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Concentrations and geographic distribution of selected organic pollutants in Scottish surface soils
2013
Rhind, S.M. | Kyle, C.E. | Kerr, C. | Osprey, M. | Zhang, Z.L. | Duff, E.I. | Lilly, A. | Nolan, A. | Hudson, G. | Towers, W. | Bell, J. | Coull, M. | McKenzie, C.
Concentrations of selected persistent organic pollutants (POPs) representing three chemical classes (polycyclic aromatic hydrocarbons (PAH), polybrominated diphenyl ethers (PBDE) and polychlorinated biphenyls (PCB) and the organic pollutant diethylhexyl phthalate (DEHP), were determined in surface soil samples (0–5 cm) collected at 20 km grid intersects throughout Scotland over a three-year period. Detectable amounts of all chemical classes and most individual congeners were present in all samples. There were no consistent effects of soil or vegetation type, soil carbon content, pH, altitude or distance from centres of population on concentrations which exhibited extreme variation, even in adjacent samples. It is concluded that soil POPs and DEHP concentrations and associated rates of animal and human exposure were highly variable, influenced by multiple, interacting factors, and not clearly related to local sources but possibly related to wet atmospheric deposition and the organic carbon content of the soil.
Mostrar más [+] Menos [-]Uptake and accumulation of four PPCP/EDCs in two leafy vegetables
2013
Dodgen, L.K. | Li, J. | Parker, D. | Gan, J.J.
Many pharmaceutical and personal care products (PPCPs) and endocrine-disrupting chemicals (EDCs) are present in reclaimed water, leading to concerns of human health risks from the consumption of food crops irrigated with reclaimed water. This study evaluated the potential for plant uptake and accumulation of four commonly occurring PPCP/EDCs, i.e., bisphenol A (BPA), diclofenac sodium (DCL), naproxen (NPX), and 4-nonylphenol (NP), by lettuce (Lactuca sativa) and collards (Brassica oleracea) in hydroponic culture, using 14C-labeled compounds. In both plant species, plant accumulation followed the order of BPA > NP > DCL > NPX and accumulation in roots was much greater than in leaves and stems. Concentrations of 14C-PPCP/EDCs in plant tissues ranged from 0.22 ± 0.03 to 927 ± 213 ng/g, but nearly all 14C-residue was non-extractable. PPCP/EDCs, particularly BPA and NP, were also extensively transformed in the nutrient solution. Dietary uptake of these PPCP/EDCs by humans was predicted to be negligible.
Mostrar más [+] Menos [-]Chlorinated pesticides in stream sediments from organic, integrated and conventional farms
2013
Shahpoury, Pourya | Hageman, Kimberly J. | Matthaei, Christoph D. | Magbanua, Francis S.
To determine if current sheep/beef farming practices affect pesticide residues in streams, current-use and legacy chlorinated pesticides were quantified in 100 sediment samples from 15 streams on the South Island of New Zealand. The study involved five blocks of three neighboring farms, with each block containing farms managed by organic, integrated and conventional farming practices. Significantly higher concentrations of dieldrin, ∑ endosulfans, ∑ current-use pesticides, and ∑ chlorinated pesticides were measured in sediments from conventional farms compared to organic and integrated farms. However, streams in the latter two farming categories were not pesticide-free and sometimes contained relatively high concentrations of legacy pesticides. Comparison of measured pesticide concentrations with sediment quality guidelines showed that, regardless of farming practice, mean pesticide concentrations were below the recommended toxicity thresholds. However, up to 23% of individual samples contained chlorpyrifos, endosulfan sulfate, ∑ DDT, dieldrin, or ∑ chlordane concentrations above these thresholds.
Mostrar más [+] Menos [-]Spatial and temporal variations in pentachlorophenol dissipation at the aerobic–anaerobic interfaces of flooded paddy soils
2013
Lin, Jiajiang | Xu, Yan | Brookes, Philip C. | He, Yan | Xu, Jianming
Pentachlorophenol (PCP) dissipation occurs naturally in flooded soils and although dissipation half-lives vary between soil profiles at the millimeter-scale the reason is poorly understood. Vertical variations of PCP dissipation were investigated in three typical Chinese paddy soils; Soil 1 (Umbraqualf), Soil 2 (Plinthudult) and Soil 3 (Tropudult). The soil depth was divided into a surface and a deep layer based upon different PCP dissipations in the surface layer of 40–93, 42–88 and 16–100% for Soils 1–3 respectively. In the deep layer, PCP was greatly dissipated in Soil 2, but much less in Soil 1 and Soil 3. Correlation analysis indicated that SO42− and Fe(III) were negatively related to PCP dissipation. SO42− and Cl- were highly mobile in the flooded soil profiles. Fe(III) reduction increased with increasing soil depth, and was inhibited by high SO42− concentrations.
Mostrar más [+] Menos [-]Covalent bonding of chloroanilines to humic constituents: Pathways, kinetics, and stability
2013
Kong, Deyang | Xia, Qing | Liu, Guoqiang | Huang, Qingguo | Lu, Junhe
Covalent coupling to natural humic constituents comprises an important transformation pathway for anilinic pollutants in the environment. We systematically investigated the reactions of chlorine substituted anilines with catechol and syringic acid in horseradish peroxidase (HRP) catalyzed systems. It was demonstrated that although nucleophilic addition was the mechanism of covalent bonding to both catechol and syringic acid, chloroanilines coupled to the 2 humic constituents via slightly different pathways. 1,4-addition and 1,2-addition are involved to catechol and syringic acid, respectively. 1,4-addition showed empirical 2nd order kinetics and this pathway seemed to be more permanent than 1,2-addition. Stability experiments demonstrated that cross-coupling products with syringic acid could be easily released in acidic conditions. However, cross-coupling with catechol was relatively stable at similar conditions. Thus, the environmental behavior and bioavailability of the coupling products should be carefully assessed.
Mostrar más [+] Menos [-]Trend of dissolved inorganic nitrogen at stations downstream from the Three-Gorges Dam of Yangtze River
2013
Sun, C.C. | Shen, Z.Y. | Xiong, M. | Ma, F.B. | Li, Y.Y. | Chen, L. | Liu, R.M.
The TRAMO/SEATS program, combined with the Hodrick–Prescott (HP) filter, was used to detect trends and potential change points in time series of dissolved inorganic nitrogen (DIN) at three stations along the Yangtze River. The trend components were extracted, and two change points were successfully detected. The components revealed that DIN has been increasing at all the stations since the 1990s, although variations exist. Changes visible before 2002 illustrate the differences in agriculture development among regions upstream from the stations. The Three-Gorges Dam (TGD), which began to impound in 2003, led to years of different trends. The DIN concentration, which had been trending upward prior to that date, began a slightly downward trend because of NH4+ depletion. Readings at the Yichang station revealed this trend most strongly; those at the Hankou station less so. The Datong station was far enough away from the TGD so that no obvious effects were seen.
Mostrar más [+] Menos [-]Hexabromocyclododecane in alpine fish from the Tibetan Plateau, China
2013
Zhu, Nali | Fu, Jianjie | Gao, Yan | Ssebugere, Patrick | Wang, Yawei | Jiang, Guibin
Hexabromocyclododecanes (HBCDs) has just been listed into Stockholm Convention as a persistent organic pollutant recently. This paper studied the HBCDs in 79 wild fish from high mountain lakes and rivers of the Tibetan Plateau. The ∑HBCDs in fish muscles ranged from non detectable levels to 13.7 ng/g lipid weight (lw) (mean value of 2.12 ng/g lw) with a high detection frequency of 65.8%. α-HBCD dominated among the isomers and accounted for 78.2% of the total burden. Concentrations of ∑HBCDs in the fish were significantly correlated with the lipid content. A decreasing trend was observed between α-HBCD and trophic level. Positive correlation was also noted between the HBCD levels in fish from lakes and the annual precipitation, and this implied the long-range atmospheric transport of HBCDs to the Tibet Plateau. This was the first work to widely explore HBCDs contamination in the aquatic ecosystems of the Tibetan Plateau.
Mostrar más [+] Menos [-]Attribution of sources to metal accumulation in an alpine tarn, the Snowy Mountains, Australia
2013
Stromsoe, Nicola | Callow, J Nikolaus | McGowan, Hamish A. | Marx, Samuel K.
This study analyses 1800 years of heavy metal accumulation in a remote alpine lake experiencing long-range atmospheric contamination and additional inputs of Ag from cloud seeding. In comparison to previous work undertaken on peats, lake sediments show limited post-industrial metal enrichment with enrichment factors of Ag: 1.3, Pb: 1.3, Zn: 1.1, Cu: 1.2 compared to Ag: 2.2, Pb: 3.3, Zn: 2.1, Cu: 4.1 for peat. We show this to be the result of substantial fluvial lithogenic flux of metals (92–97% of total metal flux) to the lake. Total annual metal flux to the lake ranges from: Ag: 4–12 ng/cm2/yr to Zn: 3 383–11 313 ng/cm2/yr. As a result, any contribution of cloud seeding to additional enrichment of Ag in lake sediments is considered negligible. Results show that metal enrichment is not necessarily ubiquitous through a landscape. This has implications for predicting the impacts of atmospheric metal pollution to complex environmental systems.
Mostrar más [+] Menos [-]Key factors affecting liver PBDE concentrations in sparrowhawks (Accipiter nisus)
2013
Crosse, John D. | Shore, Richard F. | Jones, K. C. (Kevin C.) | Pereira, M Glória
High PBDE concentrations have been detected in the eggs of the sexually dimorphic Eurasian sparrowhawk (Accipiter nisus) but little is known about contamination levels in adult birds and how this may vary with age and sex. We characterised liver PBDE concentrations in 59 sparrowhawks that had died in central Britain between 1998 and 2009 and determined how concentrations varied with sex, age, body condition and breeding status. Five BDE congeners (99 > 153 > 47 > 100 > 154) predominated and ΣPBDE concentrations were 10–15 fold and 2–3 fold higher in starved than non-starved adult and juvenile sparrowhawks, respectively. This was likely due to a combination of remobilisation of residues from other tissues and liver wastage. Liver ΣPBDE concentrations did not vary with sex but were greater in adults than juveniles, suggestive of accumulation with age. Overall, liver ΣPBDE concentrations ranged from 43.4 to 68,040 ng/g lipid weight, amongst the highest concentrations reported in birds anywhere.
Mostrar más [+] Menos [-]Impact of elevated CO2 and elevated O3 on Beta vulgaris L.: Pigments, metabolites, antioxidants, growth and yield
2013
Kumari, Sumita | Agrawal, Madhoolika | Tiwari, Supriya
The present study was conducted to assess morphological, biochemical and yield responses of palak (Beta vulgaris L. cv Allgreen) to ambient and elevated levels of CO2 and O3, alone and in combination. As compared to the plants grown in charcoal filtered air (ACO2), growth and yield of the plants increased under elevated CO2 (ECO2) and decreased under combination of ECO2 with elevated O3 (ECO2 + EO3), ambient O3 (ACO2 + AO3) and elevated O3 (EO3). Lipid peroxidation, ascorbic acid, catalase and glutathione reductase activities enhanced under all treatments and were highest in EO3. Foliar starch and organic carbon contents increased under ECO2 and ECO2 + EO3 and reduced under EO3 and ACO2 + AO3. Foliar N content declined in all treatments compared to ACO2 resulting in alteration of C/N ratio. This study concludes that ambient level of CO2 is not enough to counteract O3 impact, but elevated CO2 has potential to counteract the negative effects of future O3 level.
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