SCREENING OF SOME HEAVY METALS IN SOIL, SEDIMENTS, SPINACH AND CABBAGE FROM IRRIGATED FARMLANDS IN NARAGUTA, JOS, NIGERIA 1Pius, N.D., 1Rotbe, G, 2Mamzing, D. 2Loks, N.A. and 3Akila, L.K

International Journal of Research and Scientific Innovations         Volume 4, Number 2, 2016

© 2016 McEvans Publications

SCREENING OF SOME HEAVY METALS IN SOIL, SEDIMENTS, SPINACH AND CABBAGE FROM IRRIGATED FARMLANDS IN NARAGUTA, JOS, NIGERIA

¹Pius, N.D., ¹Rotbe, G, ²Mamzing, D. ²Loks, N.A. and ³Akila, L.K

¹Department of Basic Studies, Plateau State College of Agriculture, Garkawa.

²Department of Agricultural Technology, Plateau State College of Agriculture, Garkawa

³Department of Home and Rural Economics, Plateau State College of Agriculture, Garkawa, Plateau State, Nigeria

ABSTRACT

The study investigated heavy metal accumulation in soil, sediments and the metal concentration in two irrigated vegetables in an irrigation land at Naraguta Area of Jos  North Local Government Area Plateau State. The study was investigated using the Atomic Absorption spectrophotometer. The total metal concentrations determined in soil and sediments were, Pb, 6.66mg/kg and 106mg/kg: Cd 4.33mg/kg and 0.66mg/kg;

Cr, 32mg/kg and 61.33mg/kg; and Mn683.33mg/kg and 450mg/kg respectively. The concentrations exceed the WHO/FAO permissible limits. Pb in spinach and cabbage were Pb, 20.66mg/kg and 7.99mg/kg and Cd 2.06mg/kg and 4.66mg/kg Cr 76.99mg/kg and 46.33mg/kg and Mn92.mg/kg and 165.66mg/kg respectively. The cumulative factor of spinach and cabbage showed that spinach accumulated; Pb; 3.1 times ; Cd, 1.15 times Cr 2.40 times; and Mn, 0.13times concentration soil while cabbage accumulated; Pb, 1.19 times Cd, 1.07times; Cr, 1.44times; and Mn0.42 times. The concentrations of metals in soluble from where Pb,0.30mg/kg; Cr, was not detected; Cr, 0.68mg/kg; Mn,1.2mg/kg. The metals were within the WHO/FAO range. For carbonate and exchangeable fractions in soil Pb and Cd were not detected; Cr, 53mg/kg and 43mg/kg and Mn35.1mg/kg and not detected respectively. Carbonate and exchangeable in sediments were; Pb, 29.5mg/kg and not detected; Cd, not detected and 0.5mg/kg; Cr, was not detected in both carbonate and exchangeable and Mn, 288mg/kg and 139.5mg/kg respectively.

Key Words: Heavy metals, soil, sediments, spinach, cabbage and irrigation farmlands.   

INTRODUCTION

          Naraguta, located in Jos North Local Government Area of Plateau State, is well known for its leather works. It is bye passed by a stream whose sources are from Kabong, Laranto and Gangare. The water carries with it debris, industrial and domestic waste, human faeces and animal dungs of nearby dwellers, within Jos and environs. This water is used by the farmers for irrigating their farms along the river. The use of this water for irrigation, expose the consumers and producers of these crops to various health hazards. This water is of poor quality as a result of chemical changes in the soil conditions and Naraguta stream is a receiver of this poor quality water. As an industrial area, the soil receives heavy metals from industries, houses and irrigation water augmented, by the use of organic fertilizer and atmospheric disposition. Irrigation may increase the availability of these metals when the water level is low, this is by mixed and re-suspension of heavy metal which are then transported to agricultural parcels.

          More so, this poor quality water has a couplet variety of biotic and abiotic process, which effect the speciation and distribution of co-precipitates and microbes. Some of these processes can effectively isolate heavy metals to the biosphere, where as others cause a release of species that may be toxic to organism (Slins, 2009). There is also bioaccumulation of pollutants that enter the food chain from the environment. The factors that affect bioaccumulations include magnitude and duration of feeding and the chemical speciation (Lenntech, 2012). Often, heavy metals are thought of as being synonymous to toxic metals. However, some are essential, such as iron (Fe). They only exhibit their toxicity if their thresholds limits are exceeded. The metabolism and mode of transmission of active forms of the metals may be quite different from those of organic pollutants. Metals are sometimes metabolized to less toxic forms in tissues such as bones and liver and can be remobilized following pregnancy or menopause (Samara, 2011).

Screening of Some Heavy Metals in Soil, Sediments, Spinach and Cabbage from Irrigated Farmlands in Naraguta, Jos, Nigeria

          Effects of heavy metals in plants result in growth inhibition, structure damage and decline of physiological and biochemical activities, as well as other functions of a plant. Growing crops on a widespread unregulated agriculture soil may become a food security problem because of toxic concentration of heavy metals may be accumulated in the food chain. In addition, crops which have the availability to tolerate these high concentrations of the metal may accumulate greater concentration of the metal and become a major environment and public health hazards (Cheng, 2003).

          Heavy metal poisoning can result, for instance from striking water contamination (lead pipes) and high ambient air concentrations in near emission sources. Lead in human on long term exposure can result in acute or chronic damage to the nervous system; cadmium on long term exposure is associate with renal disorder. High exposure can lead to obstructive lung diseases and have been linked to lungs disorder, consequently damaging the respiratory system. Chromium, used in making alloys, pigments in paints and paper materials, low level exposure to it can irritate the skin and cause ulceration and long term exposure can cause liver and kidney problem and hence obstruct the circulatory system. (Emel, 2012).

          Each chemical specie has a limited physical, chemical and toxicologican proportion which greatly affects the assessment of environmental risk. Therefore the measurement of total concentration provides little indication of abiotic component present in the aquatic environment. However, recent works states that speciation of metal can partly explain variation in toxicity.

METHODOLOGY

          Study Area – Naraguta is a village at about 5 kilometres North – East of the University of Jos. It is an isolated area at the outskirt of Jos, along Jos-Bauchi road. It has stream which is feeding most irrigation farmland located along its banks. The water from nearby industries is dislodged into this stream. Amongst others are domestic waste human faeces and animal dungs of nearby dwellers are also dumped into this stream.     

Sample Collection Treatment and Analysis

          Surface soil, soil from the depth of 10cm and spinach and cabbage leaves at various stages of development were randomly collected from different locations in the irrigated lands in September,  2015 the soil and sediment were each collected using a plastic spoon, poured into already labeled polythene bags and mixed thoroughly to give a representative fraction of the samples. The water samples were collected at different point along the stream in 20ml in a polythene bottle to obtain a single sample 20ml of concentrated HNO₃ was added and stored.

Preparation of Sediments and Soil Samples

          The samples were air dried, and the dried samples were ground with a pestle and mortar, and then sieved into fine particles using sieves of size 2mm and stored in polythene bags for analysis.

Preparation of Plant Sample

          The vegetable samples were washed with delonized water, air dried and pounded with a pestle and mortar. The samples were store in polythene bags for analysis.

Digestion of Samples

          3g each of soil, sediment and vegetable samples were weighed and25ml each of trioxonitrate V acid (HNO₃)  and hydrogen chloride acid (HCL) were added in the ratio of 1:3 respectively, and was heated to dryness on a water bath inside a fume cupboard. To each of the samples, 5ml of 2M hydrogen chloride acid was added to re-dissolve it. The samples were filtered and made, and stored in polythene bags for analysis.

International Journal of Research and Scientific Innovations         Volume 4, Number 2, 2016

Exchangeable Fraction

2 grams each of soil and sediment sample was weighed and poured into conical flasks. 10ml of each of Ammonium trioxonitrate V were added into the sample. Magnetic stirrers were placed in each of the flask and covered with cotton wool sealed with aluminum foil and shaken by a mechanical shaker for 4 hrs. The sample was poured into a test-tube and centrifuged at 3000 rpm for 10 minutes. The samples were poured into a volumetric flask and made up to 100ml, and poured into polythene bags for analysis.

Trioxo Carbonate IV Fractions

The trioxocarbonate IV fraction was extracted using ethanoic acid (CH₃COOH) buffered by sodium ethanoate (CH₃COOH) at pH-5 and stored in polythene battle at room temperature. The residue from above was redissolved in 10ml of ethanoic acid, and stirred using a mechanical stirrer for 4hrs. The sample was then poured into a test tube and centrifuged at 300 rpm for 10 minutes. The sample was poured into a volumetric flask and made up to 100ml and stored in polythene bottle for analysis

Metal Analysis

          All samples and fractions were taken to the Nigerian Mining Corporation (NMC) Jos. For analysis. The method of analysis was the Atomic Absorption Spectrophotometry (AAS).

RESULTS

Table 1: Total metal concentration in soil, sediment and plants (spinach and cabbage)

S/No.	Samples	Pb (Mg/kg)	Cd (mg/kg)	Cr (mg/kg)	Mn (mg/kg)
1	Soil	6.66	4.33	32.00	683.33
2	Sediment	106	0.66	61.33	450
3	Spinach	20.66	2.06	76.99	92
4	Cabbage	7.99	4.66	46.33	165.66

Table 2: Plant cumulative factor

S/No	Element	Spinach	Cabbage
1	Pb	3.10	1.19
2	Cd	1.15	1.07
3	Cr	2.40	0.24
4	Mn	0.13	0.24

Table 3: Speciation

S/No	Element	Soil		Sediment		Soluble
		Exchangeable	Carbonate	Exchangeable	Carbonate
1	Pb	ND	ND	29.50	ND	0.3
2	Cd	ND	ND	ND	0.50	ND
3	Cr	53.00	43.00	ND	ND	0.68
4	Mn	35.10	ND	288	139.50	1.02

Table 4: WHO/FAO standard for heavy metals, 2007 guideline

S/No	Element Soil	(mg/kg)	Irrigation water	Vegetables (mg/kg)
1	Pb	100	65	0.30
2	Cd	8	10	0.20
3	Cr	100	550	0.30
4	Mn	2000	200	500

DISCUSSION

The concentration of metals in soil and sediments are: Pb, 6.66mg/kg and 10mg/kg respectively. And the WHO/FAO standard is 100/kg just as shown in Table 4 above this indicates that limit that

Screening of Some Heavy Metals in Soil, Sediments, Spinach and Cabbage from Irrigated Farmlands in Naraguta, Jos, Nigeria

of soil is within the concentration of metals range for four metal in soil and sediments as determined by atomic adsorption are Pb (106-666) mg/kg Cd (4.33-0.66) mg/kg Cr (61.33-32.00) mg/kg and Mn (683.33-450) mg/kg. This show that the concentration of  Pb in the sediments is beyond the WHO/FAO permissible limits as indicated in Table 4. The concentrations of the other metals V12 Cd, Cr and Mn are within safe limits. The concentrations of metals in spinach and cabbage range are Pb (20.66n-7.99) mg/kg, Cd (4.66-206) mg/kg Cr (76.99-33 mg/kg and Mn (165.66-92) mg/kg. These results when compared to standard acceptable limits show that only manganese is within the safe limits as approved by the WHO/FAO limits for vegetables exchange and carbonate fractions in sediments were Pb (29.50) mg/kg and 139.50 mg/kg.  

CONCLUSION

          The results showed that the concentration of Pb in soil, soluble fraction, and exchangeable fraction exceeded the permissible limits, while in soil exchangeable and carbonate fraction was not detected. Concentration in sediments, spinach and cabbage were much higher than the limit. This implies that Pb may cause grain damage and convulsions in humans. These vegetables (spinach and cabbage) can be used for the phytoremediation of this heavy metal. The concentration of chromium in spinach and cabbage, exceeded the limits and hence have the ability to cause mutagenic effects to humans, and animals.

          It is our considered opinion that consumption of these vegetables pose a great health risk on the consumers.

REFERENCES

Cheng, S. (2003). Environ Science Pollute Research International. Journal of Environmental and Health Science. Vol. 2, 145-150.

Emel Kilic, (2012). Chemical Engineering (Hacettepe University) Chemical Division Manager C.A. Gkimye Turkey.

John, M. (2010). Environmental Protection Agency Sage Drinking water Fact Sheets. Islamabad Pakistan.

Lenntech, B.V. (2012). Heavy Metal Ions Adsorptions CI &CEQ. 15 (4) 239-245.

  

Samara, D. (2011). M.A. Chemical Assistant Profession of Emergency Medicine, New York University School of Medicine, Bellevue Hospital Centre.

   

Slins, R.R. (2009). Heavy Metals Concentration in Organism in an Active Degraded, Texas Bag.