Spatio‐temporal patterns of major ions in urban stormwater under cold climate

Multiple natural and anthropogenic factors affect urban water chemistry. However, little is known about the abundance or temporal variation of major ions in urban runoff. This study explores the spatio‐temporal variation of major dissolved ions (Na, K, Ca, Mg, Cl, NO₃, and SO₄) and total dissolved solids (TDS) in cold climate urban stormwater. Three watersheds with varying degrees of urban land use intensity and imperviousness (from 36% to 66%) in Helsinki, Finland, were continuously monitored for 5 years using an automated sampling procedure to obtain stormwater discharge and ion concentrations and, thus, loadings. High‐resolution datasets, including long‐term continuous discharge, both measured and simulated (using Storm Water Management Model), and automatic water quality sampling enabled the accurate calculation of loads of ions and TDS. Water quality was related to explanatory watershed characteristics (e.g., watershed physiography and sampling time) using hierarchical clustering, nonmetric multidimensional scaling, and hierarchical partitioning methods. Urban land use contributed to increased ion concentrations and loads year‐round. This study highlights how stormwater ion concentrations are elevated across seasons, indicating chronic pollution phenomena. The greatest loads occurred during summer (except for Na and Cl), while the highest variation in loads was observed in autumn. Significant clusters among ions were found in the hierarchical cluster analysis, suggesting similar temporal patterns and sources for the ions in each cluster. The importance of land use was evident, though in the most urbanized watershed, concentrations were not linked to any of the investigated watershed characteristics. Based on our results, only Na and Cl are manageable by alternative winter road antiskid practices, whereas other ions resulted from diffuse pollution sources, being therefore more difficult to control. Finally, this study contributes to an increased understanding of the temporal and spatial patterns of ions in stormwater and highlights the need for consistent time series data for ion monitoring under cold climatic conditions in order to enable reliable estimates of their loads to adjacent water bodies. Finally, year‐round stormwater treatment is highly recommended.     

Carbon Budget and Molecular Structure of Natural Organic Matter in Bank Infiltrated Groundwater

Managed aquifer recharge (MAR) provides means to remove natural organic matter (NOM) from surface waters. Recent studies have explored the degree of NOM removal in groundwater. In this study, we further elaborate the NOM removal at a lakeside natural bank infiltration site that functions as a surrogate for MAR. Our objective was to quantify the carbon budget in the aquifer based on concentration measurements of dissolved (in)organic carbon, and the molecular changes in NOM using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). According to the carbon budget, only 25% of the dissolved carbon entering the aquifer was organic, and it predominantly originated from lake water. Of the inorganic majority, on average 40% was produced in the vadose zone above the groundwater table, 31% in the lake bank, 22% in the aquifer as a result of degrading organic matter of lake water, and 7% in the lake. Seasonal concentration variations suggested that the lake bank was the main carbon source in the summer, increasing the carbon concentration of infiltrating lake water, that is, 3.0 mg/L to 7.9 mg/L. FT-ICR MS results showed 4960 to 5330 individual compounds in lake and groundwater. NOM removal in the aquifer was selective: the relative abundance of oxygen-containing species decreased from 75 to 31%, while the relative abundance of sulfur-containing species increased from 15 to 57%. The average molecular weights of both species remained unchanged. The study highlighted the role of lake bank processes and sulfur-containing species in groundwater quality.     

Confronting the social debate: A study of the distribution of Russian recreational properties in Eastern Finland

Transborder property ownership is a growing trend in different parts of the world. In Finland, Russians make up the biggest group of foreign buyers. The article examines Russian recreational property purchases in Eastern Finland, where South Savo Region is subject to the heaviest flow of Russian purchasers. Russian purchases of second homes have been the subject of a broad social debate dominated by negative attitudes towards the phenomenon. Fears of place change and displacement have been among the main concerns. The authors reveal how arguments presented in the social debate on Russian ownership correspond to the distribution of Russian properties in South Savo. Statistics for the period 2003–2012 and GIS methods were used to analyse the distribution and density of Russian recreational properties in the region. Statistical modelling uncovered some factors that affected the location of the properties. The findings indicate that the arguments presented within the social debate have only partially derived from the distribution patterns of Russian properties. The authors conclude that a combination of factors, including distances from the border and services as well as preferences for waterside locations, have influenced the choice of location of Russian properties and led to concentrations in certain areas.     

On the solution of the carbonate chemistry system in ocean biogeochemistry models

We present a simplified method for solving the local equilibrium carbonate chemistry in numerical ocean biogeochemistry models. Compared to the methods typically used, the scheme is fast, efficient and compact. The accuracy of the solution is dictated by the number of species retained in the expression for alkalinity and there is almost no computational penalty for retaining minor contributions. We demonstrate that this scheme accurately reproduces the results of the commonly used method in the context of a three-dimensional global ocean carbon cycle model. Using this model we also show that neglecting the regional variations in surface dissolved inorganic phosphorus and silicic acid concentrations can lead to significant systematic bias in regional estimates of air–sea carbon fluxes using such models.     

Characterization and induction of cytochrome P-450 in the rainbow trout kidney

Cytochrome P-450 monooxygenases catalyze the biotransformation of a great variety of foreign, as well as endogenous, lipid-soluble compounds to more water-soluble products. As in mammals, highest concentration of cytochrome P-450 in fish is found in the liver. However, previous studies have indicated that fish kidney contains relatively high cytochrome P-450-mediated activities.^1,2 We have therefore prepared and characterized subcellular fractions from the kidney of rainbow trout suitable for studies on cytochrome P-450-dependent reactions. Furthermore, as in the liver, several cytochrome P-450-mediated reactions in the kidney were induced following treatment of the fish with β-naphthoflavone.     

The Holocene thermal maximum and late-Holocene cooling in the tundra of NE European Russia

To investigate the Holocene climate and treeline dynamics in the European Russian Arctic, we analysed sediment pollen, conifer stomata, and plant macrofossils from Lake Kharinei, a tundra lake near the treeline in the Pechora area. We present quantitative summer temperature reconstructions from Lake Kharinei and Lake Tumbulovaty, a previously studied lake in the same region, using a pollen–climate transfer function based on a new calibration set from northern European Russia. Our records suggest that the early-Holocene summer temperatures from 11,500 cal yr BP onwards were already slightly higher than at present, followed by a stable Holocene Thermal Maximum (HTM) at 8000–3500 cal yr BP when summer temperatures in the tundra were ca. 3°C above present-day values. A Picea forest surrounded Lake Kharinei during the HTM, reaching 150 km north of the present taiga limit. The HTM ended with a temperature drop at 3500–2500 cal yr BP associated with permafrost initiation in the region. Mixed spruce forest began to disappear around Lake Kharinei at ca. 3500 cal yr BP, with the last tree macrofossils recorded at ca. 2500 cal yr BP, suggesting that the present wide tundra zone in the Pechora region formed during the last ca. 3500 yr.     

Unbleached pulp mill effluents affect cytochrome P450 monooxygenase enzyme activities

The polysubstrate monooxygenase system has been shown to be highly responsive to chemical pollution. The present study summarizes the enzyme based biomonitoring of the waste waters released by a pulp mill producing unbleached pulp and paperboard. Cytochrome P4501A enzyme activities of feral and caged fish, as well as cultures of fish hepatocytes, were tested. The 7-ethoxyresorufin-O-deethylase (EROD) activity was clearly induced in fish hepatocytes exposed to biotreated unbleached pulp mill effluent fractions in vitro. The effluent increased EROD activities also in feral perch, compared with controls. Caging experiments showed similar effects to those seen in feral fish: however, the maximal induction coefficients observed were higher. Unbleached effluents contain compounds that are able to affect the P4501A activities in fish.