The recycled content of plastic products: estimating the impact of a recycling law on the input mix

The use of recycled material is a key building block for the circular economy. In this study, we explore the impact of recycling laws in Japan on the use of recycled materials in the production process of intermediate plastics. Using a difference-in-differences approach, we investigate whether the input share of recycled plastics in intermediate plastic products increased after the Container and Packaging Recycling Law (CPR Law) was enforced in 1997 in Japan. Results indicate that the input share of recycled plastics increased by 1 percentage point after the law’s implementation. Meanwhile, the input share of virgin plastic materials, such as polyethylene, polypropylene, and vinyl chloride, per plastic product decreased by 3 percentage points on average. These results suggest that the CPR law helped shift inputs from virgin plastics to recycled plastic materials even though the impact size has been small. To further encourage the use of recycled plastic materials, policy interventions should directly incentivize producers to increase the use of recycled plastics.

     

Assessing local-scale inclusive wealth: a case study of Sado Island,Japan

Present trends of urbanization are accompanied by increasing demographic and economic shrinkage of rural regions. In countries such as Japan, these rural regions trail behind metropolitan counterparts according to GDP, the conventional measure used to guide governmental policies. Yet, past research suggests that these regions may be undervalued. Further, the Inclusive Wealth Index (IWI), largely only used at the national level, may be able to capture aspects previously missed. As such, our study attempts to highlight the wealth of rural regions by comparing the inclusive wealth of Sado Island and Japan between 1990 and 2014. Minor methodological modifications were made according to data availability at the local level and to improve the accuracy of human capital estimations. Results captured the ongoing shrinkage of Sado and demonstrate the distinct potential of the IWI as a stock measure. Sado’s per capita wealth was about 10% lower than the national averages, but its natural capital was about threefold national averages. Supplementary estimations of the natural capital of fisheries and cultivated forests suggest that inclusion of additional factors in the evaluation would further increase the relative valuation of rural regions. We discuss implications of our estimations for wellbeing, and conclude with a critical appraisal of the IWI calculation towards policy implementation of the index.     

Evaluating the Impact of Distance Measures on Deforestation Simulations in the Fluvial Landscapes of Amazonia

Land use and land cover change (LUCC) models frequently employ different accessibility measures as a proxy for human influence on land change processes. Here, we simulate deforestation in Peruvian Amazonia and evaluate different accessibility measures as LUCC model inputs. We demonstrate how the selection, and different combinations, of accessibility measures impact simulation results. Out of the individual measures, time distance to market center catches the essential aspects of accessibility in our study area. The most accurate simulation is achieved when time distance to market center is used in association with distance to transport network and additional landscape variables. Although traditional Euclidean measures result in clearly lower simulation accuracy when used separately, the combination of two complementary Euclidean measures enhances simulation accuracy significantly. Our results highlight the need for site and context sensitive selection of accessibility variables. More sophisticated accessibility measures can potentially improve LUCC models’ spatial accuracy, which often remains low.     

Prospective changes in irrigation water requirements caused by agricultural expansion and climate changes in the eastern arc mountains of Kenya

Water resources and land use are closely linked with each other and with regional climate, assembling a very complex system. The understanding of the interconnecting relations involved in this system is an essential step for elaborating public policies that can effectively lead to the sustainable use of water resources. In this study, an integrated modelling framework was assembled in order to investigate potential impacts of agricultural expansion and climate changes on Irrigation Water Requirements (IWR) in the Taita Hills, Kenya. The framework comprised a land use change simulation model, a reference evapotranspiration model and synthetic precipitation datasets generated through a Monte Carlo simulation. In order to generate plausible climate change scenarios, outputs from General Climate Models were used as reference to perturbing the Monte Carlo simulations. The results indicate that throughout the next 20 years the low availability of arable lands in the hills will drive agricultural expansion to areas with higher IWR in the foothills. If current trends persist, agricultural areas will occupy roughly 60% of the study area by 2030. This expansion will increase by approximately 40% the annual water volume necessary for irrigation. Climate change may slightly decrease crops' IWR in April and November by 2030, while in May a small increase will likely be observed. The integrated assessment of these environmental changes allowed a clear identification of priority regions for land use allocation policies and water resources management.     

Adsorption and removal of antimony from aqueous solution by an activated Alumina

The adsorption of Sb(V) ions from aqueous solutions onto commercially available activated alumina (AA) was investigated. AA has a much higher adsorption capacity than presently used adsorbents. Sb(V) ions are likely adsorbed through electrostatic attraction and/or specific adsorption mechanism, while the optimum pH is found in the range of 2.8–4.3. The Sb(V) ions adsorption capacities increase with increasing temperature. The addition of nitrate, acetate, arsenite, chloride, and silicate ions affected Sb(V) ions adsorption only slightly, while the coexisting ascorbate, arsenate, phosphate, sulfate, EDTA, tartrate, and citrate ions substantially depressed Sb(V) ions adsorption.     

Accumulation and Chemical Fractionation of Heavy Metals in Andisols after a Different, 6-year Fertilization Management (8 pp)

Goal, Scope and Background Andisols are widespread in Japan and have some special properties such as high anion exchange capacity, low bulk density, and high organic matter content, which might influence the accumulation or chemical fractionation of heavy metals. However, few such data exist in Japanese andisols. The primary objective of this study was to investigate the distribution and chemical fractions of Cu, Zn, Ni, and Cr in the soil profiles and subsequently to assess their potential environmental hazard. Materials and Methods Soil samples were taken from a field experiment conducted on Japanese andisols, which had received either swine compost or chemical fertilizers for 6 years. Concentrations of Cu, Zn, Ni, and Cr were determined for all of the obtained extract solutions by ICP-AES. Results and Discussion Considerably higher total concentrations of Cu and Zn were observed in the top 20 cm layer of the compost-amended soil, relative to the unfertilized soil, while chemical fertilizers had little effect. Application of the swine compost increased the concentrations of Cu and Zn, but not Ni and Cr, in all fractions in the top 20 cm layer. The greatest increase in the organically bound fraction (OM) Cu and dilute acid-exchangeable fraction (DAEXCH) Zn was observed. This suggests that Cu and Zn are potentially bioavailable and mobile in the andisol profiles after 6-year consecutive applications of the swine compost. On the other hand, distribution of Cu, Zn, Ni and Cr among various soil fractions was generally unaffected by chemical fertilizers. Conclusions We observed that 6-year consecutive applications of the swine compost led to an increase in total metals of Cu and Zn, as well as their all-chemical fractions, in the top 20 cm soil layers. Potential hazard of heavy metals, especially of Cu and Zn, as a result of the use of swine compost on andisols, must be taken into account. Recommendations and Outlook The long-term effect of the accumulation of heavy metals, particularly Cu and Zn, in various plant tissues and soils, as well as their potential risk to surface water via runoff and groundwater via leaching, needs to be carefully considered. Further investigations in the long-term experiments are therefore necessary. - Abbreviations. EXCH, exchangeable fraction of metals; DAEXCH, dilute acid-exchangeable fraction of metals; FeMnOX, iron and manganese-oxide-bound fraction; OM, organically-bound fraction; RESD, residual fraction. COMPOST, SRNF, RANF, and CONTROL stand for compost (from swine wastes), slow-release nitrogen fertilizer (coated urea), readily available nitrogen fertilizer (including NH4-N, P, and K fertilizers), and no fertilizer application, respectively.     

Nitrate leaching in an Andisol treated with different types of fertilizers

Nitrate (NO3) leaching was studied in an Andisol treated with four N fertilizers (SC: swine compost, CU: coated urea, AN: ammonium N, or NF: no fertilizer) for 7 years. Sweet corn (Zea mays L.) was grown in summer, followed by Chinese cabbage (Brassica rapa L. var. amplexicaulis) or cabbage (Brassica oleracea L. var. capitata) in autumn each year. In chemical fertilizer plots treated with AN or CU, NO(3)-N concentrations in soil water at 1-m depth increased markedly in the summer of the second year and fluctuated between 30 and 60 mg l(-1). In the SC plot, NO(3)-N concentration started increasing in the fourth year, reaching the same level as in the AN and CU plots in the late period of the experiment. In the NF plot, NO(3)-N concentration was about 10 mg l(-1) for the first 4 years and decreased to 5 mg l(-1). The potential NO(3)-N concentrations by an N and water balance equation satisfactorily predicted NO(3)-N concentration in the AN and CU plots, but substantially overestimated that in the SC plot, presumably because a large portion of N from SC first accumulated in soil in the organic form. Our results indicate that, under the Japanese climate (Asian monsoon), excessive N from chemical fertilizers applied to Andisols can cause substantial NO3 leaching, while compost application is promising to establish high yields and low N leaching during a few years but would cause the same level of NO3 leaching as in chemically fertilized plots over longer periods.     

The effect of oxygen addition on the determination of cadmium and lead in blood and foods by graphite furnace atomic absorption spectrometry

It is well known that in the analysis of low temperature vaporized metal elements such as cadmium and lead, a high ashing temperature causes a loss of the target atoms at the ashing stage, while low ashing temperature causes incomplete decomposition of organic components in the sample. In order to solve these problems, the effect of oxygen addition on determination of cadmium and lead in blood and foods was studied. Oxygen was introduced into the atmosphere in the graphite furnace at the beginning of ashing stage for 20 seconds at 0.5 l/min. Relation between ashing temperature and sensitivity was examined, and the oxygen addition minimized signal depression by the sample matrix. It can be concluded that the addition of oxygen at the ashing stage not only reduces the background absorption, but also suppress the volatilization of target atoms at the ashing stage by the formation of their oxides.