Agriculture, Food and Natural Resources Handbook 2011

The use of lead (Pb) ammunition in the form of shot pellets has been identified as a Pb exposure risk in wildlife and their human consumers. We explore the hypothesis that Pb shot ban enforcement reduces the risk of avian Pb poisoning as well as Pb exposure in game meat consumers. We assessed compliance with a partial ban on Pb shot commencing in 2003 by examination of 937 waterbirds harvested by hunters between 2007 and 2012 in the Ebro delta (Spain). Prevalence of Pb shot ingestion was determined, as were Pb concentrations in liver and muscle tissue to evaluate the potential for Pb exposure in game meat consumers. Hunted birds with only embedded Pb shot (no steel) declined from 26.9% in 2007–08 to < 2% over the following three hunting seasons after ban reinforcement. Pb shot ingestion in mallards decreased from a pre-ban value of 30.2% to 15.5% in the post-ban period. Liver Pb levels were predominantly defined by the presence of ingested shot, whereas muscle levels were defined by the presence of both ingested and embedded shot. Only 2.5% of mallard muscle tissue had Pb levels above European Union regulations for meat (0.1 μg/g wet weight) in the 2008–09 season, when Pb shot ingestion prevalence was also at a minimum (5.1%). Effective restrictions in Pb ammunition use have a dual benefit since this reduces Pb exposure for game meat consumers due to embedded ammunition as well as reducing Pb poisoning in waterbirds

Magnetic Inhibition of Convection and the Fundamental Properties of Low-Mass Stars. I. Stars with a Radiative Core

Magnetic fields are hypothesized to inflate the radii of low-mass stars—defined as less massive than 0.8 M ☉—in detached eclipsing binaries (DEBs). We investigate this hypothesis using the recently introduced magnetic Dartmouth stellar evolution code. In particular, we focus on stars thought to have a radiative core and convective outer envelope by studying in detail three individual DEBs: UV Psc, YY Gem, and CU Cnc. Our results suggest that the stabilization of thermal convection by a magnetic field is a plausible explanation for the observed model-radius discrepancies. However, surface magnetic field strengths required by the models are significantly stronger than those estimated from observed coronal X-ray emission. Agreement between model predicted surface magnetic field strengths and those inferred from X-ray observations can be found by assuming that the magnetic field sources its energy from convection. This approach makes the transport of heat by convection less efficient and is akin to reduced convective mixing length methods used in other studies. Predictions for the metallicity and magnetic field strengths of the aforementioned systems are reported. We also develop an expression relating a reduction in the convective mixing length to a magnetic field strength in units of the equipartition value. Our results are compared with those from previous investigations to incorporate magnetic fields to explain the low-mass DEB radius inflation. Finally, we explore how the effects of magnetic fields might affect mass determinations using asteroseismic data and the implication of magnetic fields on exoplanet studies

An update of the Worldwide Integrated Assessment (WIA) on systemic insecticides. Part 2: impacts on organisms and ecosystems

New information on the lethal and sublethal effects of neonicotinoids and fipronil on organisms is presented in this review, complementing the previous WIA in 2015. The high toxicity of these systemic insecticides to invertebrates has been confirmed and expanded to include more species and compounds. Most of the recent research has focused on bees and the sublethal and ecological impacts these insecticides have on pollinators. Toxic effects on other invertebrate taxa also covered predatory and parasitoid natural enemies and aquatic arthropods. Little, while not much new information has been gathered on soil organisms. The impact on marine coastal ecosystems is still largely uncharted. The chronic lethality of neonicotinoids to insects and crustaceans, and the strengthened evidence that these chemicals also impair the immune system and reproduction, highlights the dangers of this particular insecticidal classneonicotinoids and fipronil. , withContinued large scale – mostly prophylactic – use of these persistent organochlorine pesticides has the potential to greatly decreasecompletely eliminate populations of arthropods in both terrestrial and aquatic environments. Sublethal effects on fish, reptiles, frogs, birds and mammals are also reported, showing a better understanding of the mechanisms of toxicity of these insecticides in vertebrates, and their deleterious impacts on growth, reproduction and neurobehaviour of most of the species tested. This review concludes with a summary of impacts on the ecosystem services and functioning, particularly on pollination, soil biota and aquatic invertebrate communities, thus reinforcing the previous WIA conclusions (van der Sluijs et al. 2015)

Lead shot ban compliance in Spanish wetlands: effects on Pb poisoning prevalence

Resumen del trabajo presentado al XXXth International Union of Game Biologists and Perdix XIII, celebrados en Barcelona (España) del 5 al 9 de septiembre de 2011.The prevalence of lead (Pb) shot ingestion in waterfowl hunted in Spanish wetlands around the Mediterranean coast during the 1990s was as high as 30-39 % in mallard (Anas platyrhynchos), 69 % in common pochard (Aythya ferina) and 74 % in northern pintail (Anas acuta). Lead shot use was banned in protected wetlands in Spain in 2001, however, this was not fully implemented in the Ebro delta until 2003. Here, we show results for three hunting seasons (2007-2010) where shot wintering waterfowl (n = 454) from this wetland were monitored. The type of embedded shot present in hunted birds was studied by X-ray and dissection. The prevalence of Pb shot ingestion was studied by gizzard examination. Ban compliance was relatively low in 2007-08, i.e., 26.9% of birds had embedded Pb shot, 10.6% had Pb and steel shot, 48.8 % had steel shot, and 13.8 % had no shot. After these results were produced, the ban was reinforced and compliance subsequently increased (to 1.7%, 8.2%, 74.1% and 16.0%, respectively). The prevalence of Pb shot ingestion in mallards in 2007-08 (28.6%) was comparable to the pre-ban prevalence (30.2%), but, it was significantly higher than in subsequent seasons (in 2008-09: 5.1%; in 2009-10: 13.8%). In the last year of the study, a significant proportion of birds still had embedded Pb shot and/or ingested Pb shot in their gizzards. This may be because the ban was not implemented in unprotected rice fields, where the majority of ducks often feed. By extending the ban to all waterfowl hunting (not only that undertaken in protected wetlands) the risk of Pb poisoning in waterfowl can be greatly reduced.Peer Reviewe

Reducing Pb poisoning in birds and Pb exposure in game meat consumers: The dual benefit of effective Pb shot regulation

The use of lead (Pb) ammunition in the form of shot pellets has been identified as a Pb exposure risk in wildlife and their human consumers. We explore the hypothesis that Pb shot ban enforcement reduces the risk of avian Pb poisoning as well as Pb exposure in game meat consumers. We assessed compliance with a partial ban on Pb shot commencing in 2003 by examination of 937 waterbirds harvested by hunters between 2007 and 2012 in the Ebro delta (Spain). Prevalence of Pb shot ingestion was determined, as were Pb concentrations in liver and muscle tissue to evaluate the potential for Pb exposure in game meat consumers. Hunted birds with only embedded Pb shot (no steel) declined from 26.9% in 2007-08 to <. 2% over the following three hunting seasons after ban reinforcement. Pb shot ingestion in mallards decreased from a pre-ban value of 30.2% to 15.5% in the post-ban period. Liver Pb levels were predominantly defined by the presence of ingested shot, whereas muscle levels were defined by the presence of both ingested and embedded shot. Only 2.5% of mallard muscle tissue had Pb levels above European Union regulations for meat (0.1. μg/g wet weight) in the 2008-09 season, when Pb shot ingestion prevalence was also at a minimum (5.1%). Effective restrictions in Pb ammunition use have a dual benefit since this reduces Pb exposure for game meat consumers due to embedded ammunition as well as reducing Pb poisoning in waterbirds.This study was supported by the Spanish Ministry of Science and Innovation (grants CGL2007-62797 and CGL2010-17030). NVC benefits from an FPI Fellowship (BES-2011-045670), MAT and MEOS were contracted under the Juan de la Cierva program and MMH benefits from a Marie Curie Fellowship (PIEF-GA-2011-299747).Peer Reviewe

Compliance with the ban of lead ammunition in a Mediterranean wetland, the Ebro delta

Resumen del trabajo presentado al 23rd Annual Meeting of the Society of Environmental Toxicology and Chemistry, celebrado en Glasgow (Escocia) del 12 al 16 de mayo de 2013.The ingestion of lead (Pb) shot used for hunting continues being the main cause of Pb poisoning in waterfowl. In the Ebro delta (Spain), protected wetlands are surrounded by rice fields where waterbirds feed, and where Pb ammunition is still allowed. High Pb shot densities in sediments, and in turn high ingestion prevalence in waterfowl, have been detected. The use of Pb ammunition and the accumulation of Pb by birds after shot ingestion may pose a risk for human health due to consumption of contaminated meat. We assessed the degree of compliance with the ban on Pb ammunition in the Ebro delta wetlands, and studied the effect of the ban on the prevalence of Pb shot ingestion in waterbirds and on Pb levels in game meat. Waterfowl carcasses were collected and X-rayed from hunting bags (2007-2011) to determine the percentage of Pb and non-toxic embedded shot. Concentrations of Pb were analyzed in livers and muscles. In addition, gizzards were collected from hunting bags (2007-2012) and examined to determine the percentage of Pb shot ingestion. During the first study season minimum hunter compliance, estimated as the percentage of waterbirds having only embedded steel shot (the non-toxic alternative) was 48.75%, while 26.88% of birds had only embedded Pb shot (minimum hunter noncompliance). These values changed in the subsequent seasons to 68.95% and 1.13%, respectively. The little compliance detected during the first study season led local administration to notify hunters that a total prohibition of hunting in protected wetlands would enter into force if the prohibition was not observed. Pb ingestion prevalence in 2007-2008 (28.6%) was not different from the pre-ban value (30.2%), but decreased significantly to values below 17.9% in the following seasons. Birds continue ingesting Pb shot at a relative high proportion, although their prohibition slowly contributes to reduce prevalence of ingestion. Pb muscle concentrations decreased significantly after the ban, in spite of which most species present individuals with Pb liver and muscle concentrations over the maximum safety limits. Whereas muscle Pb levels were determined by the presence of both ingested and embedded shot (all p< 0.001), liver levels largely depended on ingested shot (p< 0.001). Thus, besides restrictions in Pb ammunition use, additional mechanisms to reduce Pb ingestion prevalence in waterfowl are necessary to reduce risks for human consumers.Peer Reviewe

Diversity, Ecology and Biogeochemistry of Cyst-Forming Acantharia (Radiolaria) in the Oceans

Marine planktonic organisms that undertake active vertical migrations over their life cycle are important contributors to downward particle flux in the oceans. Acantharia, globally distributed heterotrophic protists that are unique in building skeletons of celestite (strontium sulfate), can produce reproductive cysts covered by a heavy mineral shell that sink rapidly from surface to deep waters. We combined phylogenetic and biogeochemical analyses to explore the ecological and biogeochemical significance of this reproductive strategy. Phylogenetic analysis of the 18S and 28S rRNA genes of different cyst morphotypes collected in different oceans indicated that cyst-forming Acantharia belong to three early diverging and essentially non symbiotic clades from the orders Chaunacanthida and Holacanthida. Environmental high-throughput V9 tag sequences and clone libraries of the 18S rRNA showed that the three clades are widely distributed in the Indian, Atlantic and Pacific Oceans at different latitudes, but appear prominent in regions of higher primary productivity. Moreover, sequences of cyst-forming Acantharia were distributed evenly in both the photic and mesopelagic zone, a vertical distribution that we attribute to their life cycle where flagellated swarmers are released in deep waters from sinking cysts. Bathypelagic sediment traps in the subantarctic and oligotrophic subtropical Atlantic Ocean showed that downward flux of Acantharia was only large at high-latitudes and during a phytoplankton bloom. Their contribution to the total monthly particulate organic matter flux can represent up to 3%. High organic carbon export in cold waters would be a putative nutritional source for juveniles ascending in the water column. This study improves our understanding of the life cycle and biogeochemical contribution of Acantharia, and brings new insights into a remarkable reproductive strategy in marine protists