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.

     

Aniline removal by Photocatalytic reaction of iron(iii) mediated with dissolved organic matter

When light (> 370 nm) was allowed to interact with an aqueous solution containing dissolved organic matter (DOM) and Fe(III), removal of aniline (AN) was observed. This was due to the photocatalytic reaction of Fe(III) mediated by DOM. Syringic acid (SYA) and humic acid (HA) were used as DOM in the present study. The ¹⁵N‐NMR spectrum of the product mixture from the light irradiation of the SYA/Fe(III) system demonstrated that AN was covalently bound to SYA. The kinetics of AN removal were, therefore, interpreted by assuming covalent binding between DOM and AN. The amounts of covalent binding sites and the apparent second‐order rate constants could be evaluated, and the amounts of covalent binding sites decreased with the increases of the concentration of DOM. This is attributed that the polymerization of DOM by the photo‐oxidation competed with the covalent binding between AN and DOM.     

ReefBahia, an integrated GIS approach for coral reef conservation in Bahia, Brazil

Coral reefs around the world are facing serious threats. These fragile ecosystems are in need for conservation. The coastal state of Bahia hosts the most extensive and richest area of coral reefs in the South Atlantic Ocean. Assessment, planning and management of coral reef ecosystems are particularly challenging tasks. This work shows how the creation of a GIS improves the process of management, monitoring and conservation of the Bahian reef environments The initial data input started by the vectorization of 1) bathymetric data from the Bureau of Hydrography and Navigation (DHN), 2) shoreline and mangrove areas from Landsat 7 ETM + images, 3) near surface reefs from Quickbird images, and 4) coastal and marine protected areas of federal, state and local administrations. Geological, physical, biological and social information was then included in order to create a suitable marine GIS for conservation aims. The data includes information on sediment granulometry and transport patterns, rocky substrate outcrops, sea surface temperature, wave direction, rain precipitation, major contributing river discharge, artisanal fishery, benthic cover and bleaching data. ReefBahia GIS has provided essential information for a better understanding of coral reefs of the state of Bahia geological and ecological characteristics such as mapping, representation, connectivity and biodiversity of coral reefs, geological facies, Quaternary sedimentation, numeric modeling of wave refraction and monitoring of bleaching events.     

Synthesis of calcium phosphate hydrogel from waste incineration fly ash and its application to fuel cell

Waste incineration fly ash was successfully recycled to calcium phosphate hydrogel, a type of fast proton conductor. The crystallized hydrogel from incineration fly ash had a lower electric conductivity and a lower crystallinity than that from calcium carbonate reagent. However, the difference in electric conductivity between these crystallized hydrogels decreases with temperature. This was due to the presence of potassium in the incineration fly ash. The fuel cell with a membrane electrode assembly (MEA) using the calcium phosphate hydrogel membrane prepared from incineration fly ash was observed to generate electricity. The performance of this fuel cell was almost equal to that of a mixture of K₂CO₃ and CaCO₃ reagents; further, the performance of the former was superior to the fuel cell with a perfluorosulfonic polymer membrane at temperatures greater than approximately 85 °C.     

The trail pheromone of the ant <Emphasis Type="Italic">Crematogaster castanea</Emphasis>

Summary. The major component of the trail pheromone of the myrmicine ant Crematogaster castanea has been identified as (R)-2-dodecanol from the tibial glands of the hind legs. The substance gave activity comparable to the contents of 8 tibial glands at a concentration of 1 pg per 32 cm trail.     

Plasticity in spawning visits of female damselfish, Stegastes nigricans : effect of distance to mates

Both sexes of the damselfish Stegastes nigricans hold individual territories in which they feed on filamentous algae. At dawn, females visit males' territories to spawn, and the males guard the eggs until hatching. We examined how females' spawning behavior varied according to the distances to their mates. Females usually mated with a single male per morning. The distance to the territory of a mate (0.7–12.8 m) did not affect a female's total spawning time per morning, but affected the number of her spawning visits with that male. Females made many repeated spawning visits when spawning with males at short distances, while they spawned the entire clutch in one visit when spawning with males at long distances. This plasticity in female behavior appears to be related to two costs during the spawning visits: (1) intrusions by other fish to feed on algae in the female's territory during her absence, which may cause the female to return repeatedly to her territory for defense, and (2) attacks on the female by other territorial fish, which increased with the distance to their mates' territories. To minimize the sum of both costs, females should change the number of spawning visits depending on the distance to the males' territories. Received: 30 September 1996 / Accepted after revision: 17 March 1997     

高浓度氨氮污泥脱滤液的半硝化实验研究

对高浓度氨氮污泥脱滤液进行了半硝化实验研究。运行结果表明,反应器进水氨氮浓度在402 mg/L、HRT=5.5 h、温度为22～31℃、DO〈1.0 mg/L、pH值在7.4～8.2时,半硝化反应器出水的NO 2--N/NH3-N维持在1.13～1.32,且负荷达到1.76 kg N/（m3.d）,NO2--N/NOx...     

Comparative study of microbial dechlorination of chlorinated ethenes in an aquifer and a clayey aquitard

In order to determine whether natural attenuation of chlorinated ethenes by microbial activity occurs in aquitards, sediments at a site contaminated with tetrachloroethene were vertically studied by drilling. The distribution of microbes (Dehalococcoides group and anaerobic hydrogen producers) and the ability of the sediments to sustain microbial dechlorination were determined in an aquitard as well as in an aquifer. Close-spaced sampling revealed the existence of large populations of Dehalococcoides and H(2)-producing bacteria, especially in the organic-rich clayey aquitard rather than in the aquifer. The vinyl chloride reductase gene was also detected in the clay layer. Furthermore, incubation experiments indicated that the clay sediment could sustain transformations of tetrachloroethene at least to vinyl chloride. In contrast, no significant transformation was observed in the aquifer sand. Our results indicate that dechlorination of tetrachloroethene by bacteria can take place in an organic-rich clayey aquitard, and that organic-rich clay may also be important in the natural attenuation in an adjacent aquifer, possibly supplying a carbon source or an electron donor.