The term rare earth is a misnomer arising from the rarity of the minerals from which they were originally isolated. In contrast, REEs are relatively plentiful in the Earth’s crust having an overall crushing abundance of 9,2 ppm (UK report). However, REEs rarely occur in concentrated
This results in loss of nutrient-rich and fertile top layers and reduced water retention. When the land isn 't very fertile, then not a lot of vegetation can grow. This makes it more likely for the soil to erode with the wind because there is no flora to hold on to it. Chemical degradation deals with the chemical part of the soils. In chemical degradation there is loss of nutrients that reduces the capacity of the soil to to support plant growth and crop production.
Water logging refers to the saturation of soil with water, usually through irrigation, resulting in a condition under which most crop plants cannot grow. The productivity of agriculture land is also reduces by waterlogging. The drainage system is the main cause of waterlogging. When root is not able to respire due to the excess of water, the waterlogging takes place. The adverse effects of waterlogging are creation of anaerobic condition in the crop root-zone, growth of water loving wild plants, impossibility of tillage operations, accumulation of harmful salts, lowering of soil temperature, reduction in time of maturity.
This lethal water can be unsafe to plants and creatures that use it and make it hard to clean to drink water. Crops are likewise getting less water by volume. In the worst of droughts, ranchers can 't keep up their fields in view of the droughts conditions and the confinements put on water. Farmers and harvesters will move in order to go away from places where droughts occur commonly in order to grow their crops and make profits. Plants retain the minerals from the dirt so as to survive.
Soil pollutants have an adverse effect on the physical, chemical and biological properties of the soil and reduce its productivity. Pesticides, fertilizers, organic manure, chemicals, radioactive wastes, discarded food, clothes, leather goods, plastics, paper, bottles, tins-cans and carcasses- all contribute towards causing soil pollution. Metals like iron are present in industrial wastes and reach the soil either directly with water or indirectly through air. (Example, through acid rain). The improper and continuous use of herbicides, pesticides and fungicides to protect the crops from pests, fungi etc.
For growing good crops often we used chemical fertilizer which can be harmful for environment. The use of chemical in agriculture sector mostly cause harmful for water and the living species lives in water. The impacts of pollution on freshwater species are can be cause in the loss of some species, with though some profits for some of them. For example, from the readings we knew that there is a chemical named Sumithion, which is widely used to control brittle in paddy fields and tiger bug in fish larval rearing ponds. This chemical has both good and bad affect on fish.
Mining requires the removal of topsoil containing valuable organic matters. The removal of topsoil causes the land to be barren which are unsuitable for cultivation and unproductive, which is a kind of land pollution. Due to urbanization, many construction activities are taking place. Waste materials such as wood, metal and plastic often being left at the construction site. When deforestation is committed, the green cover which helps in balancing the atmosphere is reduced and it leads to natural disasters such as global warming, flash floods and green house effect.
When it rains, the water droplets integrate with these air pollutants, so it becomes acidic and then drops on the ground in the shape of acid rain ("Environmental pollution," n.d.). Therefore, acid rain causes great harm for greens and crops. The greens and crops are damaged leads to lower production, increase poverty, and provide lung problems. Dropping the sales in the supermarkets and reducing the gain happened by lower production of crops. Consequently, that causes poverty by having no food to people eat.
Kılıç et al. (2013) reported a high yield of biodiesel (99.81%) obtained from castor oil in a very short reaction time (10 min) at 65 oC using catalyst, CH3OK (1.5% wt of oil) and methanol to oil molar ratio of 7:1. Rodríguez-Guerrero et al. (2013) also studied about the the synthesis of 9 biodiesel from castor oil at supercritical temperature (200-350 oC). The advantage with supercritical conditions and the pressure generated due to high temperature was a very less requirement of catalyst (0.1% wt) which was even lesser than that required for neutralization of the castor oil.
The two major causes of flood are natural and man-made. Some of the natural causes are heavy rainfall and overflowing of the flood ways that leads to continuous flooding. Also, flooding can’t only bring severe damage to the structures, it can also kill trees and herbal plants that we need in our lives (Devalsam, 2011). Lu (2012) stated that large area of soil looses certain amount of topsoil because of two reasons, first is erosion and the other is heavy flooding. Flood causes some amount of topsoil to lose.