Organotin compounds in seawater and Mytilus galloprovincialis mussels along the Croatian Adriatic Coast

In this work, data on the level of organotin compounds (OTCs) in seawater and mussels collected along the entire Croatian Adriatic Coast are presented. The samples were collected in 2009 and 2010 at 48 locations representing different levels of maritime activities, including marinas, ports and reference sites. Butyltins (BuTs) were found in all analyzed samples, representing >97% of OTCs, and ranged from 0.46 to 27.98 ng Sn L(-1) in seawater and from <6 to 1675 ng Sn g(-1) in mussels. The results indicate a recent input of TBT, with the highest concentrations of BuTs found in the marinas. It appears that the Adriatic coast is still polluted with TBT despite the fact that TBT-containing antifouling paints have been banned in Croatia since 2008. It is questionable how much TBT pollution decreased since 2005, when a high incidence of imposex was established in the same area.     

Contending with unequal and privileged access to natural resources and land in the Okavango Delta, Botswana

This paper reviews how state policy and regulatory instruments, including protected area alienations and concessions, have altered or denied the access to land and natural livelihood resources of the indigenous Basarwa and minority subsistence-oriented communities in the Okavango Delta (OD) in Botswana. Drawing on field research and guided by a sustainable rural livelihoods framework, the paper provides an overview of key institutional interventions – in particular the setting up of the Moremi Game Reserve, Wildlife Conservation Policy, Tourism Policy, Agricultural Development Policy and the erection of veterinary fences – that have served to privilege a foreign-owned and dominated commercialized wildlife and nature tourism sector and the export-oriented beef industry in the OD. The officially sanctioned barriers to customary and usufructory rights and access, and the non-recognition of historically embedded traditional land uses have decimated already marginalized resource-based subsistence livelihoods, and precipitated intergroup conflicts over preferential rights and access to resources and opportunities, notably wildlife, non-timber veld products, agriculture and community-based tourism schemes. Such outcomes, moreover, will have consequences for the longer-term sustainability of the OD both as a socioeconomic resource base and as a natural ecosystem.     

A comparison of seismic risk maps for Italy

National seismic risk maps are an important risk mitigation tool as they can be used for the prioritization of regions within a country where retrofitting of the building stock or other risk mitigation measures should take place. The production of a seismic risk map involves the convolution of seismic hazard data, vulnerability predictions for the building stock and exposure data. The seismic risk maps produced in Italy over the past 10 years are compared in this paper with recent proposals for seismic risk maps based on state-of-the-art seismic hazard data and mechanics-based vulnerability assessment procedures. The aim of the paper is to open the discussion for the way in which future seismic risk maps could be produced, making use of the most up-to-date information in the fields of seismic hazard evaluation and vulnerability assessment.     

Clast fabric and mass wasting on Asteroid 25143-Itokawa: Correlation with talus and other periglacial features on Earth

Regolith on Itokawa, a 300-meter diameter near-Earth asteroid, first imaged by the Hayabusa Spacecraft in 2005, provides a new database of information on surface features and different space-form (i.e. landform) assemblages. The satellite imagery was taken from distances of near-surface and 2 km to 63 m, the latter giving image resolutions of 6 mm/pixel. Small regolith-covered asteroids produce rubble-covered surface mantles, resident on slopes ranging from 27° relative to an artificial horizon, and distributed non-uniformly across the surface. Low gravity acceleration on Itokawa means that clast movement is largely the result of global vibrations caused by impacts producing seismic shaking. Gravel-network orientations, previously correlated with imbricated stream gravels on Earth by the Hayabusa Scientific Team (Miyamoto, H., Yano, H., Scheeres, D.J., Abe, S., Barnaouin-Jha, O., Cheng, A.F., Demura, H., Gaskell, R.W., Hirata, N., Ishiguro, M., Michikami, T., Nakamura, A.M., Hakamura, R., Saito, J., Sasaki, S., 2007. Regolith migration and sorting on asteroid Itokawa. Science. 316, 1011–1014, Fig. 2F), are here partly correlated with talus and stone-banked lobe accumulations on Earth. We present ‘sliderock’ accumulations on Itokawa correlated with talus accumulations on Earth from several high, middle and low latitude Cryic localities. The presence of debris-flow accumulated clastic material indicates the presence of permafrost and issuance of meltwater at some time in the past, presumably linked to an orbital or solar radiation perturbation. The available data indicate the presence of water, at least on a punctuated time scale; along with the presence of Fe, the combination of the two suggesting weathering processes and a dynamic surface geology on what was previously considered to be a dry, barren, lifeless world.     

Subduction,fluids, and accessory minerals: a celebration of the career of Sorena S. Sorensen

ABSTRACT

This is a preface to the topical issue entitled ‘Subduction, Fluids, and Accessory Minerals: A Celebration of the Career of Sorena S. Sorensen’     

Carbon Isotope Analysis to Evaluate Nanoscale Fe(O) Treatment at a Chlorohydrocarbon Contaminated Site

Remediation of groundwater contaminated by chlorinated hydrocarbons via in situ technologies such as direct injection of nanoscale zero valent iron (ZVI, Fe(O)) particles is increasingly common. However, assessing target compound degradation by abiotic processes is difficult because (1) the injection may displace the contaminant plume so that concentration measurements alone are often inconclusive and (2) biodegradation may also occur, making it challenging to identify and evaluate the abiotic degradation component. In this study, trichloroethylene (TCE) and 1,1,1-trichloroethane (1,1,1-TCA) were treated in a highly heterogeneous hydrogeologic setting. The purpose of this study was to evaluate the potential for compound-specific stable isotope analysis (CSIA) to monitor the effectiveness of ZVI injection by assessing TCE and 1,1,1-TCA degradation. Prior to ZVI injection, carbon isotope measurements demonstrated biodegradation of TCE by native microorganisms. This in situ biodegradation was quantified by measuring the enrichment of ¹³C in TCE samples downstream of the suspected source. When ZVI was injected through only two injection wells, no changes in TCE and 1,1,1-TCA isotope signatures were detected compared to preinjection values. In contrast, when ZVI was injected through 11 wells covering a greater portion of the contaminated area, 5 out of 10 monitoring wells showed further enrichment of ¹³C in either TCE or 1,1,1-TCA, indicating additional target compound transformation. The abiotic nature of this TCE transformation was confirmed through temporal trends in carbon isotope values of the putative transformation products cis-dichloroethylene (cis-DCE), ethene and ethane. This demonstrates the usefulness of CSIA in distinguishing abiotic vs. biotic transformation in the field.