Kinetics of radionuclides and heavy metals behaviour in soils: Implications for plant growth

The extent of metal and radionuclide contamination in the world is immense. In soils, metals and radionuclide can be dissolved in solution, or ion exchanged in reaction, complexed with soil organics or precipitate as pure or mixed solids. Soluble contaminants are subject to migration with soil  water, uptake by plants or aquatic organisms or loss due to volatilization. Lead, chromium, zinc, arsenic and cadmium are the most frequently identified inorganic contaminants in soil and ground water. Unlike degradable organic contaminants and ever short-lived radionuclides that can become less toxic over time, metals can be considered conservative. However, many metals, especially radio-sensitive elements such as arsenic and chromium can undergo transformation or sorption reaction that alter both mobility and relative toxicity. This paper therefore, makes a review of these behaviours of radionuclides and heavy metals in soils, in connection to soil contamination and their effects on plant growth

Detoxification of copper fungicide using EDTA-modified cellulosic material

Pesticides are poisons and can be particularly dangerous when misused or carelessly disposed. The detoxification of a copper fungicide (KOCIDE 101) using maize cob, a cellulosic material, was studied. Based on copper as the active agent (after a sorption period of 1 h), the concentration of the fungicide reduced from an initial value of 2000 to 206.25 ppm for the unmodified maize cob and to 24.31 ppm for the modified maize cob. The pseudo-first and second order rate equations were used to model thedetoxification process. The intraparticle diffusivity and mechanism of the sorption was proposed. Also, equilibrium sorption isotherms were evaluated using the Freundlich, Langmuir and Dubinin-Radushkevich isotherm models. This results show that maize cob is an effective adsorbent for copper fungicide deactivation and detoxification

Organophosphate induced chronic neurotoxicity: Health, environmental and risk exposure issues in developing nations of the world

Organophosphate insecticides account for about half of all the insecticides used in the world and have found very wide applications in agriculture and in household vector control. Exposures of human populations to a wide variety of organophosphates have generated profound concerns about theirneurotoxic consequences. Among these concerns are their potential impacts on children and exposures to the neurodegenerative diseases associated with advancing age. This paper therefore tends to make a review of the health, environmental and other risk exposure issues of organophosphates especially in Africa and other developing nations of the world where data abound toshow that many agents considered toxic and banned in many parts of the industrialized world are still in use. This paper also makes recommendations on the way out of this menace

Ecotoxicology of arsenic in the hydrosphere: Implications for public health

Arsenic is a naturally occurring metalloid element that is found in soil, air and water. Environmental arsenic exists in both organic and inorganic states. Organic arsenicals are generally considered nontoxic, whereas inorganic forms are toxic. The most acutely toxic form is arsine gas. Inorganic arsenic exists predominantly in trivalent (As3+) and pentavalent (As5+) forms, where trivalent compounds aremore toxic than pentavalent ones. Human activities have also intensified arsenic accumulation in the environment. Organs most susceptible to arsenic toxicity are those involved with absorption,accumulation or excretion, including the skin, circulatory system, gastrointestinal tract, liver and kidney. Arsenic is associated with multiple health effects, including Blackfoot diseases, diabetes,hypertension, peripheral neuropathy and multiple vascular diseases. Other effects include anemia, liver damage, portal cirrhosis, hematopoietic depression, anhydremia, sensory disturbance and weight loss. In addition to acute toxicity, long-term exposure to inorganic arsenic is associated with certain forms of cancer of the skin, lung, colon, bladder, liver and breast. Understanding the ecotoxicological effects of arsenic in the environment is paramount to mitigating its deleterious effects on ecological and human health. This paper is therefore a review of the ecotoxicological effects of arsenic on human and ecological health

Mercury levels and health parameters in the threatened Olrog’s Gull (Larus atlanticus) from Argentina

Mercury (Hg) exposure was investigated through feathers of Olrog's Gull and related to health parameters in adults (hematocrit, total plasma proteins, morphometric measures, sex) and chicks (hematocrit, total plasma proteins, immunoglobulins G and M) from a colony located in estuary of Bahia Blanca, Argentina. Mercury concentrations were 5.50 +/- 2.59 mu g g (-aEuro parts per thousand 1) (n = 44) in live adults, 1.85 +/- 0.45 mu g g (-aEuro parts per thousand 1) (n = 45) in live chicks and 1.81 +/- 0.41 mu g g (-aEuro parts per thousand 1) (n = 41) in dead chicks. Large differences were observed between live adults and live or dead chicks and small differences between live and dead chicks. In the adults, the sex of the birds was the variable that best explained Hg concentrations. Male birds had higher concentrations than females; this suggests that the clutch provides a sink for mercury during egg laying. Hg concentrations in both adults and live chicks were associated with higher hematocrits. This could be associated with upregulated erythropoiesis to compensate for increased rate of destruction of prematurely senescent, Hg-contaminated erythrocytes. Based on our results, on the levels of Hg pollution in the past in the study area, and on the dietary specialization of Olrog's Gull, we must be vigilant about potential negative effects of Hg pollution on this population and recommend continued monitoring on this threatened species