Studies on the effect of sodium arsenate & cadmium chloride on Pithophora oedogonia (Mont.) Wittrock 1877

Abstract

Heavy metals are having high atomic weight. They are 5 times denser than water (Tchounwou et al., 2012). Nowadays, it is a serious issue to keep safe environment from two important biologically hazardous heavy metals viz. Arsenic (As) and Cadmium (Cd). Since heavy metals are non-biodegradable and hence can be separated out through different physical or chemical process (Jung et al., 2017). Arsenic can be found in different forms depending upon its oxidation state or valency which ranges from +3 to +5. Arsenite with oxidation state +3 is more toxic than arsenate, which contains the oxidation state of +5 (Gupta, 2007). According to the World Health Organization (WHO, 2011), arsenic exhibit high toxicity in its inorganic form, that can be found in contaminated drinking water, food preparations from contaminated water, contaminated food crops etc. whereas cadmium is a byproduct mainly of mining origin, extracting and refining the zinc and least amount from lead and copper ores . Arsenic is a potent carcinogenic agent and can cause conjunctivitis, skin lesions and hard patches on the palms and feet; on the other hand, cadmium can damage the kidneys, lungs and livers by deposition and can exhibit chronic & acute effects respectively (Rashid & Mridha, 1998). Most importantly, cadmium deposition shows the longer half-lives in human body that sustains throughout lifetime (Andreae & Klumpp, 1979). According to WHO’s guideline value for arsenic and cadmium in drinking water should be lower than 10 μg/L and 3μg/L respectively.