| 1. |
- Blum, Kristin M., et al.
(författare)
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Removal of 30 active pharmaceutical ingredients in surface water under long-term artificial UV irradiation
- 2017
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Ingår i: Chemosphere. - : Elsevier BV. - 0045-6535 .- 1879-1298. ; 176, s. 175-182
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Tidskriftsartikel (refereegranskat)abstract
- This study investigated the i) kinetics, and ii) proportion of photolysis of 30 relatively stable active pharmaceutical ingredients (APIs) during artificial UV irradiation for 28 d in ammonium acetate buffer, filtered and unfiltered river water. Buffer was included to control removal kinetics under stable pH conditions and without particulate matter. Dark controls were used to determine removal due to other processes than photolysis and calculate the proportion of photolysis of the total removal. The removal of each API in each matrix was determined using online solid phase extraction/liquid chromatography tandem mass spectrometry (online SPE/LC-MS/MS). Most APIs transformed during the 28 d of UV irradiation and the dark controls showed that photolysis was the major removal process for the majority of the APIs studied. The half-lives ranged from 6 h (amitriptyline) in unfiltered river water to 884 h (37 d, carbamazepine) in buffer. In unfiltered river water, the proportion of APIs with short half-lives (<48 h) was much higher (29%) than in the other matrices (4%), probably due to additional organic carbon, which could have promoted indirect photolysis. Furthermore, two APIs, memantine and fluconazole, were stable in all three matrices, while alprazolam was stable in buffer and unfiltered river water and four additional APIs were stable in buffer. Considering the relatively long-term UV-exposure, this study enabled the investigation of environmentally relevant half-lives in natural waters. Many APIs showed high persistence, which is environmentally concerning and emphasizes the importance of further studies on their environmental fate and effects.
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| 2. |
- Katrantsiotis, Christos, et al.
(författare)
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Climate changes in the Eastern Mediterranean over the last 5000 years and their links to the high-latitude atmospheric patterns and Asian monsoons
- 2019
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Ingår i: Global and Planetary Change. - : Elsevier BV. - 0921-8181 .- 1872-6364. ; 175, s. 36-51
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Tidskriftsartikel (refereegranskat)abstract
- This research aims to improve the knowledge of the mid to late Holocene climate changes and the underlying drivers in the eastern Mediterranean. We focus on the Peloponnese peninsula, SW Greece, characterized by a W-E rainfall/temperature gradient and a strong climate-sensitivity to shifts in the large-scale atmospheric patterns. A radiocarbon-dated sediment core, taken from the ancient Lake Lerna, a former lake in NE Peloponnese, was analyzed for distribution and hydrogen isotope (δD) composition of n-alkanes and bulk organic geochemistry (δ13C, TOC). The predominantly macrophyte (submerged/floating)-derived δD23 profile exhibits the largest long-term fluctuation in the record and co-varies with δD of long-chain n-alkanes providing evidence for precipitation and temperature changes over the last 5000 years. The Lerna δD23 signal is sometimes in agreement with other n-alkane δD records from SW Peloponnese indicating wetter conditions in the peninsula at ca 5000–4600, ca 4500–4100, ca 3000–2600 (more unstable in SW) and after ca 700 cal BP with drier periods at ca 4100–3900 and ca 1000–700 cal BP. Conversely, a NE-SW climate see-saw is revealed at ca 4600–4500, ca 3200, ca 2600–1800, and ca 1200–1000 cal BP when the δD23 Lerna exhibits more positive trends (drier in NE) with a reversal at ca 3900–3300, ca 3200–3000 and ca 1800–1300 cal BP. These opposing and sometimes similar signals between NE and SW Peloponnese can be explained by the relative dominance of high-latitude atmospheric patterns over the peninsula. A similar signal would be expected when the North Atlantic Oscillation (NAO) exerts the main control with NAO (+) creating conditions of reduced moisture. The dipole pattern is likely driven by shifts in North Sea–Caspian Atmospheric pattern (NCP), which account for the present-day regional climate variability with NCP (+) leading to wetter and colder conditions in NE Peloponnese. The Asian monsoonal system likely has an additional impact on the δD variabilities through influencing the summer temperatures. There is a consistency between the Peloponnesian δD signals and monsoonal records after ca 4000 cal BP confirming the actualistic models. Strong monsoonal periods coincide with cooler summers (lower δD values) in Lerna, due to the northerly winds, the Etesians. On the contrary, SW Peloponnese is dominated by warmer conditions during the same periods as the area is located on the lee side of the mountain and highly influenced by the adiabatic warming associated with the subsidence over the Eastern Mediterranean.
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| 3. |
- Norström, Elin, et al.
(författare)
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Biomarker hydrogen isotope composition (D) as proxy for Holocene hydroclimatic change and seismic activity in SW Peloponnese, Greece
- 2018
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Ingår i: Journal of Quaternary Science. - : Wiley. - 0267-8179 .- 1099-1417. ; 33:5, s. 563-574
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Tidskriftsartikel (refereegranskat)abstract
- We present a 6000-year-long record tracing hydroclimate changes in SW Greece, based on hydrogen isotope composition of aquatic plant-derived n-C-23 alkanes (D-C23) in a sediment core from the Messenian plain, Peloponnese. The D-C23 record co-varies with other eastern Mediterranean records, suggesting relatively wetter conditions c. 6-4.5ka, followed by progressively drier conditions leading up to maximum aridity c. 2.8 ka. This arid phase was interrupted by a shift in D-C23 between 3.3 and 3.1ka inferring wetter conditions and/or tentative responses to anthropogenic water regulating activities during the Late Bronze Age. After 2.7ka, a return to more humid conditions was followed by increased dryness and stronger seasonality contrasts from c. 2.0ka. The D-C23 record shows three short-lived excursions (5.7, 5.3, 2.8ka), where isotope values dropped by >20 parts per thousand and immediately stabilized again. The events were paralleled by abrupt increases in sedimentation rates. We hypothesize that the isotopic shifts represent a response to mixing of ground water systems during tectonic events, followed by sealing of seismically derived cracks in the active fault. The outcome of the study is promising for future expansion of isotope-based proxies on sediments in the region, to reconstruct both hydroclimate and past seismic activity.
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| 4. |
- Norström, Elin, et al.
(författare)
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Chemotaxonomy in some Mediterranean plants and implications for fossil biomarker records
- 2017
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Ingår i: Geochimica et Cosmochimica Acta. - : Elsevier BV. - 0016-7037 .- 1872-9533. ; 219, s. 96-110
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Tidskriftsartikel (refereegranskat)abstract
- The increasing utilization of n-alkanes as plant-derived paleo-environmental proxies calls for improved chemotaxonomic control of the modern flora in order to calibrate fossil sediment records to modern analogues. Several recent studies have investigated long-chain n-alkane concentrations and chain-length distributions in species from various vegetation biomes, but up to date, the Mediterranean flora is relatively unexplored in this respect. Here, we analyse the n-alkane concentrations and chain-length distributions in some of the most common species of the modern macchia and phrygana vegetation in south western Peloponnese, Greece. We show that the drought adapted phrygana herbs and shrubs, as well as some of the sclerophyll and gymnosperm macchia components, produce high concentrations of n-alkanes, on average more than double n-alkane production in local wetland reed vegetation. Furthermore, the chain-length distribution in the analysed plants is related to plant functionality, with longer chain lengths associated with higher drought adaptive capacities, probably as a response to long-term evolutionary processes in a moisture limited environment. Furthermore, species with relatively higher average chain lengths (ACL) showed more enriched carbon isotope composition in their tissues (delta C-13(plant)), suggesting a dual imprint from both physiological and biochemical drought adaptation. The findings have bearings on interpretation of fossil sedimentary biomarker records in the Mediterranean region, which is discussed in relation to a case study from Agios Floros fen, Messenian plain, Peloponnese. The 6000 year long n-alkane record from Agios Floros (ACL, delta C-13(wax)) is linked to the modern analogue and then evaluated through a comparison with other regional-wide as well as local climate and vegetation proxy-data. The high concentration of long chain n-alkanes in phrygana vegetation suggests a dominating imprint from this vegetation type in sedimentary archives from this ecotone.
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| 5. |
- Norström, Elin, et al.
(författare)
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Leaf wax delta D inferring variable medieval hydroclimate and early initiation of Little Ice Age (LIA) dryness in southern Mozambique
- 2018
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Ingår i: Global and Planetary Change. - : Elsevier BV. - 0921-8181 .- 1872-6364. ; 170, s. 221-233
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Tidskriftsartikel (refereegranskat)abstract
- A sediment sequence from a coastal, hydrologically isolated lake in southern Mozambique was analysed for leaf wax delta D, n-alkane abundance (ACL) and bulk organic geochemistry (delta C-13, TOC, %N), providing a record of past rainfall variability and savanna dynamics over the last 1500 years. The delta D-wax a rainfall reconstruction reveals a stable hydroclimate between 500-700 CE, while ACL and delta C-13 together with previous pollen data suggest savanna vegetation was characterized by a relatively dense woody cover. Highly variable hydroclimate conditions are inferred by delta D-wax between 800-1350 CE, with repeated centennial scale intervals of extreme dry and wet conditions overlapping the Medieval Climate Anomaly (MCA; 950-1250 CE). Savanna tree cover stayed relatively intact over this phase. After ca 1250 CE, a progressive change towards drier conditions was initiated, leading up to maximum aridity during the AD 1700s, a period associated with the Little Ice age (LIA; 1500-1850 CE). Tree cover was now replaced by a more grass-dominated savanna. The clear antiphase rainfall patterns between Nhaucati and equatorial East African proxy records gives support to the notion that Indian Ocean sea surface temperature (SST) gradients act as modulator of southern African climate on a multi-decadal time scale, possibly forced by long-term El Nino Southern Oscillation (ENSO) variability. We suggest that strong ENSO variability and greater occurrence of La Nina events triggered the generally wet and unstable MCA in southern Africa. From around 1250 CE, a shift towards a predominance of El Nino induced drier conditions in south-east Africa during the LIA. Our study of vegetation and hydroclimate proxies in parallel suggests that savanna tree and shrub cover was relatively resilient to the abrupt shifts in hydroclimate over the MCA, but more sensitive to the long-term progressive drying over the LIA.
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| 6. |
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| 7. |
- Sjöström, Jenny, et al.
(författare)
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Late Holocene palaeoenvironmental reconstruction from Mpumalanga Province (South Africa) inferred from geochemical and biogenic proxies
- 2017
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Ingår i: Review of Palaeobotany and Palynology. - : Elsevier BV. - 0034-6667 .- 1879-0615. ; 246, s. 264-277
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Tidskriftsartikel (refereegranskat)abstract
- Here we present a palaecological reconstruction covering the last 1700 yr from Lydenburg fen, located in the north-eastern grassland biome, Mpumalange, South Africa. A 300 cm peat sequence was analysed for biogenic (grass phytoliths, diatoms) and geochemical proxies (delta C-13, delta N-15, carbon/nitrogen content) to infer past grassland dynamics and hydro-climatic changes. The Lydenburg record reports a C-4 dominated grassland throughout the studied period, with more or less pronounced fluxes between C-4-Chloridoideae and C-4-Panicoideae grass subfamilies. The record reflects moderate to dry conditions from AD 400 to 1000; more mesic conditions until around AD 1250; followed by a significantly drier period between c. AD 1250 and c. AD 1350, when Chloridoideae grasses expand at the expense of Panicoideae grasses. During this phase, the delta C-13-record reports more enriched values indicating higher influx of C-4 grasses. Furthermore, lithological evidence indicates highly erosive conditions, with significant gravel input from the surrounding hills. After AD 1350, proxy indications suggest a shift towards more mesic conditions. During this increasingly mesic but also unstable period, farming communities using specialized agricultural practices (e.g. the people in Bokoni) expanded their settlements into new regions (Delius et al., 2008). This expansion was also coupled to population growth, suggesting these communities applied techniques that enabled improved food production under environmentally challenging conditions. Over the last century, Lydenburg delta C-13-values indicate increased input of C-3 taxa. The phytolith record shows that this increase is not coupled to an increase in Pooideae (C-3) grasses, suggesting that the C-3 input may be related to woody encroachment.
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| 8. |
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| 9. |
- Vilches, Ana Paola, et al.
(författare)
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Direct analysis of free amino acids by mixed-mode chromatography with tandem mass spectrometry
- 2017
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Ingår i: Journal of Separation Science. - : Wiley. - 1615-9306 .- 1615-9314. ; 40:7, s. 1482-1492
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Tidskriftsartikel (refereegranskat)abstract
- We developed a straightforward, robust, and relatively fast method for the analysis of amino acids by mixed-mode high-performance liquid chromatography coupled to electrospray ionization tandem mass spectrometry. The method does not involve derivatization and allows the detection of 21 amino acids, representing a wide range of isoelectric points, in less than 40 min. Chromatographic separation was governed by a silica-based mixed-mode column providing simultaneous hydrophobic and ion exchange separation mechanisms. The use of tandem mass spectrometry increased selectivity, reducing potential problems associated with poor selectivity in the chromatographic system. For an injection volume of 1 μL, we obtained detection limits <3 μM for the majority of analytes. For all analytes, a linearity of r > 0.99 was obtained, recovery in matrix was >86%, and the retention times were highly reproducible. The method was successfully applied to soil solution and fungal culture samples, demonstrating the advantages in successfully avoiding issues associated with high amounts of substances that may interfere with derivatization-based methods. This method represents an alternative to derivatization-based methods and can be applied in areas where sample matrices are highly complex.
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