E,L, Underwood, N.F. Suttle, The mineral nutrition of livestock, 3rd edition, CABI Publishing, Wallingford, UK, 2004.
 National Research Council, Mineral tolerance of animals, National Academies Press, 2005.
 L.M. Gaetke, H.S. Chow-Johnson, C.K. Chow, “Copper: toxicological relevance and mechanisms,” Archives of toxicology, 88(11), pp.1929-1938, 2014. DOI: 10.1007/s00204-014-1355-y
 N. F. Suttle, Mineral Nutrition of Livestock, 4th edition, CABI Publishing, wallinf ford, United Kingdom, 2010.
 F.A. Nicholson, B.J. Chambers, J.R. Williams, R.J. Unwin, “Heavy metal contents of livestock feeds and animal manures in England and Wales,” Bioresource Technology, 70(1), pp.23-31, 1999. DOI:10.1016/S0960-8524(99)00017-6
 M.B. McBride, G. Spiers, “Trace element content of selected fertilizers and dairy manures as determined by ICP–MS,” Communications in Soil Science and Plant Analysis, 32(1-2), pp.139-156, 2001. DOI:10.1081/CSS-100102999
 N.Y. Yakupa, A.B. Sabowa, S.J. Saleh, G.R. Mohammed, “Assessment of heavy metal in imported red meat available in the markets of Erbil city,” Journal of University of Babylon, 26(6), pp.177-183, 2018.
 B. Doneley, “Treating liver disease in the avian patient,” In Seminars in avian and exotic pet medicine, 13 (1), pp. 8-15, 2004. DOI:10.1053/S1055-937X(03)00053-7.
 J.W. Spears, “Trace mineral bioavailability in ruminants,” The Journal of nutrition, 133(5), pp.1506S-1509S, 2003. DOI:10.1093/jn/133.5.1506S
 D.J. MacLachlan, B.J. Blaney, L.G. Cook, E.Klim, R. Scholl , M. Sexton, J. Spragg, R.Watts, “A review of potential contaminants in Australian livestock feeds and proposed guidance levels for feed,” Animal Production Science, 53(3), pp.181-208, 2013. DOI:10.1071/AN12048
 N.A. Cheleby, J.N. Bazzaz, N.Y. Yakub, A.A. Bazzaz, G.R. Hammad, “Heavy metal residues in frozen chicken meat consumed within Erbil province,” Merit Res J, 3(11), pp.517-20. 2015.
 R. Puls, Mineral levels in animal health. Diagnostic data. Sherpa international, Clearbrook, British Columbia, Canada, 1994.
 J.P. Langlands, J.E. Bowles, G.E. Donald, A.J.Smith, “Deposition of copper, manganese, selenium and zinc in Merino sheep,” Australian Journal of Agricultural Research, 35(5), pp.701-707, 1984. DOI:10.1071/AR9840701
 O. Yayayürük, A.E. Yayayürük, “Determination of mercury, lead, cadmium, copper, iron and manganese in sheep, cow and chicken liver samples in Turkey,” Gida/the Journal of Food, 42(5)., 2017. DOI:10.15237/gida.GD17018
 I. S. Ali, Water Quality Assessment for Greater Zab River and Bioaccumulation of Toxic Heavy Metals in Some Local Fish Species, Erbil, Kurdistan Region of Iraq, MSc. Thesis, Salahaddin University- Erbil, 2017.
 T.H. Herdt, W. Rumbeiha, W.E. Braselton, “The use of blood analyses to evaluate mineral status in livestock” Veterinary Clinics: Food Animal Practice, 16 (3), pp.423-444, 2000. DOI:10.1017/S0954422411000059
 P. Aljaff, B.O. Rasheed, D.M. Salh, “Assessment of heavy metals in livers of cattle and chicken by spectroscopic method,” IOSR Journal of Applied Physics, 6, pp. 23-26, 2014.
 L.R. McDowell, Minerals in animal and human nutrition, Academic press Inc. Harcourt Brace Jovanivich Publisher, San Diego, California, USA, 1992.
 W. Van der Schee, G.H. Van den Assem, R. Van der Berg, “ Breed differences in sheep with respect to the interaction between zinc and the accumulation of copper in the liver,” Veterinary Quarterly, 5(4), pp.171-174, 1983.
 F. Tacnet, P. Ripoche, M. Roux, J.M. Neumann, “31 P-NMR study of pig intestinal brush-border membrane structure: effect of zinc and cadmium ions,” European biophysics journal, 19(6), pp.317-322, 1991. https://doi.org/10.1007/BF00183321
 S.R. Gooneratne, W.T. Buckley, D.A. Christensen, “Review of copper deficiency and metabolism in ruminants,” Canadian Journal of Animal Science, 69(4), pp.819-845,1989. DOI:10.4141/cjas89-096
 M.E. Tiffany, V. Fellner, J.W. Spears, “Influence of cobalt concentration on vitamin B12 production and fermentation of mixed ruminal microorganisms grown in continuous culture flow-through fermentors,” Journal of animal science, 84(3), pp.635-640, 2006. DOI:10.2527/2006.843635x
 D.G. Kennedy, W.J. Blanchflower, J.M. Scott, D.G. Weir, A.M. Molloy, S. Kennedy, P.B. Young, “Cobalt-vitamin B-12 deficiency decreases methionine synthase activity and phospholipid methylation in sheep,” The Journal of nutrition, 122(7), pp.1384-1390, 1992. DOI:10.1093/jn/122.7.1384
 H.M. Al-Nor, H.H. Nafee, “Some heavy metals residues in beef and sheep Liver in Anbar province,” Al-Anbar Journal of Veterinary Sciences, 12(1), pp.37-49, 2019.
 W.K. Rumbeiha, W.E Braselton, D. Donch, “A retrospective study on the disappearance of blood lead in cattle with accidental lead toxicosis,” Journal of veterinary diagnostic investigation, 13(5), pp.373-378, 2001. DOI:10.1177/104063870101300501
 L.S.L.D.S. Reis, P.E. Pardo, A.S. Camargos, E. Oba, E., “Mineral element and heavy metal poisoning in animals,” Journal of medicine and medical Sciences, pp.560-579, 2010.
 S.T. Strojan, C.J.C. Phillips, “The detection and avoidance of lead-contaminated herbage by dairy cows,” Journal of dairy science, 85(11), pp.3045-3053, 2002. DOI:10.3168/jds.S0022-0302(02)74390-7
 D. Swarup, R.C. Patra, R. Naresh, P. Kumar, P. Shekhar, “Blood lead levels in lactating cows reared around polluted localities; transfer of lead into milk,” Science of the Total Environment, 347(1-3), pp.106-110, 2005. DOI:10.1016/j.scitotenv.2004.12.055
 L. Friberg, G.F. Nordberg, V.B. Vouk, Handbook on the Toxicology of Metals, Elsevier/North-Holland Biomedical Press, 1979.
 M. Gabrashanska, S. Tepavitcharova, M. Galvez-Morros, M. Mitov, “Investigation of the effect of cobalt compounds on uninfected and infected with Ascaridia galli chicks,” Experimental Pathology and Parasitology, 4(7), pp.26-32, 2001.
 M. Debnath, R.K. Saha, D. Kamilya, D. Saikia, H. Saha, “Effects of water borne iron on spawn of Indian major carps (Catla catla (Ham.), Labeo rohita (Ham.) and Cirrhinus mrigala (Ham.)),” Bulletin of environmental contamination and toxicology, 89(6), pp.1170-1174, 2012. DOI:10.1007/s00128-012-0844-z.
 P.P. Buthelezi, V. Wepener, D.P. Cyrus, “The sublethal effects of zinc at different water temperatures on selected haematological variables in Oreochromis mossambicus,” Southern African Journal of Aquatic Sciences, 25(1), pp.146-151, 2000. DOI:10.2989/160859100780177659,
 C.A. Woody, S. O’Neal, Effects of Copper on Fish and Aquatic Resources, Fisheries Research and Consulting, Alaska, USA, pp. 26. W2013ECopperF062012.pdf (conservationgateway.org)
 F. Solomon, “Impacts of copper on aquatic ecosystems and human health,” Environment and Communities, 25(8), pp.25-28, 2009.
 F. Jabeen, A.S. Chaudhry, “Monitoring trace metals in different tissues of Cyprinus carpio from the Indus River in Pakistan,” Environmental Monitoring and Assessment, 170(1-4), pp.645-656, 2010. DOI:10.1007/s10661-009-1263-4.
 N. Sakulsak, “Metallothionein: an overview on its metal homeostatic regulation in mammals,” International Journal of Morphology, 30(3), pp.1007-1012, 2012. DOI:10.4067/S0717-95022012000300039.
 J.O. Wilberforce, F. Nworie, R.O. Oti-Wilberforce, “Comparative assay of heavy metals in gills and muscles of common fishes in Afikpo, Ebonyi State, Nigeria,” World Applied Sciences Journal, 34(2), pp.268-272, 2016. DOI: 10.5829/idosi.wasj.2016.34.2.15657
 D.G. Sfakianakis, E. Renieri, M. Kentouri, A.M. Tsatsakis, “Effect of heavy metals on fish larvae deformities: a review,” Environmental research, 137, pp.246-255, 2015. DOI:10.1016/j.envres.2014.12.014.
 S.L. Shah, A. Altindağ, “Alterations in the immunological parameters of Tench (Tinca tinca L. 1758) after acute and chronic exposure to lethal and sublethal treatments with mercury, cadmium and lead,” Turkish Journal of Veterinary and Animal Sciences, 29(5), pp.1163-1168, 2005.
 P.R. Shakya, “Nickel Adsorption by Wild type and Nickel Resistant Isolate of Chlorella sp.,” Pakistan Journal of Analytical & Environmental Chemistry, 8(2), p.5, 2007.
 Institute of Medicine, Dietary reference intakes applications in dietary planning, Subcommittee on interpretation and uses of dietary reference intakes and the standing committee on the scientific evaluation of dietary reference intakes, Institute of Medicine of the National Academies, The National Academies Press, Washington DC, pp. 248, 2003. DOI: 10.17226/10609
 A.A. Hantoush, G.A. Al-Najare, A.H. Amteghy, H.T. Al-Saad, K. Abd Ali, “Seasonal variations of some trace elements concentrations in Silver Carp” Marsh Bulletin, 7(2), pp.126-136, 2012.
 A.M. Yousafzai, M. Siraj, A. Habib, D.P. Chivers, “Bioaccumulation of heavy metals in common carp: implications for human health,” Pakistan Journal of Zoology, 44(2), pp. 489-494, 2012.
 M. Mensoor, A. Said, “Determination of heavy metals in freshwater fishes of the Tigris River in Baghdad,” Fishes, 3(2), p.23, 2018. DOI:10.3390/fishes3020023
 B. Jezierska, M. Witeska, Metal toxicity to fish, 1st edition, University of Podlasie, Siedlce, Polannd, pp. 318 , 2001.
 J. Sun, Y. Ji, F. Cai, J. Li, Heavy Metal Removal Through Biosorptive Pathways. In: Sharma S., Sanghi R. (eds) Advances in Water Treatment and Pollution Prevention. Springer, Dordrecht, pp. 95-145, 2012. https://doi.org/10.1007/978-94-007-4204-8_5
 S. Faxneld, S. Danielsson, E. Nyberg, A. Bignert, “Conversion factors for metals between liver, muscle and wholebody in perch,” Report 1, Swedish Museum of Natural History, 2015. https://www.divaportal.org/smash/get/diva2:811293/FULLTEXT01.pdf
 B.H. Marouf, “Association between serum heavy metals level and cancer incidence in darbandikhan and Kalar Area, Kurdistan Region, Iraq,” Nigerian journal of clinical practice, 21(6), pp.766-771, 2018. DOI: 10.4103/njcp.njcp_384_16