Intensification of the ultrafiltration of real oil-contaminated (produced) water with pre-ozonation and/or with TiO2, TiO2/CNT nanomaterial-coated membrane surfaces

Environmental Science and Pollution Research - In the present study, commercial PES, PVDF, PTFE ultrafilter membranes, and two different nanomaterial (TiO2 and TiO2/CNT composite)-covered PVDF...     

Conflicting Frames about Ownership and Land Use Drive Wildfire Ignitions in a Protected Conservation Area

The creation of protected conservation areas may result in protracted conflicts between stakeholders. In this study we examine the drivers of anthropogenic wildfire ignitions in the National Park of “los Alerces” (NPA) in Patagonia, Argentina. The NPA was established in 1937 to protect the native “andino-patagónico” forests from wildfires as well as preserving its scenic beauty and native flora and fauna. At the time of its creation state authorities prohibited all extractive human activities in the “intangible”—fully protected—“National Park” section, while other regulated extractive and ecotourism activities were allowed to continue in the “Natural Reserve” section in an effort to accommodate the historical entitlements of the displaced populations of “pobladores” (settlers) that had been living in the NPA for over a century. Here we interviewed the main stakeholder groups—“pobladores”, forest rangers and administrators, ecolodge owners and angler club members—to identify the drivers of wildfire ignitions in the park. Wildfires have been singled out by state authorities as the main threat to the NPA though considerable scientific uncertainty exists regarding their complex ecological effects. This study argues, based on the human and biophysical system data collected, that two conflicting cultural frames exist within the NPA that provide the necessary backdrop for understanding the drivers of wildfire ignitions. In turn, these findings raise puzzling dilemmas for the main theoretical approaches that have been used to inform and design conflict management strategies in protected conservation areas.     

Adsorption studies of the herbicide simazine in agricultural soils of the Aconcagua valley, central Chile

Simazine is a s-triazine herbicide that has been applied worldwide for agriculture. This herbicide is the second most commonly detected pesticide in surface and groundwater in the United States, Europe and Australia. In this study, simazine adsorption behaviour was studied in two agricultural soils of the Aconcagua valley, central Chile. The two studied soils were soil A (loam, 8.5% organic matter content) and soil B (clay-loam, 3.5% organic matter content). Three times higher simazine adsorption capacity was observed in soil A (68.03 mg kg⁻¹) compared to soil B (22.03 mg kg⁻¹). The simazine adsorption distribution coefficients (K_d) were 9.32 L kg⁻¹ for soil A and 7.74 L kg⁻¹ for soil B. The simazine adsorption enthalpy in soil A was −21.0 kJ mol⁻¹ while in soil B the adsorption enthalpy value was −11.5 kJ mol⁻¹. These results indicate that simazine adsorption process in these soils is exothermic, governing H bonds the adsorption process of simazine in both the loam and clay-loam soils. These results and the potentiometric profiles of both soils, suggest that simazine adsorption in soil A is mainly governed by simazine–organic matter interactions and in soil B by simazine–clay interactions. The understanding of simazine sorption–desorption processes is essential to determine the pesticide fate and availability in soil for pest control, biodegradation, runoff and leaching.     

Chemical characterization of landfill leachates--400 parameters and compounds

A large number of hazardous compounds can be expected to be present in landfill leachates, many of which have not yet been identified. Thus this study screened samples from 12 Swedish municipal landfill sites for 400 parameters and compounds. More than 90 organic and metal organic compounds and 50 inorganic elements were detected, some of which seem to have not been detected before. Compounds detected include halogenated aliphatic compounds, benzene and alkylated benzenes, phenol and alkylated phenols, ethoxylates, polycyclic aromatic compounds, phthalic esters, chlorinated benzenes, chlorinated phenols, PCB, chlorinated dioxins and chlorinated furans, bromated flame-retardants, pesticides, organic tin, methyl mercury and heavy metals. The presence of this large number of hazardous compounds in landfill leachates should have a significant impact on future landfill risk assessments and the development of leachate treatment methods. We propose that future research should pay more attention to the metal-organic and organic compounds detected in this study. We also suggest using leachate sediments as a matrix for detecting hydrophobic compounds, and reflecting on the degradation phase when evaluating results from monitoring studies. The extensive compilation of compounds in this paper can be used to select compounds to search for in future studies.     

Strategies to optimize monitoring schemes of recreational waters from Salta,Argentina: a multivariate approach

Several recreational surface waters in Salta, Argentina, were selected to assess their quality. Seventy percent of the measurements exceeded at least one of the limits established by international legislation becoming unsuitable for their use. To interpret results of complex data, multivariate techniques were applied. Arenales River, due to the variability observed in the data, was divided in two: upstream and downstream representing low and high pollution sites, respectively, and cluster analysis supported that differentiation. Arenales River downstream and Campo Alegre Reservoir were the most different environments, and Vaqueros and La Caldera rivers were the most similar. Canonical correlation analysis allowed exploration of correlations between physicochemical and microbiological variables except in both parts of Arenales River, and principal component analysis allowed finding relationships among the nine measured variables in all aquatic environments. Variable’s loadings showed that Arenales River downstream was impacted by industrial and domestic activities, Arenales River upstream was affected by agricultural activities, Campo Alegre Reservoir was disturbed by anthropogenic and ecological effects, and La Caldera and Vaqueros rivers were influenced by recreational activities. Discriminant analysis allowed identification of subgroup of variables responsible for seasonal and spatial variations. Enterococcus, dissolved oxygen, conductivity, E. coli, pH, and fecal coliforms are sufficient to spatially describe the quality of the aquatic environments. Regarding seasonal variations, dissolved oxygen, conductivity, fecal coliforms, and pH can be used to describe water quality during dry season, while dissolved oxygen, conductivity, total coliforms, E. coli, and Enterococcus during wet season. Thus, the use of multivariate techniques allowed optimizing monitoring tasks and minimizing costs involved.     

Characterization of municipal waste in Kampala,Uganda

In Kampala, Uganda, about 28,000 tons of waste is collected and delivered to a landfill every month. Kampala Capital City Authority (KCCA) records show that this represents approximately 40% of the waste generated in the city. The remaining uncollected waste is normally dumped in unauthorized sites, causing health and environmental problems. However, the organic fraction of domestic waste can provide an opportunity to improve livelihoods and incomes through fertilizer and energy production. This study characterized the municipal waste generated in Kampala and delivered to Kiteezi landfill between July 2011 and June 2012, that is, covering the dry and wet months. On each sampling day, waste was randomly selected from five trucks, sorted and weighed into different physical fractions. Samples of the organic waste from each truck were analyzed for total solids, major nutrients, and energy content. During the wet months, the waste consisted of 88.5% organics, 3.8% soft plastics, 2.8% hard plastics, 2.2% paper, 0.9% glass, 0.7% textiles and leather, 0.2% metals, and 1.0% others. During the dry months, the waste consisted of 94.8% organics, 2.4% soft plastics, 1.0% hard plastics, 0.7% papers, 0.3% glass, 0.3% textile and leather, 0.1% metals, and 0.3% others. The organic waste on average had a moisture content of 71.1% and contained 1.89% nitrogen, 0.27% phosphorus, and 1.95% potassium. The waste had an average gross energy content of 17.3 MJ/kg. It was concluded that the organic waste generated can be a suitable source of some plant nutrients that are useful especially in urban agriculture.

Implications:?The result of the waste characterization in Kampala was found to be significantly different from that obtained for other Sub-Saharan African (SSA) cities, showing that studies assuming average values for the waste fractions are likely to result in erroneous results. Furthermore, no reduction in organic fraction of the waste was noticed when compared with a study done two decades ago in spite of greatly improved economic status of Kampala city, a finding that is not in agreement with several other similar studies done for other SSA cities.     

Kelp gulls attack Southern right whales: a conservation concern?

Kelp gulls (Larus dominicanus) feed on pieces of skin and blubber they rip from Southern right whales’ (Eubalaena australis) backs in their breeding areas at Península Valdés, Argentina, producing injuries. This behavior has increased since the first record in 1972, and some authors have suggested that constant gull harassment could have a negative effect on right whale population. The main goal of this study is to assess the variables that most affect the gull attacks. We analyzed 5359 whale-watching sightings made during trips from Puerto Pirámides (42o34′S, 64o16′W) along the whale breeding seasons (June–December) 2005 to 2007. The most important factors affecting the attacks include the presence of a mother–calf pair, the time within the season, the distance to the coast and the wind velocity. There is also concern of possible transmission of infectious diseases in the attacks since increasing number of whales with different patterns of skin lesions have been observed.     

Long-term changes in phytoplankton phenology and community structure in the Bahía Blanca Estuary, Argentina

The phytoplankton of the Bahía Blanca Estuary, Argentina, has been surveyed since 1978. Chlorophyll a, phytoplankton abundance, species composition and physico-chemical variables have been fortnightly recorded. From 1978 to 2002, a single winter–early spring diatom bloom has dominated the main pattern of phytoplankton interannual variability. Such pattern showed noticeable changes since 2006: the absence of the typical winter bloom and changes in phenology, together with the replacement of the dominant blooming species, i.e. Thalassiosira curviseriata, and the appearance of different blooming species, i.e. Cyclotella sp. and Thalassiosira minima. The new pattern showed relatively short-lived diatom blooms that spread throughout the year. In addition, shifts in the phytoplankton size structure toward small-sized diatoms, including the replacement of relatively large Thalassiosira spp. by small Cyclotella species and Chaetoceros species have been noticed. The changes in the phenology and composition of the phytoplankton are mainly attributed to warmer winters and the extremely dry weather conditions evidenced in recent years in the Bahía Blanca area. Changing climate has modified the hydrological features in the inner part of the estuary (i.e. higher temperatures and salinities) and potentially triggered the reorganization of the phytoplankton community. This long-term study provides evidence on species-specific and structural changes at the bottom of the pelagic food web likely related to the recent hydroclimatic conditions in a temperature estuary of the southwestern Atlantic.     

Dissipation of 2,4-D in soils of the Humid Pampa region, Argentina: a microcosm study

Phenoxy herbicides like 2,4-dichlorophenoxyacetic acid (2,4-D) are widely used in agricultural practices. Although its half life in soil is 7-14d, the herbicide itself and its first metabolite 2,4-dichlorophenol (2,4-DCP) could remain in the soil for longer periods, as a consequence of its intensive use. Microcosms assays were conducted to study the influence of indigenous microflora and plants (alfalfa) on the dissipation of 2,4-D from soils of the Humid Pampa region, Argentina, with previous history of phenoxy herbicides application. Results showed that 2,4-D was rapidly degraded, and the permanence of 2,4-DCP in soil depended on the presence of plants and soil microorganisms. Regarding soil microbial community, the presence of 2,4-D degrading bacteria was detected even in basal conditions in this soil, possibly due to the adaptation of the microflora to the herbicide. There was an increment of two orders of magnitude in herbicide degraders after 15d from 2,4-D addition, both in planted and unplanted microcosms. Total heterotrophic bacteria numbers were about 1x10(8) CFUg(-1) dry soil and no significant differences were found between different treatments. Overall, the information provided by this work indicates that the soil under study has an important intrinsic degradation capacity, given by a microbial community adapted to the presence of phenoxy herbicides.