Characterization of trace organic contaminants in marine sediment from Yeongil Bay, Korea: 1. Instrumental analyses

Concentrations of polychlorinated biphenyls (PCBs), organochlorine (OC) pesticides (HCB, HCHs, CHLs, and DDTs), polycyclic aromatic hydrocarbons (PAHs), alkylphenols (APs), and bisphenol A (BPA) were measured in 26 marine sediments collected from Yeongil Bay, Korea, in order to characterize their spatial distribution and sources. PCBs (2.85-26.5 ng/g, dry wt.) were detected mainly in the inner bay locations Mean OC pesticide ranged from 1.16 ng/g dry wt. for HCH to 0.05 ng/g dry wt. for HCB). PAH concentrations ranged from <10.0 to 1870 (mean: 309)ng/g dry wt., and were predominated 3- and 4-ring congeners. Concentrations of APs, such as nonylphenol, octylphenol, butylphenol (means 89.1, 4.61, 11.0 ng/g dry wt., respectively), were greater at locations proximal to municipal wastewater discharges. Concentrations of PCBs and PAHs were great near shipyards and industrial complexes. Vertical profiles of PAHs and APs indicated that they have been associated with sediments since the 1950s.     

Management and control of pollution in Inner Johore Strait

Coastal waters in South Johore, Malaysia are polluted to various degrees. The major pollution sources are domestric wastes from human settlements, agro-based wastes from palm oil mills and rubber processing factories, industrial effluents from industrial estates and discharges from animal farms. These pollution problems have adversely affected resources such as fisheries, recreational potential as well as the general aesthetic quality of the coastal environment particularly the Inner Johore Strait. Hence proper management and control measures are urgently needed to protect and further enhance the water quality to ensure environmentally sustainable development. This study examines various management options to control the pollution in the Inner Johore Strait. The options involve partial opening as well as complete removal of the Causeway to improve the tidal flow for more effective dilution and dispersion of pollutants. Computer simulation models are used to assess the impacts of the proposed options.     

Distribution and abundance of ophiuroids on the continental shelf and slope of the East Sea (southwestern Sea of Japan), Korea

The present study was carried out to describe the distribution of ophiuroids on the continental shelf and slope of the East Sea, off the Korean Peninsula. Three cruises were made from 1985 to 1987 in the area between 35 to 38°N and 129 to 130°E. A total of ten species was identified from the samples collected at 136 stations. Among them four species (Amphiodia craterodometa, Amphioplus macraspis, Ophiura leptoctenia and Ophiura sarsi) constituted more than 98% of abundance by number. The continental shelf off Gampo, near 35°40N, could be considered to be the southern limit of cold-water species. The abundance of dominant ophiuroids changed according to depth. Three faunal zones, namely, the inner shelf, the shelf edge and the slope zones, coincided with the topographic divisions of continental shelf and slope. The major inhabitant of the inner shelf was A. craterodometa and that of the continental slope was O. leptoctenia. The shelf edge area revealed a transitional zone where all four species occurred, contributing to the total number of individuals with almost equal proportions. The temperature of bottom waters was considered to be a factor determining zonal distribution. The sediment characteristics were not closely related to ophiuroid distribution.     

Using algal biomass-phosphorus (P) relationships and nutrient limitation theory to evaluate the adequacy of P water quality criteria for regulated monsoon rivers and reservoirs

Different P criteria have been set for lotic and lentic waters where the latter had stricter criteria than the former. The binary P criteria have been developed due to differences in limnological features and this helps avoid unneeded costs with stricter criteria for flowing waters that normally have lower potential of algal blooms. However, if different criteria are warranted, the responses of Chl a to TP and TN:TP ratio should vary distinctively between rivers and reservoirs. Contrary to these predictions, inconsistent and statistically indistinguishable variations have been observed between the two types of waterbody in Chl a yield per unit TP. Additionally, there was no significant difference in the strength of relationship between Chl a and TN:TP ratio between waterbody types, although the mass ratio of TN to TP was significantly higher in reservoirs than in rivers. Hence, the data suggest that there is no scientifically defensible reason that lotic and lentic waters require different TP standards and specifically that lentic waters do not necessarily require stricter P criteria. A more holistic and nuanced approach would aid in developing revised or new TP criteria in which water quality issues can be addressed scientifically as well as pragmatically.     

Environmental risk assessment of genetically engineered herbicide-tolerant Zoysia japonica

Herbicide-tolerant Zoysia grass (Zoysia japonica Steud.) has been generated previously through Agrobacterium tumefaciens-mediated transformation. The genetically modified (GM) Zoysia grass survived Basta spraying and grew to maturity normally while the wild-type (WT) grass stopped growing and died. GM Zoysia grass will permit more efficient weed control for various turf grass plantings such as home lawns, golf courses, and parks. We examined the environmental/biodiversity risks of herbicide-tolerant GM Zoysia before applying to regulatory agencies for approval for commercial release. The GM and WT Zoysia grass' substantial trait equivalence, ability to cross-pollinate, and gene flow in confined and unconfined test fields were selectively analyzed for environmental/biodiversity effects. No difference between GM and WT Zoysia grass in substantial traits was found. To assess the potential for cross-pollination and gene flow, a non-selective herbicide, Basta, was used. Results showed that unintended cross-pollination with and gene flow from GM Zoysia grass were not detected in neighboring weed species examined, but were observed in WT Zoysia grass (on average, 6% at proximity, 1.2% at a distance of 0.5 m and 0.12% at a radius of 3 m, and 0% at distances over 3 m). On the basis of these initial studies, we conclude that the GM Zoysia grass generated in our laboratory and tested in the Nam Jeju County field does not appear to pose a significant risk when cultivated outside of test fields.     

Effects of human demand on conservation planning for biodiversity and ecosystem services

Safeguarding ecosystem services and biodiversity is critical to achieving sustainable development. To date, ecosystem services quantification has focused on the biophysical supply of services with less emphasis on human beneficiaries (i.e., demand). Only when both occur do ecosystems benefit people, but demand may shift ecosystem service priorities toward human-dominated landscapes that support less biodiversity. We quantified how accounting for demand affects the efficiency of conservation in capturing both human benefits and biodiversity by comparing conservation priorities identified with and without accounting for demand. We mapped supply and benefit for 3 ecosystem services (flood mitigation, crop pollination, and nature-based recreation) by adapting existing ecosystem service models to include and exclude factors representing human demand. We then identified conservation priorities for each with the conservation planning program Marxan. Particularly for flood mitigation and crop pollination, supply served as a poor proxy for benefit because demand changed the spatial distribution of ecosystem service provision. Including demand when jointly targeting biodiversity and ecosystem service increased the efficiency of conservation efforts targeting ecosystem services without reducing biodiversity outcomes. Our results highlight the importance of incorporating demand when quantifying ecosystem services for conservation planning.     

Birds defend oil palms from herbivorous insects.

Top-down forces are expected to be important in regulating herbivore populations in most agricultural systems where primary productivity is high and species diversity is low. Under such conditions, trophic cascades are predicted to occur when predator populations are reduced or removed. Studies on how predator removal indirectly affects herbivory rates in agricultural systems are lacking. Through a bird-exclosure experiment, I test the hypothesis that insectivorous birds indirectly defend oil palms (Elaeis guineensis) from herbivorous insects. Results show that bird exclusion significantly increased herbivory damage to oil palms, and that the size of this exclusion effect increased with bird density, although the latter result was not statistically significant. These findings suggest that insectivorous birds deliver a natural pest control service for oil palm agriculture, which is important not only for the direct benefits it delivers for human welfare, but also in strengthening the economic justifications for conserving the remaining natural habitats and biodiversity in agricultural landscapes.     

Distribution of organochlorine pesticides in sediments from Kyeonggi Bay and nearby areas, Korea

The residues of oragnochlorine pesticides (OCPs) in 62 sediments from Kyeonggi Bay and nearby areas in the west coast of Korea were determined. The concentrations of chlordanes (CHLs) and DDTs showed a distinctive gradient of contamination between inner and outer sites of Incheon North Harbor (INH), whereas hexachlorocyclohexanes (HCHs) were uniformly distributed at most sites studied. The distribution of CHLs and DDTs was strongly correlated with total organic carbon contents in sediments while HCH residue levels were independent. Relationship between contaminant's concentration and environmental factors was analyzed by principal component analysis. Distribution patterns of T-CHLs, T-DDTs, and TOC were similar while those of T-HCHs, mud content, and grain size were similar. The notable contamination by CHLs and DDTs was found in INH where these levels were one or two orders of magnitude higher than other sites. The dominant OCPs in sediments were beta-HCH among HCH compounds, trans-chlordane among CHL compounds, and p,p'-DDD among DDT compounds. The higher concentrations and compositional pattern of OCPs in INH sediments indicate that INH is in the vicinity of the source.