Comparison of gut-evacuation rates of feeding and non-feeding Calanus marshallae

Gut-evacuation rates were compared for feeding and non-feeding Calanus marshallae collected near Yaquina Bay, Oregon (44°37N; 124°04W) from June 1986 through May 1987. Evacuation rates were measured at four concentrations of Thalassiosira weissflogii from the decline of gut-pigment fluorescence following transfer of copepods to filtered seawater and from the loss of cells labelled with 68-germanium, a radioactive analog of silicon. There was no significant difference between gut-evacuation rates of feeding and non-feeding copepods over both short-term (20 min) and long-term (90 min) evacuation times. Furthermore there was no difference between rates obtained using either pigment or ⁶⁸Ge as tracers of gut food-passage. These results are discussed in the light of possible dilution of tracer in the guts of feeding copepods due to mixing with unlabelled food. Gut-evacuation rates measured at food concentrations ranging from 500 to 4000 cells ml^-1 were not significantly different, regardless of the technique employed.     

EPA SITE demonstration of the BioTrol soil washing process.

A pilot-scale soil washing process, patented by BioTrol, Inc., was demonstrated on soil contaminated by wood treating waste, primarily pentachlorophenol (PCP) and creosote-derived polynuclear aromatic hydrocarbons (PAHs). Although soil washing was the main object of this demonstration, the treatment train that was evaluated included two other BioTrol technologies for treatment of waste streams from the soil washer. The three technologies were: The BioTrol Soil Washer (BSW)--a volume reduction process, which uses water to separate contaminated soil fractions from the bulk of the soil. The BioTrol Aqueous Treatment System (BATS)--a biological water treatment process. The Slurry Bioreactor (SBR)--a BioTrol biological slurry treatment process conducted in an EIMCO BIOLIFT reactor. The sandy soil at the site, consisting of less than 10 percent of fines, was well suited for treatment by soil washing. The soil washer was evaluated in two tests on soil samples containing 130 ppm and 680 ppm of PCP, respectively. The BSW successfully separated the feed soil (dry weight basis) into 83 percent of washed soil, 10 percent of woody residues, and 7 percent of fines. The washed soil retained about 10 percent of the feed soil contamination while 90 percent of the feed soil contamination was contained within the woody residues, fines, and process water. The soil washer achieved up to 89 percent removal of PCP and 88 percent of total PAHs, based on the difference between their levels in the as-is (wet) feed soil and the washed soil.(ABSTRACT TRUNCATED AT 250 WORDS)     

Forest cover dynamics in the Selva Maya of Central and Southern Quintana Roo,Mexico: deforestation or degradation?

ABSTRACT

Forest cover dynamics (1993-2018) was assessed in two regions on the Yucatan Peninsula: Zona Maya (ZM), 67% indigenous with shifting cultivation and community forestry; and Bacalar–Rio Hondo (BRH), mainly commercial agriculture and pastureland. Degradation (12,915 ha y^?1) exceeded deforestation (5882 ha y^?1) and was worse in BRH. In BRH there was a net forest loss (?1.6% y^?1) associated with pastureland and commercial agriculture. In ZM, mature forest recovery (1.4% y^?1) and dynamic forest cover (continuous loss and gain) were associated with shifting cultivation. Changes were more intense during 2011–2018 and gains of mature forest in ZM and deforested areas in BRH targeted secondary vegetation. Fragments of mature and secondary vegetation decreased, and connectivity improved in ZM, but opposite trends occurred in BRH. Reporting and monitoring deforestation using Global Forest Watch data is inadequate since 62% of forest cover loss represent degrading or recovering forest cover.     

Investigation of volatile methyl siloxanes in biogas and the ambient environment in a landfill

Landfill biogas is a potential alternative for fossil fuel,but the containing impurities,volatile methyl siloxanes(simplified as siloxanes),often cause serious problems in gas turbines when applied to generate electricity.In this research,a collecting and analyzing method based on solvent adsorption and purge and trap-gas chromatography-mass spectrometry was established to determine the siloxanes in biogas from a landfill in Jinan,China,and adjacent ambient samples,such as soil,air,and leachate of the landfill.The results showed that,octamethylcyclotetrasiloxane(D4) and decamethylcyclopentasiloxane(D5) accounted for 63% of total siloxanes;and without considering D4 and D5,the order of detected siloxanes in concentration was found relating to Gibbs free energies of molecules,namely that higher abundant siloxane(except for D4 and D5) usually had lower Gibbs free energy.Additionally,the mass ratio between D4 and octamethyltrisiloxane(L3) in the bio gas varied with different garbage age in landfills,possibly revealing the breaking-down of larger siloxane molecules with time.The samples,which were collected from environmental samples adjacent to the landfill,such as soil,water,and air,presented much higher siloxane level than urban or rural area away from landfills.The current H2 S scrubber of the landfill biogas could decrease the total siloxanes from 10.7 to 5.75 mg/m~3 due to Fe2 O3 and a refrigerant drier in a purification system and cyclic siloxanes were more easily removed than linear ones.     

Hiding in Plain Sight? It’s Time to Investigate Other Possible Transmission Routes for Hepatitis E Virus (HEV) in Developed Countries

Historically in developed countries, reported hepatitis E cases were typically travellers returning from countries where hepatitis E virus (HEV) is endemic, but now there are increasing numbers of non-travel-related (“autochthonous”) cases being reported. Data for HEV in New Zealand remain limited and the transmission routes unproven. We critically reviewed the scientific evidence supporting HEV transmission routes in other developed countries to inform how people in New Zealand may be exposed to this virus. A substantial body of indirect evidence shows domesticated pigs are a source of zoonotic human HEV infection, but there is an information bias towards this established reservoir. The increasing range of animals in which HEV has been detected makes it important to consider other possible animal reservoirs of HEV genotypes that can or could infect humans. Foodborne transmission of HEV from swine and deer products has been proven, and a large body of indirect evidence (e.g. food surveys, epidemiological studies and phylogenetic analyses) support pig products as vehicles of HEV infection. Scarce data from other foods suggest we are neglecting other potential sources of foodborne HEV infection. Moreover, other transmission routes are scarcely investigated in developed countries; the role of infected food handlers, person-to-person transmission via the faecal–oral route, and waterborne transmission from recreational contact or drinking untreated or inadequately treated water. People have become symptomatic after receiving transfusions of HEV-contaminated blood, but it is unclear how important this is in the overall hepatitis E disease burden. There is need for broader research efforts to support establishing risk-based controls.     

Effectiveness of terrestrial protected areas for conservation of lake fish communities

Freshwater protected areas are rare even though freshwater ecosystems are among the most imperiled in the world. Conservation actions within terrestrial protected areas (TPAs) such as development or resource extraction regulations may spill over to benefit freshwater ecosystems within their boundaries. Using data from 175 lakes across Ontario, Canada, we compared common indicators of fish‐assemblage status (i.e., species richness, Shannon diversity index, catch per unit effort, and normalized‐length size spectrum slopes) to evaluate whether TPAs benefit lake fish assemblages. Nearest neighbor cluster analysis was used to generate pairs of lakes: inside versus outside, inside versus bordering, and bordering versus outside TPAs based on lake characteristics. The diversity and abundance indicators did not differ significantly across comparisons, but normalized‐length size spectrum slopes (NLSS) were significantly steeper in lakes outside parks. The latter indicated assemblage differences (greater abundances of small‐bodied species) and less‐efficient energy transfer through the trophic levels of assemblages outside parks. Although not significantly different, pollution‐ and turbidity‐tolerant species were more abundant outside parks, whereas 3 of the 4 pollution‐intolerant species were more abundant within parks. Twenty‐one percent of the difference in slopes was related to higher total dissolved solids concentrations and angling pressure. Our results support the hypothesis that TPAs benefit lake fish assemblages and suggest that NLSS slopes are informative indicators for aquatic protected area evaluations because they represent compositional and functional aspects of communities.     

Pharmaceutical and personal care products (PPCPs) in urban receiving waters

The transport pathways of pharmaceutical and personal care products (PPCP) discharges within the urban water cycle include both combined and separate sewer systems with only the former receiving treatment. The dry-weather flow dilution patterns for selected PPCPs following discharge from a sewage treatment works (STW) to a North London stream indicate a persistent downstream increase in concentration. The dilution ratio analysis also indicates that the STW's final effluent only contributes a dilution of the endogenous concentrations already present in the river flow which reflects a progressive PPCP load with increasing urbanization; "worst-case" scenarios being probably related to wet-weather conditions. Maximum PPCP concentrations fall above the reported PEC levels and the analysis highlights the deficiencies of conventional acute toxicity for the evaluation of long-term effects of episodic urban discharges. Groundwater analysis points to sewer exfiltration which is limited in terms of PPCP impact to 25-50 cm depths.