How to stay together? Habitat use by three sympatric sharks in the western coast of Baja California Sur,Mexico

Environmental Science and Pollution Research - Sharks are top predators and play an important role in the regulation of marine ecosystems at lower trophic position. Mustelus californicus, Sphyrna...     

Testing isosource: stable isotope analysis of a tropical fishery with diverse organic matter sources

We sampled consumers and organic matter sources (mangrove litter, freshwater swamp-forest litter, seagrasses, seagrass epiphytes, and marine particulate organic matter [MPOM]) from four estuaries on Kosrae, Federated States of Micronesia for stable isotope (sigma13C and sigma34S) analysis. Unique mixing solutions cannot be calculated in a dual-isotope, five-endmember scenario, so we tested IsoSource, a recently developed statistical procedure that calculates ranges in source contributions (i.e., minimum and maximum possible). Relatively high minimum contributions indicate significant sources, while low maxima indicate otherwise. Litter from the two forest types was isotopically distinguishable but had low average minimum contributions (0-8% for mangrove litter and 0% for swamp-forest litter among estuaries). Minimum contribution of MPOM was also low, averaging 0-13% among estuaries. Instead, local marine sources dominated contributions to consumers. Minimum contributions of seagrasses averaged 8-47% among estuaries (range 0-88% among species). Minimum contributions of seagrass epiphytes averaged 5-27% among estuaries (range 0-69% among species). IsoSource enabled inclusion of five organic matter sources in our dual-isotope analysis, ranking trophic importance as follows: seagrasses > seagrass epiphytes > MPOM > mangrove forest > freshwater swamp-forest. IsoSource is thus a useful step toward understanding which of multiple organic matter sources support food webs; more detailed work is necessary to identify unique solutions.     

Cultivation of garden vegetables in Peoria Pool sediments from the Illinois River: a case study in trace element accumulation and dietary exposures

This case study was conducted to evaluate the use of reclaimed lake sediment as a growth media for vegetable production and to estimate whether accumulation of micronutrients and heavy metals in the vegetables would impact human nutrition or health, respectively. Five plant species, bean (Phaseolus vulgaris L.), broccoli (Brassica oleracea L.), carrot (Daucus carota L.), pepper (Capsicum annum L.), and tomato (Lycopersicon esculentum L.), were grown in pots containing either reclaimed sediment from the Illinois River or a reference soil. Edible and vegetative tissues from the plants were analyzed for 19 elements, including As, Cd, Cr, Cu, Hg, Mo, Ni, Pb, Se, and Zn. Tomato and pepper grown in sediment showed significantly greater biomass and yield as compared to plants from the reference soil. Elemental analysis of the tissues revealed that Zn and Mo were the only elements that were significantly greater in sediment-grown plants on a consistent basis. While significant, Zn concentrations were no more than 3-fold higher than those in plants from the reference soil. The same trend was observed for Mo, except for bean tissues, which showed a 10-fold greater concentration in sediment-grown plants. The projected dietary intake of Cu, Mo, and Zn from consumption of sediment-grown vegetable tissues was significantly higher than for soil-grown plants, although the contribution to the recommended dietary allowances (RDAs) for these elements was substantial only for Mo. Intake of sediment-grown beans would have provided 500% of the dietary Mo RDA. While this is below the lowest observable adverse effect level (LOAEL) value for this element, there is no evidence to indicate that there would be a nutritional or therapeutic benefit from the consumption of bean containing this level of Mo. The dietary exposures to Cd and Pb would have been below the pertinent limits for all age and gender groups with the exception of the cumulative dietary Cd exposure to the 1-3 year age group. The results from this study suggest that this reclaimed sediment can be utilized for the production of vegetables intended for human consumption. The results from this case study also suggest that sediment material with similar physicochemical characteristics and elemental concentrations that fall within the pertinent regulatory guidelines should also be a suitable and safe medium for vegetable production.     

Ontogenetic development of digestive enzyme activities in larval walleye pollock,Theragra chalcogramma

Activities of digestive enzymes trypsin, amylase and lipase in laboratory-reared walleye pollock, Theragra chalcogramma, were measured from hatching to Day 39 (just before notochord flexion) in 1993. All measurements were conducted individually or semi-individually (groups of two larvae of the same standard length). Close relationships between digestive enzyme activities and morphological development of digestive organs were observed. Activities of trypsin and lipase were low during the transition period from endogenous to exogenous energy. Amylase activity was constant with large variance during the same period. Specific enzyme activities of trypsin and amylase indicated high values with large variance during the early period. All three enzyme activities increased with age afterthe transition period, and the specific enzyme activities became constant. The existence of two types of lipase was suggested. One lipase showed a peak of specific activity at Day 4 and might be related to yolk-sac absorption. The activity of the other lipase increased with age after Day 14 and might be related to digestion of prey lipid. Our results suggest that digestive enzymes included in food organisms supplement larval pollock digestive enzymes.     

Global hexachlorobenzene emissions

Information from a variety of sources has been assembled to give a global picture of hexachlorobenzene (HCB) emissions in the mid 1990s. No single overwhelming source of HCB was identified. The best estimates of global HCB emissions from different categories of sources are as follows: pesticides application - 6500 kg/yr; manufacturing - 9500 kg/yr; combustion - 7000 kg/yr, includes 500 kg from biomass burning. This adds up to total current HCB emissions of approximately 23,000 kg/yr with an estimated range 12,000-92,000 kg/yr. A substantial portion of HCB measured in the atmosphere is thought to come from volatilization of "old" HCB on the soil from past contamination along with unidentified sources. No information on potential sources in developing countries was available.     

Analysis of per- and polyfluorinated alkyl substances in air samples from Northwest Europe

Air samples were collected from 4 field sites in Europe: 2 sites from the UK, Hazelrigg (semi-rural) and Manchester (urban); 1 site from Ireland: Mace Head (rural); and 1 site from Norway: Kjeller (rural). Additionally, air samples were taken from indoor locations in Troms?, Norway. Air samples were collected using high-volume air samplers employing sampling modules containing glass-fibre filters (GFFs, particle phase), and glass columns with a polyurethane foam (PUF)-XAD-2-PUF sandwich (gaseous phase). Typical outdoor air volumes required for the determination of per- and polyfluorinated alkyl substances (PFAS) ranged from 500-1800 m3. GFFs and PUF-XAD columns were analysed separately to obtain information on phase partitioning. All air samples were analysed for volatile, neutral PFAS, with selected GFF samples halved for analysis of both neutral and airborne particle-bound ionic PFAS. Volatile PFAS were extracted from air samples by cold-column immersion with ethyl acetate, and were analysed by gas chromatography-mass spectrometry in the positive chemical ionisation mode (GC-PCI-MS). Ionic PFAS were extracted from GFFs by sonication in methanol, and were analysed by liquid chromatography-time-of-flight-mass spectrometry (LC-TOF-MS) using electrospray ionisation in the negative ion mode (ESI-). Perfluorooctanoate (PFOA) was often the predominant analyte found in the particulate phase at concentrations ranging from 1-818 pg m(-3), and 8:2 fluorotelomer alcohol (FTOH) and 6:2 FTOH were the prevailing analytes found in the gas phase, at 5-243 pg m(-3) and 5-189 pg m(-3), respectively. These three PFAS were ubiquitous in air samples. Many other PFAS, both neutral and ionic, were also present, and levels of individual analytes were in the 1-125 pg m(-3) range. Levels of some PFAS exceeded those of traditional persistent organic pollutants (POPs). In this study, the presence of 12:2 FTOH and fluorotelomer olefins (FTolefins), and ionic PFAS other than perfluorooctane sulfonate (PFOS) and PFOA, are reported in air samples for the first time. Concentrations of neutral PFAS were several orders of magnitude higher in indoor air than outdoor air, making homes a likely important diffuse source of PFAS to the atmosphere. Our repeated findings of non-volatile ionic PFAS in air samples raises the possibility that they might directly undergo significant atmospheric transport on particles away from source regions, and more atmospheric measurements of ionic PFAS are strongly recommended.     

Sustainable production in circular economy: aerogel upscaling production

Environmental Science and Pollution Research -     

Ecosystems for future generations

Environmental Science and Pollution Research -     

Growth responses of Avicennia germinans and Batis maritima seedlings to weathered light sweet crude oil applied to soil and aboveground tissues

Environmental Science and Pollution Research - Oil spills are a significant stressor to coastal and maritime environments worldwide. The growth responses of Batis maritima and Avicennia germinans...     

Unmanned aerial vehicle images in the machine learning for agave detection

Environmental Science and Pollution Research - In this study, six supervised classification algorithms were compared. The algorithms were based on cluster analysis, distance, deep learning, and...