Araştırma Makalesi
BibTex RIS Kaynak Göster

DETERMINATION OF SEASONAL CHANGES ON SOME HEAVY METAL (Cd, Pb, Cr) LEVELS OF SHRIMP AND PRAWN SPECIES FROM NORTH-EASTERN MEDITERRANEAN SEA, GULF OF MERSIN, TURKEY

Yıl 2016, , 42 - 49, 01.04.2016
https://doi.org/10.3153/JAEFR16006

Öz

The concentration levels of some potentially toxic trace elements such
as
Cd, Cr, and Pb in the muscle
tissue of some shrimp and prawn species
from North­eastern Mediterranean Sea, Gulf of Mersin, Turkey were seasonally
determined in this study. The effects of seasons on the potentially toxic trace
elements levels of regional commercially valuable five different shrimp and
prawn species
(green tiger
prawn-Penaeus semisulcatus, kuruma
prawn-Marsupenaeus japonicus,
caramote prawn-Melicertus kerathurus,
deepwater pink shrimp-Parapenaeus
longirostris,
speckled shrimp-Metapenaeus
monoceros
) were determined. 30 individuals of each species were caught by
bottom trawling
from the Mediterranean Sea (Gulf of Mersin) in four seasons in 2013. Shrimp and prawn samples were
extracted using digestion method with concentrated nitric acid and per chloric
acid and metal levels were measured using ICP/MS.
The differences in Cd, Cr and Pb levels of
muscle tissue in all species were determined as 0.44-1.40 µg/g dw, 1.38-5.80
µg/g dw, and 1.99-13.42 µg/g dw, respectively. The quantitative relationships
generally found in the metal levels of muscle in all the species were: Pb>
Cr> Cd, but the concentration of each potentially toxic heavy metal varied seasonally.
If the data obtained by this study were evaluated with respect to the data in
U.S. Food and Drug Administration (2013), it would be obviously seen that all
the shrimp and prawn species living in Gulf of Mersin were not contaminated
with Cd and Cr but contaminated with Pb. However, if it is analyzed in
accordance with European Commission (2011) and Turkish Food Codex (2011), all
species except winter and spring samples of Parapenaeus
longirostris
are contaminated with Cd and Pb.  

Kaynakça

  • Alexander, J., Benford, D., Boobis, D., Ceccatelli, S., Cravedi, J.P., Di Domenico, A., & van Leeuwen, R. (2010). Scientific opinion on lead in food. The European Food Safety Authority Journal, 8, 1-147.
  • Ayas, D., & Özoğul, Y., (2011). The Chemical Composition of Carapace Meat of Sexually Mature Blue Crab (Callinectes sapidus, Rathbun 1896) in the Gulf of Mersin. Journal of FisheriesSciences.com, 5(3), 262-269.
  • Ayas, D., & Özoğul, Y., (2011). The Chemical Composition of Sexually Mature Blue Swimmer Crab (Portunus pelagicus, Linnaeus 1758) in the Gulf of Mersin. Journal of FisheriesSciences.com, 5(4), 308-316.
  • Ayas, D., & Ozoğul, Y., (2011). The effects of sex and seasonality on the metal levels of different muscle tissues of mature Atlantic blue crabs (Callinectes sapidus) in Gulf of Mersin, north-eastern mediterranean. International Journal of Food Science and Technology, 46, 2030-2034.
  • Ayas, D., Kalay, M., & Sangün, M.K., (2009). Mersin Körfezi'nden Örneklenen Yüzey Suyu ve Patella Türlerindeki (Patella caerulea, Patella rustica) Cr, Cd ve Pb Düzeylerinin Belirlenmesi. Ekoloji, 18(70), 32-37.
  • Barrento, S., Marques, A., Teixeira, B., Vaz-Pires, P., Carvalho, M.L., & Nunes, M.L., (2008). Essential elements and contaminants in edible tissues of European and American lobsters. Food Chemistry, 111, 862-867.
  • Canli, M., & Atli, G., (2003). The relationships between heavy metal (Cd, Cr, Cu, Fe, Pb, Zn) levels and size of six Mediterranean fish species. Environmental Pollution, 121, 129-136.
  • Coğun, H.Y., Yüzereroğlu, T.A., Firat, O., Gök, G., & Kargin, F., (2006). Metal Concentrations in Fish Species from the Northeast Mediterranean. Environmental Monitoring and Assessment, 121, 431-438.
  • D’Adamo, R., Di Stasio, M., Fabbrocini, A., Petitto, F., Roselli, L. & Volpe, M.G., (2008). Migratory crustaceans as biomonitors of metal pollution in their nursery areas. The Lesina lagoon (SE Italy) as a case study. Environmental Monitoring and Assessment, 143(1-3), 15-24.
  • Dökmeci, A.H., Yildiz, T., Ongen, A., & Sivri, N., (2014). Heavy metal concentration in deepwater rose shrimp species (Parapenaeus longirostris, Lucas, 1846) collected from the Marmara Sea Coast in Tekirdağ. Environmental Monitoring and Assessment, 186, 2449-2454.
  • Ersoy, B., & Çelik, M., (2010). The essential and toxic elements in tissues of six commercial demersal fish from Eastern Mediterranean Sea. Food and Chemical Toxicology, 48, 1377-1382.
  • European Commission. (2011). Commission regulation (EU) No 420/2011 of 29 April 2011 amending Regulation (EC) No 1 881/2006 setting maximum levels for certain contaminants in foodstuffs. Official J. Eur. Union L, 11, 1. Available at: http://eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=CELEX:32011R0420&from=EN accessed in August, 2015
  • Fernandes, C., Fontaínhas-Fernandes, A., Peixoto, F., & Salgado, M.A., (2007). Bioaccumulation of heavy metals in Liza saliens from the Esmoriz-Paramos coastal lagoon, Portugal. Ecotoxicology and environmental safety, 66, 426-431.
  • Firat, Ö., Gök, G., Çoğun, H.Y., Yüzereroğlu, T. A., & Kargin, F., (2008). Concentrations of Cr, Cd, Cu, Zn and Fe in crab Charybdis longicollis and shrimp Penaeus semisulcatus from the Iskenderun Bay, Turkey. Environmental Monitoring and Assessment, 147(1-3), 117-123.
  • Food and Drug Administration. (2013). National Shellfish Sanitation Program–Guide for the control of molluscan shellfish: 2013 Revision. Department of Health and Human Services. U.S Food and Drug Administration, Washington (2013). Available at: http://www.fda.gov/downloads/Food/GuidanceRegulation/FederalStateFoodPrograms/UCM415522.pdf. accessed in August, 2015
  • Forster, U., & Whittmann, G.T.W., (1983). Metal Pollution in the Aquatic Environment. Springer- Verlag, Berlin.
  • Google Maps. Available at: https://www.google.com/maps/d/edit?hl=tr&mid=z3R8whB fz1vU.kCM7LLF9hjUQ, accessed in August, 2015
  • Hanan, A.T., Madlen, M.H., & Hanaa, M.S., (2009). Residues of some heavy metals and hormones in freshwater prawn (Macrobrachium rosenbergii) and marine shrimps (Penaeus semisulcatus) with reference to their nutritive value. World Journal of Zoology, 4(3), 205-215.
  • Joint FAO/WHO Expert Committee on Food Additives. Meeting. (2007). Evaluation of Certain Food Additives and Contaminants: Sixty-eighth Report of the Joint FAO/WHO Expert Committee on Food Additives [Geneva from 19 to 28 June 2007] (Vol. 947). World Health Organization.
  • Kalay, M., Sangün, M.K., Ayas, D., Göçer, M. (2008). Chemical Composition and Some Trace Element Levels of Thinlip Mullet, Liza ramada Caught from Mersin Gulf. Ekoloji, 17, 11-16.
  • Kalay, M., Koyuncu, C.E., & Donmez, A.E., (2004). Comparison of Cadmium Levels in the Muscle and Liver Tissues of Mullus barbatus (L. 1758) and Sparus aurata (L. 1758) Caught from the Mersin Gulf. Ekoloji, 13, 23-27.
  • Kargın, F., Dönmez, A., & Çoğun, H.Y., (2001). Distribution of heavy metals in different tissues of the shrimp Penaeus semisulcatus and Metapenaeus monocerus from the Iskenderun gulf, Turkey: Seasonal variations. Bulletin of Environmental Contamination and Toxicology, 66, 102-109.
  • Kucuksezgin, F., Kacar, A., Kucuksezgin, G., & Uluturhan, E., (2010). Monitoring metal contamination levels and fecal pollution in clam (Tapes decussatus) collected from Izmir Bay (Turkey). Environmental monitoring and assessment, 162, 407-415.
  • Meria, E., (Ed). (1991). Metals and Their Compounds in the Environment. Occurrence, Analysis and Biological Relevance. Verlag Chemie, New York.
  • Nordberg, G.F., Fowler, B.A., Nordberg, M., & Friberg, L. (Eds.)., (2011). Handbook on the Toxicology of Metals. Nordberg, G.F., Nogawa, K., Nordberg, M., & Friberg, L. Cadmium (Chapter 23).
  • Official Journal of the European Communities, Commision Regulation, (2001). No: 466, Maximum levels for certain contaminants in foodstuffs, pp:7-11.
  • Özden, Ö., (2010). Seasonal differences in the trace metal and macrominerals in shrimp (Parapenaus longirostris) from Marmara Sea. Environmental Monitoring and Assessment, 162(1-4), 191-199.
  • Rahimi, E., Zaker, S., Farfani, M.D., Araghi, M. R., Vafaei, M., & Goudarzi, M.A., (2013). Cadmium concentrations in shrimp (Penaeus semisulcatus and Penaeus monodon) caught from the coastal areas in southern Iran. Toxicology and Industrial Health, 29(3), 272-275.
  • Turan, C., Dural, M., Oksuz, A. & Oztürk, B., (2009). Levels of heavy metals in some commercial fish species captured from the Black Sea and Mediterranean coast of Turkey. Bulletin of Environmental Contamination and Toxicology, 82, 601-604.
  • Turkish Food Codex, (2011). Türk Gıda Kodeksi Bulaşanlar Yönetmeliği, Ek1: Gıdalardaki Bulaşanların Maksimum Limitleri (in Turkish). Gıda, Tarım ve Hayvancılık Bakanlığı, Ankara. Available at: http://www.resmigazete.gov.tr/eskiler/2011/12/20111229 M3-8-1.pdf accessed in August, 2015
  • Türkmen, A., Türkmen, M., Tepe, Y., & Akyurt, İ., (2005). Heavy metals in three commercially valuable fish species from Iskenderun Bay, Northern East Mediterranean Sea, Turkey. Food Chemistry, 91, 167-172.
  • Yılmaz, A.B., Sangün, M.K., Yağlıoğlu, D., & Turan, C., (2010). Metals (major, essential to non-essential) composition of the different tissues of three demersal fish species from Iskenderun Bay, Turkey. Food Chemistry, 123: 410-415.
  • Yılmaz, A.B., & Yılmaz, L., (2007). Influences of sex and seasons on levels of heavy metals in tissues of green tiger shrimp (Penaeus semisulcatus de Hann, 1844). Food Chemistry, 101(4), 1664-1669.
Yıl 2016, , 42 - 49, 01.04.2016
https://doi.org/10.3153/JAEFR16006

Öz

Kaynakça

  • Alexander, J., Benford, D., Boobis, D., Ceccatelli, S., Cravedi, J.P., Di Domenico, A., & van Leeuwen, R. (2010). Scientific opinion on lead in food. The European Food Safety Authority Journal, 8, 1-147.
  • Ayas, D., & Özoğul, Y., (2011). The Chemical Composition of Carapace Meat of Sexually Mature Blue Crab (Callinectes sapidus, Rathbun 1896) in the Gulf of Mersin. Journal of FisheriesSciences.com, 5(3), 262-269.
  • Ayas, D., & Özoğul, Y., (2011). The Chemical Composition of Sexually Mature Blue Swimmer Crab (Portunus pelagicus, Linnaeus 1758) in the Gulf of Mersin. Journal of FisheriesSciences.com, 5(4), 308-316.
  • Ayas, D., & Ozoğul, Y., (2011). The effects of sex and seasonality on the metal levels of different muscle tissues of mature Atlantic blue crabs (Callinectes sapidus) in Gulf of Mersin, north-eastern mediterranean. International Journal of Food Science and Technology, 46, 2030-2034.
  • Ayas, D., Kalay, M., & Sangün, M.K., (2009). Mersin Körfezi'nden Örneklenen Yüzey Suyu ve Patella Türlerindeki (Patella caerulea, Patella rustica) Cr, Cd ve Pb Düzeylerinin Belirlenmesi. Ekoloji, 18(70), 32-37.
  • Barrento, S., Marques, A., Teixeira, B., Vaz-Pires, P., Carvalho, M.L., & Nunes, M.L., (2008). Essential elements and contaminants in edible tissues of European and American lobsters. Food Chemistry, 111, 862-867.
  • Canli, M., & Atli, G., (2003). The relationships between heavy metal (Cd, Cr, Cu, Fe, Pb, Zn) levels and size of six Mediterranean fish species. Environmental Pollution, 121, 129-136.
  • Coğun, H.Y., Yüzereroğlu, T.A., Firat, O., Gök, G., & Kargin, F., (2006). Metal Concentrations in Fish Species from the Northeast Mediterranean. Environmental Monitoring and Assessment, 121, 431-438.
  • D’Adamo, R., Di Stasio, M., Fabbrocini, A., Petitto, F., Roselli, L. & Volpe, M.G., (2008). Migratory crustaceans as biomonitors of metal pollution in their nursery areas. The Lesina lagoon (SE Italy) as a case study. Environmental Monitoring and Assessment, 143(1-3), 15-24.
  • Dökmeci, A.H., Yildiz, T., Ongen, A., & Sivri, N., (2014). Heavy metal concentration in deepwater rose shrimp species (Parapenaeus longirostris, Lucas, 1846) collected from the Marmara Sea Coast in Tekirdağ. Environmental Monitoring and Assessment, 186, 2449-2454.
  • Ersoy, B., & Çelik, M., (2010). The essential and toxic elements in tissues of six commercial demersal fish from Eastern Mediterranean Sea. Food and Chemical Toxicology, 48, 1377-1382.
  • European Commission. (2011). Commission regulation (EU) No 420/2011 of 29 April 2011 amending Regulation (EC) No 1 881/2006 setting maximum levels for certain contaminants in foodstuffs. Official J. Eur. Union L, 11, 1. Available at: http://eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=CELEX:32011R0420&from=EN accessed in August, 2015
  • Fernandes, C., Fontaínhas-Fernandes, A., Peixoto, F., & Salgado, M.A., (2007). Bioaccumulation of heavy metals in Liza saliens from the Esmoriz-Paramos coastal lagoon, Portugal. Ecotoxicology and environmental safety, 66, 426-431.
  • Firat, Ö., Gök, G., Çoğun, H.Y., Yüzereroğlu, T. A., & Kargin, F., (2008). Concentrations of Cr, Cd, Cu, Zn and Fe in crab Charybdis longicollis and shrimp Penaeus semisulcatus from the Iskenderun Bay, Turkey. Environmental Monitoring and Assessment, 147(1-3), 117-123.
  • Food and Drug Administration. (2013). National Shellfish Sanitation Program–Guide for the control of molluscan shellfish: 2013 Revision. Department of Health and Human Services. U.S Food and Drug Administration, Washington (2013). Available at: http://www.fda.gov/downloads/Food/GuidanceRegulation/FederalStateFoodPrograms/UCM415522.pdf. accessed in August, 2015
  • Forster, U., & Whittmann, G.T.W., (1983). Metal Pollution in the Aquatic Environment. Springer- Verlag, Berlin.
  • Google Maps. Available at: https://www.google.com/maps/d/edit?hl=tr&mid=z3R8whB fz1vU.kCM7LLF9hjUQ, accessed in August, 2015
  • Hanan, A.T., Madlen, M.H., & Hanaa, M.S., (2009). Residues of some heavy metals and hormones in freshwater prawn (Macrobrachium rosenbergii) and marine shrimps (Penaeus semisulcatus) with reference to their nutritive value. World Journal of Zoology, 4(3), 205-215.
  • Joint FAO/WHO Expert Committee on Food Additives. Meeting. (2007). Evaluation of Certain Food Additives and Contaminants: Sixty-eighth Report of the Joint FAO/WHO Expert Committee on Food Additives [Geneva from 19 to 28 June 2007] (Vol. 947). World Health Organization.
  • Kalay, M., Sangün, M.K., Ayas, D., Göçer, M. (2008). Chemical Composition and Some Trace Element Levels of Thinlip Mullet, Liza ramada Caught from Mersin Gulf. Ekoloji, 17, 11-16.
  • Kalay, M., Koyuncu, C.E., & Donmez, A.E., (2004). Comparison of Cadmium Levels in the Muscle and Liver Tissues of Mullus barbatus (L. 1758) and Sparus aurata (L. 1758) Caught from the Mersin Gulf. Ekoloji, 13, 23-27.
  • Kargın, F., Dönmez, A., & Çoğun, H.Y., (2001). Distribution of heavy metals in different tissues of the shrimp Penaeus semisulcatus and Metapenaeus monocerus from the Iskenderun gulf, Turkey: Seasonal variations. Bulletin of Environmental Contamination and Toxicology, 66, 102-109.
  • Kucuksezgin, F., Kacar, A., Kucuksezgin, G., & Uluturhan, E., (2010). Monitoring metal contamination levels and fecal pollution in clam (Tapes decussatus) collected from Izmir Bay (Turkey). Environmental monitoring and assessment, 162, 407-415.
  • Meria, E., (Ed). (1991). Metals and Their Compounds in the Environment. Occurrence, Analysis and Biological Relevance. Verlag Chemie, New York.
  • Nordberg, G.F., Fowler, B.A., Nordberg, M., & Friberg, L. (Eds.)., (2011). Handbook on the Toxicology of Metals. Nordberg, G.F., Nogawa, K., Nordberg, M., & Friberg, L. Cadmium (Chapter 23).
  • Official Journal of the European Communities, Commision Regulation, (2001). No: 466, Maximum levels for certain contaminants in foodstuffs, pp:7-11.
  • Özden, Ö., (2010). Seasonal differences in the trace metal and macrominerals in shrimp (Parapenaus longirostris) from Marmara Sea. Environmental Monitoring and Assessment, 162(1-4), 191-199.
  • Rahimi, E., Zaker, S., Farfani, M.D., Araghi, M. R., Vafaei, M., & Goudarzi, M.A., (2013). Cadmium concentrations in shrimp (Penaeus semisulcatus and Penaeus monodon) caught from the coastal areas in southern Iran. Toxicology and Industrial Health, 29(3), 272-275.
  • Turan, C., Dural, M., Oksuz, A. & Oztürk, B., (2009). Levels of heavy metals in some commercial fish species captured from the Black Sea and Mediterranean coast of Turkey. Bulletin of Environmental Contamination and Toxicology, 82, 601-604.
  • Turkish Food Codex, (2011). Türk Gıda Kodeksi Bulaşanlar Yönetmeliği, Ek1: Gıdalardaki Bulaşanların Maksimum Limitleri (in Turkish). Gıda, Tarım ve Hayvancılık Bakanlığı, Ankara. Available at: http://www.resmigazete.gov.tr/eskiler/2011/12/20111229 M3-8-1.pdf accessed in August, 2015
  • Türkmen, A., Türkmen, M., Tepe, Y., & Akyurt, İ., (2005). Heavy metals in three commercially valuable fish species from Iskenderun Bay, Northern East Mediterranean Sea, Turkey. Food Chemistry, 91, 167-172.
  • Yılmaz, A.B., Sangün, M.K., Yağlıoğlu, D., & Turan, C., (2010). Metals (major, essential to non-essential) composition of the different tissues of three demersal fish species from Iskenderun Bay, Turkey. Food Chemistry, 123: 410-415.
  • Yılmaz, A.B., & Yılmaz, L., (2007). Influences of sex and seasons on levels of heavy metals in tissues of green tiger shrimp (Penaeus semisulcatus de Hann, 1844). Food Chemistry, 101(4), 1664-1669.
Toplam 33 adet kaynakça vardır.

Ayrıntılar

Konular Hidrobiyoloji
Bölüm Makaleler
Yazarlar

Deniz Ayas

Ali Rıza Köşker Bu kişi benim

Mustafa Durmuş Bu kişi benim

Mısra Bakan Bu kişi benim

Yayımlanma Tarihi 1 Nisan 2016
Yayımlandığı Sayı Yıl 2016

Kaynak Göster

APA Ayas, D., Köşker, A. R., Durmuş, M., Bakan, M. (2016). DETERMINATION OF SEASONAL CHANGES ON SOME HEAVY METAL (Cd, Pb, Cr) LEVELS OF SHRIMP AND PRAWN SPECIES FROM NORTH-EASTERN MEDITERRANEAN SEA, GULF OF MERSIN, TURKEY. Journal of Aquaculture Engineering and Fisheries Research, 2(2), 42-49. https://doi.org/10.3153/JAEFR16006
AMA Ayas D, Köşker AR, Durmuş M, Bakan M. DETERMINATION OF SEASONAL CHANGES ON SOME HEAVY METAL (Cd, Pb, Cr) LEVELS OF SHRIMP AND PRAWN SPECIES FROM NORTH-EASTERN MEDITERRANEAN SEA, GULF OF MERSIN, TURKEY. J Aquacult Eng Fish Res. Nisan 2016;2(2):42-49. doi:10.3153/JAEFR16006
Chicago Ayas, Deniz, Ali Rıza Köşker, Mustafa Durmuş, ve Mısra Bakan. “DETERMINATION OF SEASONAL CHANGES ON SOME HEAVY METAL (Cd, Pb, Cr) LEVELS OF SHRIMP AND PRAWN SPECIES FROM NORTH-EASTERN MEDITERRANEAN SEA, GULF OF MERSIN, TURKEY”. Journal of Aquaculture Engineering and Fisheries Research 2, sy. 2 (Nisan 2016): 42-49. https://doi.org/10.3153/JAEFR16006.
EndNote Ayas D, Köşker AR, Durmuş M, Bakan M (01 Nisan 2016) DETERMINATION OF SEASONAL CHANGES ON SOME HEAVY METAL (Cd, Pb, Cr) LEVELS OF SHRIMP AND PRAWN SPECIES FROM NORTH-EASTERN MEDITERRANEAN SEA, GULF OF MERSIN, TURKEY. Journal of Aquaculture Engineering and Fisheries Research 2 2 42–49.
IEEE D. Ayas, A. R. Köşker, M. Durmuş, ve M. Bakan, “DETERMINATION OF SEASONAL CHANGES ON SOME HEAVY METAL (Cd, Pb, Cr) LEVELS OF SHRIMP AND PRAWN SPECIES FROM NORTH-EASTERN MEDITERRANEAN SEA, GULF OF MERSIN, TURKEY”, J Aquacult Eng Fish Res, c. 2, sy. 2, ss. 42–49, 2016, doi: 10.3153/JAEFR16006.
ISNAD Ayas, Deniz vd. “DETERMINATION OF SEASONAL CHANGES ON SOME HEAVY METAL (Cd, Pb, Cr) LEVELS OF SHRIMP AND PRAWN SPECIES FROM NORTH-EASTERN MEDITERRANEAN SEA, GULF OF MERSIN, TURKEY”. Journal of Aquaculture Engineering and Fisheries Research 2/2 (Nisan 2016), 42-49. https://doi.org/10.3153/JAEFR16006.
JAMA Ayas D, Köşker AR, Durmuş M, Bakan M. DETERMINATION OF SEASONAL CHANGES ON SOME HEAVY METAL (Cd, Pb, Cr) LEVELS OF SHRIMP AND PRAWN SPECIES FROM NORTH-EASTERN MEDITERRANEAN SEA, GULF OF MERSIN, TURKEY. J Aquacult Eng Fish Res. 2016;2:42–49.
MLA Ayas, Deniz vd. “DETERMINATION OF SEASONAL CHANGES ON SOME HEAVY METAL (Cd, Pb, Cr) LEVELS OF SHRIMP AND PRAWN SPECIES FROM NORTH-EASTERN MEDITERRANEAN SEA, GULF OF MERSIN, TURKEY”. Journal of Aquaculture Engineering and Fisheries Research, c. 2, sy. 2, 2016, ss. 42-49, doi:10.3153/JAEFR16006.
Vancouver Ayas D, Köşker AR, Durmuş M, Bakan M. DETERMINATION OF SEASONAL CHANGES ON SOME HEAVY METAL (Cd, Pb, Cr) LEVELS OF SHRIMP AND PRAWN SPECIES FROM NORTH-EASTERN MEDITERRANEAN SEA, GULF OF MERSIN, TURKEY. J Aquacult Eng Fish Res. 2016;2(2):42-9.