Blood serum concentrations of perfluorinated compounds in men from Greenlandic Inuit and European populations

Perfluorinated compounds (PFCs), such as perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), are used in large quantities. They are persistent and found in measurable levels in human serum around the world. They have been associated with developmental, hepatic, and carcinogenic effects in animal studies. The aim of the present study was to describe levels of PFCs in serum among Inuits from Greenland and inhabitants from Warsaw, Poland and Kharkiv, Ukraine. Furthermore, the aim was to define social- and lifestyle related determinants of exposure for these compounds. Serum levels of seven PFCs were analyzed by liquid chromatography/tandem mass spectrometry (LC/MS/MS). The concentrations of PFOS and PFOA were the highest of all PFCs in all three populations with a total amount of almost 90% of the PFCs. The mean levels of PFOS and PFOA were in the Greenlandic Inuits 52 and 4.8 ng mL(-1), in Poland 19 and 5.2 ng mL(-1), and in Ukraine 8.1 and 1.9 ng mL(-1), respectively. Thus, levels of PFCs in the serum of Inuits on Greenland were among the highest described in a general population whereas the levels in Poland were similar to other industrialized countries. The exposure in Ukraine was rather low. In the Greenlandic Inuit population, intake of seafood, tea, age and area of living were significant determinants of PFOS concentrations and explained about 22% of the variation. For the other populations no strong determinants were found.     

Effects of long-term chlorpyrifos exposure on mortality and reproductive tissues of Banded Gourami (Trichogaster fasciata)

Abstract

This study assessed the long-term toxicity of chlorpyrifos on survival and reproduction of Banded Gourami by using mortality, gonado-somatic index (GSI) and histopathological observations as endpoints. Adult fish were exposed to five different concentrations of chlorpyrifos (0, 15, 50, 150, 500?µg/L) in 15 PVC tanks for 15, 30, 45, 60 and 75?days. Results showed that all male and female fish died after 15?days of 500?µg/L chlorpyrifos exposure. No consistent significant effect was observed for both male and female GSI. Furthermore, results showed dose- and time-dependent histopathological alterations for both ovary and testes. The 60-d No Observed Effect Concentration (NOEC) for most histopathological alterations of Banded Gourami ovary and testes was 50?μg/L, while 60-d NOEC for mortality of both male and female fish was < 15?μg/L. The results show that the long-term exposure to chlorpyrifos not only affect the reproductive tissues of Banded Gourami at exposure concentrations but also cause their mortality. Future studies should evaluate effects at lower concentrations.     

Dissolved phosphorus transport from soil to surface water in catchments with different land use

Diffuse phosphorus (P) export from agricultural land to surface waters is a significant environmental problem. It is critical to determine the natural background P losses from diffuse sources, but their identification and quantification is difficult. In this study, three headwater catchments with differing land use (arable, pasture and forest) were monitored for 3 years to quantify exports of dissolved (<0.45 µm) reactive P and total dissolved P. Mean total P exports from the arable catchment ranged between 0.08 and 0.28 kg ha^?1 year^?1. Compared with the reference condition (forest), arable land and pasture exported up to 11-fold more dissolved P. The contribution of dissolved (<0.45 µm) unreactive P was low to negligible in every catchment. Agricultural practices can exert large pressures on surface waters that are controlled by hydrological factors. Adapting policy to cope with these factors is needed for lowering these pressures in the future.     

Phaeocystis blooms and eutrophication of the continental coastal zones of the North Sea

It is suggested that novel nuisance algal blooms can result from major shifts in N/P or NH₄ ⁺/NO₃ ^- ratios. Inland hydraulic engineering caused a shift from P-limitation (before 1977) towards N-limitation (after 1977) in the Marsdiep area (Dutch coastal waters). Following this shift the colonial flagellate Phaeocystis sp. became more abundant and started to bloom during the nutrient-controlled period (later spring to autumn). Competition experiments showed that the N/P ratio can influence the species composition of marine phytoplankton. In addition, the natural distribution of some species like Rhodomonas sp. and Emiliania huxleyi may be affected by the frequency of nutrient pulses in the system. Phaeocystis was a poor competitor under P-limitation and a good competitor under N-limitation. Colony formation was absent under P- and NH₄ ⁺-limitation. Colonies were formed under NO₃ ^--limitation. These preliminary results suggest that colony-forming Phaeocystic blooms may be restricted (besides light-controlled environments) to those N-controlled environments where nitrate is consumed by Phaeocystis. The distribution of Phaeocystis along the European continental coast is evaluated on the basis of its ability to compete for nutrients and to form colonies when nitrate is the major N-source.     

Optimizing the biodiversity gain from agri-environment schemes

How best to optimize the biodiversity gain from agri-environment schemes (AES) has recently been identified as a key policy-relevant question. Here, the effects of two features of lowland agricultural landscapes on the abundance and diversity of larger moths are contrasted. Although both features bring about positive effects, hedgerow trees have a larger impact than 6 m wide grassy field margins. Whilst AES payments are given to create and maintain grass margins, no financial reward is currently offered for the retention of hedgerow trees. Furthermore, it was only in areas where the amount of land under AES was experimentally increased, by targeting farmers, that the presence of hedgerow trees resulted in a substantially higher abundance (+60%) and diversity (+38%) of moths. Thus, by using larger moths as bio-indicators of landscape-scale quality, it is demonstrated that improvements to the cost-effectiveness of AES could be achieved, firstly, by providing more appropriate financial rewards to farmers for different landscape features, and secondly, through landscape-scale targeting of farmers to encourage participation in AES.     

Predictability of marine nematode biodiversity

In this paper, we investigated: (1) the predictability of different aspects of biodiversity, (2) the effect of spatial autocorrelation on the predictability and (3) the environmental variables affecting the biodiversity of free-living marine nematodes on the Belgian Continental Shelf. An extensive historical database of free-living marine nematodes was employed to model different aspects of biodiversity: species richness, evenness, and taxonomic diversity. Artificial neural networks (ANNs), often considered as “black boxes”, were applied as a modeling tool. Three methods were used to reveal these “black boxes” and to identify the contributions of each environmental variable to the diversity indices. Since spatial autocorrelation is known to introduce bias in spatial analyses, Moran's I was used to test the spatial dependency of the diversity indices and the residuals of the model. The best predictions were made for evenness. Although species richness was quite accurately predicted as well, the residuals indicated a lack of performance of the model. Pure taxonomic diversity shows high spatial variability and is difficult to model. The biodiversity indices show a strong spatial dependency, opposed to the residuals of the models, indicating that the environmental variables explain the spatial variability of the diversity indices adequately. The most important environmental variables structuring evenness are clay and sand fraction, and the minimum annual total suspended matter. Species richness is also affected by the intensity of sand extraction and the amount of gravel of the sea bed.     

Assessment of labile phosphorus fractions and adsorption characteristics in relation to soil properties of West African savanna soils

A large proportion of total P in the soils of the area is unavailable to plants and consequently P is the second most limiting nutrient. The labile and moderately labile phosphorus fractions and adsorption characteristics of surface and subsurface horizons of eleven soil profiles in the derived savanna (DS) and the northern Guinea savanna (NGS) of West Africa were assessed. The labile P fractions are the resin and HCO₃-extractable inorganic (Pi) and organic (Po) P. The moderately labile fractions are the NaOH-extractable portion of soil P in the Hedley sequential procedure. In the DS soils, the resin P, considered the most readily available fraction, varied from 1 to 14 mg kg⁻¹, HCO₃-Pi ranged from 3.3 to 11, and HCO₃-PO was between 4 and 12 mg kg⁻¹ in the surface horizon. In the NGS, the topsoil contained 1.5–3 mg kg⁻¹ of resin P, 5–8 mg kg⁻¹ of HCO₃-Pi, and 7.5–9.7 mg kg⁻¹ of HCO₃-Po. Sodium hydroxide-Po was the largest of the fractions in all the soils studied. It ranged from 23 to 55 mg kg⁻¹ in the topsoil. In general, the labile P levels were higher in soils of the DS than of the NGS and were related to the oxalate-extractable Fe (Fe_ox), and Al (Al_ox) as well as to soil texture. The subsoil of Kasuwan Magani (profile KS 9–21 cm) required 153 mg P kg⁻¹ to maintain 0.2 mg P l⁻¹ in solution (standard P requirement), and Danayamaka (profile DD 7–32 cm) required 145 mg P kg⁻¹. These could translate to 214 and 200 kg P ha⁻¹ if a plow layer of 10 cm is assumed. Because these are within the plow layer, more P fertilizer would be needed for crop production than in the other soils. The standard P requirement and the adsorption maxima were related to Fe_ox and Al_ox, dithionite-Fe (Fe_d), and texture. The increase in labile P content with decreasing Fe_ox and Al_ox could imply that management practices capable of reducing the activities of Fe and Al in solution might improve P availability.     

Assessment of natural coagulants to remediate Tunisian textile wastewater by combining physicochemical,analytical, and toxicological data

Environmental Science and Pollution Research - Due to the complexity and variability of textile wastewater composition, a constant search for new treatment strategies that are efficient,...     

Predictions of in situ solid/liquid distribution of radiocaesium in soils

Previous work has demonstrated that plant uptake of radiocaesium (RCs) is related to the activity concentration of RCs in soil solution, which is linked to the soil/soil solution distribution coefficient, K(D). The solid-liquid distribution of RCs is generally studied in soil suspensions in the laboratory and there are few reported measurements for in situ soil solutions. From a data set of 53 different soils (contaminated with either 134CsCl or 137CsCl) used in pot trials to investigate grass uptake of RCs, we analysed the variation of in situ K(D) with measured soil properties. The soils differed widely in % clay (0.5-58%), organic matter content (1.9-96%) and pH (2.4-7.0, CaCl2). The K(D) varied between 29 and 375,000 L kg-' (median 1460 L kg(-1)). Stepwise multiple regression analysis showed a significant correlation between the log K(D) and pH (p < 0.001), log %clay (p < 0.01) and log exchangeable K (p < 0.001) (overall R2 = 0.70). The in situ K(D) values were further compared to K(D)S predicted using an existing model, which assumes that RCs sorption occurs on specific sites and regular ion-exchange sites on the soil solid phase. Sorption of RCs on specific sites was quantified from the radiocaesium interception potential (RIP) measured for each soil and the soil solution concentrations of K+ and NH4+. The in situ log K(D) correlated well with the predicted K(D) (R2 = 0.85 before plant growth, R2 = 0.83 after plant growth). However, the observations were fivefold to eightfold higher than the predictions, particularly for the mineral soils. We attribute the under-prediction to the long contact times (minimum 4 weeks) between the RCs tracers and our experimental soils relative to the short (24 h) contact times used in RIP measurements. We conclude that our data confirmed the model but that ageing of RCs in soil is a factor that needs to be considered to better predict in situ KD values.     

Factors controlling sediment and phosphorus export from two Belgian agricultural catchments

Sediment and total phosphorus (TP) export vary through space and time. This study was conducted to determine the factors controlling sediment and TP export in two agricultural catchments situated in the Belgian Loess Belt. At the outlet of these catchments runoff discharge was continuously measured and suspended sediment samples were taken during rainfall events. Within the catchments vegetation type and cover, soil surface parameters, erosion features, sediment pathways, and rainfall characteristics were monitored. Total P content and sediment characteristics such as clay, organic carbon, and suspended sediment concentration were correlated. Total sediment and TP export differ significantly between the monitored catchments. Much of the difference is due to the occurrence of an extreme event in one catchment and the morphology and spatial organization of land use in the catchments. In one catchment, the direct connection between erosive areas and the catchment outlet by means of a road system contributed to a high sediment delivery ratio (SDR) at the outlet. In the other catchment, the presence of a wide valley in the center of the catchment caused sediment deposition. Vegetation also had an effect on sediment production and deposition. Thus, many factors control sediment and TP export from small agricultural catchments; some of these factors are related to the physical catchment characteristics such as morphology and landscape structure and are (semi)permanent, while others, such as vegetation cover and land use, are time dependent.