Table 1.

Detailed summary of form(s), sources, entry routes, associated symptoms and pronounced health effects corresponding to different metals.

Metal	Form(s)	Sources	Route of Entry	Symptoms		Health Effects	References
				Acute	Chronic
Mercury, At. No: 80, At. Mass: 200.6	Hg, Hg2+, Hg+, Hg-organic Oxidation state: +1, +2	Fossil fuel combustion, mining, smelting, solid waste combustion, fertilizers industrial wastewater, use in electrical switches, fluorescent bulbs Mercury arc lamps, incineration of municipal wastes, emissions from mercury products: batteries, thermometers, Mercury amalgams	Inhalation, ingestion and absorption through skin	GI pain, vomiting, diuresis, anemia, hypovolemic shock, renal toxicity, tension, irritability, intention tremors, insomnia, fatigue	Gingivitis, tachycardia, goiter, high urine Hg	Disruption of the nervous system, damage to brain functions, DNA damage and chromosomal damage, allergic reactions, tiredness and headaches, negative reproductive effects, such as sperm damage, birth defects and miscarriages	[22]
Arsenic, At. No: 33, At. Mass: 74.92	AsIII, AsV, Oxidation state: +3, +5	Pesticides, mining, smelting of gold, Lead, Copper and Nickel, Production of iron and steel, combustion of coal, tobacco smoke	Inhalation and ingestion	Mucosal damage, hypovolemic shock, fever, sloughing, gastro-intestinal pain, anorexia	Weakness, hepatomegaly, melanosis, arrhythmias, peripheral neuropathy, peripheral vascular disease, carcinogenicity, liver angiosarcoma, skin and lung cancer	Birth defects, Carcinogen: lung, skin, liver, bladder, Kidneys, Gastrointestinal damage, Severe vomiting, diarrhea, death	[25]
Lead, At. No: 82, At. Mass: 207.19	Pb2+, Oxidation state: +2, +4	Application of lead in gasoline, fuel combustion, industrial processes, solid waste combustion, used in paints, used in ceramics and dishware, Lead is used in some types of PVC mini-blinds	Inhalation and ingestion	Nausea, vomiting, thirst, diarrhea/constipation, abdominal pain, hemoglobinuria, oligura leading to hypovolemic shock	Lead colic, lead palsy and lead encephalopathy	Aanemia (less Hb), hypertension, kidney damage, miscarriages, disruption of nervous systems, brain damage, infertility, intellectual disorders	[26,27]