ASSESSMENT OF HEAVY METALS AND pH OF SOIL, WATER AND SOME VEGETABLES IN SELECTED VILLAGES IN RIVERS STATE, NIGERIA
ABSTRACT
The heavy metals concentration in soil, water and vegetables (Telfairia occidentalis and Amaranthus hybridus) and the pH of soil and water were assessed in three communities (Mbiama, Ikodi and Okarki from Ahoada) of Rivers State, Nigeria. Pb, Cu, Zn and Cr were analysed using Atomic Absorption Spectroscopy (AAS). pH of soil and water ranged from 5.78 to 8.49 and 4.57 to 5.97 respectively. Heavy metals level in soil ranged as follows: Pb (32.70267.2 mg/kg), Cu (16.25-42.50 mg/kg), Zn (0.00-0.00 mg/kg) and Cr (0.00-0.00 mg/kg). Concentrations in water ranged as follows: Pb (0.05-6.84 mg/kg), Cu (0.38-0.62 mg/kg), Cr (0.00-2.266 mg/kg), Zn (0-0 mg/kg). Concentrations in Telfairia occidentalis ranged as follows:
Pb (10.65-39.45 mg/kg), Cu (23.20-64.45 mg/kg), Zn (0.00-29.80 mg/kg) and Cr (0.000.00mg/kg) while concentrations in Amaranthus hybridus ranged as follows: Pb (33.90-183.75 mg/kg), Cu (26.75-48.85 mg/kg), Zn (10.30-30.40 mg/kg) and Cr (0.00-69.7 mg/kg). Most of the concentrations exceeded WHO permissible limits. Statistical analysis was done by comparing the mean of samples from the three sites with the control site by using one way ANOVA analysis of variance. P value < 0.05 showed that there was a significant difference. P values gotten after performing one way ANOVA analysis of variance were as follows: for soil in the metals were Cu; 0.03, Zn; 0.50, Pb; 0.04 and Cr; 0.50 while in water, Cu; 0.03, Zn; 0.50, Pb; 0.003 and Cr; 0.03. For Amaranthus hybridus: Cu; 0.01, Zn; 0.03, Pb; 0.002 and Cr; 0.003 while in Telfairia occindentalis, Cu; 0.003, Zn; 0.02, Pb; 0.002 and Cr; 0.50. From the results, it showed that soil samples were slightly acidic to alkaline pH and water samples tested to be acidic in nature, while metal pollution was present in all communities with measurable amount shown in the soil, water and vegetables tested. It can be concluded that both the pH of the soil and water had an effect on the concentrations of the heavy metals from each location and also the cause of these heavy metals being introduced into the communities may be linked to “oil bunkering” increased the concentrations of heavy metals in the soil, water and vegetables in these communities.
CHAPTER ONE
1.0INTRODUCTION
Heavy metals are classified as natural elements with a high atomic mass (greater than 23) and a high density (greater than 5 g/cm3). They occur in low concentrations and are found all over the surface of our planet (Koller and Saleh, 2018).They are also classified as hazardous metallic elements with a high density and specific gravity. Lead, mercury, and cadmium are examples of heavy metals. Any metal containing a possibly dangerous health or environmental effect, such as cobalt, chromium, lithium, or iron, may be regarded as a heavy metal (Helmestine, 2019).
Organs such as the brain, kidney, lungs, liver, and blood could be damaged and respective functioning disrupted as an outcome of these heavy metal poisoning, leaving the individual with severe or permanent implication. It can induce muscular, physical, and neurological decline in the same way as diseases like Parkinson’s, multiple sclerosis, muscular dystrophy, and Alzheimer’s do. Additionally some heavy metals vulnerability may result in cancer (Engwa et al., 2018).
Different heavy metals are required by different living creatures. Iron, cobalt, copper, manganese, molybdenum, and zinc are all essential minerals for humans, but excessive levels can be hazardous to the body (Singh et al., 2019). Heavy metals cannot be broken or eliminated, and they bind together in living beings (Atieh, 2017). However, the majority of environmental pollution and the display of these heavy metals to humans are caused by activities such as mining, industrial construction and use, domestic and agricultural use of metals (Tchounwou et al., 2014). Oil spills are another source of heavy metal pollution.
Crude oil is a combination of hydrocarbons and non-hydrocarbons, including heavy metals, seen in subterranean sediments around the world. Oil spillage is the result of oil being released into the surrounding ecosystem from actions like crude oil extraction, refinery, distribution, and storing. Issues such as inadequate engineering equipment maintenance, as well as deliberate acts such as oil bunkering and vandalism, can contribute to leakage. The Niger Delta district has an unusually high amount of oil spills because it is the centre of Nigeria‟s crude oil industry
(Enegide and Chukwuma, 2018). Heavy metals have an impact on all aspects of the ecosystem, including the seas on the earth’s surface, the earth’s crust, and all life forms. Geogenic, manufacturing, agriculture, pharmacological, home emissions, and atmospheric sources all contribute to the release of these metals into the air (Tchounwou et al., 2014).
Cadmium, lead, and mercury are frequent air polluting heavy metals that are predominantly released as a result of a variety of industrial activities.
Heavy metals that are toxic to both aquatic and terrestrial environments pose a serious threat. They affect natural water bodies, sediments, and soils when they are discharged from natural and man-made sources and make their way into the soil, crops, and water. Chromium (Cr), Nickel (Ni), Copper (Cu), Zinc (Zn), Cadmium (Cd), Lead (Pb), Mercury (Hg), and Arsenic (As) are the most significant environmental heavy metals (Ali, 2019). The evaluation and observation of levels of heavy metals in various environmental sectors is critical to ensure the safety of our water supply systems and land, especially agricultural lands.
Heavy metals have negative effects on soil microbes (bacteria, archaea, fungi) causing differences in the abundance, population size, and function of micro biota (Singh et al, 2011). They accumulate in soil regularly, and they eventually gain access to the plants being grown, increasing their relative abundance as they move along the food chain, heavy metals enter the food chain by the soaking up or absorption by plant roots. This could pose a potential health hazard to animals and humans when such crops are consumed. Temperature, moisture, organic matter, pH, and nutrition availability are all elements that influence heavy metal uptake and buildup in plant tissue (Singh et al., 2011).
The physiochemical properties of soil can be altered by heavy metals and, more changes in chemical characteristics of soil which includes soil ph, soil salinity, may be observed, as some heavy metals may produce complex Phosphorus or Zinc compounds that are inaccessible to plants (Hussain et al., 2015).
Lead (Pb), cadmium (Cd), mercury (Hg), copper (Cu), cobalt (Co), zinc (Zn), chromium (Cr), nickel (Ni), manganese (Mn), iron (Fe), arsenic (As), and vanadium (Va) are examples of heavy metals found in soil throughout Africa and high levels of these metals in food, water, and edible crops have had harmful impacts on humans (Yabe et al., 2010). They also tend to impair crop yield and have an impact on the food chain due to bio – accumulation (Adikesavan et al., 2019).
Lead, Chromium, Copper, Arsenic, Zinc, Mercury, Nickel, and Cadmium are the most common heavy metals discovered in Nigerian agricultural soil, and the metals’ sources include urban and industrial pollution, sewage pipe deterioration, treatment water works, waste water, fertilizers, and pesticides (Musa et al., 2017).
Even in small levels, heavy metals including arsenic, lead, cadmium, nickel, mercury, chromium, cobalt, and zinc are exceedingly dangerous (Masindi and Muedi, 2017). The traces of these heavy metals detected in water can still be toxic to humans and other ecosystems, causing major health concerns. This is because the organisms that come in contact with a metal, the metal’s nature and physiological purpose, and the length of time that the species have been subjected to the metal all have a role in determining the extent of the metal’s toxicity (Masindi and Muedi, 2017). In water they negatively affect aquatic species and subsequently human beings from the food chain when the consumable species living in water are eaten by humans (Ali et al., 2019). The heavy metal source in the water systems varies across the continents, where mining, manufacturing and rock weathering is dominant in Asia and Europe. Use of fertilizer and pesticide with mining and manufacturing are the main sources in North America, while in South America it includes mining, manufacturing, fertilizer and pesticide use, rock weathering and waste discharge and finally in Africa the dominant sources are fertilizer and pesticide use, with rock weathering (Qiaoqiao et al.,2020),
Rivers state soil, flora and river bodies have all been subjected to oil spills and heavy metals poisoning. Aniefiok et al., (2013), explained an oil spill that occurred in the Ogoni community’s coastal waters in the year 2008, had a devastating impact on the fisheries that the inhabitants depend on for their food and income as most of them were involved in fish farming. This shows the dangerous impact of oil spillage, as it is not only a source of heavy metals but can also lead to destruction of basic necessities like food and water for livelihood.
Eleme is a community in Rivers State, Nigeria, which is one of the oil-producing and agroecological regions in the Niger-Delta region, with abundant resources such as decent weather and agricultural land. The area experienced an oil spill that resulted in the extinction of wild life, loss of fertile soil, contamination of air and water, and ecosystem destruction of the host communities. In addition to these impacts, other results reported as a result of the oil leak involved, brownish vegetation, soil erosion, loss and natural ecosystem resources and fruitless land (Abii and Nwosu, 2010). This impact on life and health has resulted in a potential risk for female fertility and miscarriage (Gull et al., 2018). Heavy metal poisoning may also cause alterations in fetal cell division and differentiation during pregnancy (Wai et al., 2017). Children are impacted, as heavy metals have a greater impact on child’s health than on adults’. Intellectual disability, neurological impairments, behavioral issues, breathing difficulties, cancer, and cardiovascular diseases could all be consequences for children’s health (Osman et al., 2019). To avoid such negative consequences, much emphasis should be placed to the spread of heavy metals in the ecosystems.
Telfairia occidentalis (Fluted pumpkin), sometimes known as ugwu, is one of Nigeria’s most popular vegetables. It is commonly referred to as a leaf and seed vegetable. The soft and edible leaves, as well as the unripe seeds, are cooked and eaten like a vegetable. Telfairia occidentalis has the ability to rejuvenate testicular injury and improve spermatogenesis (Nwangwa et al., 2007). Its high iron content aids in blood replenishment, and it’s used to treat anemia, chronic fatigue, and diabetes. Many people use Telfairia occidentalis leaf extract in oxidative damage conditions as tonics for new moms since it is high in anti-oxidants and has free radical collector abilities (Dina et al., 2006).
The people of Ahoada west local government consume and sell this vegetable locally on a daily basis. This explains the use of this particular vegetable in this research. Despite its high nutritional, medicinal, and economic value, Telfairia occidentalis has not been able to meet domestic demand in Nigeria due to factors that affect the vegetable production and its profitability in different areas (Obianuju and Asa, 2015).
Amaranthus hybridus, sometimes known as “Amaranth or Pigweed,” is an annual herbaceous plant that grows to be 1 to 6 feet tall. Green amaranth, African spinach and silky pigweed are among of the common names. A. hybridus leaves are mixed with condiments and used to make soup in Nigeria (Mepha et al, 2007). Amaranth leaves are good sources of carotenoids and proteins, and they also contain lysine and methionine which are essential amino acids and also minerals like calcium, potassium, iron, phosphorus and manganese (Umakanta and Shinya, 2020). Amaranthus hybridus is cultivated on a large scale in the southern part of Nigeria, and it is mostly used as diet in the middle and southern parts of Nigeria, which includes Rivers state
(Mofunanya et al., 2015)
1.1 STATEMENT OF PROBLEM
Rivers state is prone to oil theft which brings about oil spillage with the potential to contaminate soil and water. However, the status of heavy metal contamination in farm produce, soil and water of Mbiama, Ikodi and Okarki communities in Ahoada West Local Government Area; a predominantly fishing and farming community is limited. Therefore the need to fill this knowledge gap is important.
1.2 JUSTIFICATION
Mbiama, Ikodi and Okarki are all situated in Ahoada West Local Government Area, located northwest of Port Harcourt, Rivers State. Crude oil theft and illegal refinement, also known as oil bunkering, have occurred in the city of Ahoada till date. Fishermen and peasant farmers produce arable crops there, which they sell in markets locally. Heavy metals pose a threat to their produce with the potential to harm their livelihood if the soils and water become contaminated. There is paucity of information on heavy metal concentrations in the soil and water in the villages in Ahoada West Local Government Area.
1.3 AIMS AND OBJECTIVES
AIM
The aim of this study is to determine the level of heavy metals content in soil, water and vegetables and also to assess the ph of soil and water samples from selected locations: Mbiama, Ikodi and Okarki in Ahoada West Local Government Area.
OBJECTIVES
- Determine the pH of soil and water samples taken from the various locations.
- Determine the levels of certain heavy metals in the soil samples.
- Determine the heavy metal concentrations in chosen vegetable plant samples.
- Determine the heavy metal concentration in water samples.
- Compare the pH of the readings collected from the chosen site.
- Compare heavy metal concentrations in soil, vegetable plants, and water samples from the chosen area.
ASSESSMENT OF HEAVY METALS AND pH OF SOIL, WATER AND SOME VEGETABLES IN SELECTED VILLAGES IN RIVERS STATE, NIGERIA