Assessment of ecological risk from bioaccumulation of PCDD/Fs and dioxin-like PCBs in a coastal lagoon

The ecological risk posed by dioxin-like PCBs and PCDD/Fs congeners mixtures in five organisms representative of the food web of the lagoon of Venice (Italy) was estimated by applying the US-EPA [US-EPA. Guidelines for Ecological Risk Assessment. EPA/630/R-95/002F. Final Report. U.S. Environmental Protection Agency, Washington, DC; 1998.] procedure. Experimental concentrations of dioxin-like PCBs and PCDD/Fs in sediments, water, and organisms in six lagoon zones were used to define the spatial distribution of the pollutant homolog patterns. The Principal Component Analysis of homolog patterns in biota permitted to remark the difference between PCDD/Fs and dioxin-like PCBs bioaccumulation. Dioxin-like PCBs were found almost unaltered in all selected organisms, while PCDD/Fs homologs underwent an enrichment of low chlorinated furans in fish. The ecological risk for the dioxin-like PCBs and PCDD/Fs was estimated in the selected lagoon zones according to the Hazard Quotient approach by comparing the biota experimental concentrations in TEQ with an Internal No Effect Concentration of the 2,3,7,8-TCDD, estimated from both Ambient Quality Criteria and literature toxicity data. A high potential risk was found for benthic biota (i.e. clam and crab) and for mussel, while a negligible risk was estimated for fish. Moreover, the ecological risk resulted higher in the central part of the lagoon, and lower in the northern lagoon. Finally, the comparison between the TEQ concentrations of each homolog in biota and the estimated ecological risk highlighted that the risk was determined essentially by lower chlorinated PCDD/Fs (i.e. pentachloro and hexachloro PCDD/Fs), and by pentachloro-PCBs. These compounds should be regarded as homologs of concern and preferentially investigated in environmental monitoring of sediment, water, and biota.     

Individual and combined toxic effects of cypermethrin and chlorpyrifos on earthworm

Toxicities were assessed for a pyrethroid (cypermethrin) and an organophosphate insecticide (chlorpyrifos) individually and in combination. A series of tests were conducted on di erent responses (acute, chronic, behavioral) of earthworms of species Eisenia fetida andrei in the ecological risk assessment of these pesticides. The results showed that the toxicity of the mixture of cypermethrin and chlorpyrifos was significantly higher than either of these pesticides individually, especially on the earthworm’s chronic responses. At a concentration of 5 mg/kg, the mixture caused significant reductions on the growth and reproduction rates of earthworms, but did not cause any significant e ect when the individual was tested. The increase in toxicity of the pesticide mixture means that the use of toxicity data obtained exclusively from single-pesticide experiments may underestimate the ecological risk of pesticides that actually present in the field.     

Efficacy of natural biocide on control of microbial induced corrosion in oil pipelines mediated by Desulfovibrio vulgaris and Desulfovibrio gigas

We compared the efficacy of a natural biocide with four chemical tetrakishydroxymethyl phosphonium sulfonate, benzyl trimethyl ammonium chloride, and formaldehyde, glutaraldehyde, to control microbial induced corrosion in oil pipelines. The efficacy of biocides were monitored against Desulfovibrio vulgaris and Desulfovibrio gigas in experimental pipes by measuring cell counts, H2S production, Fe(II) production, production of extracellular polymeric substances and structure of biofilm. The treatment with cow urine had minimum planktonic cell counts of 3 102 CFU/mL as well as biofilm cell counts of 9 101 CFU/mL as compared with tetrakishydroxyl methyl phosphonium sulfonate, benzyl trimethyl ammonium chloride, formaldehyde and glutaraldehyde. Sulfide production was the lowest with cow urine (0.08 mmol/L), followed by tetrakishydroxymethyl phosphonium sulfonate 0.72 mmol/L. On day 90 of treatment, Fe(II) production was also found to be the lowest with cow urine. The scanning electron microscopic studies indicated that the biofilm bacteria were killed by cow urine. These results demonstrate the cow urine mediated control of microbially induced corrosion, and this is indicative of its potential as a viable substitute of toxic biocides. To the best of our knowledge, this seems to be the first report which screens possible biocidal activity by cow urine as compared to the most common biocides which oil industry is currently using.     

Nitrogen mass balance in a constructed wetland treating piggery wastewater effluent

The nitrogen changes and the nitrogen mass balance in a free water surface flow constructed wetland （CW） using the four-year monitoring data from 2008 to 2012 were estimated. The CW was composed of six cells in series that include the first settling basin （Cell 1）, aeration pond （Cell 2）, deep marsh （Cell 3）, shallow marsh （Cell 4）, deep marsh （Cell 5） and final settling basin （Cell 6）. Analysis revealed that the NH4＋-N concentration decreased because of ammonification which was then followed by nitrification. The NO4＋-N and NO4＋-N were also further reduced by means of microbial activities and plant uptake during photosynthesis. The average nitrogen concentration at the influent was 37,819 kg/year and approximately 45% of that amount exited the CW in the effluent. The denitrification amounted to 34% of the net nitrogen input, whereas the accretion of sediment was only 7%. The biomass uptake of plants was able to retain only 1% of total nitrogen load. In order to improve the nutrient removal by plant uptake, plant coverage in four cells （i.e., Cells 1, 3, 4 and 5） could be increased.     

Financing for innovative technologies and best practices to reduce persistent organic pollutants

Persistent Organic Pollutants (POPs) threaten human health and the global environment. Recognizing their dangers many countries began to limit or ban POPs production, use, and release in the 1990s. Eventually the Stockholm Convention on POPs, was adopted in 2001 and entered into force in 2004. The Global Environment Facility (GEF) provides financial support to developing country Parties for the implementation of the Stockholm Convention. The GEF’s POPs investment portfolio focuses on: 1) strengthening the capacity of developing country Parties to implement the Stockholm Convention; 2) establishing and supporting partnerships to develop and implement National Implementation Plans (NIPs), and 3) demonstrating and deploying best technologies and practices to reduce POPs emission, including development of safe alternatives. Since 2001 the GEF has committed US$568.8 million to POPs projects and leveraged some US$1474.5 million in co-financing from partners in the public and private sectors, bringing the total value of the GEF POPs portfolio to over US$2 billion. With GEF support, 108 developing country Parties have developed their NIPs. The GEF also financed 109 projects for the implementation of the Convention. Upon completion, these GEF POPs investments will contribute to the disposal of more than 70,000 tons of Polychlorinated Biphenyls (PCBs) oil, contaminated equipments, and waste, more than 40,000 tons of obsolete POPs pesticides and associated waste, and reducing dioxin/furan and mercury emission by introducing environmentally sound technologies and best practices. This paper summarizes: 1) direct and indirect GEF investments to support the goals of the Stockholm Convention; 2) investment case studies on PCB, DichloroDiphenylTrichloroethane (DDT), chlordane and mirex, medical waste, obsolete POPs and engaging civil society; and 3) lessons learned in terms of GEF financing strategies, best technologies and environmental practices to address POPs.     

A new Dasypodini armadillo (Xenarthra: Cingulata) from San Gregorio Formation,Pliocene of Venezuela: affinities and biogeographic interpretations

We describe Pliodasypus vergelianus gen. et sp. nov., a Dasypodini armadillo from the middle Pliocene of Venezuela (Vergel Member, San Gregorio Formation). Although scarce, the remains are remarkable because of their geochronologic proximity to the main phase of Great American Biotic Interchange (GABI). The cladistic analysis conducted reveals that Pliodasypus groups with Dasypus and both are sister taxa of Propraopus, whereas Anadasypus is at a basal position. With respect to the records of tribe Dasypodini, after its oldest representative (Anadasypus, middle and late Miocene), the chronologically subsequent form is Pl. vergelianus (middle Pliocene), followed by Dasypus bellus in higher northern latitudes (late Pliocene), and then by widespread occurrences in the Pleistocene of North America (D. bellus) and South America (Propraopus, Dasypus punctatus, and Dasypus novemcinctus). Thus, we infer that Dasypus differentiated in the late Pliocene at low latitudes in the northern South America. It leads to two alternative hypotheses of dispersal: (a) some early Dasypus remained cryptically in South America until the Pleistocene, whereas others dispersed to North America between 2.2 and 2.7 Ma, or (b) they dispersed to North America subsequently to the emersion of the Panamanian isthmus and D. bellus differentiated there; later, during the Pleistocene, D. bellus entered South America and experienced speciation. The same process of re-ingression has been proposed to other xenarthrans, breaking with the traditional assumption that the GABI was unidirectional.     

A time-compressed simulated geomagnetic storm influences the nest-exiting flight angles of the stingless bee Tetragonisca angustula

Insects have been used as models for understanding animal orientation. It is well accepted that social insects such as honeybees and ants use different natural cues in their orientation mechanism. A magnetic sensitivity was suggested for the stingless bee Schwarziana quadripunctata, based on the observation of a surprising effect of a geomagnetic storm on the nest-exiting flight angles. Stimulated by this result, in this paper, the effects of a time-compressed simulated geomagnetic storm (TC-SGS) on the nest-exiting flight angles of another stingless bee, Tetragonisca angustula, are presented. Under an applied SGS, either on the horizontal or vertical component of the geomagnetic field, both nest-exiting flight angles, dip and azimuth, are statistically different from those under geomagnetic conditions. The angular dependence of ferromagnetic resonance (FMR) spectra of whole stingless bees shows the presence of organized magnetic nanoparticles in their bodies, which indicates this material as a possible magnetic detector.     

Distribution and dietary regulation of an associated facultative Rhizobiales-related bacterium in the omnivorous giant tropical ant,Paraponera clavata

We document a facultative Bartonella-like Rhizobiales bacterium in the giant tropical ant, Paraponera clavata. In a lowland tropical rainforest in Costa Rica, 59 colonies were assayed for the prevalence of the Bartonella-like bacterium (BLB), 14 of which were positive. We addressed three questions: First, how does the prevalence of BLB within colonies vary with environmental conditions? Second, how does diet affect the prevalence of BLB in P. clavata? Third, how does the distribution of BLB among colonies reflect ambient differences in food resources and foraging habits? A variety of environmental variables that may be predictive of the presence of BLB were measured, and diet manipulations were conducted to test whether the prevalence of BLB responded to supplemental carbohydrate or prey. The ambient frequency of BLB is much higher in young secondary forests, but is nearly absent from older secondary forests. The prevalence of BLB inside field colonies increased over the duration of a 2-week carbohydrate supplementation; however, water and prey supplementation did not alter the prevalence of BLB. The diets of the colonies located in young secondary forest, compared to other habitats, have a diet richer in carbohydrates and lower in prey. The abundance of carbohydrate, or the relative lack of N, in a colony’s diet influences the occurrence of the BLB microbe in P. clavata. As experimental diet manipulations can affect the facultative presence of an N-cycling microbe, a consistent diet shift in diet may facilitate the emergence of tighter symbioses.     

Direct evidence of trophic interactions among apex predators in the Late Triassic of western North America

Hypotheses of feeding behaviors and community structure are testable with rare direct evidence of trophic interactions in the fossil record (e.g., bite marks). We present evidence of four predation, scavenging, and/or interspecific fighting events involving two large paracrocodylomorphs (=‘rauisuchians’) from the Upper Triassic Chinle Formation (～220–210 Ma). The larger femur preserves a rare history of interactions with multiple actors prior to and after death of this ～8–9-m individual. A large embedded tooth crown and punctures, all of which display reaction tissue formed through healing, record evidence of a failed attack on this individual. The second paracrocodylomorph femur exhibits four unhealed bite marks, indicating the animal either did not survive the attack or was scavenged soon after death. The combination of character states observed (e.g., morphology of the embedded tooth, ‘D’-shaped punctures, evidence of bicarination of the marking teeth, spacing of potentially serial marks) indicates that large phytosaurs were actors in both cases. Our analysis of these specimens demonstrates phytosaurs targeted large paracrocodylomorphs in these Late Triassic ecosystems. Previous distinctions between ‘aquatic’ and ‘terrestrial’ Late Triassic trophic structures were overly simplistic and built upon mistaken paleoecological assumptions; we show they were intimately connected at the highest trophic levels. Our data also support that size cannot be the sole factor in determining trophic status. Furthermore, these marks provide an opportunity to start exploring the seemingly unbalanced terrestrial ecosystems from the Late Triassic of North America, in which large carnivores far outnumber herbivores in terms of both abundance and diversity.     

Trail laying during tandem-running recruitment in the ant Temnothorax albipennis

Tandem running is a recruitment strategy whereby one ant leads a single naïve nest mate to a resource. While tandem running progresses towards the goal, the leader ant and the follower ant maintain contact mainly by tactile signals. In this paper, we investigated whether they also deposit chemical signals on the ground during tandem running. We filmed tandem-running ants and analysed the position of the gasters of leaders and followers. Our results show that leader ants are more likely to press their gasters down to the substrate compared to follower ants, single ants and transporter ants. Forward tandem-run leaders (those moving towards a new nest site) performed such trail-marking procedures three times more often than reverse tandem leaders (those moving towards an old nest site). That leader ants marked the trails more often during forward tandem runs may suggest that it is more important to maintain the bond with the follower ant on forward tandem runs than on reverse tandem runs. Marked trails on the ground may serve as a safety line that improves both the efficiency of tandem runs and their completion rates.