It has been reported that Pb contains from the car’s exhaust is very high since it varies from 20 up to 50 μg / L. In addition, contamination zone of such metals Pb, Cr, and Co had been found in roads’ soils on both sides of the highway (Su et al., 2014). According to Lindqvist (1995), the effects of heavy metals on soils and soil creatures are influenced by many soil factors such as acidity or base cations’ concentrations, and it is difficult to demonstrate the effects of heavy metals separately. However, it may be first noticed that heavy metals can cause reserve effect on the soil respiration, nitrogen mineralization, and in the process of humic
Waste water has always been a major threat to the environmental imbalance. Process waste streams from the mining operations, metal plating facilities, paper industries, power generation facilities, electronic device manufacturing units, and tanneries may contain plethora of heavy metals, for example zinc, copper, cadmium, lead, chromium, mercury, nickel etc are disposed above the hazardous limit of the local discharge zones. These heavy metals are not biodegradable and pose great threat to human health and environment. Heavy metal pollution is a problem related with areas and zones where intensive industry, road ways, areas of dumpsites and automobiles activities takes place. Usage and their uncontrolled discharge in to the environment has
The chemicals spread through the air easily due to its smaller particle size. The accumulation of construction contaminants in the soil can persists over longer periods of time such as polycyclic aromatic hydrocarbons (PAHs). In addition, mining activities are the other causes of soil pollution. Mining activities are the extraction of minerals from the Earth. It involves the crushing and processing of raw materials such as heavy metals which emit toxic substances.
Route of exposure : Ingestion, inhalation, dermal and injection 3. age, Sex, Health, Environmental factors and Individual characteristics Heavy metals : It refers to any metallic chemical element which has a high density and poisonous at high concentrations. Such as mercury, cadmium, arsenic, chromium, thallium, and lead. Heavy metals cannot be degraded to a small extent they enter our bodies via food, drinking water and air. Some heavy metals like copper, selenium and zinc are essential to maintain the metabolism of the human body but at higher
additional treatments to meet the standard quality for human consumption. For example, in 2000, the water quality of the river in terms of pH, aluminium, iron and manganese were reported to exceed the Malaysian standard for drinking water quality (Norris & Hawkins, 2000). These subsequently affected the normal operation of the water treatment plant and thus upset the normal supply of drinking water to the community. Pollution of this river by heavy metals is a serious problem, because many such pollutants are both highly toxic and not biodegradable in the natural environment (Morillo et al., 2002). Heavy metal contamination in aquatic and soil environments threatens aquatic ecosystems, agriculture and human health (Overesch et al., 2007).
Heavy metals are elements having atomic weights between 63.5 and 200.6, and a specific gravity greater than 5.0 . With the rapid development of industries such as metal plating facilities, mining operations, fertilizer industries, tanneries, batteries, paper industries and pesticides, etc., heavy metals wastewaters are directly or indirectly discharged into the environment increasingly, especially in developing countries. Unlike organic contaminants, heavy metals are not biodegradable and tend to accumulate in living organisms and many heavy metal ions are known to be toxic or carcinogenic. Toxic heavy metals of particular concern in treatment of industrial wastewaters include zinc, copper, mercury, cadmium, chromium, lead and nickel.
Environmental pollution through the discharge of toxic heavy metal ions considered one of the most important issues that threat all biological systems including human, animal and plant kingdoms. For this reason, several attempts have been made for effective removal of these metal ions, particularly from industrial wastewater [1, 2]. As a pollutant, mercury (Hg) regarded as an extremely poisonous heavy metal with enormous harmful effect on our health . Numerous studies confirmed that sever medical diseases could be related to long term exposure to Hg2+ ions. Mercuric ions biomethylation could retain in blood and continuously deposit in some organs like kidneys, liver or brain and consequently cause chronic diseases ended with death [4, 5].
I. Introduction Environmental pollution is currently one of the most important issues facing humanity. It was increased exponentially in the past few years and reached alarming levels in terms of its effects on living creatures. The presence of toxic metals in the environment specifically in various water resources is of major concern because of their toxicity, non-biodegradable nature and threat to human, animal and plant life. Electroplating, painting, metallurgical, mining, textile, municipal incineration and chemical manufacturing industries all generate toxic metals of various levels.
Plants in nature are constantly exposed to various abiotic stresses resulting from unfavorable environmental conditions which negatively affect their growth and development (Atkinson and Urwin, 2012). Most crops are exposed to stress during some stages of their life cycle (Bartels and Nelson, 1994). Changes in temperatures, starvation, drought, change in nutrients abundance, flooding, air pollution, soil pollution and osmotic alterations are some of the examples present in nature (Apel and Hirt, 2004). In literatures, there are many definitions of the term stress. Koehn and Bayne (1989) defined the stress as the environmental changes that result in the reduction of the organism fitness and consequently decrease its growth and development.
12. CHAPTER 7 12.1. DNA DAMAGE 12.1.1. INTRODUCTION Toxic metal pollutants in marine water tend to increase steadily thereby representing the greatest hazard to aquatic organism. Investigations on the toxic effect of metals upon bivalves is accompanied by the analysis of changes in nucleic acid indices (Hoyle et al., 2007).