Potentially toxic metals elevated levels

Chromium has proved effective in counteracting the deleterious effects of cadmium in rats and of vanadium in chickens. High mortality rates and testicular atrophy occurred in rats subjected to an intraperitoneal injection of cadmium salts however, pretreatment with chromium ameliorated these effects (Stacey et al. 1983). The Cr-Cd relationship is not simple. In some cases, cadmium is known to suppress adverse effects induced in Chinese hamster (Cricetus spp.) ovary cells by Cr (Shimada et al. 1998). In southwestern Sweden, there was an 80% decline in chromium burdens in liver of the moose (Alces alces) between 1982 and 1992 from 0.21 to 0.07 mg Cr/kg FW (Frank et al. 1994). During this same period in this locale, moose experienced an unknown disease caused by a secondary copper deficiency due to elevated molybdenum levels as well as chromium deficiency and trace element imbalance (Frank et al. 1994). In chickens (Gallus sp.), 10 mg/kg of dietary chromium counteracted adverse effects on albumin metabolism and egg shell quality induced by 10 mg/kg of vanadium salts (Jensen and Maurice 1980). Additional research on the beneficial aspects of chromium in living resources appears warranted, especially where the organism is subjected to complex mixtures containing chromium and other potentially toxic heavy metals. 

An interesting finding regarding potentially toxic chromium (and cobalt) in the body is elevated blood and urine levels of these metals in patients who have undergone total hip replacement.5 The conclusion of the study was that devices such as prosthetic hips that involve metal-to-metal contact may result in potentially toxic levels of metals in biological fluids. 

A possible source of soil contamination results from recycling industrial wastes for fertilizer. According to data compiled by the Environmental Working Group (EWG) during the 1990s, approximately 25 million kg per year of potentially toxic wastes were used to prepare fertilizers that contained elevated levels of arsenic, cadmium, lead, radioactive materials, and dioxins. A potential source of heavy metal pollution in fertilizers is ash from furnaces used to recycle steel, commonly processed to provide zinc in zinc-deficient soils. 

Certain substances have been reported to potentiate the toxicity of paraquat. These include transition metal ions such as copper (Kohen and Chevion 1985) and ethanol (Kuo and Nanikawa 1990). Blood paraquat levels showed significant elevation in rabbits, and the mortality rates increased when the animals were orally administered paraquat combined with ethanol in amounts of 2.0 and 3.8 g/kg. Continuous breathing of high oxygen concentrations 12-24 hours after administration of paraquat caused severe and extensive pulmonary lesions and interstitial fibrosis (Selman et al. 1985). On the other hand, a reverse sequence of treatment— inhalation of high oxygen concentrations followed by paraquat administration—caused no mortality and pulmonary lesions. 

---