| 41. |
- Lidman, Johan, et al.
(författare)
-
Availability of specific prey types impact pied flycatcher (Ficedula hypoleuca) nestling health in a moderately lead contaminated environment in northern Sweden
- 2020
-
Ingår i: Environmental Pollution. - : Elsevier. - 0269-7491 .- 1873-6424. ; 257
-
Tidskriftsartikel (refereegranskat)abstract
- Anthropogenic metal contamination can cause increased stress in exposed organisms, but it can be difficult to disentangle the anthropogenic influence from natural variation in environmental conditions. In the proximity of a closed lead (Pb)/zinc (Zn) mine in northern Sweden, the health effects of Pb exposure, essential element (calcium [Ca] and Zn) uptake, and prey availability and composition were estimated on pied flycatcher (Ficedula hypoleuca) nestlings, using hemoglobin (Hb) level as a proxy for health. Pb concentration in nestling blood range between 0.00034 and 2.21 mu g/g (ww) and nestlings close to the mine had higher Pb concentrations and lower Hb, but contrary to our hypothesis, Hb was not directly related to Pb accumulation. Proportions of flying terrestrial and aquatic insects in available prey and availability of flying terrestrial insects were positively associated with nestling Hb, whereas the proportion of terrestrial ground living prey, the most common prey type, showed a negative association. This suggests that positive influence of certain prey, which does not have to be the most common in the surroundings, can counteract the negative effects from Pb contamination on bird health. Nestlings inhabiting sites adjacent to lakes had an advantage in terms of prey composition and availability of preferred prey, which resulted in higher Hb. As such, our results show that during moderate exposure to metals, variation in natural conditions, such as prey availability, can have great impact on organism health compared to Pb exposure.
|
|
| 42. |
- Lidman, Johan, et al.
(författare)
-
Effect of past century mining activities on sediment properties and toxicity to freshwater organisms in northern Sweden
- 2023
-
Ingår i: Science of the Total Environment. - : Elsevier. - 0048-9697 .- 1879-1026. ; 872
-
Tidskriftsartikel (refereegranskat)abstract
- The release of toxic metals from local mining activities often represents a severe environmental hazard for nearby lake ecosystems. Previous studies on the impact of mining have primarily focused on single lakes, with less emphasis on spatial and temporal recovery patterns of multiple lakes within the same catchment, but with different hydrological connection and distance to the pollutant source. This knowledge gap prevents us from assessing the real environmental risk of abandoned mines and understanding ecosystem recovery. This study explores the intensity and spatial patterns of sediment contamination and the potential for ecosystem recovery in three lakes in close vicinity of a lead (Pb) and zinc (Zn) mine in Sweden that has been inoperative for >20 years. Dated (210Pb and 137Cs) sediment cores from each lake were used to reconstruct temporal patterns in trace element deposition and relate those with past mining activities. Results show that all lakes were affected by mining, indicated by increasing Pb and Zn concentrations and decreasing organic matter content, at the onset of mining. However, the extent and timing of mining impact differed between lakes, which was partly ascribed to differences in the historical use of tailings and settling ponds. Assessment of toxicity levels in sediments, based on normalized Probable Effect Concentration Quotient (PEC-Q) to organic matter content, provided more consistent results with the historical mining than conventional methods, showing a decreasing impact in lakes once the operations ceased. Still, sediment Pb concentrations were > 10 times higher than pre-mining values, evidencing the urgent need for remediation actions in the study lakes. This study highlights the importance of considering spatial heterogeneity in metal deposition, sediment organic matter content, and hydrological connectivity with tailings when risk assessments are performed in mining-impacted lakes. The use of normalized PEC-Q in toxic assessments is also recommended.
|
|
| 43. |
- Lidman, Johan, 1988-
(författare)
-
Metals take flight : Transport and effects across ecosystems
- 2021
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Metal contamination can have severe toxic effects in the ecosystems, resulting in loss of biodiversity, reduced abundance of organisms, and loss of ecosystem services. Traditionally, aquatic ecosystems have been regarded as a sink of metal contamination. However, lakes could also act as a source, as metals can be transported by emerging aquatic insects from the aquatic to the terrestrial ecosystem. The consequence of this transport for terrestrial organisms has previously gained little focus. In this thesis, I study metal contamination transport and toxic effects on metal exposed aquatic invertebrates and the terrestrial insectivorous bird, pied flycatcher (Ficedula hypoleuca), in aquatic and terrestrial environments contaminated by metals from a closed lead (Pb) and zinc (Zn) mine. Studied lakes adjacent to the mine all displayed elevated metal concentrations from the start of the mining operation, but with different temporal and spatial patterns with lakes used as part of the mining activity even more affected. Factors affecting metal toxicity, such as organic matter concentration in lakes, varied during the mining and post-mining period, indicating fluctuating toxicity despite similar metal concentrations. The contamination level and toxicity risk are still high 15 years after closure of the mine, but ecosystems are starting to recover. Despite high metal concentrations in lake water and sediment, no effect on invertebrate abundance or composition of aquatic invertebrates was observed. However, when focusing on metamorphosis, proportionally fewer insects emerged from more contaminated lakes. In contrast, in lab mesocosm was no effect on metamorphosis observed of non-biting midges (Chironomus riparus), although larval survival decreased, and emergence was delayed at higher metal concentrations in sediments. Emerging adult insects transported a significant amount of metals to terrestrial ecosystems, observed both in the lab and in the field. Emerging aquatic insect and ants were major dietary metal exposure routes for pied flycatcher’s nestlings. Thus, aquatic-derived metals can influence terrestrial consumers, especially in riparian zones of contaminated lakes where availability of aquatic insects is high. Increasing accumulation of Pb has been observed to reduce hemoglobin (Hb) levels in birds. Despite elevated Pb concentrations in nestling blood in contaminated environments, nestling Hb levels, used also as indicator of nestling health, was more affected by availability of different prey than Pb levels in the blood, where availability of aquatic insects and aerial terrestrial insect had positive impact on nestling health. Overall, this thesis show that metal contamination of aquatic ecosystems also influences terrestrial organisms by decreasing their food availability and increasing metal exposure via diets. Thus, potential effects on terrestrial systems should to larger extent be included when studying aquatic contaminants. Further, indirect effects and metal bioavailability could alter the toxic effects on metal-exposed organism and should be included to accurately estimate direct toxic effects.
|
|
| 44. |
- Lidman, Johan, et al.
(författare)
-
The effect of aquatic and terrestrial prey availability on metal accumulation in pied flycatcher (Ficedula hypoleuca) nestlings
- 2022
-
Ingår i: Environmental Research. - : Elsevier. - 0013-9351 .- 1096-0953. ; 209
-
Tidskriftsartikel (refereegranskat)abstract
- Ingestion of contaminated prey is a major route for metal exposure in terrestrial insectivores. In terrestrial ecosystems adjacent to lakes and streams, emerging aquatic insects can transport metals, accumulated during their larval stage, from aquatic to terrestrial ecosystems. However, contaminant exposure via aquatic insects has often been ignored in terrestrial environments, despite such insects representing a substantial part of the diet for terrestrial insectivores living close to lakes and streams. In this study, we investigated how dietary lead (Pb) and calcium (Ca) exposure from different aquatic and terrestrial prey types affects Pb accumulation in pied flycatcher (Ficedula hypoleuca) nestlings living close to a former Pb/zinc (Zn) mine in northern Sweden, which closed in 2001. Stable isotope analysis (δ 13C and δ15N) of nestling blood and different prey types was used to estimate nestlings' diet. Ants, Lepidoptera larvae and Trichoptera were the most common prey types in the nestlings’ diet, in which aquatic prey types (Trichoptera included) accounted for 2.0–96.4%. Ingestion of specific prey groups, such as aquatic insects and ants, were important for Pb accumulation in nestlings, and when access to aquatic prey was low, ants were the predominant source of Pb. The influence of dietary Ca on Pb accumulation was less consistent, but Ca availability was relatively high and often co-occurred with high Pb concentrations in invertebrates. The study shows that both the proportion of different prey and their individual metal concentrations need to be considered when estimating exposure risks for insectivores. Further, it highlights the need to account for metal exposure from emerging aquatic insects for terrestrial insectivores living close to lakes and streams.
|
|
| 45. |
- Lidman, Johan, et al.
(författare)
-
The effect of lead (Pb) and zinc (Zn) contamination on aquatic insect community composition and metamorphosis
- 2020
-
Ingår i: Science of the Total Environment. - : Elsevier. - 0048-9697 .- 1879-1026. ; 734
-
Tidskriftsartikel (refereegranskat)abstract
- Metal contamination of freshwater ecosystems is a great threat to aquatic insect communities. In the past, focus has been on the toxic effects on the insect larvae, despite emerging evidence showing that negative effects can occur during metamorphosis to adults. There is therefore a risk that traditional studies on insect larvae would underestimate effect from metals. In this study, we investigated the effect of lead (Pb) and zinc (Zn) on aquatic insect abundance, including metamorphosis and adult emergence at 9 lakes, near an abandoned Pb/Zn mine, with different Pb and Zn concentrations in sediment and water. Further, differences in response to metal contamination among taxa, and potential community composition changes, were also investigated. Total insect abundance was not affected by metal contamination, but Zn had a negative effect on metamorphosis and proportionally less adults emerged compared to larval abundance when the bioavailable Zn concentration in water increased. The opposite pattern was found for bioavailable Pb (negative effect on larvae but not on adult emergence). All studied insect groups had similar response to metal contamination, and no change in community structure towards dominance of more tolerant taxa was observed. Our study shows that it is important to include metamorphosis when metal toxicity is evaluated in aquatic insects, and that metals can have opposite and contradicting effects. Thus, although combined cocktail effects of metal mixtures are important to assess, effects of individual metals can be underestimated.
|
|
| 46. |
|
|
| 47. |
- Malvandi, Hassan, et al.
(författare)
-
Measurement of metal concentrations in feathers of bird-vehicle collisions, Sabzevar, Iran
- 2021
-
Ingår i: Environmental Science and Pollution Research. - : Springer. - 0944-1344 .- 1614-7499. ; 28:41, s. 57686-57694
-
Tidskriftsartikel (refereegranskat)abstract
- The purpose of the present study is to compare the concentrations of lead, copper, and zinc in feathers of birds struck in collisions with vehicles. Two main assumptions were investigated: that there is a significant difference between species with different diets and that large and old species have higher concentrations of lead than small and young species because of their longer life span and longer exposure time to pollutants. Mean concentrations were obtained for lead 0.122, 0.006, 0.007, 0.010, and 0.014, for copper 0.718, 0.783, 0.530, 0.853, and 0.793, and for zinc 0.891, 0.940, 0.787, 0.932, and 1.003 in house sparrow (Passer domesticus), tree sparrow (Passer montanus), European roller (Coracias garrulus), Little bittern (Ixobrychus minutus), and Levant sparrowhawk (Accipiter brevipes), respectively. The results showed that there were no significant differences in the concentrations of the studied elements between species with different diets and as well as between large and small size or juveniles and adults; thus, the two hypotheses were rejected. The concentrations of the studied elements were lower than the “negative effects” threshold values suggested by previous studies; thus, they are not likely to pose a serious threat to the selected species. However, it is important to include not only other non-essential elements in future studies but also larger sample sizes. It is also noteworthy that this is the first study to determine the concentration of metals in two of the species, Coracias garrulous and Accipiter brevipes.
|
|
| 48. |
- Merz, Luisa M., et al.
(författare)
-
The Role of Buffer, Pyridoxal 5'-phosphate and Light on the Stability of the Silicibacter Pomeroyi Transaminase
- 2022
-
Ingår i: ChemCatChem. - : Wiley. - 1867-3880 .- 1867-3899. ; n/a:n/a
-
Tidskriftsartikel (refereegranskat)abstract
- Transaminases are pyridoxal 5’-phosphate (PLP)-dependent enzymes that transfer amino-functions. The transaminase from Silicibacter pomeroyi (SpATA) exhibits a broad substrate spectrum. In this work we examined the effect of different conditions (light, buffer and PLP-concentration) on the stability of SpATA, as well as the causes for these effects. The enzyme was stored either in TRIS or CHES with 0–10 mM added PLP at 22 °C. The samples were either kept dark or they were exposed to light. The results show that invariably, all samples kept in darkness exhibited longer half-life times than the ones exposed to light. An increase in the half-life from 8 h to 720 h could be achieved solely by keeping the sample dark. Especially samples in CHES buffer inactivated faster in light the more PLP was present, due to the degradation of PLP. In TRIS however, an imine-bond between TRIS and PLP protects PLP from degradation.
|
|
| 49. |
|
|
| 50. |
|
|
