Effect of low levels of dietary available phosphorus on phosphorus utilization,bone mineralization,phosphorus transporter mRNA expression and performance in growing pigs

A study was conducted to examine the effects of different dietary levels of available phosphorus (aP) on P excretion, bone mineralization, performance and the mRNA expression of sodium-dependent P transporters in growing pigs. Sixty-day old growing pigs (n = 54) with an average initial BW of 19.50 ± 1.11 kg were randomly allocated to a control diet (C) containing 0.23% available phosphorus (aP), T1 containing 0.17% aP and T2 containing 0.11% aP. There were 6 pens per treatment with 3 pigs per pen. Body weight and feed intake were measured weekly. At the end of each week, one pig from each pen was housed in a metabolic crate for 24 h to collect fecal and urine samples and then sacrificed to obtain third metacarpal (MC3) bones and jejunal and kidney samples. Bones were scanned by Dual Energy X-ray Absorptiometry (DEXA). Fecal and urine samples were sub-sampled and analyzed for P content. The expression of P transporter mRNA in jejunum and kidney samples was measured using quantitative real-time polymerase chain reaction (qRT-PCR). Data were analyzed using GLM procedure of the Statistical Analysis System (SAS Institute version 9.2). Pigs fed the T2 diet had reduced (P < 0.05) average daily gain (ADG) and gain to feed (G:F) compared to those fed the C diet during week 2. Overall, ADG and G:F were also reduced (P < 0.05) in pigs fed the T2 diet compared to those fed the C and T1 diets. Bone mineral density (BMD) and bone mineral content (BMC) were reduced (P < 0.05) in pigs fed the T2 diet compared to those fed the C diet throughout the experiment. At week 1, jejunal mRNA expression of Na (+)-dependent phosphate transporter 2 (SLC34A2) was increased (P < 0.01) in pigs fed the T2 diet compared to C diet. Renal mRNA expression of Na(+)-dependent phosphate transporter 1 (SLC34A1) and SLC34A3 were increased (P < 0.05) in pigs fed the T2 diet compared to those fed the C diet at week 2 and was accompanied by lower (P < 0.05) urinary P in pigs fed the T2 diet during week 2 and week 3. In conclusion, growing pigs are highly sensitive to low dietary P as shown by reduced ADG, bone mineralization and urinary P level, but moderate reduction in dietary P up to 0.17% aP in the diet has the potential to reduce environmental pollution by reducing P concentration in swine manure and without compromising performance.     

Can the legacy of industrial pollution influence antimicrobial resistance in estuarine sediments?

Antimicrobial resistance (AMR) represents a major global health threat, as well as a major hazard to sustainable economic development and national security. It remains, therefore, vital that current research aligns to policy development and implementation to alleviate a potential crisis. One must consider, for example, whether drivers of antibiotic resistance can be controlled in the future, or have they already accumulated in the past, whether from antibiotics and/or other pollutants? Unfortunately, industrial heritage and its pollution impact on the prevalence of environmental AMR have largely been ignored. Focussing on industrialised estuaries, we demonstrate that anthropogenic pollution inputs in addition to the natural diurnal environmental conditions can sufficiently create stressful conditions to the microbiome and thus promote selective pressures to shift the resistome (i.e., collection of resistance traits in the microbiological community). Unfortunately, the bacteria’s survival mechanisms, via co-selective pressures, can affect their susceptibility to antibiotics. This review highlights the complexity of estuarine environments, using two key contaminant groups (metals/toxic elements and polyaromatic hydrocarbons), through which a variety of possible chemical and biological pollutant stressors can promote the emergence and dissemination of antimicrobial resistance. We find compelling divers to call on more focused research on historically disrupted ecosystems, in propagating AMR in the real world.

     

Assisted species migration and hybridization to conserve cold-adapted plants under climate change

Temperature rise due to climate change is putting many arctic and alpine plants at risk of extinction because their ability to react is outpaced by the speed of climate change. We considered assisted species migration (ASM) and hybridization as methods to conserve cold-adapted species (or the genes thereof) and to minimize the potential perturbation of ecosystems due to climate change. Assisted species migration is the deliberate movement of individuals from their current location to where the species’ ecological requirements will be matched under climate projections. Hybridization refers to crossbreeding of closely related species, where for arctic and alpine plants, 1 parent is the threatened cold-adapted and the other its reproductively compatible, warm-adapted sibling. Traditionally, hybridization is viewed as negative and leading to a loss of biodiversity, even though hybridization has increased biodiversity over geological times. Furthermore, the incorporation of warm-adapted genes into a hybrid may be the only means for the persistence of increasingly more maladapted, cold-adapted species. If approached with thorough consideration of fitness-related parameters of the source population and acknowledgement of the important role hybridization has played in shaping current biodiversity, ASM and hybridization could help save partial or whole genomes of key cold-adapted species at risk due to climate change with minimal negative effects on ecosystem functioning.     

Late season pharmaceutical fate in wetland mesocosms with and without phosphorous addition

The fate of six human-use drugs was assessed and predicted in mesocosms designed to mimic shallow constructed wetlands during the onset of fall and senescence. Mesocosms were monitored for 28 days after the addition of carbamazepine, clofibric acid, fluoxetine and naproxen (nominal initial concentrations of 5 μg/L each), sulfamethoxazole, and sulfapyridine (nominal initial concentrations of 150 μg/L each), with and without phosphorous (P) addition at 1.6 mg/L. We hypothesized that addition of P would stimulate primary productivity and enhance removal of pharmaceuticals from the water column. Carbamazepine, clofibric acid, fluoxetine, and naproxen had half-lives of 8.7, 11, 1.5, and 2.5, and 8.6, 11.0, 1.4, and 2.5 days in treatments with and without P amendment, respectively. Sulfamethoxazole and sulfapyridine had half-lives of 17 and 4.9 days in mesocosms with P amendment and 17 and 4.7 days without amendment. A concurrent pulse of P with pharmaceuticals did not significantly enhance the removal of these compounds. Predicted half-lives from modeling efforts were consistent with observed values, with photolysis the greatest contributor to chemical attenuation.

     

Hg Vapor Emission from Broken Compact Fluorescent Lamps (CFLs) in an Acrylic Chamber

The United States Environmental Protection Agency/Environmental Response Team (US EPA/ERT), in collaboration with St. John's College, Dr. B. R. Ambedkar University, Agra, India, is conducting a study to determine Hg vapor emission rates resulting from broken compact fluorescent lamps (CFLs) in a residential setting. The overall objectives of the study are to determine Hg vapor emission data and provide homeowners with cleanup procedures and disposal options for broken CFLs. Most of the currently available CFLs in the US market are manufactured in China for US companies. Several different types of CFLs were purchased from local stores and their Hg content was determined. Based on previous studies, such as the 2011 study by Singhvi and colleagues, five popular spiral CFLs were selected for emission studies in an acrylic chamber. This study found that Hg vapor emissions from CFLs may be significantly greater than those from beads of liquid Hg with weights comparable to the Hg content of the CFLs. The average 24-hour Hg loss into the atmosphere from CFLs broken on a plastic surface ranged from 0.6% to 22% of the bulb content, while that for CFLs broken on carpet ranged from 2.6% to 28%. Projections for a 12 foot × 9.33 foot × 8 foot (25.4 m³) room based on the chamber measurements in this study indicate that CFL breakage in some household settings may produce 24-hour Hg concentrations above the 2000 Agency for Toxic Substances and Disease Registry (ATSDR) minimum risk level (MRL) of 0.2 μg/m³, for typical air exchange rates. This study also indicates that Hg emission may not be proportional to exposed surface area based on experiments using liquid Hg with different surface areas.     

Decision-making for sustainable location of a cement plant in the state of Florida

Site selection is a typical strategic decision for many industries that deals with specifying the most appropriate location for a facility. In the context of sustainable development, site selection decisions need to be improved by adopting environmental, economic and social requirements. This study aims to frame sustainable location decisions by conducting a case study of siting a new cement plant in the state of Florida. As a part of the study, a wide range of technical and sustainability criteria has developed. These criteria can help decision-makers in the cement industry evaluate the selection of a location with the requirements of sustainable development. The sustainability characteristics of alternative sites in the state of Florida are evaluated based on the criteria to identify the most appropriate ones. The analytical hierarchy processand geographic information system techniques are utilized to weight the criteria and evaluate the characteristics of site candidates.     

Comparing PFAS to other groundwater contaminants: Implications for remediation

Established groundwater contaminants such as chlorinated solvents and hydrocarbons have impacted groundwater at hundreds of thousands of sites around the United States and have been responsible for multibillion dollar remediation expenditures. An important question is whether groundwater remediation for the emerging contaminant class comprised of per‐ and polyfluoroalkyl substances (PFAS) will be a smaller, similar, or a larger‐scale problem than the established groundwater contaminants. A two‐pronged approach was used to evaluate this question in this paper. First, nine quantitative scale‐of‐remediation metrics were used to compare PFAS to four established contaminants: chlorinated solvents, benzene, 1,4‐dioxane, and methyl tert‐butyl ether. These metrics reflected the prevalence of the contaminants in the U.S., attenuation potential, remediation difficulty, and research intensity. Second, several key challenges identified with PFAS remediation were evaluated to see similar situations (qualitative analogs) that have been addressed by the remediation field in the past. The results of the analysis show that four out of nine of the evaluated quantitative metrics (production, number of potential sites, detection frequency, required destruction/removal efficiency) indicate that the scale of PFAS groundwater remediation may be smaller compared to the current scale of remediation for conventional groundwater contaminants. One attenuation metric, median plume length, suggests that overall PFAS remediation could pose a greater challenge compared to hydrocarbon sites, but only slightly larger than chlorinated volatile organic compounds sites. The second attenuation metric, hydrophobic sorption, was not definitive regarding the potential scale of PFAS remediation. The final three metrics (regulatory criteria, in‐situ remediation capability, and research intensity) all indicate that PFAS remediation might end up being a larger scale problem than the established contaminants. An assessment of the evolution of groundwater remediation capabilities for established contaminants identified five qualitative analogs for key PFAS groundwater remediation issues: (a) low‐level detection analytical capabilities; (b) methods to assess the risk of complex chemical mixtures; (c) nonaqueous phase dissolution as an analog for partitioning, precursors, and back diffusion at PFAS sites; (d) predictions of long plume lengths for emerging contaminants; and (e) monitored natural attenuation protocols for other non‐degrading groundwater contaminants. Overall the evaluation of these five analogs provided some comfort that, while remediating the potential universe of PFAS sites will be extremely challenging, the groundwater community has relevant past experience that may prove useful. The quantitative metrics and the qualitative analogs suggest a different combination of remediation approaches may be needed to deal with PFAS sites and may include source control, natural attenuation, in‐situ sequestration, containment, and point‐of‐use treatment. However, as with many chlorinated solvent sites, while complete restoration of PFAS sites may be uncommon, it should be possible to prevent excessive exposure of PFAS to human and ecological receptors.     

Application of multiple-population viability analysis to evaluate species recovery alternatives

Population viability analysis (PVA) is a powerful conservation tool, but it remains impractical for many species, particularly species with multiple, broadly distributed populations for which collecting suitable data can be challenging. A recently developed method of multiple-population viability analysis (MPVA), however, addresses many limitations of traditional PVA. We built on previous development of MPVA for Lahontan cutthroat trout (LCT) (Oncorhynchus clarkii henshawi), a species listed under the U.S. Endangered Species Act, that is distributed broadly across habitat fragments in the Great Basin (U.S.A.). We simulated potential management scenarios and assessed their effects on population sizes and extinction risks in 211 streams, where LCT exist or may be reintroduced. Conservation populations (those managed for recovery) tended to have lower extinction risks than nonconservation populations (mean = 19.8% vs. 52.7%), but not always. Active management or reprioritization may be warranted in some cases. Eliminating non-native trout had a strong positive effect on overall carrying capacities for LCT populations but often did not translate into lower extinction risks unless simulations also reduced associated stochasticity (to the mean for populations without non-native trout). Sixty fish or 5–10 fish/km was the minimum reintroduction number and density, respectively, that provided near-maximum reintroduction success. This modeling framework provided crucial insights and empirical justification for conservation planning and specific adaptive management actions for this threatened species. More broadly, MPVA is applicable to a wide range of species exhibiting geographic rarity and limited availability of abundance data and greatly extends the potential use of empirical PVA for conservation assessment and planning.