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Rho T.K.,Ocean Observation and Information Section | Coverly S.,BLTEC Korea Ltd | Kim E.-S.,Ocean Observation and Information Section | Kang D.-J.,Marine Chemistry and Geochemistry Research Center | And 7 more authors.
Ocean Science Journal

In this study we describe measures taken in our laboratory to improve the long-term precision of nitrate and ammonia analysis in seawater using a microflow segmented-flow analyzer. To improve the nitrate reduction efficiency using a flow-through open tube cadmium reactor (OTCR), we compared alternative buffer formulations and regeneration procedures for an OTCR. We improved long-term stability for nitrate with a modified flow scheme and color reagent formulation and for ammonia by isolating samples from the ambient air and purifying the air used for bubble segmentation. We demonstrate the importance of taking into consideration the residual nutrient content of the artificial seawater used for the preparation of calibration standards. We describe how an operating procedure to eliminate errors from that source as well as from the refractive index of the matrix itself can be modified to include the minimization of dynamic refractive index effects resulting from differences between the matrix of the samples, the calibrants, and the wash solution. We compare the data for long-term measurements of certified reference material under two different conditions, using ultrapure water (UPW) and artificial seawater (ASW) for the sampler wash. © 2015, Korea Ocean Research & Development Institute (KORDI) and the Korean Society of Oceanography (KSO) and Springer Science+Business Media Dordrecht. Source

Song K.-H.,Marine Chemistry and Geochemistry Research Center | Choi K.-Y.,East Sea Research Institute | Kim C.-J.,Marine Chemistry and Geochemistry Research Center | Kim Y.-I.,East Sea Research Institute | Chung C.-S.,Marine Chemistry and Geochemistry Research Center
Ocean Science Journal

As with many countries, the Korea government has made a variety of efforts to meet the precautionary principle under the London Convention and Protocol acceded in 1994 and 2009. However, new strategies for the suitable marine dumping of waste materials have since been developed. In this study, the distribution and contamination of heavy metals including Al, Fe, Mn, Li, Co, Cr, Ni, Cu, Zn, As, Cd, Pb and Hg in bottom sediments were analyzed and compared to various criteria in order to evaluate the effectiveness of the management of the East Sea-Jung (ES-Jung) dumping site by the Korea government. The results indicate that the average metal concentrations were significantly lower than Effects Range Low (ERL) values, and generally similar to or lower than the Threshold Effect Levels (TEL) from the Sediment Quality Guidelinces (SQGs). According to analyses of various metal contamination indexes (Enrichment Factor: EF, Pollution Load Index: PLI and the Index of Geoaccumulation: Igeo), most areas were found to be uncontaminated by heavy metals with the exception of several moderately contaminated stations (ESJ 33, 54, 64 and ESJR 20). Heavy metal concentrations in areas grouped as G1, G2, DMDA, N-Ref and S-Ref which showed similar characteristics between 2007-2013 and 2014, were compared. Unexpectedly, most concentrations in the northern reference area (N-Ref) were much higher than those in the actual dumping areas (G1 and G2), may be due to the influences from nearby cities to the west of the ES-Jung site, rather than from the dumping site itself. Additionally, heavy metal concentrations in the dredged material dumping area (DMDA) were found to be low although they have slightly increased over time and those in the southern reference area (S-Ref) were found to have gradually decreased with year. The concentrations of most metals in the East Sea-Jung dumping site were similar to or less than those in the Earth’s crust and approximately the same as those in continental sediments. As a result, this site can be considered as uncontaminated or slightly contaminated. This implies that the efforts made by the Korea government to manage and govern the dumping site through various policies, including ‘the focal point system’, ‘the responsibility zones system’ and ‘the principle of pollution causing party liability’, have been successful. © 2015, Korea Ocean Research & Development Institute (KORDI) and the Korean Society of Oceanography (KSO) and Springer Science+Business Media Dordrecht. Source

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