高硫高铁土壤全硫提取和测定方法的改进

硫酸钡分光光度比浊法是大批量测定土壤环境样品硫含量的常用方法,但影响测定结果的因素较多,如稳定剂的选择、酸度的控制、BaCl：的形态和用量等均可对测定结果产生影响。在多金属硫化物矿区,由于长期的采矿冶炼活动,造成周边土壤中硫、铁含量增加,用比浊法测定硫含量时,铁的含量也对测定结果产生显著影响。针对这些影响因素,本研究在用硝酸．高氯酸湿法对土壤进行消解后,优化了硫酸钡分光光度比浊法测定高硫高铁样品的实验条件和实验步骤,并对多金属硫化物矿区的土壤样品进行了测定,得到了较好的结果。实验证明,称取0．50g土壤样品,消解后过滤,取滤液7mL,加入1mL研（1＋2）甘油．乙醇]=6％的甘油．乙醇为稳定剂,1mL浓磷酸掩蔽Fe3＋与cl-反应所显的黄色,定容到10mL,加入w（BaCl2）=10％的氯化钡溶液10mL,电磁搅拌1min,静置20-40min,在波长440nm处,比浊法测定土壤全硫含量,相对误差〈10％,取得良好的测定结果。此方法简单、快捷、方便,适合大批量环境样品的测定。     

Removal of Cr(VI) from aqueous solutions by the culm of bamboo grass treated with concentrated sulfuric acid

We prepared a carbonaceous sorbent for Cr(VI) from the culm of Sasa kurilensis by dehydration with concentrated H₂SO₄. The removal of Cr(VI) by the sorbent was highly solution pH dependent and mainly governed by physicochemical sorption. The equilibrium data fit well in the Langmuir isotherm model and indicate the endothermic nature of the Cr(VI) sorption. The desorption experiments suggest that the Cr(VI) sorption is generally irreversible, owing to strong interaction of HCrO₄⁻ with the active sites of the sorbent.     

Seasonality,lunar periodicity of settlement and microhabitat association of juvenile humpback red snapper <Emphasis Type="Italic">Lutjanus gibbus</Emphasis> (Lutjanidae) in an Okinawan coral reef

Snappers (Lutjanidae) are one of the important fisheries resources in tropical and subtropical waters. However, there have been few studies clarifying the ecology of newly settled juvenile snappers. The aims of the present study were to clarify the seasonality and lunar periodicity of the larval settlement, and the microhabitat association of newly settled juveniles for Lutjanus gibbus in an Okinawan coral reef. Fifteen coral patches were chosen and underwater visual surveys were conducted during a 2-year period. The larval settlement of the species mainly occurred between May and October during the 2-year survey period. In terms of lunar periodicity of the settlement, the newly settled juveniles were mainly found between the last quarter moon and new moon during the main settlement season. Back calculations of settlement dates based on otolith microstructure showed that most juveniles settled during the last quarter moon and new moon. Stepwise multiple regression analyses revealed that the newly settled juveniles were mainly found on coral patches with a large number of holes on the top of the coral patch and this tendency was mainly consistent during the study period. The volume of holes at the base of coral patches had also a positive effect on the abundance of newly settled juveniles in some cases. The results of the present study suggest that larval settlement has a strong seasonal and lunar periodicity, and newly settled juveniles select coral patches with available refuge spaces.     

广东采石场的特点及复绿方法选用

通过对广东省采石场的调查,阐述了采石场高、陡、缺土、缺水、生境恶劣等特点.提出了采石场复绿点、线、面种植复绿的三大类方法,并对各种方法所对应的坡面地质条件作出了论述.同时提出了复绿的各种配套措施,包括给排水、植物配置、种植土配制等.     

Waste prevention for sustainable resource and waste management

Although the 2Rs (reduce and reuse) are considered high-priority approaches, there has not been enough quantitative research on effective 2R management. The purpose of this paper is to provide information obtained through the International Workshop in Kyoto, Japan, on 11–13 November 2015, which included invited experts and researchers in several countries who were in charge of 3R policies, and an additional review of 245 previous studies. It was found that, regarding policy development, the decoupling between environmental pressures and economy growth was recognized as an essential step towards a sustainable society. 3R and resource management policies, including waste prevention, will play a crucial role. Approaches using material/substance flow analyses have become sophisticated enough to describe the fate of resources and/or hazardous substances based on human activity and the environment, including the final sink. Life-cycle assessment has also been developed to evaluate waste prevention activities. Regarding target products for waste prevention, food loss is one of the waste fractions with the highest priority because its countermeasures have significant upstream and downstream effects. Persistent organic pollutants and hazardous compounds should also be taken into account in the situation where recycling activities are globally widespread for the promotion of a material-cycling society.     

Vertical distributions of (99)Tc and the (99)Tc/(137)Cs activity ratio in the coastal water off Aomori, Japan

Using a sector-field ICP-MS the vertical distributions of the ⁹⁹Tc concentration and ⁹⁹Tc/¹³⁷Cs activity ratio were measured in the coastal waters off Aomori Prefecture, Japan, where a spent-nuclear-fuel reprocessing plant has begun test operation. The ⁹⁹Tc concentrations in surface water ranged from 1.8 to 2.4 mBq/m³, no greater than the estimated background level. Relatively high ⁹⁹Tc/¹³⁷Cs activity ratios (10-12 × 10⁻⁴) would be caused by the inflow of the high-⁹⁹Tc/¹³⁷Cs water mass from the Japan Sea. There is no observable contamination from the reprocessing plant in the investigated area. The ⁹⁹Tc concentration and the ⁹⁹Tc/¹³⁷Cs activity ratio in water column showed gradual decreases with depth. Our results implied that ⁹⁹Tc behaves in a more conservative manner than ¹³⁷Cs in marine environments.     

Eco-balance analysis of land use combinations to minimize environmental impacts and maximize farm income in northern Japan

Relationships among global warming potential (GWP), farmland surplus nitrogen (FSN) and income for major land uses in the Ikushunbetsu watershed were compared using the eco-balance method. An empirical model was created for carbon dioxide, methane and nitrous oxide for both uplands and paddy rice using monitoring data from 22 fields. The greenhouse gas emissions were converted into GWP, whereas yield and FSN were obtained from interviews with farmers and a literature survey. Land use distribution was obtained by ground surveys in 2002, 2005 and 2007. The analysis showed that paddy rice and soybeans were characterized by a high GWP, low FSN and high income, whereas onions and vegetables had a high FSN but low GWP and moderate income. Wheat showed a negative GWP in some years, and abandoned areas always exhibited negative values. The total GWPs for the region were 14,184, 11,085 and 8,337 Mg CO₂ year⁻¹ for 2002, 2005 and 2007, respectively. The contribution of paddy rice to GWP was highest, ranging from 40 to 75%. To find optimal land use combinations that provide higher incomes and lower GWPs and FSNs than at present, all possible land use combinations were analyzed by changing the land use proportion from 0 to 100% at an interval of 10%. The number of land use combinations meeting the requirements in the three investigated years was 205. Abandoned area, which had the smallest environmental load, was included in every land use combination, indicating that land uses with low environmental impacts should be maintained at a certain proportion to mitigate the environmental load accompanying land uses with high production.     

Development, maturation, brood size and generation length of the mesopelagic amphipod Cyphocaris challengeri (Gammaridea: Lysianassidae) off southwest Hokkaido, Japan

 Using the number of segments of pleopod rami as a marker of instar number, the population structure (instar composition) of the mesopelagic gammarid amphipod Cyphocaris challengeri was investigated by monthly samplings from May 1997 to April 1999 at a station off southwest Hokkaido, Japan. Laboratory-rearing experiments were also conducted to establish the relationship between the number of segments of pleopod rami and instar number, and to estimate the growth pattern of this gammarid based on the intermolt period and molt-increment data. Stratified sampling in the field (0 to 200 and 200 to 400 m depth strata) showed this species occurred mainly at 200 to 400 m depth during the day. Instar analysis indicated that C. challengeri has 12 instars in females and 11 instars in males. Based on observations of secondary sexual characters, Instars 1 to 6 were designated juveniles (Instars 1 to 3 occurred in the marsupia of gravid females); in males, 7 to 9 were immature and 10 and 11 were mature, while in females 7 and 8 were immature and 9 to 12 were mature. Off southwest Hokkaido, Instar 4 (just released from a female's marsupium) was found throughout the year, with a peak abundance occurring in April to July of each year. A sequential development of Instar 4 to 9 (youngest adult instar) through the year was observed. Generation length (i.e. the time required to grow from Instar 4 to 10) was estimated from a laboratory-obtained growth curve to be 216 to 584 d at the in situ temperature range (2 to 5 °C), which is consistent with observations on field populations. Specimens older than Instar 9 were rare in the field and could not be used in laboratory-rearing experiments, so longevity could not be estimated. Eggs were oval and measured 0.6 mm (large diameter). Brood size ranged from 20 to 65. Comparing the present results with those of epipelagic hyperiid amphipods, the nearly identical growth rates together with the production of fewer but larger eggs seen in C. challengeri appear to reflect to the typical life mode of deep-living pelagic crustaceans. Received: 14 February 2000 / Accepted: 6 July 2000     

Assessment of organic and inorganic contaminants in sediments of an urban tropical eutrophic reservoir

Although the Ibirité reservoir (an urban tropical eutrophic reservoir) has been the recipient of the discharge of a large volume of raw urban sewage, the key cause of ecosystem degradation has been historically solely attributed to the discharge of effluents from an oil refinery. This fact motivated an investigation to unravel the compositions of contaminants in the sediments to evaluate their distributions, possible sources, and potential impacts on sediment–water quality. The concentrations of polycyclic aromatic and aliphatic hydrocarbons and of metals and metalloids were, in general, significantly lower than some selected polluted sites used for comparison. Calculated distribution indexes showed that the hydrocarbon sources were petrogenic, pyrogenic, and biogenic. Only a few PAHs exceeded the threshold effects level (TEL) guideline. Industrial activities are the presumed sources of metals and metalloids except for copper, which is from copper sulfate used as algaecide in the reservoir. The bioavailable concentrations of some metal and metalloid exceeded the TEL–PEL guidelines. The acid volatile sulfide concentration was greater than that of the simultaneously extracted metals in the clayey–silty reservoir sediments, whereas the opposite result was observed for the sandy sediments of the tributaries. The sediment interstitial water toxic units were >1 for metals, thus indicating that metals are potentially toxic to the benthos. Considering the data set generated in this study, it can be concluded that the degradation of Ibirité reservoir and its tributaries cannot be solely attributed to the input of hydrocarbons, but predominantly to the discharge of raw urban sewage and effluents from other industrial sources.     

Investigation of an accidental explosion due to unintended mixing involving reactive chemicals at a waste storage tank

An accidental explosion occurred in a waste storage tank at an incineration plant in Kawasaki, Japan, on May 11, 1997. The accident was caused primarily by unintended mixing involving reactive chemicals, such as organic peroxides (POs) and acrylonitrile (AN). The PO initiated polymerization of AN and the heat released during the polymerization led to a runaway reaction and explosion. POs are widely used in the chemical industry and can be self-reactive and hazardous when mixed with other chemicals such as acids and alkalis. The goal of this study was to obtain a better understanding of the mixing hazard of chemicals through an evaluation of POs with other chemicals using conventional experimental techniques such as glass test-tube tests, Dewar vessel tests, and differential scanning calorimetry (DSC). Seven types of POs were mixed with AN. Test results were classified into four ranks based on the hazard criteria. In addition, di(2-ethylhexyl)-peroxydicarbonate/AN mixtures were investigated in detail and the influences of the mixing ratio and the stirring rate were examined.