Identification of Mn-oxide minerals in some soils from Devon,UK, and their varying capacity to adsorb Co and Cu

A number of Mn-oxide minerals in soils from a farm in North Devon have been tentatively identified using a combination of advanced analytical techniques: scanning electron microscopy (SEM), scanning electron microprobe (SEMP), X-ray diffraction (XRD) and bulk chemical analysis by wet digestion followed by inductively-coupled plasma spectrometry (ICP). The minerals lithiophorite and hollandite are thought to occur throughout the study area although there is considerable geographical variation in the proportions of minerals present. Bimessite, vernadite, romanechite, todorokite and cryptomelane may also be present, although in smaller amounts. The use of SEMP, together with a simple sorption experiment, has allowed a study of the extent of uptake of Co and Cu by different Mn-oxide minerals. Lithiophorite appears to take up Co and Cu more effectively than hollandite within a pH range of 4–6.     

PATTERNS OF ENERGY CONSUMPTION BY THE RURAL AND URBAN POOR IN DEVELOPING COUNTRIES

From the rudimentary data available on the domestic energy consumption of the urban and rural poor in developing countries it appears that consumption by the poor in much of the developing world is at bare subsistence levels. Despite generally higher incomes, the domestic energy consumption of the urban poor appears to be no higher in Btu terms than that of the rural poor due to the more thermally efficient fuel supplies used by the urban poor. A further tentative conclusion is that for similar reasons related to the changing efficiency of the fuel supply system, energy consumption measured in quantity terms rises within a given area by less than the rise in income at lower income levels. As incomes rise there is a tendency to switch to more efficient fuels in a manner analogous to the contrast in energy consumption patterns between urban and rural areas. Thus a rising demand for energy services can be accomodated by a less than proportionate gross input. En examinant les données rudimentaires dont on dispose sur la consommation domestique en énergie des classes urbaines et rurales défavorisées des pays en développement, il ressort que la consommation de ces classes dans la plupart de ces pays se situe à des niveaux de simple subsistence. Malgré des revenus généralement plus élevés, la consommation domestique en énergie des classes urbaines défavorisées ne semble pas étre supérieure en termes d'unités thermiques britanniques à celle des classes rurales défavorisées en raison d'approvisionnements en combustibles thermiques à meilleur rendement dans les villes. Une autre conclusion provisoire envisage que pour des raisons similaires ayant trait aux fluctuations de l'efficacité du système d'approvisionnement en combustibles, la consommation énergétique mesurée en termes quantitatifs augments dans une zone donnée moins rapidement que les revenus aux échelons inférieurs. Au fur et à mesure que les revenus progressent, la tendance à utiliser des combustibles a meilleur rendement reflète le même contraste existant dans les modes de consommation en énergie entre les zones urbaines et rurales. On peut donc satisfaire les besoins croissants en matière d'énergie par des coûts de production proportionnellement moins élevés. Por los datos rudimentarios disponibles sobre el consumo doméstico de energía de los estratos probres rural y urbano de los países en desarrollo, parece ser que dicho consumo está en los límites del nivel de subsistencia. A pesar del relativo mayor ingreso de los estratos pobres urbanos, el consumo de energía de éstos no parece ser, en términos fíisicos, mayor que la de los estratos pobres rurales debido a que aquellos emplean combustibles que pueden usarse con mayor eficiencia térmica. Otra conclusión tentativa es que debido a razones similares a esta disparidad de eficiencia, la cantidad de energía consumida en un sector pobre aumenta en una proporción menor que el aumento del ingreso. En forma análoga a la deferencia entre las tendencias de consumo entre grupos ru rales y urbanos, a mayores niveles de ingreso en una misma área hay una tendencia a usar combustibles más eficientes. Como resultado una demanda creciente de energía puede ser satisfecha con un amento proporcionalmente menor de suministrode combustible.     

The acetochlor registration partnership surface water monitoring program for four corn herbicides

A surface drinking water monitoring program for four corn (Zea mays L.) herbicides was conducted during 1995-2001. Stratified random sampling was used to select 175 community water systems (CWSs) within a 12-state area, with an emphasis on the most vulnerable sites, based on corn intensity and watershed size. Finished drinking water was monitored at all sites, and raw water was monitored at many sites using activated carbon, which was shown capable of removing herbicides and their degradates from drinking water. Samples were collected biweekly from mid-March through the end of August, and twice during the off-season. The analytical method had a detection limit of 0.05 microg L(-1) for alachlor [2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl)-acetamide] and 0.03 microg L(-1) for acetochlor [2-chloro-N-(ethoxymethyl)-N-(2-ethyl-6-methylphenyl)-acetamide], atrazine [6-chloro-N-ethyl-N'-(1-methylethyl)-1,3,5-triazine-2,4-diamine], and metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)-acetamide]. Of the 16528 drinking water samples analyzed, acetochlor, alachlor, atrazine, and metolachlor were detected in 19, 7, 87, and 53% of the samples, respectively. During 1999-2001, samples were also analyzed for the presence of six major degradates of the chloroacetanilide herbicides, which were detected more frequently than their parent compounds, despite having higher detection limits of 0.1 to 0.2 microg L(-1). Overall detection frequencies were correlated with product use and environmental fate characteristics. Reservoirs were particularly vulnerable to atrazine, which exceeded its 3 microg L(-1) maximum contaminant level at 25 such sites during 1995-1999. Acetochlor annualized mean concentrations (AMCs) did not exceed its mitigation trigger (2 microg L(-1)) at any site, and comparisons of observed levels with standard measures of human and ecological hazards indicate that it poses no significant risk to human health or the environment.     

Antipredator activity and endogenous biosynthesis of defensive secretion in larval and pupal Delphastus catalinae (Horn) (Coleoptera: Coccinellidae)

Delphastus catalinae (Horn) is a predatory ladybird beetle (Coccinellidae) commonly used as a biocontrol agent against greenhouse infestation by whiteflies. It belongs to the basal subfamily Microweisinae, a group for which chemical defenses have not been previously investigated. The larval and pupal stages of D. catalinae possess minute secretory hairs that produce droplets containing compounds of both isoprenoid and polyketide origin. Bioassays with the predatory ant Crematogaster lineolata showed both the larval and pupal secretions to be deterrent. Moreover, isolated secretion components, from both classes of compounds, displayed antipredator activity against the ant. Experiments with D. catalinae larvae fed isotopically labeled glucose showed ¹³C-incorporation into both categories of compounds within the pupal secretion, demonstrating that these antipredator compounds, which differ from the typical nitrogenous defensive molecules of coccinellids, are biosynthesized endogenously. This suggests that the wide use of alkaloids by more derived coccinellids may have arisen after their divergence from the more basal Microweisinae.     

Tissue distribution of perfluoroalkyl acids and health status in wild Mozambique tilapia (Oreochromis mossambicus) from Loskop Dam, Mpumalanga, South Africa

This study examined concentrations of 15 perfluoroalkyl acids (PFAAs) in tissues from male Mozambique tilapia (Oreochromis mossambicus) collected at Loskop Dam, Mpumalanga, South Africa in 2014 and 2016. Nine of the 15 PFAAs were detected frequently and were included in statistical analysis and included two of the most commonly known PFAAs, perfluorooctanesulfonic acid (PFOS) (median, 41.6 ng/g) and perfluorooctanoic acid (PFOA) (median, 0.0825 ng/g). Of the tissues measured, plasma (2016 and 2014 median, 22.2 ng/g) contained the highest PFAA burden followed by (in descending order): liver (median, 11.6 ng/g), kidney (median, 9.04 ng/g), spleen (median, 5.92 ng/g), adipose (median, 2.54 ng/g), and muscle (median, 1.11 ng/g). Loskop Dam tilapia have been affected by an inflammatory disease of the adipose tissue known as pansteatitis, so this study also aimed to investigate relationships between PFAA tissue concentrations and incidence of pansteatitis or fish health status. Results revealed that healthy tilapia exhibited an overall higher (p-value < 0.05) PFAA burden than pansteatitis-affected tilapia across all tissues. Further analysis showed that organs previously noted in the literature to contain the highest PFAA concentrations, such as kidney, liver, and plasma, were the organs driving the difference in PFAA burden between the two tilapia groups. Care must be taken in the interpretations we draw from not only the results of our study, but also other PFAA measurements made on populations (human and wildlife alike) under differing health status.     

Phytoextraction of lead-contaminated soil using vetivergrass (<Emphasis Type="Italic">Vetiveria zizanioides</Emphasis> L.), cogongrass (<Emphasis Type="Italic">Imperata cylindrica</Emphasis> L.) and carabaograss (<Emphasis Type="Italic">Paspalum conjugatum</Emphasis> L.)

Background, Aims and Scope The global problem concerning contamination of the environment as a consequence of human activities is increasing. Most of the environmental contaminants are chemical by-products and heavy metals such as lead (Pb). Lead released into the environment makes its way into the air, soil and water. Lead contributes to a variety of health effects such as decline in mental, cognitive and physical health of the individual. An alternative way of reducing Pb concentration from the soil is through phytoremediation. Phytoremediation is an alternative method that uses plants to clean up a contaminated area. The objectives of this study were: (1) to determine the survival rate and vegetative characteristics of three grass species such as vetivergrass, cogongrass and carabaograss grown in soils with different Pb levels; and (2) to determine and compare the ability of the three grass species as potential phytoremediators in terms of Pb accumulation by plants. Methods The three test plants: vetivergrass (Vetiveria zizanioides L.); cogongrass (Imperata cylindrica L.); and carabaograss (Paspalum conjugatum L.) were grown in individual plastic bags containing soils with 75 mg kg⁻¹ (37.5 kg ha⁻¹) and 150 mg kg⁻¹ (75 kg ha⁻¹) of Pb, respectively. The Pb contents of the test plants and the soil were analyzed before and after experimental treatments using an atomic absorption spectrophotometer. This study was laid out following a 3 × 2 factorial experiment in a completely randomized design. Results On the vegetative characteristics of the test plants, vetivergrass registered the highest whole plant dry matter weight (33.85–39.39 Mg ha⁻¹). Carabaograss had the lowest herbage mass production of 4.12 Mg ha⁻¹ and 5.72 Mg ha⁻¹ from soils added with 75 and 150 mg Pb kg⁻¹, respectively. Vetivergrass also had the highest percent plant survival which meant it best tolerated the Pb contamination in soils. Vetivergrass registered the highest rate of Pb absorption (10.16 ± 2.81 mg kg⁻¹). This was followed by cogongrass (2.34 ± 0.52 mg kg⁻¹) and carabaograss with a mean Pb level of 0.49 ± 0.56 mg kg⁻¹. Levels of Pb among the three grasses (shoots + roots) did not vary significantly with the amount of Pb added (75 and 150 mg kg⁻¹) to the soil. Discussion Vetivergrass yielded the highest biomass; it also has the greatest amount of Pb absorbed (roots + shoots). This can be attributed to the highly extensive root system of vetivergrass with the presence of an enormous amount of root hairs. Extensive root system denotes more contact to nutrients in soils, therefore more likelihood of nutrient absorption and Pb uptake. The efficiency of plants as phytoremediators could be correlated with the plants’ total biomass. This implies that the higher the biomass, the greater the Pb uptake. Plants characteristically exhibit remarkable capacity to absorb what they need and exclude what they do not need. Some plants utilize exclusion mechanisms, where there is a reduced uptake by the roots or a restricted transport of the metals from root to shoots. Combination of high metal accumulation and high biomass production results in the most metal removal from the soil. Conclusions The present study indicated that vetivergrass possessed many beneficial characteristics to uptake Pb from contaminated soil. It was the most tolerant and could grow in soil contaminated with high Pb concentration. Cogongrass and carabaograss are also potential phytoremediators since they can absorb small amount of Pb in soils, although cogongrass is more tolerant to Pb-contaminated soil compared with carabaograss. The important implication of our findings is that vetivergrass can be used for phytoextraction on sites contaminated with high levels of heavy metals; particularly Pb. Recommendations and Perspectives High levels of Pb in localized areas are still a concern especially in urban areas with high levels of traffic, near Pb smelters, battery plants, or industrial facilities that burn fuel ending up in water and soils. The grasses used in the study, and particularly vetivergrass, can be used to phytoremediate urban soil with various contaminations by planting these grasses in lawns and public parks. ESS-Submission Editor: Dr. Willie Peijnenburg (wjgm.peijnenburg@rivm.nl)     

Teleconnections,midlatitude cyclones and Aegean Sea turbulent heat flux variability on daily through decadal time scales

We analyze daily wintertime cyclone variability in the central and eastern Mediterranean during 1958–2001 and identify four distinct “cyclone states,” corresponding to the presence or absence of cyclones in each basin. Each cyclone state is associated with wind flows that induce characteristic patterns of cooling via turbulent (sensible and latent) heat fluxes in the eastern Mediterranean basin and Aegean Sea. The relative frequency of occurrence of each state determines the heat loss from the Aegean Sea during that winter, with largest heat losses occurring when there is a storm in the eastern but not central Mediterranean (eNOTc) and the smallest occurring when there is a storm in the central but not eastern Mediterranean (cNOTe). Time series of daily cyclone states for each winter allow us to infer Aegean Sea cooling for winters prior to 1985, the earliest year for which we have daily heat flux observations. We show that cyclone states conducive to Aegean Sea convection occurred in 1991/1992 and 1992/1993, the winters during which deepwater formation was observed in the Aegean Sea, and also during the mid-1970s and the winters of 1963/1964 and 1968/1969. We find that the eNOTc cyclone state is anticorrelated with the North Atlantic Oscillation (NAO) prior to 1977/1978. After 1977/1978, the cNOTe state is anticorrelated with both the NAO and the North Caspian Pattern, showing that the area of influence of large-scale atmospheric teleconnections on regional cyclone activity shifted from the eastern to the central Mediterranean during the late 1970s. A trend toward more frequent occurrence of the positive phase of the NAO produced less frequent cNOTe states since the late 1970s, increasing the number of days with strong cooling of the Aegean Sea surface waters.