Elemental composition of bottom-sediments from Pangani river basin,Tanzania: lithogenic and anthropogenic sources

River-bed sediments from the Pangani basin, Tanzania, were characterized for elemental compositions, following contamination risks from rapid expansions of human activities in the area. Samples were collected during two individual seasons and analyzed by high-polarizing beam energy dispersive X-ray fluorescence (EDXRF) for eight major and 14 trace elements. Evaluation of enrichment factors (EFs) was used to investigate the elemental flux and assess the contributions of natural and anthropogenic influences. The abundances of the major elements followed the order Si?>?Al?>?Fe?>?Ca?>?K?>?Ti?>?Mn?>?P, similar to that of the upper earth's crust, and were generally from the weathering of the bed-rock. The high concentrations of typical anthropogenic trace-elements (Cr??1, V??1, Ni??1, Cu??1, La??1) coupled with high EFs (>2) in some locations indicated contamination associated with agricultural and industrial activities. Factor analysis extracted five principal components that contributed to 96.0% of the total observed variance. The results indicated that river-bed sediments of the Pangani basin were influenced to a larger extent by lithogenic sources than anthropogenic impacts.     

Dendrochronology of Atriplex portulacoides and Artemisia maritima in Wadden Sea salt marshes

The study uses a rather unusual method, dendrochronology, to investigate the growth and survival of Atriplex portulacoides L. and Artemisia maritima L. on salt marshes at two field sites on the Dutch North Sea barrier islands of Terschelling and Ameland. By providing information on longevity of these typical salt-marsh shrubs, dendrochronology offers an indirect way to investigate the influence of management regime – grazing in this case – on marsh quality and areal extent. Diminishment of salt marshes is a continuing concern in the northern Netherlands. The two shrub species studied here, A. portulacoides and A. maritima, are common to salt marshes. With their extensive roots and branches, they facilitate sedimentation and stabilize salt marshes. Using dendrochronology, this study found that annual growth rings could be identified to determine shrub age and growth. In A. portulacoides these rings took the form of a narrow band of terminal parenchyma. In A. maritima they were made up of unlignified marginal parenchyma together with higher vessel density at the beginning of the growing season. Growth rings indicated that intense grazing was clearly detrimental to the survival of A. portulacoides at the Terschelling site. However, grazing facilitated survival of A. maritima at the Ameland site by reducing light and nutrient competition from grasses. No growth trends could be found, however, as the lifespan for both species is short and many other influences on shrub growth could be identified.     

The Precautionary Principle and Pesticides

In 1998, Greenpeace, Natuur en Milieu(Nature and Environment), Milieudefensie(Environmental Defense), and the National ConsumersUnion presented a report about the possible risks andhazards associated with pesticide residues on fruitsand vegetables. Although these organizationsexplicitly denied having unassailable evidence on theharmful effects of pesticides, they claimed that bynow there are sufficient indications that pesticidesmay indeed lead to such health hazards. They used anappeal to the so-called precautionary principle tounderpin their claims. The committee officially incharge of deciding on the admission of pesticidesaccused the organizations of scaremongering. Afterdistinguishing three possible versions of theprecautionary principle, we then show that the fourorganizations used in their campaign an improperversion of the precautionary principle to convince thegeneral public.     

Performance evaluation of using evacuated tubes solar collector,perforated fins,and pebbles in a solar still – experimental study and CO2 mitigation analysis

Environmental Science and Pollution Research - The combination of various methods of increasing evaporation rate can highly impact the performance of solar desalination. This investigation aims to...     

Effect of IUCN Red List category on public attention to mammals

Cultural data is a powerful tool to analyze public awareness of key societal issues, including the conservation of nature. I used two publicly available repositories of cultural data, Google Trends and Google Ngram, to quantify the effect of the International Union for the Conservation of Nature (IUCN) Red List conservation status on public attention toward 4539 mammal species. With Google Trends, I calculated whether Google searches for their common and scientific names have been increasing or decreasing over time. I also ran an anomaly detection analysis to investigate whether a change in red-list status directly results in an increase in Google searches. Additionally, I quantified the mentions of species’ common and scientific names in English texts with Google Ngram. Overall, Google searches for most mammal species remained at similar levels or increased since 2008. The severity of species’ IUCN Red List status was a significant predictor of increasing Google searches, although the effect size was relatively small. Red-list status seemed strongly confounded with mammal body size. Species that moved to a higher-risk category spiked significantly in Google searches directly after the new designation. The mention of species’ common names in the Google Ngram's English 2019 corpus significantly increased as the red-list category increased. These results provide valuable insight into the importance of the IUCN Red List for increasing public awareness and the usefulness of publicly available cultural data on examining the effectiveness of specific conservation efforts and thus evaluating targets for support and funding.     

Plant extract-mediated synthesis of aluminum oxide nanoparticles for water treatment and biomedical applications: a review

Environmental Chemistry Letters - Nanotechnologies have contributed to disease control and prevention, but conventional synthesis of nanoparticles rarely meets the strict requirements of green...     

An Evaluation of the Influence of Natural Science in Regional-Scale Restoration Projects

Regional-scale restoration is a tool of growing importance in environmental management, and the number, scope, and complexity of restoration programs is increasing. Although the importance of natural science to the success of such projects generally is recognized, the actual use of natural science in these programs rarely has been evaluated. We used techniques of program evaluation to examine the use of natural science in six American and three Western European regional-scale restoration programs. Our results suggest that ensuring the technical rigor and directed application of the science is important to program development and delivery. However, the influence of science may be constrained if strategies for its integration into the broader program are lacking. Consequently, the influence of natural science in restoration programs is greatest when formal mechanisms exist for incorporating science into programs, for example, via a framework for integration of science and policy. Our evaluation proposes a model that can be used to enhance the influence of natural science in regional-scale restoration programs in the United States and elsewhere.     

Changes in Nutrient Emissions, Fluxes and Retention in a North-Eastern European Lowland Drainage Basin

Despite dramatic reductions in the 1990s of N and P emissions in the drainage basin, Lake Peipsi/Chudskoe (Estonia/Russia) is still suffering from algal blooms, probably caused by low N:P ratios of the lake water. To quantify the sources and changes of N and P inputs to the lake as a result of economic changes, we modelled emissions, transfer and in-stream retention using a GIS model. The model was calibrated using river monitoring data from the 1985–1989 period, and used to simulate emissions and loads for five future scenarios for 2015–2019. During the 1985–1999 period, diffuse P emissions decreased relatively more than N diffuse emissions, but this was not reflected in the loads to the lake. P loads decreased relatively less than N loads, which caused a decrease in the N:P ratio of the rivers. About 30–45% of diffuse N emissions and only 3–10% of diffuse P emissions reaches the river network. In-stream retention reduces N and P loads to the lake by about 62% and 72%, respectively. Point sources contribute negligibly to the N load to the lake, but form about one-third of the P load. A target/fast development scenario is the most likely scenario for the 2015–2019 period, resulting in higher nutrient loads than in recent years. We conclude that effective load reductions can be achieved by focussing on diffuse N and P emissions close ( < 50 km²) to the lake and by upgrading P removal capacity in wastewater treatment plants of towns.     

Assessment of Temporal and Spatial Variation of Nitrate Removal in Riparian Zones

The aim of this study was to monitor long-term temporal and spatial groundwater NO₃^- removal efficiencies in different riparian zones via a limited number of sampling wells. Groundwater NO₃^- concentrations were measured fortnightly or monthly over a period of two years using transects of ground water sampling wells. Depending on the level of the NO₃^- load (up to 120mgNL^-1 at the input side of the riparian zone a distance of 10 to 30m was needed to remove NO₃^- from the groundwater below 11.3mgNL^-1. Considering all seasons, the mixed vegetation and grass riparian site succeeded to remove groundwater NO₃^- efficiently (92—100% within a distance of 30m. The forested riparian zone removed 72—90% of the total NO₃^- input within a distance of 30m. Evidence emerged that NO₃^- could also be removed actively at depths up to 2m, due to the presence of organically enriched layers of alluvial deposits or roots. Our four dimensional approach (three dimensional space and time), in combination with a limited number of sampling wells, was shown to be a useful monitoring tool to assess the variability of NO₃^- removal in riparian zones.     

Assessment of Air Quality After the Implementation of Compressed Natural Gas (CNG) as Fuel in Public Transport in Delhi, India

Public transport in Delhi was amended by the Supreme Court of India to use Compressed Natural Gas (CNG) instead of diesel or petrol. After the implementation of CNG since April 2001, Delhi has the highest fraction of CNG-run public vehicles in the world and most of them were introduced within 20 months. In the present study, the concentrations of various criteria air pollutants (SPM, PM₁₀, CO, SO₂ and NO_x) and organic pollutants such as benzene, toluene, xylene (BTX) and polycyclic aromatic hydrocarbons (PAHs) were assessed before and after the implementation of CNG. A decreasing trend was found for PAHs, SO₂ and CO concentrations, while the NO_x level was increased in comparison to those before the implementation of CNG. Further, SPM, PM₁₀, and BTX concentrations showed no significant change after the implementation of CNG. However, the BTX concentration demonstrated a clear relation with the benzene content of gasoline. In addition to the impact of the introduction of CNG the daily variation in PAHs levels was also studied and the PAHs concentrations were observed to be relatively high between 10 pm to 6 am, which gives a proof of a relation with the limited day entry and movement of heavy vehicles in Delhi.