The importance of solid-phase distribution on the oral bioaccessibility of Ni and Cr in soils overlying Palaeogene basalt lavas, Northern Ireland

Potentially toxic elements (PTEs) including nickel and chromium are often present in soils overlying basalt at concentrations above regulatory guidance values due to the presence of these elements in underlying geology. Oral bioaccessibility testing allows the risk posed by PTEs to human health to be assessed; however, bioaccessibility is controlled by factors including mineralogy, particle size, solid-phase speciation and encapsulation. X-ray diffraction was used to characterise the mineralogy of 12 soil samples overlying Palaeogene basalt lavas in Northern Ireland, and non-specific sequential extraction coupled with chemometric analysis was used to determine the distribution of elements amongst soil components in 3 of these samples. The data obtained were related to total concentration and oral bioaccessible concentration to determine whether a relationship exists between the overall concentrations of PTEs, their bioaccessibility and the soils mineralogy and geochemistry. Gastric phase bioaccessible fraction (BAF %) ranged from 0.4 to 5.4 % for chromium in soils overlying basalt and bioaccessible and total chromium concentrations are positively correlated. In contrast, the range of gastric phase BAF for nickel was greater (1.4–43.8 %), while no significant correlation was observed between bioaccessible and total nickel concentrations. However, nickel BAF was inversely correlated with total concentration. Solid-phase fractionation information showed that bioaccessible nickel was associated with calcium carbonate, aluminium oxide, iron oxide and clay-related components, while bioaccessible chromium was associated with clay-related components. This suggests that weathering significantly affects nickel bioaccessibility, but does not have the same effect on the bioaccessibility of chromium.     

Tetracycline antibiotics in the environment: a review

Tetracycline antibiotics are one of the primarily antibiotics groups used for veterinary purposes, for human therapy and for agricultural purposes. Amongst the different antibiotics used, more attention is paid to tetracycline’s as it exhibits serious environmental problems including ecological risks and human health damages. Due to their extensive usage, most of the actual evidence suggests that tetracycline antibiotics are omnipresent compounds found in different ecological compartments. After medication, more than 70 % of tetracycline antibiotics are excreted and released in active form into the environment via urine and feces from humans and animals. Their highly hydrophilic character and low volatility have resulted in significant persistence in the aquatic environment. Very few studies describe the fate and toxicity of tetracycline antibiotics in the environment. Here, we review several important issues with regard to: (1) the toxicity of these compounds on aquatic and terrestrial organisms; (2) their estrogenic effects; (3) their behavior in different ecological systems and; (4) the by-products generated during water treatment. These antibiotics residues promote the development of antibiotic resistant microorganisms, which can induce adverse effect to human health by increasing the risk of certain infections. Based on recent research results, the occurrence of tetracycline antibiotics in the environment inhibits the growth of some terrestrial and aquatic species. Besides, the residual concentrations of such drugs could affect steroidogenic pathway and consequently may cause endocrine disruption of aquatic species. Most of the wastewater treatment plants are not capable of removing effectively the tetracycline antibiotics. Therefore, there is a need to develop alternative processes to remove them from waters. Advanced oxidation processes have been proposed as alternative methods to ensure higher degradation and mineralization of tetracycline antibiotics are present in waters.     

Suppressed recovery of plant community composition and biodiversity on dredged fill of a hurricane-induced inlet through a barrier island

In September 2003, Hurricane Isabel created an inlet over 500 m wide and 10 m deep that connected the Atlantic Ocean and Pamlico Sound. This breach was subsequently filled with sediments dredged from the adjacent sound. The purpose of this study was to determine if the barrier island terrestrial plant communities were naturally re-establishing through primary succession. In 2006–2008, we compared plant communities, soil carbon and nitrogen, and Aeolian transport of sediments in undisturbed back-dunes, undisturbed shrub thickets, putative back-dunes, and putative shrub thickets. We found that species richness and evenness were low on the filled area relative to adjacent plant communities that had persisted through the storm. Plants on the filled area were almost entirely limited to a band of primarily Spartina patens found at the margin of the sound and there were no signs of establishing the typical zonation of back dune grasses, shrubs, and salt marsh. Evaluation of soil quality suggests that nutrients and organic material are not limiting recovery. Aeolian transport, however, was demonstrably higher across the filled area, where no dense stands of taller plants buffered the airflow. Plant re-establishment is suppressed by wind erosion inhibiting deposition of seeds. Recovery of the site will likely depend on the rhizomatous spread of S. patens from the sound shore. S. patens can then potentially facilitate the colonization of other species by buffering the wind and trapping seeds of other plants. Ironically, this slow recovery may benefit federally threatened bird species that require sparse vegetation for nesting success.     

Room to move? Threatened shorebird habitat in the path of sea level rise—dynamic beaches, multiple users, and mixed ownership: a case study from Rhode Island, USA

Accelerated sea level rise (slr) is expected to transform vulnerable Atlantic coastal habitats in the United States during this century. Low-elevation sandy beaches, important nesting habitat for the continued recovery of the federally threatened piping plover (Charadrius melodus) in Rhode Island, are especially vulnerable. These beaches, under a mix of private and public ownership, exist in a heterogeneous landscape of dunes, rocky headlands, salt ponds, and heavily developed areas. Understanding the extent to which piping plover nesting beaches can retreat landward under projected slr is important for prioritizing future conservation actions across multiple jurisdictions. This research examines habitat change in response to slr (0.5, 1.0, and 1.5 m) under stationary and migration beach responses and whether development blocks habitat migration for five productive piping plover nesting beaches. We found that under the stationary habitat model, all beaches lose area under all slr scenarios. For the habitat migration model, future habitat availability differs by beach depending on elevation, landward topography, and presence of development. However, across the majority of beach area, piping plover habitat will be able to migrate landward if unconstrained by future development. A coalition of public and private stakeholders already supports management efforts to help ensure plover population recovery in the area. With emerging habitat change prediction tools, these stakeholders and other partners can engage in innovative, local-level planning needed to protect wildlife habitat and commercial, residential, and infrastructure assets from sea level rise.     

Improving vulnerability assessment towards Integrated Coastal Zone Management (ICZM): a case study of small islands in Indonesia

Vulnerability assessment is one of the methods currently being used to measure the ocean and coastal sustainability in order to enable better evaluation and redesign of land-based development and policy-making. Because of different geological and geographical formations, the elements that comprise the vulnerability indicators are different from each other, and there are various vulnerability equations that have been used. At the present time, there are no unified vulnerability indicators that can be applied universally to every country. The Seribu Islands, Indonesia, also known in English as the Thousand Islands, consisting of 105 islands located to the north of Jakarta, have been chosen as a study area for vulnerability assessment according to the basic principles of Integrated Coastal Zone Management theory. The results indicate that in practice, Indonesian Integrated Coastal Zone Management legal systems do exist and that in some cases, part of the responsibility for the problems rests with legislation that imposes complex systems of administration, unrealistic sanctions and impractical solutions. This research also shows that inter-sectoral, inter-governance and spatial developments are the three components that need to be improved for the successful implementation of Integrated Coastal Zone Management in the region.     

The effects of partial mortality on the fecundity of three common Caribbean corals

The recent intensification of human disturbances in the Caribbean has increased the prevalence of partial mortality on coral colonies. Partial mortality can change colony size by directly shrinking colonies or by splitting colonies into fragments. A reduction in colony size can also adversely affect fecundity and fitness as internal resources shift away from reproduction toward colony maintenance. This study aimed to determine whether three Caribbean coral species, Siderastrea siderea, Montastraea faveolata, and Diploria strigosa, along the reef tract in Puerto Morelos, Mexico (20^o52′N, 86^o51′W), continued to dedicate resources to reproduction when colonies were fragmented to pre-maturation size. Contrary to expectations, eggs were found in colonies that were smaller than the maturation size and had been subjected to partial mortality. The continued dedication of resources toward reproduction, even in the smallest colonies, suggests that resource trade-offs away from reproduction are not as rigid as previously suggested in stressed corals.     

Regression-type estimators for adaptive two-stage sequential sampling

Adaptive two-stage sequential sampling (ATSSS) design was developed to observe more rare units and gain higher efficiency, in the sense of having a smaller variance estimator, than conventional sampling designs with equal effort for rare and spatially cluster populations. For certain rare populations, incorporating auxiliary variables into a sampling design can further improve the observation of rare units and increase efficiency. In this article, we develop regression-type estimators for ATSSS so that auxiliary variables can be incorporated into the ATSSS design when warranted. Simulation studies on two populations show that the regression-type estimators can significantly increase the efficiency of ATSSS and the detection of more rare units as compared to conventional sampling counterparts. Simulation of sampling of desert shrubs in Inner Mongolia (one of the two populations studied) showed that by incorporating a GIS auxiliary variable into ATSSS with the regression estimators resulted in a gain in efficiency over ATSSS without the auxiliary variable. Further, we found that the use of the GIS auxiliary variable in a conventional two-stage design with a regression estimator did not show a gain in efficiency.     

How safe is the playground? An environmental health risk assessment of As and Pb levels in school playing fields in NE England

The risk from potentially toxic elements in playground soils is of concern to children’s health as a result of the potential for intentional or unintentional consumption. Current approaches, based on total potentially toxic element concentration, may overestimate the risk. This has resulted in the development and use of in vitro gastrointestinal extraction protocols. The concentration of arsenic (As) and lead (Pb) in soils collected from 12 schools in north-east England has been compared with Soil Guideline Values from seven countries as well as reported literature concentrations for playgrounds and recreational parks. It was found that the mean As concentration of 14.1 ± 5.4 mg/kg does not exceed the England residential Soil Guideline Value in any location, while the mean Pb concentration of 298 ± 380 mg/kg is high but not excessive. Both concentrations have been assessed using the maximum potential daily intake from soil that a child could ingest. Based on this protocol Pb does not exceed the tolerable daily intake in any playground location, while As is generally 10 times lower than the oral index dose in the majority of playgrounds. The oral bioaccessibility of As and Pb was investigated. It was concluded that the highest concentrations were determined in the gastric phase with maximum bioaccessibilities of 54 and 46 % for As and Pb, respectively. Here we have demonstrated that minimal risk arises from the investigated playgrounds provided that good personal hygiene is adhered to.     

Ostrich chick humoral immune responses and growth rate are predicted by parental immune responses and paternal colouration

One of the most important measures of offspring performance is growth rate, which is often traded off against another important survival trait, immune function. A particular feature of ostrich chicks maintained in farmed environments is that cohorts of chicks vary widely in size. As parents can have a profound effect on the phenotype and fitness of their offspring, we investigated whether chick growth and immune defence were related to variation in levels of immune defence in their genetic parents. As secondary sexual traits of sires could serve as indicators of male quality, and be used in female mating decisions, we also investigated whether chick growth rate and immune defence were related to male plumage and integumentary colouration. We found that offspring growth rates and humoral responses were related to the humoral responses of their parents, suggesting that at least some components of humoral immune capacity are heritable. The white colour of male ostrich feathers was correlated to the humoral response and growth rate of their offspring, suggesting that this visual cue involved in the male courtship display could serve as an important signal to females of male quality, thereby forming the basis of mate choice in this species.