Proximate and elemental composition and energy content of mesopelagic crustaceans from the Eastern Gulf of Mexico

The proximate and elemental chemical compositions of 25 species of pelagic decapod and mysid crustaceans collected from the eastern Gulf of Mexico (27°N; 86°W, 1984 to 1989) was examined. Water level ranged from 63 to 95% and increased slightly with species' increased depth of occurrence. Protein levels were generally high (1.5 to 18.3% wet wt, WW; 27.6 to 62.4% ash-free dry wt, AFDW) and comprised the primary organic component in the majority of species. Protein, both as % WW and % AFDW, decreased with increased depth of occurrence. In contrast to protein, lipid levels were low (0.5 to 8.9% WW; 5.7 to 60.9% AFDW), and increased with increased depth of occurrence. Carbon and nitrogen best mirrored measured lipid and protein levels when considered as non-protein carbon and non-chitin nitrogen, respectively. C:N ratios increased with increased depth, consistent with changes in protein and lipid with depth. Because of their compositional attributes, resident Gulf of Mexico species have a low total wet weight energy content relative to species from more productive regions. Energy content showed no significant trend with depth. Vertical migration patterns were distinctly different between shallow-and deep-living gulf species and these differences were largely responsible for the relationships observed between composition and depth. In migrating species, the protein and nitrogen content were higher, the lipid and carbon contents and C:N ratio lower, than in non-migrating species. Three deep-living species of the genus Acanthephyra were found to be compositionally atypical, resembling shallow, migrating types rather than other deep-living, non-migratory species.     

Freshwater stress on small island developing states: population projections and aridity changes at 1.5 and 2 °C

Small island developing states (SIDS) face multiple threats from anthropogenic climate change, including potential changes in freshwater resource availability. Due to a mismatch in spatial scale between SIDS landforms and the horizontal resolution of global climate models (GCMs), SIDS are mostly unaccounted for in GCMs that are used to make future projections of global climate change and its regional impacts. Specific approaches are required to address this gap between broad-scale model projections and regional, policy-relevant outcomes. Here, we apply a recently developed methodology that circumvents the GCM limitation of coarse resolution in order to project future changes in aridity on small islands. These climate projections are combined with independent population projections associated with shared socioeconomic pathways (SSPs) to evaluate overall changes in freshwater stress in SIDS at warming levels of 1.5 and 2 °C above pre-industrial levels. While we find that future population growth will dominate changes in projected freshwater stress especially toward the end of the century, projected changes in aridity are found to compound freshwater stress for the vast majority of SIDS. For several SIDS, particularly across the Caribbean region, a substantial fraction (~?25%) of the large overall freshwater stress projected under 2 °C at 2030 can be avoided by limiting global warming to 1.5 °C. Our findings add to a growing body of literature on the difference in climate impacts between 1.5 and 2 °C and underscore the need for regionally specific analysis.     

A Quantitative Safety Assessment Model For Transgenic Protein Products Produced In Agricultural Crops

Transgenic plants are now being used to develop pharmaceutical and industrial products in addition to their use in crop improvement. Using confinement requirements, these transgenic plants are grown and processed under conditions that prevent intermixing with commodity crops. Regulatory agencies in the United States have provided guidance of zero tolerance of these new industrial crops with commodity crops. While this is a worthy goal, it is theoretically unattainable. In spite of the best containment practices, there is a potential risk using any system of production due to unforeseen incidences including natural disasters or exposure to workers. The precautionary principle has been used for numerous regulated articles in addressing the potential risks of new products and technology based on a risk assessment in similar situations. We present here a risk assessment model that could be used as a start to develop an accepted model for the industry. The model is based on current risk models used for other regulated articles, but adapted for these types of products. This could be used to determine action levels in the event of an unintended exposure or to ensure that detection or confinement methods are adequate to avoid risks. As an example, aprotinin, a therapeutic protein now being produced in maize, was evaluated for potential risk to humans using this model.     

Relating Background NO2 Concentrations in Air to Air Mass History Using Non-Parametric Regression Methods: Application at Two Background Sites in Ireland

The concentration of nitrogen dioxide (NO₂) in background air varies temporally and spatially and is influenced by meteorological and anthropogenic factors. Background concentrations used in local air quality modelling studies have a significant effect on the accuracy of the overall result and when based on short-term monitoring data, variation in concentrations with air mass history is often unaccounted for. The current paper presents a powerful tool for the quantification and separation of local and regional air mass effects on background air quality. The origin of and the regions traversed by an air mass prior to reaching a receptor has been modelled using HYsplit-4. Trajectories (between 12 and 96?h duration) were defined based on the frequency with which they passed into 16 predefined compass quadrants and each represented as a vector. Using this vector as the predictor variable and the background concentration as the response variable, non-parametric regression using a Gaussian kernel function was carried out. A graphical output indicated the trajectory direction of maximum NO₂ concentration, while allowing distinction to be made between spurious and true peaks. In all cases, air mass history was found to have a statistically significant effect on NO₂ concentrations. Incorporating emissions data into the analysis local and regional effects were separated and quantified. It was found that emissions in the UK and Europe have a significant effect on background NO₂ concentrations in Ireland and in some instances supersede domestic emissions. The methods can be used to identify source regions, separate local and regional effects and improve predictions of background concentrations based on limited monitoring data. In particular, the results highlight the importance of considering air mass history when assessing background concentration levels for use in local air quality modelling studies.     

Risk of polycyclic aromatic hydrocarbon (PAH) exposure from ingested food: the Azerbaijan case study

Risks due to polycyclic aromatic hydrocarbons (PAHs) exposure from food consumption for the population of Azerbaijan were determined using deterministic and probabilistic methods. The guidelines and methods described and presented in the United States Environmental Protection Agency (U.S. EPA) Risk Assessment Guidance for Superfund (RAGS) Part A was used in performing the risk assessments. The current study utilized concentration data from different sources representing international studies performed over the past decade to determine those food products that contribute the most exposure to PAHs through ingestion for the Azeri population. Due to lack of concentration data from middle-Eastern countries, only European countries were considered and used for this analysis. Using the benzo[a]pyrene (BaP) toxicity equivalency factors (TEFs) to adjust the concentrations of the individual PAH compounds to BaP equivalent concentrations, risk analyses were performed. Deterministic risk estimates fell within probabilistic risk estimates. Child risks were consistently four to seven times higher in magnitude than adult risks. Risk potentials determined for the food exposure pathway were also determined to be up to ten times higher in magnitude than risks determined from exposures due to other pathways such as soil contamination. It was observed that three major factors contributed to the variability in the assessment results, which were child and adult body weights, consumption rates of the different food groups, and the variances of the input data. The most prevalent pathways of PAH exposure from the dietary patterns of the Azerbaijani population were determined to be from bread and bakery products, milk and dairy products, and egg products.     

Proximate composition of Antarctic mesopelagic fishes

Eleven mesopelagic fish species from the Weddell/Scotia Sea region of the Antarctic captured during the austral spring 1983, austral fall 1986, and austral winter 1988, were analyzed for proximate composition. Water, ash level, protein, lipid and carbohydrate were examined in relation to depth of occurrence and season. No depth-related trends were evident, primarily due to a low species diversity and minimal differences in those species' vertical distributions. The Antarctic speciesElectrona antarctica showed a significant increase in lipid level (% wet wt and % ash-free dry wt) between spring, fall and winter. The increase may signify an accumulation over the productive season, possibly as a reserve for the winter months. Lipid levels (% wet wt and % ash-free dry wt) were significantly lower in the Weddell Sea specimens examined in this study than in previously examined identical and congeneric species taken during the same season from a more productive near-shore Antarctic region. Comparisons with congeners and confamilials from tropical-subtropical and temperate systems revealed variable trends. The Antarctic speciesE. antarctica andCyclothone microdon had lower water and protein (% wet wt) levels than similar species from tropical-subtropical or temperate regions. Lipid levels of the two species are similar to temperate individuals, while energy levels are slightly higher. In contrast, species of the genusBathylagus show no trends in composition as a function of latitude. Differences in productivity, water-column temperature-structure, and seasonality are important considerations when examining trends among mesopelagic species.     

Analysis of 2,3,7,8-Tetrachlorodibenzo-p-dioxin in Great Lakes fish

In fish samples from Lake Ontario and Lake Huron 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) was found at concentrations from 2 to 162 pg/g (ppt) and from 2.5 to 29 ppt respectively. Fish from the other Great Lakes (Lake Superior, Lake Michigan and Lake Erie) generally had no detectable signals for TCDD although a few samples had < 3 ppt.     

Matrix-immobilized organoclay for the sorption of polycyclic aromatic hydrocarbons and pentachlorophenol from groundwater

Sorbent materials consisting of organoclay immobilized onto the surface of a solid support were evaluated for use in pentachlorophenol (PCP) and polycyclic aromatic hydrocarbon (PAH) remediation of groundwater at a creosote-contaminated Superfund site. Cetylpyridinium-exchanged low pH montmorillonite clay (CP-LPHM) was bonded to either sand (CP-LPHM/sand) or granular activated carbon (GAC) (CP-LPHM/GAC) using the free acid form of carboxymethylcellulose as an adhesive. Effluent from an oil-water separator was eluted through equal bed volumes of composite (4 g 3:2 CP-LPHM/GAC or 13 g CP-LPHM/sand), affinity-extracted, and quantitatively analyzed by GC/MS. PCP, naphthalene, fluorene, phenanthrene, pyrene, and total PAHs were initially reduced by both CP-LPHM/GAC (> or =99%, 61%, 99%, > or =99%, 97%, and 94%, respectively) and CP-LPHM/sand (90%, 70%, 94%, 95%, 93%, and 86%, respectively). Complete breakthrough of naphthalene occurred after approximately 15 h of elution through 3:2 CP-LPHM/GAC and 22 h through CP-LPHM/sand. PCP showed complete breakthrough following 18 h of elution through 3:2 CP-LPHM/GAC and 26 h through CP-LPHM/sand. However, 50% breakthrough was not attained for higher molecular weight PAHs, as fluoranthene, pyrene, benzo[a]anthracene, and chrysene continued to be greatly reduced with both 3:2 CP-LPHM/GAC (98%, 95%, 94%, and 95%, respectively) and CP-LPHM/sand (75%, 73%, 76%, and 78%, respectively) after 48 h of continuous elution. Results confirm prior studies, indicating that these organoclay-containing composites have a high capacity for contaminants found in wood preserving waste. Further, results suggest that the inclusion of CP-LPHM may be useful as part of an effective strategy for groundwater remediation of high concentrations of PCP and PAHs, in particular high molecular weight and carcinogenic PAHs.     

Proximate composition and nucleic acid content of premetamorphic leptocephalus larvae of the congrid eel Ariosoma balearicum

Water, ash, proximate composition (protein, lipid, carbohydrate, hexosamine), and nucleic acid (DNA, RNA) content were measured in premetamorphic larvae of the congrid eel Ariosoma balearicum (Delaroche) collected from the eastern Gulf of Mexico. Specimens ranged from 15.0 to 202.3 mm total length (TL) and 0.0116 to 4.3860 g wet mass (WM). Water content increased linearly with increasing specimen mass over the entire size range; consequently, percent water was uniform and had a mean value of 92.9±1.09% WM. Ash content also increased linearly with specimen mass, but only up to a mass of 2.5 g WM (165 mm TL). Ash content in specimens >165 mm TL showed only a small increase with mass, suggesting an improved osmoregulatory capability in larger individuals. The absolute amount of all proximate components increased with increasing specimen size, but rates of deposition among the components varied, resulting in different patterns in the relative concentrations of each with growth. Protein dominated the ash-free dry mass (AFDM) throughout development (29 to 59% AFDM); carbohydrate and hexosamine occurred in similar proportions (8 to 24% AFDM). Lipid was a significant proportion of the AFDM in only the smallest individuals. Lipid concentrations decreased initially as mass increased in individuals smaller than 0.4 g WM (90 mm TL), indicating a low rate of lipid deposition in small individuals. In specimens >90 mm TL, lipid concentrations were uniform and had a mean of 12% AFDM. Trends for biochemical components and nucleic acids suggest that growth of Phase I leptocephali occurs in two subphases (Ia and Ib). Phase Ia is characterized by cellular proliferation, preferential synthesis of protein and carbohydrate relative to lipid, and growth manifested more as increased length rather than increased mass. For A. balearicum, Phase Ia extends from yolk-sac absorption to 90 mm TL. In Phase Ib, nucleic acid content levels off, lipid deposition increases, and mass increases exponentially.