Nationwide survey on the natural radionuclides in industrial raw minerals in South Korea

A Nationwide survey on the natural radioactivity in industrial raw mineral commodities (17 kinds of domestic and 18 kinds of imported) that are representative minerals used in production and consumption in South Korea was conducted. The target industrial minerals can be categorized into two groups. The first group covers non-metallic and metallic raw minerals with low levels of radioactivity such as clay, silica sand, carbonates, bituminous and anthracite coal, iron ores, ilmenite, rutile, and phosphate ore. The other group comprises minerals with high levels of radioactivity including zircon and monazite. One hundred and sixty-four domestic and imported samples were analysed by gamma-ray spectroscopy using an HPGe detector. The (40)K content ranges from <0.00131 to 2.69Bq g(-1), and (226)Ra and (232)Th range over <0.0006 to 0.630 and <0.0008 to 0.474Bq g(-1), respectively. There was no anthropogenic radioactive signal in any of the samples.     

Thermal dependency of burrowing in three species within the bivalve genus <Emphasis Type="Italic">Laternula</Emphasis>: a latitudinal comparison

The upper thermal limits for burrowing and survival were compared with micro-habitat temperature for anomalodesmatan clams: Laternula elliptica (Antarctica, 67°S); Laternula recta, (temperate Australia, 38°S) and Laternula truncata (tropical Singapore, 1°N). Lethal limits (LT₅₀) were higher than burrowing limits (BT₅₀) in L. elliptica (7.5–9.0 and 2.2°C) and L. recta (winter, 32.8–36.8 and 31.1–32.8°C) but the same range for L. truncata (33.0–35.0 and 33.4–34.9°C). L. elliptica and L. truncata had a BT₅₀ 0.4 and 2.4–3.9°C, respectively, above their maximum experienced temperature. L. recta, which experience solar heating during midday low tides, had a BT₅₀ 0.7–2.4°C below and a range for LT₅₀ that spanned their predicted environmental maximum (33.5°C). L. recta showed no seasonal difference in LT₅₀ or BT₅₀. Our single genus comparisons contrast with macrophysiological studies showing that temperate species cope better with elevated temperatures. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Pheromone-based female mate choice and its effect on reproductive investment in a spitting spider

Numerous studies have focused on whether organisms can signal or perceive pheromones and use chemical signals in species and mate recognition. Recently, there have been an increasing number of studies investigating whether pheromones are used in mate choice. Yet, little attention has been paid in exploring the effects of pheromone-based mate choice on reproductive investment. We first tested this hypothesis by providing virgin Scytodes sp. females with a choice between two virgin males in the presence of chemical signals alone and found strong evidence of an odor-based mate preference. We then examined the consequences of the odor-based mate choice by allowing female Scytodes sp. that had previously made an odor-only mate choice to mate with preferred and non-preferred males, respectively. We measured the success of copulation, mortality of male, pre-oviposition interval, egg-sac weight, egg weight, fecundity, fertility, embryonic period, and size of offspring at hatching. Females that mated with the preferred males produced significantly heavier egg sacs that contained more and larger eggs with a greater fertility. Significantly more non-preferred males than preferred males were killed by spitting. However, pre-oviposition interval, embryonic period, and hatchling size were not affected by female mate choice. This study is the first to demonstrate that female spiders are able to regulate their highly valuable reproductive investment based solely on chemical signals.     

Land use in Korean tidal wetlands: impacts and management strategies

The coastal landscapes in southwestern Korea include a diverse array of tidal wetlands and salt marshes. These coastal zones link the ecological functions of marine tidal wetlands and freshwater ecosystems with terrestrial ecosystems. They are rich in biological diversity and play important roles in sustaining ecological health and processing environmental pollutants. Korean tidal wetlands are particularly important as nurseries for economically important fishes and habitats for migratory birds. Diking, draining, tourism, and conversion to agricultural and urban uses have adversely affected Korean tidal wetlands. Recent large development projects have contributed to further losses. Environmental impact assessments conducted for projects affecting tidal wetlands and their surrounding landscapes should be customized for application to these special settings. Adequate environmental impact assessments will include classification of hydrogeomorphic units and consideration of their responses to biological and environmental stressors. As is true worldwide, Korean laws and regulations are changing to be more favorable to the conservation and protection of tidal wetlands. More public education needs to be done at the local level to build support for tidal wetland conservation. Some key public education points include the role of tidal wetlands in maintaining healthy fish populations and reducing impacts of nonpoint source pollution. There is also a need to develop procedures for integrating economic and environmental objectives within the overall context of sustainable management and land uses.     

Polarity effect of pulsed corona discharge for the oxidation of gaseous elemental mercury

The effect of polarity on the oxidation of Hg⁰ was examined in the presence of O₂ via a pulsed corona discharge (PCD). The experimental result showed no difference in the energy yield of Hg⁰ oxidation at both positive and negative PCDs (∼8 μg Hg W h⁻¹ at following conditions: total flow rate = 2 L min⁻¹ (Hg⁰ = 50 μg N m⁻³, O₂ = 10%, and N₂ balance), temperature = 150 °C, and specific energy density = 5-15 W h N m⁻³). This suggests that the positive PCD process used to control gaseous air pollutants may play an essential key role in Hg⁰ oxidation because it consumes enough energy (∼15 W h N m⁻³) but an electrical precipitator could not because it consumes less energy (∼0.3 W h N m⁻³) to oxidize Hg⁰.     

Research priorities for managing the impacts and dependencies of business upon food,energy, water and the environment

Delivering access to sufficient food, energy and water resources to ensure human wellbeing is a major concern for governments worldwide. However, it is crucial to account for the ‘nexus’ of interactions between these natural resources and the consequent implications for human wellbeing. The private sector has a critical role in driving positive change towards more sustainable nexus management and could reap considerable benefits from collaboration with researchers to devise solutions to some of the foremost sustainability challenges of today. Yet opportunities are missed because the private sector is rarely involved in the formulation of deliverable research priorities. We convened senior research scientists and influential business leaders to collaboratively identify the top forty questions that, if answered, would best help companies understand and manage their food-energy-water-environment nexus dependencies and impacts. Codification of the top order nexus themes highlighted research priorities around development of pragmatic yet credible tools that allow businesses to incorporate nexus interactions into their decision-making; demonstration of the business case for more sustainable nexus management; identification of the most effective levers for behaviour change; and understanding incentives or circumstances that allow individuals and businesses to take a leadership stance. Greater investment in the complex but productive relations between the private sector and research community will create deeper and more meaningful collaboration and cooperation.     

Fifteen years of monitoring of POPs in the breast milk, Czech Republic, 1994–2009: trends and factors

Background, aim and scope

The breast milk has been recommended to carry out as a monitoring tool for effectiveness evaluation of the Stockholm Convention on Persistent Organic Pollutants (POPs). Polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloro-ethane (DDT) and its metabolites (DDX), hexachlorbenzene (HCB) and isomers of hexachlocyklohexane (HCHs) have been monitored in the breast milk of nursing mothers in the Czech Republic since 1994 as a part of The Environmental Health Monitoring System. Knowledge about long-term POPs distribution and accumulation in the human body is crucial to understanding uptake, degradation and subsequent effects as well as to conduct risk assessments. The main aim of this study is to evaluate 15-years long-term trends of selected POPs in human milk in the Czech Republic and to elucidate the questionnaire information about the age, parity and social habits, to the final concentrations. This effectiveness evaluation of POPs restriction is quite precisely after 15-years monitoring campaigns.

Materials, methods and results

The human milk samples (4,753 samples) were analysed for a number of chlorinated organic chemicals including PCBs and selected chlorinated pesticides (OCPs, HCB, HCHs, DDX). The relative change of concentration per year for all chemicals was analysed. The remaining percentages of POPs in breast milk in comparison to 1994 are also expressed. Czech population half-lives of POPs in breast milk, derived from either linear or exponential models were computed.

Conclusions and perspectives

The long-term data indicates a continuation of a decreasing trend of POPs concentrations on breast milk. Our study did not confirm lactation and parity as an important outflux resulting in the decrease in concentrations in mothers, which is in the antagonism with most of the studies. The higher BMI was associated with higher amounts of HCB and lower amounts of higher chlorinated PCBs. The results confirm the effectiveness of restrictions of POPs usage in the Czech Republic. This ongoing long-term study is very useful tool for parametric effectiveness evaluation of Stockholm Convention.     

Oxidation of elemental mercury using atmospheric pressure non-thermal plasma

The oxidation of gas phase elemental mercury (Hg0) by atmospheric pressure non-thermal plasma has been investigated at room temperature, employing both dielectric barrier discharge (DBD) of the gas mixture of Hg0 and injection of ozone (O3) into the gas mixture of Hg0. Results have shown that the oxidative efficiencies of Hg0 by DBD and the injection of O3 are 59% and 93%, respectively, with energy consumption of 23.7 J L(-1). This combined approach has indicated that O3 plays a decisive role in the oxidation of gas phase Hg0. Also the oxidation of Hg0 by injecting O3 into the gas mixture of Hg0 proceeds with better efficiency than DBD of the gas mixture of Hg0. These results have been explained by the incorporation of the competitive reaction pathways between the formation of HgO by O3 and the decomposition of HgO back to Hg0 in the plasma environment.     

Identification of potential biomarkers for diazinon exposure to Japanese Medaka (Oryzias latipes) using annealing control primers

A new differential display-polymerase chain reaction (PCR) method based on annealing control primers was used to screen and identify potential biomarkers from differentially expressed genes (DEGs) in medaka exposed to sub-lethal concentration of diazinon (100 ppb). Among the differentially expressed genes identified, the majority were in functional categories of protein biosynthesis, transport and metabolism according to the gene ontology classification. The differential expression of ribosomal protein genes was quantified by real time PCR. The genes encoding ribosomal proteins including L3 and S17 were selected as potential biomarkers for diazinon exposure in medaka fish.     

The induction of larval settlement and metamorphosis of two sea urchins,Pseudocentrotus depressus and Anthocidaris crassispina,by free fatty acids extracted from the coralline red alga Corallina pilulifera

Lipophilic inducers of larval settlement and metamorphosis of Pseudocentrotus depressus and Anthocidaris crassispina, two commercially important sea urchin species in Japan, were isolated from the foliose coralline red alga Corallina pilulifera (collected in 1990 near Saga, Japan) and identified. Larval assays of the fractions obtained by silica gel column chromatography of the total lipids showed that non-polar groups of lipids were effective at inducing larval settlement and metamorphosis. The effective fractions were further subjected to gel filtration (Sephadex LH-20) and also to silica gel column chromatography, and the effective components isolated as single spots by thin-layer chromatography. The components at a concentration of ca. 0.4 mg paper^-1 (sample was adsorbed on a paper with 20 cm²) induced high rates of larval settlement of both P. depressus and A. crassispina. Chemical analyses of the components revealed a mixture of free fatty acids (FFAs), dominated by eicosapentaenoic acid (20:5, 41 to 50%), palmitic acid (16:0, 11 to 17%), arachidonic acid (20:4, 9 to 15%), and palmitoleic acid (16:1, 4 to 5%). In assays with the four standard FFAs, only 20:4 and 20:5 induced larval settlement and metamorphosis of the two species, while 16:0 and 16:1 were ineffective. The larvae underwent significant rates of settlement and metamorphosis in response to the two former FFAs at levels as low as 0.18 mg paper^-1. Amongst the free fatty acid components of the alga, 20:5 was isolated as the chemical inducer of larval settlement and metamorphosis of the sea urchins in the laboratory.