Immobilisation of PAH in waste materials

This paper gives an overview of the results of a research project into the possibilities of immobilising polycyclic aromatic hydrocarbons (PAH), that are present in waste materials. The results show that with hydraulic binders the waste materials can be solidified. The PAH do still leach to a relatively high extent. However, this PAH leaching can be decreased by more than a factor 10 by means of the addition of a specific additive. The immobilisation product fulfils technological requirements for the use as a road base construction material, such as compressive strength.     

Practical guide to coproduction in conservation science

We considered a series of conservation-related research projects on the island of Pemba, Tanzania, to reflect on the broad significance of Beier et al.’s recommendations for linking conservation science with practical conservation outcomes. The implementation of just some of their suggestions can advance a successful coproduction of actionable science by small research teams. Key elements include, first, scientists and managers working together in the field to ensure feedback in real time; second, questions jointly identified by managers and researchers to facilitate engaged collaboration; third, conducting research at multiple sites, thereby broadening managers’ abilities to reach multiple stakeholders; and fourth, establishing a multidisciplinary team because most of the concerns of local managers require input from multiple disciplines.     

Distribution, speciation and availability of antimony (Sb) in soils and terrestrial plants from an active Sb mining area

Here, we present one of the first studies investigating the mobility, solubility and the speciation-dependent in-situ bioaccumulation of antimony (Sb) in an active Sb mining area (Xikuangshan, China). Total Sb concentrations in soils are high (527-11,798 mg kg⁻¹), and all soils, including those taken from a paddy field and a vegetable garden, show a high bioavailable Sb fraction (6.3-748 mg kg⁻¹), dominated by Sb(V). Elevated concentrations in native plant species (109-4029 mg kg⁻¹) underpin this. Both chemical equilibrium studies and XANES data suggest the presence of Ca[Sb(OH)₆]₂, controlling Sb solubility. A very close relationship was found between the citric acid extractable Sb in plants and water or sulfate extractable Sb in soil, indicating that citric acid extractable Sb content in plants may be a better predictor for bioavailable Sb in soil than total acid digestible Sb plant content.     

Observed climate-induced changes in plant phenology in the Netherlands

We determined whether climate change in the Netherlands has caused phenological changes since 1868. We analysed over 150,000 plant phenological observations of 320 plant species, obtained by four volunteer networks and one series collected by Mr. Braaksma. With the network data, we compared the timing of life cycle events in three different periods: 1894–1932 (Period 1), 1940–1968 (Period 2) and 2001–2010 (Period 3). For the Braaksma series, we compared the periods 1953–1968 (Period A) with 1969–1992 (Period B). We conclude that until the beginning of the 1990s, there have been no significant changes in the timing of life cycle events. The timing of life cycle events in Period 3 showed an average advance of flowering, leaf unfolding and fruit ripening of 14 days compared with Period 1 and 13 days compared with Period 2. Some species have advanced up to over 35 days. Autumn events occurred up to an average of 7 days later in Period 3 compared to earlier periods. This study shows that, based on network data, changes in climate explain on average 66 % of the variation in timing of phenological events from year to year. For the Braaksma data, this is 38 %. The expected future changes in climate will undoubtedly result in a further lengthening of the growing season. We believe that phenological networks, supported by thousands of volunteers, are needed to quantify, analyse, predict and communicate these phenological changes so various sectors in society can adapt to these changes and prevent significant socio-economic impacts.     

The value of coastal wetlands for hurricane protection

Coastal wetlands reduce the damaging effects of hurricanes on coastal communities. A regression model using 34 major US hurricanes since 1980 with the natural log of damage per unit gross domestic product in the hurricane swath as the dependent variable and the natural logs of wind speed and wetland area in the swath as the independent variables was highly significant and explained 60% of the variation in relative damages. A loss of 1 ha of wetland in the model corresponded to an average USD 33,000 (median = USD 5000) increase in storm damage from specific storms. Using this relationship, and taking into account the annual probability of hits by hurricanes of varying intensities, we mapped the annual value of coastal wetlands by 1 km x 1 km pixel and by state. The annual value ranged from USD 250 to USD 51,000 ha(-1) yr(-1), with a mean of USD 8240 ha(-1) yr(-1) (median = USD 3230 ha(-1) yr(-1)) significantly larger than previous estimates. Coastal wetlands in the US were estimated to currently provide USD 23.2 billion yr(-1) in storm protection services. Coastal wetlands function as valuable, selfmaintaining "horizontal levees" for storm protection, and also provide a host of other ecosystem services that vertical levees do not. Their restoration and preservation is an extremely cost-effective strategy for society.     

Early maturing Kipsigis women have higher reproductive success than late maturing women and cost more to marry

Summary Demographic analyses from 3 cohorts of Kenyan Kipsigis women married between 1940 and 1973 demonstrate that early maturing women have higher reproductive success than do late maturing women, due to longer reproductive lifespans and higher fertility. This result is independent of confounding effects of husband's wealth, but not of the wealth of a woman's parents which affects both menarcheal age and subsequent reproductive success. Data on bridewealth payments at 194 marriages occurring after 1959 show that men make higher marriage payments for early maturing women than for late maturing women. Together these results suggest that Kipsigis men vary their marriage payments in accordance with the reproductive value of their brides. The question of why men use age at menarche rather than bride's parents' wealth as a cue to their bride's subsequent reproductive performance is discussed in the light of changing social and economic conditions experienced by Kipsigis since the late 1920s.     

Preterm delivery rate and fetal outcome in structurally affected twin pregnancies: A retrospective matched control study

Data from 23 twin pregnancies with one structurally affected fetus were compared with data from 23 twin pregnancies with proven absence of structural fetal anomalies and matched for maternal age, parity, and year of delivery. The preterm delivery rate ( < 37 weeks) was high in both groups but not significantly different (57 vs. 48 per cent). Perinatal mortality was significantly higher in the structurally affected twin pregnancies (65 vs. 9 per cent). In the affected twins, birth weight of the anomalous fetus was significantly lower than that of the normal co-twin. Since there was no difference in the incidence of maternal disease (hypertensive disorders, diabetes), it was concluded that the higher perinatal mortality was determined mainly by the nature of the anomaly and not by the preterm delivery rate.     

Prediction of complete bioremediation periods for PAH soil pollutants in different physical states by mechanistic models

Mass-transfer models and biodegradation models were developed for three theoretical physical states of polycyclic aromatic hydrocarbons (PAHs) in soil. These mechanistic models were used to calculate the treatment periods necessary for complete removal of the PAH pollutants from the soil under batch conditions. Results indicate that the bioremediation of PAHs in such systems is mainly mass-transfer limited. The potential for bioremediation as a treatment technique for PAH contaminated soils is therefore mainly determined by the mass-transfer dynamics of PAHs. Under mass-transfer limited conditions simplified mathematical models, based on the assumption of a zero dissolved PAH concentrations, can be used to predict the period of time needed for complete bioremediation.     

Substance flows through the economy and environment of a region

In the tradition of the study of materials flows through society, the Substance Flow Analysis (SFA) method and its software tool SFINX are presented. SFA aims at providing the relevant information for a country’s overall management strategy regarding single substances or coherent groups of substances. Three modelling techniques and their possibilities and limitations are discussed: Bookkeeping, static modelling, and dynamic modelling. The computer program SFINX can be used for varoius purposes: (1) to obtain an overview of stocks and flows of a substance in, out and through a nation’s economy and environment for a specific year, (2) to trace the origins of specific pollution problems, and (3) to estimate the effectiveness of certain abatement measures. Each application has its own requirements with regard to data and modelling.     

Substance flows through the economy and environment of a region

Part I: Abstract  In the tradition of the study of materials flows through society, the Substance Flow Analysis (SFA) method is presented. SFA aims at providing the relevant information for a country’s overall management strategy regarding single substances or coherent groups of substances. This article is dedicated to the presentation of a threestep general framework for SFA-type studies, and elaborates on its first step the systems definition. Attention is given to the definition of the external and internal system boundaries, the categorization of the system’s elements, aspects of materials choice, time, and space, and how these depend on the aim of the conducted study. Moreover, a broader discussion is started on the need for standardization of materials flow studies in general. Part II: Abstract  In the tradition of the study of materials flows through society, the Substance Flow Analysis (SFA) method and its software tool SFINX are presented. SFA aims at providing the relevant information for a country’s overall management strategy regarding single substances or coherent groups of substances. Three modelling techniques and their possibilities and limitations are discussed: Bookkeeping, static modelling, and dynamic modelling. The computer program SFINX can be used for varoius purposes: (1) to obtain an overview of stocks and flows of a substance in, out and through a nation’s economy and environment for a specific year, (2) to trace the origins of specific pollution problems, and (3) to estimate the effectiveness of certain abatement measures. Each application has its own requirements with regard to data and modelling.