**7. Copper (Cu)**

Copper is the first known element that is relatively red in color and has high electrical and thermal conductivity. Copper is one of the most widely used metals in industry. Copper in industries such as electronics (in wires, cathode ray lamps, in IC, vacuum lamps, switches and electronic amplifiers), military industries (production of weapons), metal industries (production of alloys and preparation of coins), tools Kitchen, water purification, is used as a reagent in chemistry and preparation of agricultural pesticides [98, 99]. Copper is one of the common elements in nature, which is found in abundance in the environment due to natural phenomena [100]. Many copper compounds are deposited in sediments or soil particles or stick to these

### *Heavy Metals in Surface Soils and Crops DOI: http://dx.doi.org/10.5772/intechopen.108824*

particles. Soluble compounds of copper may be harmful to human health. Usually copper is released in the environment as water-soluble compounds after agricultural activities. Copper is generally found near mines, industrial sites and waste disposal sites. Copper does not decompose in the environment, and for this reason, when it is in the soil, it accumulates in plants and animals [101]. In copper-rich soils, a limited number of plants have a chance of survival. This is the reason why there is not much vegetation near the copper factories. Due to the effects of copper on plants, depending on the acidity of the soil and the amount of organic matter, this element is considered a serious threat to farms. When fields are contaminated with copper, animals absorb higher concentrations of copper, which harms their health [92, 102].

Copper is abundant in the human body and is important for several physiological functions. Copper is actually a mineral that is essential and important for maintaining natural health and for survival. Liver, brain, heart, kidneys and skeleton are important organs where copper is stored. Copper plays an important role in increasing the absorption of other metals such as iron. In addition, copper is also present in the collagen of the supporting tissue. Copper acts as a cofactor for several enzymes and thus are involved in the regulation of various physiological processes. Copper is part of hair and elastic tissues. This element is present in several important substances containing structural and functional proteins in the body [103]. Also, studies show that plants and animals need sufficient amounts of copper for normal growth and maintaining their health. The appropriateness of yield of crops and seeds is also related to copper concentration. Therefore, copper is an important mineral for producers (green plants) and therefore is very important for maintaining the food chain [96].

It is obvious that the element copper is one of the essential elements of the body of living organisms, but it should be noted that large amounts of copper can cause acute effects such as discomfort in the digestive system, damage to the circulatory system such as the liver and kidney systems, and anemia.. The most well-known metabolic disorder resulting from the accumulation of copper in the body is Wilson's disease, in which the blood ceruloplasmin concentration is severely reduced [76].

### **8. Arsenic (As)**

Arsenic is one of the natural elements and the source of global pollution that is found in rocks, soil, water, air and food [104]. Arsenic has a complex chemical structure and can be found in common inorganic forms, arsenite, arsenate, and ternary organic forms. Organic arsenic combines with carbon and hydrogen ions and forms. Organic arsenic compounds are found in fish and shellfish [105]. Inorganic arsenic found in soil and water has been classified by the US Environmental Protection Agency as a human carcinogenic pollutant [106]. High doses of organic arsenic can produce the same toxic effects as a lower amount of inorganic arsenic [107]. Mineral arsenic is present in some man-made resource industries, including waste of industrial products, coal, copper, lead and glass products [85]. The use of arsenic compounds as herbicides, pesticides and fungicides is another source of arsenic pollution [79].

Absorption of arsenic through inhalation is strongly dependent on the solubility and size of the particles that enter the respiratory system, and arsenic is well absorbed from the digestive system, in other words, soluble arsenic compounds can be absorbed from the digestive system [108]. The biological half-life of absorbed inorganic arsenic is about 10 hours and about 50–80% is excreted in about 3 days, while

the half-life of methyl arsenic is 30 hours [85, 88]. Absorbed arsenic can cross the placenta and lead to cord blood concentrations similar to maternal blood concentrations [109]. The mechanism of arsenic toxicity involves a number of sulfhydryl-containing proteins and enzyme systems that change with arsenic exposure [110]. The specialized food committee determined the acceptable weekly intake for inorganic arsenic at 0.015 mg/kg [111]. It seems that consumption of organic arsenic at about 0.05 mg/kg of body weight per day causes dangerous effects for humans [112]. This element has no role in biological interactions in the human body and affects the cardiovascular system and skin, central and peripheral nervous system, kidneys and hematopoietic system of the body and causes carcinogenesis. The health effects of ingested inorganic arsenic include skin cancer, internal cancer, and non-cancerous effects on the skin, vascular system, digestive system, and liver. In general, soluble inorganic arsenic compounds are more toxic than organic types, and trivalent forms of arsenic are more toxic than pentavalent forms of arsenic, and various body systems and organs, including the skin, respiratory, cardiovascular, immune, genetic, and reproductive systems., digestive and nervous systems are affected by this substance and combined side effects are observed.
