Low-density geochemical mapping in Hungary

Ódor, László; Horváth, István; Fügedi, Ubul

doi:10.1016/s0375-6742(97)00025-3

Cited by 36 publications

(6 citation statements)

References 3 publications

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“…3; Basu & Pick, 1996;van Nieuwenhuyse & Jones, 1996;Chételat et al, 2006). This was partly due to the high geochemical background of P in the Carpathian Basin (Ó dor et al, 1997;Salminen et al, 2005). High nutrient concentratons, however, supported conspicuously lower levels of Chl at the majority of our sites compared to other studies (Figs.…”

Section: Determinants Of Sestonic Chlmentioning

confidence: 99%

Efficiency of nutrient management in controlling eutrophication of running waters in the Middle Danube Basin

Istvánovics

Honti

2012

Hydrobiologia

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Nutrient emission dropped significantly during the last two decades in the Danube Basin. To assess the effect of reduced nutrient loads on the trophic status of running waters, this regional study analyzed the relationships between nutrients (P and N) and suspended chlorophyll (Chl) using long-term monitoring data in Hungary. Including the upstream catchments of trans-boundary rivers, the study covered an approximate area of 400,000 km 2 , equivalent to the half of the entire Danube catchment. Decadal median Chl was unrelated to P and N concentrations in the whole data set and weakly related to total P (TP) at natural-moderately polluted (N-MP) sites, which were distinguished from highly polluted (HP) sites by using cutoff values for chloride, chemical oxygen demand and TP. At both the N-MP sites and most of the HP sites, Chl increased with channel length. This indicated that water residence time was a more important determinant of Chl than nutrients. Nutrient concentrations showed a significant downward trend in time at half of our sites. With a nearly equal frequency, a parallel trend might or might not occur in Chl. The apparent efficiency of nutrient management was expressed as the quotient of the slopes of linear trends in Chl and nutrients. At sites within 150 km from source, this efficiency was marginal. In larger rivers, efficiency improved steeply. The highest efficiency was observed in the downstream reach of the Danube (upstream length [1,300 km) where P availability might frequently limit algal growth. The results suggest that eutrophication management in rivers should be based on Chl response functions, rather than universal nutrient criteria. Four Chl response classes were identified based on the observed longitudinal P and Chl gradients.

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Section: Determinants Of Sestonic Chlmentioning

confidence: 99%

Efficiency of nutrient management in controlling eutrophication of running waters in the Middle Danube Basin

Istvánovics

Honti

2012

Hydrobiologia

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“…Textural differences therefore exist between the ®ne-grained, clay-rich Tisza¯oodplain soils and the coarser textured, sandy Danube±Tisza inter¯uve soils that possess the properties of classic loess deposits. Sediment deposition is the main factor controlling the geochemical patterns with the Danube deposits being primarily calcareous and the Tisza¯oodplain having a slightly acidic nature (Maianu, 1983;Odor et al, 1997). Solonchak soils have developed in the Danube±Tisza inter¯uve region which is the largest region of alluvium sandy soil in Hungary (Kozak and Egerszegi, 1974) as the coarser texture and higher hydraulic conductivity limits the development of the poor hydrological conditions that solonetz soils depend on for their maintenance.…”

Section: Hungarymentioning

confidence: 99%

Causal processes of soil salinization in Tunisia, Spain and Hungary

2001

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Soil salinization arises due to the build up of soluble salts at or near the soil surface. Salts accumulate by primary and secondary processes that alter the soils physicochemical properties and lead to direct and indirect soil degradation. Results are presented here from the study of three contrasting salt-affected landscapes. The Chott el Fedjadj, Tunisia, is a naturally salt-affected basin containing saline sediments deposited during a marine incursion. The endoreic conditions lead to salt recirculation, concentration and reprecipitation. In the Guadalentin Valley, Spain, increased irrigated agriculture has led to aquifer overexploitation releasing gas and salts. Irrigating with the resultant contaminated groundwater has induced soil salinization. The salt accumulation and translocation is dictated predominantly by irrigation method, water quality and quantity. Hungary has the largest expanse of naturally salt-affected soil in Europe, with the dominant soil type being solonetz. In Hungary the type of salt-affected soil development is related to the salts present, hydraulic properties of the soil and depth and quality of the watertable. In Tunisia a catenary relationship of increased water and soil salinity towards the centre of the chott is found, whereas in Spain the highest salinities were found under¯ood irrigation with the valley displaying a complex spatial distribution of soil salinity. The sediment distribution in Hungary dictates that solonchak soils are found mostly in the Danube± Tisza inter¯uve and solonetz soils in the Tisza¯oodplain, with localized variations in soil type related to watertable characteristics.

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“…The Fe and Mn level of the Hungarian oxbows in the Upper-Tisza region is recently reported to be high as a result of our previous assessment [48] since when we started to conduct model experiments involving these elements. Based on the pollution index of sediment samples, the studied oxbows were characterized by moderate levels of contamination for Fe and Mn, since the mean geochemical concentration in the upper level (0-10 cm) of floodplain sediments is exceeded for both elements (35.000 mg kg −1 for Fe 2 O 3 and 1000 mg kg −1 for MnO) [49] [50]. In our first study the Fe and Mn retention was investigated via the rearing water media [28], while in this paper the results of accumulation tendency through food ingestion is described.…”

Section: Introductionmentioning

confidence: 99%

Iron and Manganese Retention of Juvenile Zebrafish (Danio rerio) Exposed to Contaminated Dietary Zooplankton (Daphnia pulex)—a Model Experiment

Herman

Fehér

Molnár

et al. 2020

Biol Trace Elem Res

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In present study the effect of iron (Fe) and manganese (Mn) contamination was assessed by modeling a freshwater food web of water, zooplankton (Daphnia pulex), and zebrafish (Danio rerio) under laboratory conditions. Metals were added to the rearing media of D. pulex, and enriched zooplankton was fed to zebrafish in a feeding trial. The elemental analysis of rearing water, zooplankton, and fish revealed significant difference in the treatments compared to the control. In D. pulex the Mn level increased almost in parallel with the dose of supplementation, as well as the Fe level differed statistically. A negative influence of the supplementation on the fish growth was observed: specific growth rate (SGR%) and weight gain (WG) decreased in Fe and Mn containing treatments. The redundancy analysis (RDA) of concentration data showed strong correlation between the rearing water and D. pulex, as well as the prey organism of Fe- and Mn-enriched D. pulex and the predator organism of D. rerio. The bioconcentration factors (BCF) calculated for water to zooplankton further proved the relationship between the Fe and Mn dosage applied in the treatments and measured in D. pulex. Trophic transfer factor (TTF) results also indicate that significant retention of the metals occurred in D. rerio individuals, however, in a much lower extent than in the water to zooplankton stage. Our study suggests that Fe and Mn significantly accumulate in the lower part of the trophic chain and retention is effective through the digestive track of zebrafish, yet no biomagnification occurs.

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Low-density geochemical mapping in Hungary

Cited by 36 publications

References 3 publications

Efficiency of nutrient management in controlling eutrophication of running waters in the Middle Danube Basin

Efficiency of nutrient management in controlling eutrophication of running waters in the Middle Danube Basin

Causal processes of soil salinization in Tunisia, Spain and Hungary

Iron and Manganese Retention of Juvenile Zebrafish (Danio rerio) Exposed to Contaminated Dietary Zooplankton (Daphnia pulex)—a Model Experiment

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