CHAPTER ONE
INTRODUCTION
1.1 Background of study
Pollutants are contaminants that gets introduced into the natural environment beyond permitted limits and adversely affect wildlife and impact human health. This may include Land, Water, Air, Radioactive, Thermal, Light and Sound pollution. Even low levels of pollutants in the environment pose a risk due to potential accumulation at higher trophic levels, a process called biomagnification. Organic contaminants are usually xenobiotic to plants, but inorganic contaminants such as metals are commonly found in low concentration in the soil. Metals such as cobalt (Co), copper (Cu), iron (Fe), molybdenum (Mo), manganese (Mn) and zinc (Zn) are critical for plant growth, and are classified as essential micronutrients.Other metals that are commonly found as contaminants, and are non-essential for plants, include arsenic (As),Cadmium (Cd), chromium (Cr), mercury (Hg), nickel (Ni),Lead (Pb), selenium (Se), uranium (U), vanadium (V), andWolfram (W). Metals can have toxic effects on plants, even at low concentrations. Metal uptake byPlants generally takes place by specific transporters (channel proteins) or H+ coupled carrier proteins located on the cell membrane of the root. For example, the Fe regulated transporter (IRT1) allows the uptake of Fe.Uptake of other metals also occurs via IRT1 transporters, especially if very low concentrations of Fe exist in the soil. Inadvertent uptake of non-essential metals also takes place via other cell membrane transporters.For example, uptake of as (as AsO3) occurs inadvertently via phosphorus-transporters. Organic molecules enter plant roots via simple diffusion.
Phytoremediation basically refers to the use of plants and associated soil microbes to reduce the concentrations or toxic effects of contaminants in the environment. Phytoremediation is widely accepted as a cost-effective environmental restoration technology. Phytoremediation is an alternative to engineering procedures that are usually more destructive to the soil. Phytoremediation of contaminated sites should ideally not exceed one decade to reach acceptable levels of contaminants in the environment. Phytoremediation is, however, limited to the root-zone of plants. Also, this technology has limited application where the concentrations of contaminants are toxic to plants. Phytoremediation technologies are available for various environments and types of contaminants. These involve different processes such as in situ stabilization or degradation and removal (i.e., Volatilization or extraction) of contaminants.
Some phytoremediation technologies include;
Phytostabilization: this aims at retaining contaminants in the soil and prevents further dispersal. Contaminants can be stabilized in the roots or within the rhizosphere. Revegetation of mine tailings is a common practice to prevent further dispersal of contaminant.
Phytodegradation:this involves the degradation of organic contaminants directly, through the release of enzymes from roots, or through metabolic activities within planttissues. In phytodegradation organic contaminants are taken up by roots and metabolized in plant tissues to less toxic substances.
Phytovolatilization: this involves the uptake of contaminants by plant roots and its conversion to a gaseous state, and release into the atmosphere. This process is driven by the evapotranspiration of plants. Plants that have high evapotranspiration rate are sought after in phytovolatilization.
Phytoextraction: this uses the ability of plants to accumulate contaminants in the aboveground, harvestable biomass. This process involves repeated harvesting of the biomass in order to lower the concentration of contaminants in the soil. Phytoextraction is either a continuous process (using metal hyperaccumulating plants, or fast growing plants), or an induced process (using chemicals to increase the bioavailability of metals in the soil).Continuous phytoextraction is based on the ability of certain plants to gradually accumulate contaminants (mainly metals) into their biomass. Certain plants can hyperaccumulate metals without any toxic effects. These plants are adapted to naturally occurring, metalliferous soils. More than 400 plant species can hyperaccumulate various metals. However, most plants can only hyperaccumulate one specific Meta.
Moringa (Moringaoleifera) is a type of local medicinal Indian herb which has turn out to be familiar in the tropical and subtropical countries. The other terms used for Moringa are Horseradish tree, Mulangay, Mlonge, Benzolive, Drumstick tree, Sajna, Kelor, SaijihanandMarango.
Moringaoleifera division to become from Kingdom: Plantae, Division: Magnoliphyta, Class: Magnoliopsida, Order: Brassicales, Family: Moringaceae, Genus: Moringa, Species: M. Oleifera (Fahey, 2005).
Moringaoleifera is one of the vegetables of the brassica order and belongs to the family Moringaceae.The Moringaceae is a single genus family with 13 known species (Khawaja et al., 2010). Moringaoleifera is a small native tree of the sub-Himalayan regions of North West India, which is now indigenous to many regions in Africa, Arabia, South East Asia, the Pacificand CaribbeanIslands and South America. Traditionally, besides being a daily used vegetable among people of these regions, Moringa is also widely known and used for its health benefits among commoners, it has earned its name as ‘the miracle tree’ due to its amazing healing abilities for various ailments and even some chronic diseases. Several investigations were carried out to isolate bioactive compounds from various parts of the plant due to itsvarious applications (Guevara et al., 1999). Therefore, herbal plants in medicine or known as phytomedicineare still trustworthy and widely applied as one of the alternative way in medicinal field due to its affordablecost (Abalakaet al., 2009). For centuries and in many cultures around the world, the medicinal usage ofMoringa has been used to treat problems such as skin infections, anaemia, anxiety, asthma, blackheads, blood impurities, bronchitis, catarrh, chest congestion, cholera and many other illnesses (Khawaja et al., 2010; Hamza, 2010; Singh et al., 2012).
Moringaoleifera also consist of anti-inflammatory, anti-pasmodic, anti-hypertensive, anti-tumor, anti-oxidant, anti-pyretic, anti-ulcer, anti-epileptic, diuretic, cholesterol lowering, renal, anti-diabetic, (Paliwalet al., 2011; Sharma et al., 2012) and hepatoprotective activities (Lai et al., 2010; Huang et al., 2012). It has also long been labelled for its great cosmetic value in which in recent years. Moringa has commonly been found to be used in various health care products including body and hair moisturizers and conditioners. It was also discovered that Moringa oil was used in skin ointments ever since the Egyptian times. Moringa was claimed to be ‘the most nutrient-rich plant yet discovered’ by Khawaja et al. (2010). Further studies for the mechanism of action and constituents of Moringa plant may provide incredible capabilities to develop pharmacological products.
The modern society is based on the use of the car, which cannot operate without lubricants. With the increase of population and the number of vehicles, the quantity of waste oils has increased. The term “waste oil” characterizes any lubricating oil, mineral or synthetic, that has become unusable for the purpose for which it was originally intended (Abdallaet al.,4 2017). Degradation of lubricating oil occurs when different additives or foreign substances (metallic powders, sulfur, water, carbon, ash, etc.) Impurify the oil, modifying its chemical composition and affecting its properties (Diphareet al.,2013). As it is insoluble, persistent and has a high content of heavy metals and other pollutants, it is necessary to collect and recycle waste oil, in order to avoid contamination of the environment (Andrews, L., 2008). Also, its use contributes to the conservation of natural resources and to the reduction of pollution from the exploitation of fossil fuels. In this sense, in the last decades a series of recycling techniques have been developed, which aim to solve the ecological, technical and economic problems associated with waste oils.