.46 Very high 9.58 15.57 6.24 1.52 0.49 26.33 0.04 59.77 Very high 9.58 15.55 6.10 1.56 0.48 24.00 0.06 57.33 Very high 9.57 15.52 6.11 1.54 0.50 27.67 0.05 60.96 Very high 9.56 15.62 6.18 1.51 0.51 25.00 0.05 58.43 Very high 9.57 15.53 6.16 1.54 0.53 26.33 0.05 59.71 Very high 9.56 15.58 6.21 1.45 0.54 30.00 0.04 63.38 Very high 9.56 15.55 6.24 1.53 0.50 28.33 0.05 61.76 Very high 9.56 15.52 6.12 1.44 0.51 23.67 0.06 56.88 Very high 9.57 15.45 6.13 1.47 0.48 29.00 0.05 62.15 Very high 9.58 15.48 6.25 1.51 0.49 27.67 0.06 61.04 Very high 9.56 15.49 6.16 1.49 0.52 30.33 0.05 63.60 Very high 9.58 15.62 6.14 1.47 0.52 27.67 0.05 61.05 Very high 9.58 15.58 6.29 1.53 0.49 28.33 0.06 61.86 Very high 9.58 15.50 6.19 1.55 0.48 27.00 0.04 60.34 Very high 9.58 15.56 6.26 1.56 0.53 26.67 0.05 60.21 Very high 9.57 15.53 6.22 1.48 0.51 28.33 0.05 61.69 Very high 9.58 15.62 6.27 1.49 0.53 29.33 0.05 62.82 Very high Average 9.57 15.55 6.19 1.51 0.51 27.63 0.05 61.01 Very high

**Cr As Pb Co Ni Cd Zn**

*DOI: http://dx.doi.org/10.5772/intechopen.89582*

The average index of geoaccumulation values and contamination levels from the

As indicated in **Table 10**, Pollution load index (PLI) ranged from 2.56–2.75, with

various sampling points within the study area as shown on **Table 10** reveals an uncontaminated status for Co (0.01), Ni (1.09) and Zn (3.39) respectively. However, Cr and Pb within the area showed a moderately contamination level with average Igeo values being 1.85 and 1.42 respectively. The site was however moder-

mean value 2.67. PLI values of the different stations are above 1 which strongly indicate that the sediments are all polluted by heavy metals, an indication of dete-

ately to strongly contaminated with As (2.34) and Cd (2.91).


*Evaluation of Trace Elemental Levels as Pollution Indicators in an Abandoned Gold Mine Dump… DOI: http://dx.doi.org/10.5772/intechopen.89582*

#### **Table 9.**

Lead (Pb) is the largely known immobile nonessential element among the heavy metals with most of its compounds being noxious in nature. Pb on the earth crust has an average concentration of 0.1 mg/kg. There is a gradual phase out of Pb from the materials regularly used by humans due to it being a metal toxicant. Mostly via food chain, Pb penetrates human or animal metabolism. The observed Pb content within the samples was very high and have been reported globally to be very harmful to humans and other animals as a long-term exposure could result in the bioaccumulation and biomagnification that end up in serious neurological health challenges. In plants, concentrations above 5 mg/kg of Pb causes severe growth retardation, discoloration, and morphological deformities. Pb accumulates in the body organs (i.e., brain), which may lead to poisoning (plumbism) or even death. The presence of lead often affects the gastrointestinal tracts, kidneys, and central nervous system. Infants exposed to lead are likely to suffer impaired development, lower IQ, shortened attention span, hyperactivity, and mental deterioration [62]. Adults usually suffer decreased reaction time, loss of memory, nausea, insomnia, anorexia, and weakness of the joints when exposed to Pb [63]. Lead performs no known essential function in the human body, it can merely do harm after uptake

*Trace Metals in the Environment - New Approaches and Recent Advances*

Industrial waste materials, lime, fertilizer and sewage sludge constitute the major sources of nickel into soils [64]. Till date, nickel (Ni) remains a heavy metal of environmental concern as a result of decreased soil pH, due to reduced use of soil liming in agricultural soils and mobilization arising from increased acid rain in industrialized areas [65]. With decreasing pH, Ni exhibits increased solubility and mobility, thus, soil pH is the major factor controlling its solubility, mobility and sorption, while clay content, iron- manganese mineral and soil organic matter are of secondary importance [66]. Nickel (Ni) concentrations were observed to be high which could result in toxic effects to both plants and animals due to its ability to replace other metal ions in enzymes, proteins or bind to cellular compounds [65]. Nickel (Ni) is reported to interact with at least 13 essential elements namely calcium, chromium, cobalt, copper, iodine, iron, magnesium, manganese, molybdenum, phosphorus, potassium, sodium and zinc [67]. As a result, prolong exposure of humans to oxides and sulfides of nickel is linked with possible risk to lung and nasal tumors, skin allergies, nasal sinusitis, rhinitis and dermatitis [68]. Symptoms of nickel toxicity in plants besides inhibited growth include chlorosis, stunted root growth and brown

Cadmium (Cd) is being discussed on a global platform as one of the most eco-

toxic metals with a tendency of adversely affecting biological activities, plant metabolism, soil health and human health. The usage of Cadmium (Cd) is widely seen in Ni/Cd batteries, as rechargeable or secondary power sources exhibiting high output, long life, low maintenance, and high tolerance to physical and electrical stress. Observed levels of Cadmium was high and of great concern because it is very biopersistent and, once absorbed by an organism, remains resident for many years. In humans, Cadmium is known to affect several enzymes. Previous research revealed that renal damage that results in proteinuria is the consequence of Cd adversely affecting enzymes responsible for reabsorption of proteins in kidney tubules [70]. A prolong exposure to this metal even at very low concentration also reduces the activity of delta-aminolevulinic acid synthetase, arylsulfatase, alcohol dehydrogenase, and lipoamide dehydrogenase, which often cause anemia, cardiovascular disorders and hypertension whereas it enhances the activity of deltaaminolevulinic acid dehydratase, pyruvate dehydrogenase, and pyruvate decarbox-

from food, air, or water.

interveinal necrosis [69].

ylase [71].

**92**

*Contamination factor (CF) and degree of contamination at various sampling station at the Blesbokspruit abandoned gold mine tailings site.*

#### **4.3 Pollution status**

The assessment of the overall contamination of the studied area was based on the contamination factor **Table 9**. The average contamination factor for single metal from this study revealed the sediments as slightly contaminated with Ni and Zn, moderately contaminated with Co and highly contaminated with Cr, As, Pb and Cd. The highest average contamination factor value was that of Cd (27.63). Overall, the degree of contamination values of the sediments from the study site indicate very high contamination.

The average index of geoaccumulation values and contamination levels from the various sampling points within the study area as shown on **Table 10** reveals an uncontaminated status for Co (0.01), Ni (1.09) and Zn (3.39) respectively. However, Cr and Pb within the area showed a moderately contamination level with average Igeo values being 1.85 and 1.42 respectively. The site was however moderately to strongly contaminated with As (2.34) and Cd (2.91).

As indicated in **Table 10**, Pollution load index (PLI) ranged from 2.56–2.75, with mean value 2.67. PLI values of the different stations are above 1 which strongly indicate that the sediments are all polluted by heavy metals, an indication of deterioration of the study site.


staple crops that are cultivated within the vicinity of the dump site, to ascertain the levels of heavy metals within such crops. Stringent mitigation plans or conversion of

*Evaluation of Trace Elemental Levels as Pollution Indicators in an Abandoned Gold Mine Dump…*

We thank the Mineral Processing and Technology Research Centre of the University of Johannesburg for providing the resources used in conducting

the tailings into value-added products should be considered.

*DOI: http://dx.doi.org/10.5772/intechopen.89582*

The authors declare no conflict of interest.

\*, Mamookho Makhatha<sup>1</sup>

1 Department of Metallurgy, School of Mining, Metallurgy and Chemical Engineering, Faculty of Engineering and the Built Environment, University of

2 Department of Chemical Engineering, Faculty of Engineering and the Built Environment, University of Johannesburg, Johannesburg, South Africa

3 Department of Biotechnology and Food Technology, Faculty of Science,

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

University of Johannesburg, Johannesburg, South Africa

\*Address all correspondence to: guokereafor@gmail.com

, Lukhanyo Mekuto<sup>2</sup>

**Acknowledgements**

**Conflict of interest**

**Author details**

Godwin Okereafor<sup>1</sup>

and Vuyo Mavumengwana<sup>3</sup>

Johannesburg, Johannesburg, South Africa

provided the original work is properly cited.

**95**

this study.

#### **Table 10.**

*Geoaccumulation index (Igeo) and pollution load index (PLI) at various sampling station at the Blesbokspruit abandoned gold mine tailings site.*

It is evident from the present study that the abandoned gold mine tailings site is not polluted with Zn and Cu, but heavily polluted with Cd, Cr and Pb when evaluated by comparison with the sediment quality guideline proposed by USEPA.

### **5. Conclusion**

The successful assessment of trace metal contamination of the abandoned gold mine tailings at Blesbokspruit-Ekurhuleni was done using indices such as geoaccumulation index, contamination factor, and degree of contamination and pollution load index. The sediment was mostly dominated by fine sand and silt/clay. Based on sediment quality guidelines proposed by the USEPA, the contamination of the sediment by Zn and Cu was negligible while Cd, Cr and Pb were detected at high concentrations. The evaluated pollution load index indicated that the sediments in the tailings dump are polluted while the geoaccumulation index revealed that Cr, Pb, and As contaminated the site, thus indicating very high degrees of contamination of the sediments at the mine dump. The high metal contaminants could be attributed to anthropogenic activities from previous extensive gold mining activities that took place within the area. Considering agricultural activities and human dwellers within the surrounding areas of the mine tailings, there are high tendencies of deleterious impacts. As a further precaution, this study strongly supports the call for analysis of the stream and drinking water quality, including the *Evaluation of Trace Elemental Levels as Pollution Indicators in an Abandoned Gold Mine Dump… DOI: http://dx.doi.org/10.5772/intechopen.89582*

staple crops that are cultivated within the vicinity of the dump site, to ascertain the levels of heavy metals within such crops. Stringent mitigation plans or conversion of the tailings into value-added products should be considered.
