• Journal of Environmental Impact Assessment
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• v.26 no.6
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• pp.538-552
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• 2017

In this study, total mercury (THg) of Black-tailed Gull (Larus crassirostris) eggs laid on Baengnyeongdo, West Sea of Korea was analyzed in order to compare the THg concentrations of eggs depending on egg-laying order. The first-laid eggs ($mean{\pm}standard$ error, $234.4{\pm}11.2ng/g\;wet$, n=18, t=8.4, p<0.01) significantly had higher THg concentrations than the second-laid eggs ($182.8{\pm}9.1ng/g\;wet$, n=18). Also, the first-laid eggs had higher values in biometrics (length $63.10{\pm}0.49mm$, t=2.4, p<0.05; width $44.51{\pm}0.19mm$, t=4.3, p<0.01; weight $65.53{\pm}0.87g$, t=4.2, p<0.01) than the second-laid eggs (length $62.37{\pm}0.40mm$, width $43.55{\pm}0.17mm$, and weight $62.48{\pm}0.72g$). These differences might be attributed to the amount of food eaten by females relating to males' courtship feeding pattern (males increase courtship feeding rate before the first eggs are laid, and decrease the rate following the laying of the first eggs). Moreover, the lower food intake of females could diminish the quantities of egg albumen that contains a protein binds to most of methylmercury during the period of egg production. Therefore, it is necessary to consistently apply one of egg selection methods (targeted selection (the first-laid egg or the second-laid egg), random selection, and etc.) in one nest for ensuring comparability of mercury concentrations among monitoring sites and monitoring years.

• Journal of the Korean Society for Marine Environment & Energy
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• v.17 no.3
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• pp.212-223
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• 2014

For the better understanding of long-term and seasonal variations of water quality in Masan Bay, South Sea of Korea, we analyzed the archive data monitored at three stations of the bay during the last 13 years (2000-2012). The average concentrations of the chemical oxygen demand (COD), the dissolved inorganic nitrogen (DIN) and the dissolved inorganic phosphorus (DIP) during the monitoring period are $2.70{\pm}0.09{\mu}/L$, $19.66{\pm}1.84{\mu}m$ and $1.39{\pm}0.13{\mu}m$ in surface water, respectively, and $2.22{\pm}0.07{\mu}/L$, $18.53{\pm}1.36{\mu}m$ and $1.47{\pm}0.12{\mu}m$ in bottom water, respectively. The trophic state of the surface water was the eutrophic level in Masan Bay during the four seasons. The DIN concentrations of both surface and bottom waters increased from August to November and showed the highest average in November. However, The DIN decreased from February to May and showed the lowest average in May. The concentrations of the DIP and the dissolved silicate (DSi) in bottom waters had the highest averages in August because of the high water temperature and oxygen deficient condition. The results of correlation analysis and factor analysis showed that the main factors of surface waters were inflow of nutrients from terrestrial areas and internal production, and the main factors of bottom waters were the variations of the dissolved oxygen (DO), the DIP, and the DSi. The DIN and DIP average concentrations (2007~2012) had decreased in range of 68.1%~76.0% and 66.2~76.6%, respectively from 2007 in which the "Regulation of Total Emission" was established in Masan Bay. Therefore, it could have had positive effects on water quality improvement to take the "Regulation of Total Emission" and other actions such as reducing water pollutions in Masan Bay from 2007.