J. Bio. Env. Sci.19( 6), 159-164, December 2021
The Cagayan de Oro River and the Iponan River are two major rivers in the City of Cagayan de Oro—a highly urbanized city in the southern part of the Philippines. The waters of these two rivers were monitored at the downstream, midstream, and upstream portions for 8 months to establish the levels of mercury and cadmium. A total of 11 samples have been taken and analyzed for mercury using AAS equipped with a mercury/hydride system and for cadmium using flame AAS. The analysis methods used were validated in terms of detection limit, quantitation limit, signal-to-noise ratio, and percent recovery using USEPA-based procedure. On the average, the mercury for the Cagayan de Oro River came out at a concentration of 0.073 ppb and was highest at the downstream; for the Iponan River, it averaged at 0.067 and was highest at the upstream. The cadmium for the Cagayan de Oro River turned out at 0.048ppm and was uniform throughout; for the Iponan River, it was 0.033ppm and relatively somewhat higher at the upstream. Risk characterization based on the ANZECC guideline trigger values yielded risk quotients that indicated no risk to the two river ecosystems as far as mercury, but an enormous risk is suggested due to cadmium for both river ecosystems.
Abasolo LG, Ontal RJ, Rusiana AA. 2006. Characterization of water quality of selected rivers in Misamis Oriental. Undergraduate thesis. Mindanao University of Science and Technology, Cagayan de Oro City.
Ampit JO, Cuerquis MJT, Quirante KJP. 2013. Mercury, Lead and Nitrate Accumulation Assessment Using Shrimp as Bioindicator in Iponan River. Undergraduate thesis. Mindanao University of Science and Technology, Cagayan de Oro City.
ANZECC. 2000. Australian and New Zealand Guidelines for Fresh and Marine Water Quality. Australian and New Zealand Environment and Conservation Council. Retrieved from https://www. environment.gov.au/system/files/resources/53cda9ea-7ec2-49d4-af29-d1dde09e96ef/files/nwqms-guidelines-4-vol1.pdf
Betancor MCA, Gomez LA, Salon JS. 2013. Analysis of heavy metals in key mining areas in Iponan River, Cagayan de Oro City. Undergraduate thesis. Mindanao University of Science and Technology, Cagayan de Oro City.
Chen Y, Chen M. 2001. Heavy metal concentrations in nine species of fish caught in coastal waters off Ann-Ping, S.W. Taiwan. Journal of Food and Drug Analysis 9(2), 107-114.
DENR-EMB. 1990. DENR Administrative Order No. 34. Retrieved from www.emb.gov.ph/laws/water%20quality%20management/dao90-34.pdf
DNR. 1996. Analytical Detection Limit Guidance and Laboratory Guide for Determining Method Detection Limits. Wisconsin Department of Natural Resources. Retrieved from http://www.dnr.wi.gov. regulastions/labcert/documents/guidance/-labguide
Ebarat EM, Sabornido RC. 2009. Spectrophotometric determination of selected metal contaminants in water and sediment samples in Iponan river, Cagayan de Oro City. Undergraduate thesis. Mindanao University of Science and Technology, Cagayan de Oro City.
Järup L. 2003. Hazards of heavy metal contamination. British Medical Bulletin 68, 167-182.
Martin S, Griswold W. 2009. Human Health Effects of Heavy Metals. Retrieved from http://www.engg.ksu.edu/CHSR/outreach/docs/15/HumanHealthEffectofHeavy Metals.pdf
Olsen K. 2000. Arctic Monitoring and Assessment Program: Heavy Metals. Retrieved from www.amap.no/documents/download/93
Pasia LS, Miranda MCD, Navarro SA. 2006. Determination of nitrates and phosphates in the waters of selected rivers in Cagayan de Oro City and an assessment of their water quality using Allium test. Undergraduate thesis. Mindanao University of Science and Technology, Cagayan de Oro City.
USEPA. 2014. Mercury: Basic Information. U. S. Environmental Protection Agency. Retrieved from http://www.epa.gov/hg/about.htm