Zinc toxicity

Many studies have reported the effects of metals on general soil microbiological processes. Metals including cadmium, chromium, copper, lead, mercury, nickel, and zinc have been reported to inhibit many of the microbial processes listed above. Metal toxicity in the environment ultimately decreases litter decomposition, which can be measured by the rate of mass loss. Both copper (0.5 mg Cu g4 soil) and zinc (1.0 mg Zn g 1 soil) were shown to decrease the rate of decomposition of unpolluted Scots pine needle litter near a brass mill in Sweden.61 Duarte et al.63 also determined that copper and zinc toxicity reduced leaf decomposition rates and fungal reproduction. Other metals, such as cadmium, nickel, and lead, have also been reported to decrease litter decomposition.77... 

Toussaint, M.J.M. and H. Nederbragt. 1993. Copper and zinc toxicity in two rat hepatoma cell lines varying in differentiation. Comp. Biochem. Physiol. 104C 253-262. 

Adults 600 Preexposure for 14 days increased resistance 28% over controls in 96-h zinc toxicity assays 72... 

Burton, D.T., A.H. Jones, and J. Caims, Jr. 1972. Acute zinc toxicity to rainbow trout (Salmo gairdneri) confirmation of the hypothesis that death is related to tissue hypoxia. Jour. Fish. Res. Bd Can. 29 1463-1466. 

Donker, M.H., H.M. Abdel-Lateif, M.A. Khalil, B.M. Bayoumi, and N.M. Van Straalen. 1998. Temperature, physiological time, and zinc toxicity in the isopod Porcellio scaber. Environ. Toxicol. Chem. 17 1558-1563. Droual, R., C.U. Meteyer, and F.D. Galey. 1991. Zinc toxicosis due to ingestion of a penny in a gray-headed chachalaca (Ortalis cinereiceps). Avian Dis. 35 1007-1011. 

Fosmire, G.J. 1990. Zinc toxicity. Amer. Jour. Clin. Nutr. 51 225-227. 

Francis, J.C. and F.W. Harrison. 1988. Copper and zinc toxicity in Ephydatiafluviatilis (Porifera Spongillidae). Trans. Amer. Microscop. Soc. 107 67-78. 

Gasaway, W.C. and I.O. Buss. 1972. Zinc toxicity in the mallard duck. Jour. Wildl. Manage. 36 1107-1117. 

Handy, R.D., F.B. Eddy, and G. Romain. 1989. In vitro evidence for the ionoregulatory role of rainbow trout mucus in acid, acid/aluminium and zinc toxicity. Jour. Fish Biol. 35 737-747. 

Hilmy, A.M., N.A. El-Domiaty, A.Y. Daabees, and H.A.A. Latife. 1987a. Some physiological and biochemical indices of zinc toxicity in two freshwater fishes, Clarias lazera and Tilapia zilli. Comp. Biochem. Physiol. 87C 297-301. 

Leonard, A. and G.B. Gerber. 1989. Zinc toxicity does it exist Jour. Amer. Coll. Toxicol. 8 1285-1290. 

Palafox, A.L. and E. Ho-A. 1980. Effect of zinc toxicity in laying white leghorn pullets and hens. Poult. Sci. 59 2024-2028. 

Paulauskis, J.D. and R.W. Winner. 1988. Effects of water hardness and humic acid on zinc toxicity to Daphnia magna Straus. Aquat. Toxicol. 12 273-290. 

Reece, R.L., D.B. Dickson, and P.J. Bunowes. 1986. Zinc toxicity (new wire disease) in aviary birds. Austral. Veterin. Jour. 63 199. 

Saxena, R., R.S. Bedwal, and R.S. Mathur. 1989b. Zinc toxicity and male reproduction in rats a histological and biochemical study. Trace Elem. Medic. 6 119-133. 

Stewart, F.M., L.R. Monteiro, and R.W. Furness. 1997. Heavy metal concentrations in Cory s shearwater, Calonectris diomedea, fledglings from the Azores, Portugal. Bull. Environ. Contam. Toxicol. 58 115-122. Straube, E.F., N.H. Schuster, and A.J. Sinclair. 1980. Zinc toxicity in the ferret. Jour. Comp. Pathol. 90 355-361. Sullivan, P.A., W.E. Robinson, and M.P. Morse. 1988. Isolation and characterization of granules from the kidney of the bivalve Mercenaria. Mar. Biol. 99 359-368. 

Sunda, W. G. and Huntsman, S. A. (1996). Antagonisms between cadmium and zinc toxicity and manganese limitation in a coastal diatom, Limnol. Oceanogr., 41, 373-387. 

Most of the research on the influence of zinc on calcium bioavailability has been in connection with zinc toxicity or the effects of high levels of dietary zinc on various animal systems. Such studies and/or investigations have been conducted on a variety of animal species and humans, but those studies which have revealed a possible effect of zinc on calcium bioavailability have generally involved the lamb, pig, and rat. This paper will be primarily a discussion of the effects of high levels of dietary zinc on calcium status in the rat. The effect of zinc on phosphorus status, however, has been included because there is the possibility that the effect of zinc on calcium bioavailability may be dependent upon the phosphorus status of the system. 

The first experimental indication of an adverse effect of excess dietary zinc on animals was revealed by Sutton and Nelson (1) in 1937. These researchers observed decreased growth, anemia, and reproductive failures in rats fed diets containing 0.5% to 1% zinc. Following this initial report, several studies were conducted by various researchers, but most of the studies pertaining to zinc toxicity between the late 1930 s and the early 1950 s primarily focused on the effects of zinc toxicity on growth and on copper and iron metabolism. During 1951 and 1952 a series of reports by... 

The effect of zinc toxicity on the calcium balance of young rats is presented in Table V. Marked increases in the fecal excretion of calcium was noted in the zinc-fed rats, and the overall effect of zinc toxicity was a substantial decrease in the apparent retention of calcium. The effects of zinc on calcium retention were noted as early as one week of the experimental period. 

Table V. Effect of Zinc Toxicity on Calcium Retention in Young Rats...

The data presented in this paper indicate that excess levels (0.75%) of dietary zinc result in decreases in the bioavailability of calcium and phosphorus in rats and interfere with normal bone mineralization. High dietary levels of calcium or zinc appeared to cause a shift in the excretion of phosphorus from the urine to the feces, while the presence of extra phosphorus tended to keep the pathway of phosphorus excretion via the urine. The presence of large amounts of phosphorus in the Intestinal tract due to high intakes of zinc would increase the possibility of the formation of insoluble phosphate salts with various cations, including calcium, which may be present. A shift in phosphorus excretion from the feces to the urine, however, could result in an environmental condition within the system which would tend to increase the bioavailability of cations to the animal. The adverse effect of zinc toxicity on calcium and phosphorus status of young rats could be alleviated with calcium and/or phosphorus supplements. 

Judy, R.D., Jr. and Davies, P.H. Effects of calcium addition as Ca(N03)2 on zinc toxicity to fathead minnows, Pimephales promelas, Rafinesque, BuU. Environ. Contam. Toxicol, 28(l/2) 88-94, 1979. 

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