Browsing by Subject "heavy metals"

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  • Huurtomaa, Satu (Helsingin yliopisto, 2019)
    The Baltic Sea is a vulnerable marine environment and susceptible to pollution. The situation is especially severe in the Gulf of Finland due to a large catchment area compared to the size of the Gulf. The north eastern Gulf of Finland has been described as one of the most contaminated areas of the entire Baltic Sea, with extensive pollution load via river Kymi in the past. Still today, the currents bring contaminants from the eastern part of the Gulf – the Neva estuary and the Bay of Viborg. The concentrations of V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Mo, Cd, Sb, Hg, Pb, Bi and La were studied in the surface sediments and three GEMAX cores. The vertical distribution revealed the temporal change in the metal accumulation. The spike in the Cs concentration, indicating the Chernobyl disaster in 1986, enabled the estimation of the accumulation of studied elements over time. The horizontal distribution maps based on the concentrations in the surface sediments enabled the discovery of the sites with most intense metal accumulation. Correlation coefficients showed the effect of carbon and sediment grain size in the distribution of metals. The comparison of the metal concentrations to the natural background levels and the Canadian sediment quality guidelines (SQGs) enabled the estimation of the degree of contamination of the area. The metal concentrations have declined during the last decades in the north eastern Gulf of Finland, indicating lower contamination input towards present day. However, in the oxidized Ravijoki core, the decline was not that obvious, probably due to metal scavenging by Fe and Mn oxides and bioturbation. The regional metal distribution was strongly affected by the grain size and carbon – most metals showed high positive correlations with carbon and finer sediment fraction. Mn was an exception, showing negative correlations with both carbon and clay, probably due to the Mn reduction at sites with high organic matter accumulation. The regional distribution pattern suggested main Cd pollution arriving from the eastern part of the Gulf. The distribution of Hg, Mo, Cu and Zn also suggested a possible source in the east. High concentrations of Hg, Pb and Cu were discovered in the outlets of river Kymi. According to the Canadian SQGs, the sediments in the north-eastern Gulf of Finland were contaminated. The situation is especially severe in the case of Zn – the higher reference value PEL, above which adverse biological effects frequently occur, was exceeded even in the oxidized Ravijoki sediments. The highest concentrations of the elements with defined SQGs (Cd, Cr, Zn, Cu, Hg, Pb and As) exceeded the lower reference values in the surface sediments, indicating that all these metals could, at least locally, pose a severe threat to benthic species.
  • Vizueta, Joel; Macias-Hernandez, Nuria; Arnedo, Miguel A.; Rozas, Julio; Sanchez-Gracia, Alejandro (2019)
    The coexistence of multiple eco-phenotypes in independently assembled communities makes island adaptive radiations the ideal framework to test convergence and parallelism in evolution. In the radiation of the spider genus Dysdera in the Canary Islands, species diversification occurs concomitant with repeated events of trophic specialization. These dietary shifts, to feed primarily on woodlice, are accompanied by modifications in morphology (mostly in the mouthparts), behaviour and nutritional physiology. To gain insight into the molecular basis of this adaptive radiation, we performed a comprehensive comparative transcriptome analysis of five Canary Island Dysdera endemics representing two evolutionary and geographically independent events of dietary specialization. After controlling for the potential confounding effects of hemiplasy, our differential gene expression and selective constraint analyses identified a number of genetic changes that could be associated with the repeated adaptations to specialized diet of woodlice, including some related to heavy metal detoxification and homeostasis, the metabolism of some important nutrients and venom toxins. Our results shed light on the genomic basis of an extraordinary case of dietary shift convergence associated with species diversification. We uncovered putative molecular substrates of convergent evolutionary changes at different hierarchical levels, including specific genes, genes with equivalent functions and even particular amino acid positions. This study improves our knowledge of rapid adaptive radiations and provides new insights into the predictability of evolution.
  • Seleiman, Mahmoud F.; Selim, Shaimaa; Jaakkola, Seija; Makela, Pirjo S. A. (2017)
    Maize cultivation for silage could be a sustainable option in Boreal conditions, especially when combined with nutrient recycling. Effects of digestate (sludge from biogas of domestic origin) application in comparison with synthetic fertilizer and two maturity stages on chemical composition and in vitro digestibility of whole-crop maize were investigated. Starch, neutral detergent fiber, water soluble carbohydrate (WSC) and digestible organic matter (DOM) contents of maize did not differ in response to the two fertilizer treatments. However, starch, DOM and metabolizable energy of maize increased, while ash, crude protein and WSC contents decreased with increasing maize maturity. Heavy metals in maize fertilized with digestate remained low. The results indicate that whole-crop maize fertilized with digestate and harvested at 150 days after sowing is a promising feed and has good nutritive value, even in Boreal conditions.
  • Bramryd, Torleif (Suomen metsätieteellinen seura, 1981)
  • Ingves, Jonas (Helsingin yliopisto, 2021)
    The underlying bedrock is known to have effects on metal contents in soil and water, and thereby onto the major and trace nutrient balances in plants. Heavy metal contents in different rock types are highly variable and changes in the composition of the bedrock can happen over small distances. In Finland, the locally relatively abundant black shales in the eastern part of the country contain elevated amounts of several heavy metals, while the generally more common felsic rock types are in comparison depleted in them. The influence of elemental contents in bedrock on metal distribution in nature can be assessed through comparing metal amounts in various kinds of environmental samples, which at the same time enables identification of areas of potential environmental concern. The aim of this study is to assess the influence of bedrock on heavy metal contents in peat, ditch water, and needle samples between areas underlain by felsic or black shale bedrock in nine peatland catchments in Kainuu in eastern Finland. In addition to comparing differences in elemental contents, effort is put into evaluating strengths of correlations between metal concentrations and ash contents in peat samples and to assess which metals have a tendency of occurring together in peat. For ditch water samples, correlations will be evaluated between concentrations of metals and of dissolved organic carbon (DOC) and of amounts of precipitation. In addition to influences of bedrock, other possible reasons behind differences in heavy metal amounts between areas will be looked at. Comparisons with data from other publications will in places also be made. The study is based on material collected by the Natural Resources Institute Finland in the years 2008–2015, which here includes 70 peat, 634 ditch water, and 80 needle samples. All samples were collected in nine separate forestry drained peatland catchments. Five of the catchments were located on areas underlain by felsic bedrock and four by black shales. The peat samples examined in this study range from the surface of the peat layers to 40 cm depth. The ditch water samples were collected from outlet ditches from all nine peatland catchments and needle samples were taken in eight catchments from either Scots pine (Pinus sylvestris L.) or Norway spruce (Picea abies [L.] Karst). Half of the samples were of current year’s and half of previous year’s needles. Laboratory analyses of peat samples included measurements of As, Cd, Co, Cr, Cu, Mn, Ni, Pb, U, and Zn concentrations by either ICP-MS or ICP-AES -methods and of ash contents through loss-on-ignition (LOI). Ditch water samples were analysed for Cd, Cr, Cu, Mn, Ni, Pb, and Zn concentrations with the ICP-AES method, for DOC concentrations by TOC-V CPH/CPN analysis and for sulphate (SO4-S) by ion chromatography. Tree needles were measured for contents of Cr, Cu, Mn, Ni and Zn with ICP-AES. Statistical differences in metal amounts in samples by bedrock were tested with the Mann–Whitney U test and correlations using Spearman’s rank correlation coefficient or the Pearson correlation coefficient. Metal concentrations in peat samples were for some tests recalculated to take into account ash contents using a linear general model. Metal stocks in peat layers (mg/m2) were also calculated for the sampling sites. As the main results, the ash corrected metal concentrations in peat were statistically significantly higher in samples collected on black shale as opposed to felsic bedrock in terms of As, Cd, Co, Mn, Ni, and Zn, while metal stocks in peat were significantly different in terms of Ni. In ditch water, samples from black shale areas had significantly higher concentrations of Cd, Cr, Cu, Ni, and Zn, and in tree needle samples similar significances were observed for Ni. The only cases were samples from felsic areas had significantly higher concentrations than those form black shale areas were the ash corrected concentrations of U and Cu concentrations in needle samples. Regardless of the underlying bedrock, large variations in metal amounts in all sample types were observed between catchment areas. Correlations between metal concentrations and ash contents in peat were generally relatively strong. Correlations between metals in peat were variable, and often stronger in samples collected in felsic areas. In water samples, correlations between metal and DOC concentrations were variable both between metals and catchments. The correlations between precipitation and metal concentrations in ditch water were generally weak. Overall, the composition of the bedrock was noticed to have some effects on metal concentrations in all sample types. But it was evident by the results that there are also other factors controlling metal amounts between catchments.
  • Adusei-Mensah, Frank; Essumang, David Kofi; Agjei, Richard Osei; Kauhanen, Jussi; Tikkanen-Kaukanen, Carina; Ekor, Martins (2019)
  • Johnsen, Ib (Suomen metsätieteellinen seura, 1981)
  • Vekkeli, Santtu (Helsingin yliopisto, 2019)
    Elintarvikehyönteisten kulutus on yleistynyt länsimaissa viimeisen viiden vuoden aikana. Tämän tutkimuksen tarkoituksena on esitellä uusin tieteellinen tieto elintarvikehyönteistuotannon riskitekijöistä. Työssä esitellään todellinen kaksitäpläsirkan (Gryllus bimacultus) tuotantoketju kasvatuslaitokselta valmiiksi kuivatuotteeksi. Valmistusketjun omavalvontaan tutustutaan mikrobiologisten ja kemiallisten analyysien näkökulmasta ja lopputuotteen turvallisuutta arvioidaan vastaavilla analyyseillä. Työssä esitellään myös salmonellavapauden osoittaminen kasvatuslaitoksella positiivisen löydöksen jälkeen. Kuivatun lopputuotteen analyysien, kuten raskasmetallien, mykotoksiinien tai tutkittujen patogeenisten mikrobien, osalta ei ilmennyt laatua heikentäviä vaaratekijöitä, vaikkakin tuotteen vesipitoisuuden havaittiin vaihtelevan. Havaintoon liittyen kehitettiin tuotantoketjun omavalvontaa tuotantolaitoksen ilmankosteuden seurannan ja raja-arvojen osalta. Tuontihyönteisistä löydetyn salmonellalöydöksen jälkeen kontaminaatioita ei havaittu kotimaisesta kasvatuslaitoksesta tai tuotetuista hyönteisistä otetuista näytteistä, joten salmonellan leviäminen kasvatuslaitoksen sisällä vaikuttaa epätodennäköiseltä. Kontaminaation lähtöpisteeksi epäillyltä ulkomaiselta kasvatuslaitokselta salmonellaa löytyi jatkotutkimuksissa munitusastiasta, jollaisesta myös alkuperäinen löydös oli tehty. Elintarvikehyönteisten riskinarviointi perustuu yhä kohtuullisen pieneen määrään kokemusta ja tutkimusta. Suuri osa kaksitäpläsirkan elintarviketurvallisuuteen ja prosessointiin liittyvästä tutkimustiedosta on jouduttu johtamaan toisista hyönteisistä, kuten kotisirkasta (Acheta domesticus), saadusta tiedosta. Tarve uudelle tutkimukselle on suuri ja useat perusasiatkin, kuten säilyvyysaika ja olosuhdevaatimukset, perustuvat vähäiseen tietoon. Tuotaessa hyönteisiä ulkomailta on tehtävä kohdennetusti patogeenien analyysejä, jotta voidaan estää kontaminaatioiden mahdollista leviämistä tuotantolaitoksiin.
  • Heliövaara, Kari; Väisänen, Rauno (Suomen metsätieteellinen seura, 1989)
  • Plociniczak, Tomasz; Sinkkonen, Aki; Romantschuk, Martin; Sulowicz, Stawomir; Piotrowska-Seget, Zofia (2016)
    Environmental pollution by heavy metals has become a serious problem in the world. Phytoextraction, which is one of the plant-based technologies, has attracted the most attention for the bioremediation of soils polluted with these contaminants. The aim of this study was to determine whether the multiple-tolerant bacterium. Brevibacterium casei MH8a isolated from the heavy metal-contaminated rhizosphere soil of Sinapis alba L., is able to promote plant growth and enhance Cd, Zn, and Cu uptake by white mustard under laboratory conditions. Additionally, the ability of the rifampicin-resistant spontaneous mutant of MH8a to colonize plant tissues and its mechanisms of plant growth promotion were also examined. In order to assess the ecological consequences of bioaugmentation on autochthonous bacteria, the phospholipid fatty acid (PLFA) analysis was used. The MH8a strain exhibited the ability to produce ammonia, 1-amino-cyclopropane-1-carboxylic acid deaminase, indole 3-acetic acid and HCN but was not able to solubilize inorganic phosphate and produce siderophores. Introduction of MH8a into soil significantly increased S, alba biomass and the accumulation of Cd (208%), Zn (86%), and Cu (39%) in plant shoots in comparison with those grown in non-inoculated soil. Introduced into the soil, MH8a was able to enter the plant and was found in the roots and leaves of inoculated plants thus indicating its endophytic features. PLFA analysis revealed that the MH8a that was introduced into soil had a temporary influence on the structure of the autochthonous bacterial communities. The plant growth-promoting features of the MH8a strain and its ability to enhance the metal uptake by white mustard and its long-term survival in soil as well as its temporary impact on autochthonous microorganisms make the strain a suitable candidate for the promotion of plant growth and the efficiency of phytoextraction.
  • Ervasti, Annika (Helsingin yliopisto, 2020)
    The aim of this study was to examine if eating Finnish cereals and oil seeds cause more health benefits or harm. Cadmium was considered as the chemical hazard and dietary fiber as the useful nutrient. In this study food consumptions, the heavy metal contents and exposures, fiber intake and the biggest safe doses for cereals and seeds were evaluated. DALYs (disability adjusted life years) were used to compare benefits and harms. Exposure was estimated using the statistical BIKE model. To date, no risk benefit analysis concerning cereal and seed consumption is known to have been done. A common method for risk benefit analysis has not yet been developed, but generally a stepwise approach is recommended. Of the foods examined, poppy and sunflower seeds contained the most cadmium, pumpkin seed the least. In the long term, the most consumed seed was sesame and the most consumed cereal was wheat. The greatest cadmium exposure was due to wheat consumption, and for nickel oat consumption. Wheat was clearly the biggest source of fiber. Low fiber intake resulted in more DALYs than cereals’ cadmium resulted in osteoporotic DALYs in 2012. Compared to the situation in 2012, significantly less DALYs were resulted in scenario where 232 g of whole grains per day are consumed. It is because in the scenario, DALYs caused by low fiber intake, which amount is much higher than cadmium DALYs, are not formed. Based on the results obtained, with bigger cereal consumption than in 2012, the health benefits outweigh the disadvantages, as the impact of reducing the DALYs due to low fiber intake is much more significant than the impact of the increase of cadmium DALYs caused by higher intake. In the future, it would be beneficial to have a more comprehensive study of the health effects of the foods examined. However, this requires a lot of information that was not available in this study.
  • Gelman, Valeria (Helsingfors universitet, 2014)
    The increased rates of population growth and urbanization worldwide raises the question of food security and self-reliance in cities. In view of this situation, in recent years there has been a re-emergence of urban agriculture in its traditional form and in new variations, such as on urban rooftops. A number of rooftop urban farms exist in the world; however, very few studies have been done to establish the quality of crops they produce, specifically concerning the concentrations of contaminants. The main purpose of this study was to investigate levels of contamination in edible plants grown on urban rooftops. I determined concentrations of polycyclic aromatic hydrocarbons (PAH) and trace metals in the biomass of three types of horticultural crops grown in the city of Helsinki, Finland. Lettuce, radish and peas were planted on five rooftops in various areas of Helsinki and control samples were acquired from local food stores and markets. Both groups of crops were analyzed for concentrations of 11 trace elements using the Elan 6000 ICP-MS and 16 PAHs using Shimadzu GC-MS-QP2010 Ultra system with the AOC-20i /AOC-20s autosampler. Additionally, lettuce and pea samples from the roofs were analyzed washed and unwashed to establish levels of particulate contamination on the surface of plants that can be mechanically removed through washing. Results obtained suggest that concentrations of PAHs and trace metals in rooftop vegetables in Helsinki are very low and the differences in their concentrations compared to control (store) samples are insignificant. This demonstrates that the consumption of vegetables produced in uncontaminated soil on urban roofs in Helsinki is safe. All samples showed concentrations well below the safety limits for heavy metals and PAHs established in the European Union (EC, 2006). Finally, there was a difference in concentration of PAHs and trace metals between washed and unwashed samples, however most of the results did not show statistical significance.
  • Voigt, H.-R. (Karolinum-Nakladatelstvi Univerzity Karlovy, 2000)