Establishment of Diatom Profile for Improving Reliability of Diagnosis of Drowning - Centered on the Main Drowning Sites of Han River / 대한법의학회지

Diatomology has provided important evidences for diagnosis of drowning in forensic practice. However, conflicting opinions about the reliability of diatom test still exist. As a part of efforts to end this controversy, it is very important to secure the diatom profile in the water sample of drowning site. Our results obtained in this study show the characteristics of temporal and spatial distribution of diatom collected from the main drowning sites of Han river in Korea. During spring, 111 taxa (98 species and 13 varieties) were identified from 31 genera, and 87 taxa (77 species and 10 varieties) were identified from 22 genera during summer. At the level of genus Achnanthes, Cyclotella, Cymbella, Fragilaria, Navicula, Nitzschia, and Stephanodiscus represented the highest numbers, and were the most widely occurred during two seasons. The centric diatoms, Stephanodiscus hantzschii f. tenuis and Cyclotella atomus were typical of spring and summer, respectively, and identified as dominant indicator species. The commonly occurred species, including dominant species in the seasonal cluster analysis influenced the formation of site - specific groups. As a result, our results will be able to be used not only as the comparison data of diatom found in the drowning victim's tissue but also a reference data to rule out the possibility of contamination.

Seasonal variation of water qualities in the upper and middle reaches of the Han River(1998.8~1989.9) / 예방의학회지

This study was conducted to investigate of water qualities in the upper and middle reaches of the Han River. For this purpose, water was sampled at Kwangjin and 1st Han-River Bridges of the Han River in Seoul and analysed from August, 1988 to September, 1989. The results are summarized as follows: 1. Water quality at 1st Han-River Bridge was more polluted than that at Kwangjin Bridge. 2. Except biological oxygen demand (BOD), turbidity, suspended solid (SS), dissolved oxygen (DO), DO saturation (DOS), ammonia nitrogen (NH3-N), nitrite nitrogen (NO2-N) and chloride ion (Cl-) at Kwangjin and 1st Han-River Bridges were lower as compared with the previous data before redevelopment of the Han River. 3. SS, DO and pH at Kwangjin and 1st Han-River Bridges could be classified to the 1st grade in environmental water quality standard. DOS at Kwangjin Bridge was over 100% and that at 1st Han-River Bridge was below 100% in the Han River. BOD at Kwangjin Bridge could be classified to 2nd grade and that at 1st Han-River Bridge to 3rd grade in environmental water quality standard. 4. The higher the level of water was, the lower the levels of turbidity and SS, and NH3-N was decreased with increasing water level at 1st Han-River Bridge. DO was decreased as water temperature went up but DOS was increased with DO. BOD was positively correlated with nitrite-nitrogens. 5. Turbidity and SS at the both sites and Chloride ion (Cl-) at Kwangjin Bridge were increased in July and August. And DO at the both sites and NH3-N at 1st Han-River Bridge were decreased in at July and August.

Interactive Water Quality Simulation of the Han River Using Computer Graphics

The water quality simulatin of the Han River was performed by computer-aided design methods using interactive computer graphic routine. The model used to simulate water quality in the Han River was based upon the U.S. Environmental Protection Agency's QUAL-II program. The constituents which were simulated include temperature, conservative substances, coliform bacteria, BOD and DO. Discretization of the model over space was done using the Galerkin finite element method. Data input requirements for the model included rate constants, meteorological data, and headwater, point and non-point source concentrations. The point and non-point source waste loadings were assumed to be constant over time. Several options for dealing with simulation results were available. These included listings or graphs showing the concentration values by constituent, either for all sites at one point in time, or for one site at all times. By merging spatial and temporal data, a three-dimensional surface of concentration as a function of site location and time of day could be plotted for any constituent. A pictoral display of water quality throuthout the Han River, using various colors to indicate different concentrations of constituents or degrees of temperature, also is possible. Water quality profiles of the Han River were developed using 1981 waste loadings. These results were compared to observed data in order to determine the best values for model parameters. Calibration of the model was aided by the interactive use of statistical tests, including linear regression analysis and t-tests of two means. Using estimates of population and industrial growth for the Han River Basin, simulations for expected 1986 and 1991 conditions were undertaken. Results indicate that without increased investments in wastewater treatment facilities and associated collection systems, most of the river will contain BOD concentratins which greatly exceed the maximum 6 ppm allowed. In addition, the numbber of coliform bacteria will be substantially more than the maximum permitted number, 10,000 MPN/100 ml, for water supply sources requiring highest levels of treatment. These results also suggest where monitoring statins should be established, and where proper management practices will have the greatest impact on controlling the extent of river pollution resulting from the discharge of waste effuent from urban communities, industries, and agricultural land along the Han River.