Table 1.
Limit, sources, and effects of various heavy metal ion contaminations. Reprinted from [3], Copyright 2015, with permission from Elsevier.
| Metals | WHO Limit a (mgL−1) | Common Sources | Effects |
|---|---|---|---|
| Lead (Pb) | 0.05 | PVC pipes in sanitation, agriculture, recycled PVC lead paints, jewellery, lead batteries, lunch boxes, etc. | Penetrates through protective blood brain barrier (BBB) and is proving to be a risk factor for Alzheimer’s disease and senile dementia; leads also to neuro-degenerative diseases, decreases IQ, kidney damage, decreased bone growth, behavioral issues, ataxia, hyperirritability and stupor |
| Cadmium (Cd) | 0.005 | Paints, pigments, electroplated parts, batteries, plastics, synthetic rubber, photographic and engraving process, photoconductors and photovoltaic cells | Renal toxicity, hypertension, weight loss, fatigue, microcytic hypochromic anaemia, lymphocytosis, pulmonary fibrosis, atherosclerosis, peripheral neuropathy, lung cancer, osteomalacia, osteoporosis and hyperuricemia |
| Mercury (Hg) | 0.001 | Combustion of coal, municipal solid waste incineration and volcanic emissions | Impaired neurologic development, effects on digestive system, immune system, lungs, kidneys, skin and eyes, minamata, acrodynia, increases salivation, hypotonia and hypertension |
| Arsenic (As) | 0.05 | Wooden electricity poles that are treated with arsenic based preservatives, pesticides, fertilizers, release of untreated effluents, oxidation of pyrite (FeS) and arseno pyrite (FeAsS) | Causes effects on central nervous system (CNS), peripheral nervous system (PNS), cardiovascular, pulmonary diseases, gastrointestinal tract (GI), genitourinary (GU), haemopoietic, dermatologic, foetal and teratogenic diseases, anorexia, brown pigmentation, hyper-pigmentation, localized edema and skin cancer |
| Chromium (Cr) | 0.05 | Leather industry, tanning, and chrome plating industries | Reproductive toxicity, embryotoxicity, teratogenicity, mutagenicity, carcinogenicity, lung cancer, dermatitis, skin ulcers, perforation of septum and irritant contact dermatitis |
| Silver (Ag) | 0.1 | Refining of copper, gold, nickel, zinc, jewellery and electroplating industries | Argyria, gastroenteritis, neuronal disorders, mental fatigue, rheumatism, knotting of cartilage, cytopathological effects in fibroblast, keratinocytes and mast cells |
| Zinc (Zn) | 5 | Soldering, cosmetics and pigments | Respiratory disorders, metal fume fever, bronchiolar leukocytes, neuronal disorder, prostate cancer risks, macular degeneration and impotence |
| Copper (Cu) | 1.3 | Fertilizers, tanning and photovoltaic cells | Adreno-corticol hyperactivity, allergies, anaemia, alopecia, arthritis, autism, cystic fibrosis, diabetes, haemorrhaging and kidney disorders |
a World Health Organization (WHO) tolerable limits for heavy metal ions in water.