Agricultural soil as a potential source of input of organochlorine pesticides into a nearby pond

A study was conducted in the southeastern region of Buenos Aires province, Argentina, to assess an agricultural soil as a potential source of organochlorine (OC) pesticides for the aquatic biota of a nearby pond. We analyzed gamma-HCH (lindane), still in use, and the following banned compounds: DDT, DDE, DDD heptachlor, heptachlor epoxide, aldrin, dieldrin and endrin in soil, bulrush, grass shrimp and fish using gas chromatography with electron capture detection (GC-ECD). Among the OC pesticides, lindane was most dominant in the soil (32.6 ng/g dry wt in the upper and 173.9 ng/g dry wt in the lower horizon) and bulrush (1.9 pg/g lipid). Macrophyte also accumulated high levels of heptachlor epoxide (1.5 pg/g lipid). Heptachlor, although present in the soil, was below the detection limit in all aquatic biota studied. Its primary degradation product, heptachlor epoxide, was found in both soil and biota samples. DDT was found at low levels in the surface soil (6.8 ng/g dry wt), but at higher concentrations in fish (3.6 pg/g lipid), although levels were still below permissible levels for human consumption. Since most of the compounds were found in both soil and aquatic biota, our study suggests that agricultural soil could be an important source for OC pesticides in the nearby pond.     

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)     

The effects of light and thallus scour from<Emphasis Type="Italic"> Ecklonia radiata</Emphasis> canopy on an associated foliose algal assemblage: the importance of photoacclimation

Kelp canopies have long been recognised for their influence on the structure of algal assemblages on sublittoral reefs. In Marmion Lagoon, Western Australia, we investigated how a canopy of the small kelp Ecklonia radiata affected the associated foliose algal assemblage and what potential mechanisms were responsible for the effects we observed. Light levels and physical abrasion (thallus scour) by an E. radiata canopy were manipulated in an orthogonal fixed-factor experiment that revealed that changes in light, but not thallus scour, had a significant effect on the composition of the algal assemblage. Reduced light levels were associated with a decrease in the Shannon-Wiener diversity index and an increased dominance of the foliose algae Pterocladia lucida and Rhodymenia sonderi. Photobiological investigations of three foliose species, P. lucida, R. sonderi and Chauviniella coriifolia indicated that they were able to photoacclimate to low light levels by increasing thallus absorption by up to 11%. Photoacclimation was also evident by an increase in the maximum rate of electron transport under low-light conditions. We conclude that the E. radiata canopy in Marmion Lagoon structures the foliose algal assemblage through the modification of the light environment and that this effect may be mediated by differences in the ability of different species of foliose algae to photoacclimate.Communicated by M.S. Johnson, Crawley     

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.     

Altai pika (<Emphasis Type="Italic">Ochotona alpina</Emphasis>) alarm calls: individual acoustic variation and the phenomenon of call-synchronous ear folding behavior

Non-hibernating pikas collect winter food reserves and store them in hay piles. Individualization of alarm calls might allow discrimination between colony members and conspecifics trying to steal food items from a colony pile. We investigated vocal posture, vocal tract length, and individual acoustic variation of alarm calls, emitted by wild-living Altai pikas Ochotona alpina toward a researcher. Recording started when a pika started calling and lasted as long as possible. The alarm call series of 442 individual callers from different colonies consisted of discrete short (0.073–0.157 s), high-frequency (7.31–15.46 kHz), and frequency-modulated calls separated by irregular intervals. Analysis of 442 discrete calls, the second of each series, revealed that 44.34% calls lacked nonlinear phenomena, in 7.02% nonlinear phenomena covered less than half of call duration, and in 48.64% nonlinear phenomena covered more than half of call duration. Peak frequencies varied among individuals but always fitted one of three maxima corresponding to the vocal tract resonance frequencies (formants) calculated for an estimated 45-mm oral vocal tract. Discriminant analysis using variables of 8 calls per series of 36 different callers, each from a different colony, correctly assigned over 90% of the calls to individuals. Consequently, Altai pika alarm calls are individualistic and nonlinear phenomena might further increase this acoustic individualization. Additionally, video analysis revealed a call-synchronous, very fast (0.13–0.23 s) folding, depression, and subsequent re-expansion of the pinna confirming an earlier report of this behavior that apparently contributes to protecting the hearing apparatus from damage by the self-generated high-intensity alarm calls.     

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.