Phosphorus speciation in sediments from the Baltic Sea,evaluated by a multi-method approach

Journal of Soils and Sediments - Phosphorus (P) is a crucial element for living organisms at both land and sea, but simultaneously, it can cause environmental problems especially in marine...     

An Estimation of the Potential Fluxes of Nitrogen Phosphorus, Cadmium and Lead from Sea Ice and Snow in the Northern Baltic Sea

The amount of nutrients (N and P) and trace elements (Cd and Pb)accumulated and incorporated into the snow and sea ice cover was assessed for the northern Baltic Sea, resulting in an estimate for the potential flux of nutrients and trace elements to underlying waters during sea ice and snow melt. From the atmosphere the sea ice and snow cover accumulate less than 3% of the annual N and P load, and about 5% of the annual Cd and Pb load to the Bothnian Bay. The atmospheric deposition of nutrients to the northern Baltic Sea has declined considerably during the last decade. The total accumulation in the snow and ice, from the atmosphere and seawater, make up to 6% of the annual nutrient and up to 40% of the annual Cd and Pb load into the Bothnian Bay. Thus sea ice plays an important, but still poorly understood role in chemical cycling, transformations, and budgets. The fate of substances accumulated and released from snow and sea ice merit further investigation, especially if sea ice is a source and a platform for transformation of accumulated substances, thus indirectly affecting their toxicity and/or bioavailability before they are released to the water column.     

Effects of feral mink removal on seabirds, waders and passerines on small islands in the Baltic Sea

We studied the effects of removing introduced American mink (Mustela vison) on the number of birds breeding on small islands in the Baltic Sea. During autumn 1992-2001 mink were removed from a 72 km² area, while mink were not removed from a 35 km² control area. Second removal (125 km²) and control areas (130 km²) were established during 1998-2001. The breeding densities of ringed plover (Charadrius hiaticula), arctic skua (Stercorarius parasiticus), arctic tern (Sterna paradisaea) and rock pipit (Anthus petrosus) increased markedly in the removal areas in comparison to the control areas. Turnstone (Arenaria interpres), common gull (Larus canus) and wheatear (Oenanthe oenanthe) also appeared to increase. Two species already extinct in one of the removal areas, razorbill (Alca torda) and black guillemot (Cepphus grylle), returned to breed in the area. Breeding densities of great black-backed gull (Larus marinus), oystercatcher (Haematopus ostralegus) and white wagtail (Motacilla alba) were unaffected. We conclude that it is possible to remove feral mink from large archipelagos with many small islands, and that mink removal increases the breeding densities of many bird species in this habitat.     

Retention and Long Term Accumulation of EOCl from Pulp Mill Effluents in a Baltic Sea Recipient

The total inventory and distribution of ExtractableOrganic Chlorine (EOCl) has been investigated in anestuary exposed to pulp mill effluents for over 50 yr.The estuarine turnover of suspended particulate matter(SPM) and associated pollutants was studied using a modeldescribing important processes for EOCl accumulation. Therecipient has a low retention of SPM due to dominatingstratified conditions in the water column. The totalinventory of EOCl in the sediment is therefore relativelylow as compared with the total discharge. It was foundthat the vertical distribution of EOCl has a closerelationship to the extent of chlorine use at the mill.Discharges of SPM from the pulp production process play amajor role in establishing the chronology of the sediment.A modernisation of the mill from 1986 to 1991 considerablyreduced the discharges of chlorinated substances. In the near future there will be an accumulation of EOCl in the estuary.     

Human health risk assessment and risk source analysis of arsenic in soil from a coal chemical plant in Northwest China

Purpose

Arsenic (As) is a potentially toxic element and poses risks to human health during coal chemical technology application. Human health risk of As in coal chemical industry was seldom reported. The results of As human health risk distribution for the entire coal chemical plant in our study may provide theoretical and practical support to reduce human health risk of As in coal chemical industry.

Materials and methods

We collected 153 soil samples with a chessboard sampling method in a coal chemical plant in northwestern China. Arsenic concentrations in the soil were measured with inductively coupled plasma mass spectrometry (ICP-MS) after the soil samples were digested. Human health risk of As was assessed through three exposure pathways including inhalation, skin contact, and oral intake. A human health risk distribution map of As for the entire plant was obtained by kriging method.

Results and discussion

The integrated carcinogenic risk of As in the soil was 8.59–13.31 times of the acceptable standard (1.00E-06), which was established by the Ministry of Environmental Protection of China, while the hazard quotient was within the acceptable range (<?1.00). Oral intake, through which 76.61% of the total carcinogenic risk was contributed, was the main pathway of As to human body and gave the smallest control threshold (1.59 mg kg^?1) among the three exposure pathways. The smallest control threshold was recommended as the safety control threshold of As in this plant. Moreover, the highest carcinogenic risk and the largest hazard quotient were found in the Power Unit and its downwind direction (in the southeast of plant) because of As disposal and the local prevailing wind.

Conclusions

In the present study, As spatial distribution in the soil was obtained. A map of As human health risk distribution for the entire coal chemical plant was obtained with kriging method based on limited sampling points, which was more robust compared with traditional methods. Arsenic human health risk sources were also analyzed. The results may be applied in the process of reducing human health risk of As in coal chemical industry.

     

Characteristics of SO2, NO2, Soot and Benzo(a)Pyrene Concentration Variation on the Eastern Coast of the Baltic Sea

The investigation of SO₂, NO₂, soot and benzo(a)pyrene (BP) has been performed at the background station on the eastern coast of the Baltic Sea since 1980. A significant decreasing trend has been observed for SO₂ and NO₂, while soot and BP concentrations were changing insignificantly. The decreasing SO₂ and NO₂ high concentrations (>10µg·m^?3) have been determined in the air masses coming from the Western and Central Europe to Lithuania since 1900. The concentration of SO₂ in a range of 0–5µg·m^?3 and the concentration of NO₂ in a range of 0–10µg·m^?3 are characteric of the background atmospheric air.     

Behaviour of the endocrine disrupting chemical nonylphenol in soil: Assessing the risk associated with spreading contaminated waste to land

There is increasing environmental concern about the impact of endocrine disrupting chemicals (EDCs) on ecosystem sustainability and human health. Many EDCs are present within wastes which are routinely spread to land (e.g. biosolids). The aim of this study was to investigate the behaviour and fate of the EDC, 4-nonylphenol (NP), in a range of soils and to assess the potential risk it may pose to soil and freshwaters environments. We showed that NP was not persistent in soil, that NP mineralization was concentration-dependent and was stimulated by the addition of organic residues (e.g. biosolids, glucose, dead roots) but not by the presence of a rhizosphere. NP had no negative effect on soil respiration or plant growth unless present at extreme concentrations (?10,000 mg NP kg⁻¹) and the uptake of NP by plants was very low. While NP was sorbed to the solid phase it could easily be leached from soil. Taking all of our results together, we conclude that the spreading of NP contaminated waste soil to soil probably poses a very low environmental risk to freshwater ecosystems and human health.     

Sediment Accumulation of Nutrients (N, P) in the Eastern Gulf of Finland (Baltic Sea)

Dry weight (DW), ignition loss (IL) and concentrations of total nitrogen (TN) and total phosphorus (TP) of the sediment surface layer (0 to 10 cm, 1 cm slices) were analyzed from 20 sites in the eastern Gulf of Finland. The distance of the sampling sites from the mouth of the River Neva explained the nutrient concentrations of the sediments well, while the effect of water depth was negligible. The increase of TN and the decrease of TP along the transect from the river mouth towards the open Gulf were caused by the diminishing share of allochthonous material supplied from the River Neva. The mean TN concentration of the different accumulation areas was about 40 % higher in the sediment surface than in the deeper layer (9 to 10 cm). The corresponding difference for TP varied from 53 to 56 %. The results suggest considerable netflux of nutrients from sediment to water. The net sediment accumulation of nutrients were estimated as 6.0 g m-2 a-1 of N and 1.7 g m-2 a-1 of P corresponding 22 000 t a-1 of N and 6 100 t a-1 of P for the whole eastern Gulf.     

Changes in hydrology,sediment loss and microtopography of a vegetated mine waste rock dump impacted by fire

Dry season burning to control wildfire is conducted in Kakadu National Park in the Northern Territory. The ERA Ranger Mine is adjacent to the park, and it is likely that at some stage the post-mining landform will be affected by fire. Rainfall simulations were conducted on a vegetated site on the mine waste rock dump. The site was then burnt and the rainfall simulation series repeated. Initially, there was little difference between sediment loss and runoff from the vegetated condition and sediment loss and runoff from the burnt condition. As simulations continued, total sediment loss from the burnt condition increased as a result of increasing runoff compared to the vegetated condition. Burning of vegetation affected the surface hydrology of the site, resulting in increased erosion under saturating rainfall similar to rainfall expected at the commencement of a wet season. Litter dams formed during runoff from the burnt condition providing areas of localized deposition. The distribution of the dams was non-random. If fire is used as a management tool to control wildfire, placement of artificial microdams on steep slopes may provide areas of sediment deposition and seedbank storage to reduce the effects of elevated runoff and sediment loss and facilitate vegetation regeneration. Copyright © 1999 John Wiley & Sons, Ltd.     

Composition and settling properties of suspended particulate matter in estuaries of the Chesapeake Bay and Baltic Sea regions

Purpose

Our goal was to understand how differences in source material (allochthonous vs. autochthonous) and phytoplankton communities (diatoms vs. cyanobacteria) influence composition and settling properties of suspended particulate matter.

Materials and methods

We characterized the composition and settling properties of suspended particulate matter in two systems—one which has a high hydrologic loading factor (watershed to surface area ratio), and a diatom-dominated phytoplankton community (James River Estuary, USA), and a second, where hydrologic inputs are proportionally smaller, and the summer phytoplankton community is  dominated by cyanobacteria (Curonian Lagoon, Lithuania).

Results and discussion

In the James, we found that TSS concentrations were positively related to discharge, whereas POC concentrations were negatively correlated with discharge and positively correlated with Chl-a. We infer that suspended particulate matter in this system was largely derived from allochthonous inputs, but that the organic matter fraction was derived from autochthonous production. In the Curonian Lagoon, TSS concentrations were correlated with Chl-a, but not discharge, indicating that suspended particulate matter was largely of autochthonous origin. In the James, the proportion of settleable materials was greater during high TSS concentrations, indicating that high discharge events delivered heavier particulates. In the Curonian Lagoon, we observed a seasonal decline in settling rates associated with the shift from mixed (diatoms and chlorophytes) to cyanobacteria-dominated phytoplankton, which we attribute to the presence of positively buoyant cyanobacteria.

Conclusions

We found that a comparative approach yielded useful insights regarding sources, composition, and settling properties of suspended particulate matter in two estuaries that differ in hydrologic loading and phytoplankton community composition. Our findings suggest that the presence of positively buoyant cyanobacteria favors export losses of particulate C, N, and P to marine waters over retention through sedimentation in transitional zones.

     

Evolution of soil chemical properties in the past 50 years in the Tai Lake Region, China

The Tai Lake Region (TLR) is traditionally an ecologically sustainable agricultural area due to the intensive application of traditional organic fertilizer. However in the past 50 years, agricultural management practices such as fertilizer usage and cropping systems changed this situation. In order to investigate how these changes affected soil chemical properties and ultimately the sustainability of agriculture production, a case study was conducted in Taicang County in the TLR. It was found that soil organic carbon (SOC) content significantly decreased from 22.8 g kg⁻¹ in 1959 to 12.9 g kg⁻¹ in 1981 while soil total nitrogen (TN) increased significantly from 1.2 g kg⁻¹ in 1959 to 1.6 g kg⁻¹ in 1981 due to the application of mineral fertilizer especially N fertilizer nearly entirely replacing of traditional organic fertilizer, and then both slightly increased to 14.0 g kg⁻¹ and 1.7 g kg⁻¹, respectively in 2004. Soil total phosphorus (TP), total potassium (TK), and available K (AK) contents showed little changes from 1981 to 2004 but soil available P (AP) content increased significantly from 7 mg kg⁻¹ in 1981 to 26 mg kg⁻¹ in 2004. The changes of soil properties from 1959 to 1981 were attributed to the changes of fertilizer usage and the changes of soil properties from 1981 to 2004 were attributed to the changes of cropping systems and fertilizer application, particularly vegetable production which resulted in the significant changes of fertilizer usage.     

Temperature,pH and photoperiod effects on mercury bioaccumulation by nymphs of the burrowing mayflyHexagenia rigida

Accumulation of HgCl₂ and CH₃HgCl byHexagenia rigida nymphs from contaminated sediment and water column was investigated experimentally, taking into account 3 abiotic factors (temperature, pH and photoperiod). When the contamination of the experimental units was based on sediment compartment, Hg concentrations at the whole organism level revealed very high bioaccumulation differences between the two chemical forms of Hg (ratio close to 20 in favour of MeHg). When Hg compounds were added to the water column, the highest Hg accumulation rates were observed for MeHg, but with a small difference between the 2 compounds (ratio close to 2.0–3.0). These bioaccumulation processes were very dependent on the 3 abiotic factors taken into account, especially temperature and water column pH.     

Identification of the astringent taste compounds in black tea infusions by combining instrumental analysis and human bioresponse

Application of taste dilution analyses on freshly prepared black tea infusions revealed neither the high molecular weight thearubigen-like polyphenols nor the catechins and theaflavins, but a series of 14 flavon-3-ol glycosides as the main contributors to the astringent taste perceived upon black tea consumption. Among these glycosides, the apigenin-8-C-[alpha-l-rhamnopyranosyl-(1-->2)-O-beta-d-glucopyranoside] was identified for the first time in tea infusions. Depending on the structure, the flavon-3-ol glycosides were found to induce a velvety and mouth-coating sensation at very low threshold concentrations, which were far below those of catechins or theaflavins; for example, the threshold of 0.001 micromol/L found for quercetin-3-O-[alpha-l-rhamnopyranosyl-(1-->6)-O-beta-d-glucopyranoside] is 190000, or 16000 times below the threshold determined for epigallocatechin gallate or theaflavin, respectively. Moreover, structure/activity considerations revealed that, besides the type of flavon-3-ol aglycon, the type and the sequence of the individual monosaccharides in the glycosidic chain are key drivers for astringency perception of flavon-3-ol glycosides.     

Mercury transport,transformation, and bioaccumulation in the ecosystem of mercury — stibium geochemical province

A simple analytic technique — isotope dilution — was used for determination of the contents of total and methilated Hg in water, sediments, soils and biological objects collected in the basin of the river Katun. The inspected region is located on a territory of two mercury-stibium geochemical provinces. Evaluation of the Hg transport, transformation and bioaccumulation in aquatic and terrestrial ecosystems of the region showed that the main Hg transport occurs on suspended solids after Hg has been washed out from soil and bedrock by water of the river Katun and its tributaries and also by underground waters. Bottom sediments of some rivers of the basin content increased Hg concentrations. This effect is also noted in the sediments of a small reservoir formed on one of the tributaries. The investigations showed that Hg originating from natural sources differs considerably in its biochemical characteristics from Hg compounds coming from anthropogenic sources. So, natural Hg compounds have lower bioavailability for the water and terrestrial organisms of the region.     

Successful analysis of gut contents in fungal-feeding oribatid mites by combining body-surface washing and PCR

The feeding habits of soil mesofauna have been a mystery for decades, and depending on the methods used, different degrees of feeding specialisation have been observed. A new way to study the almost unknown feeding habits of soil mesofauna e.g. oribatid mites is to use PCR-based techniques. When applying PCR on these small organisms, the low amount of ingested DNA can cause problems. Even more important is to certify that the amplified DNA does not originate from body-surface contamination. The aim of this study was to analyse if washing of the body surface combined with PCR can be a successful approach when identifying the food ingested by fungivorous mites. The method was developed in a laboratory system where we used the oribatid mite Archegozetes longisetosus as a model organism due to its relatively short life cycle and ease of laboratory culturing. The results demonstrated that surface contamination is a serious problem. Both washing and dissection was needed to remove surface contamination on such small organisms. To get a reliable result the samples also had to contain at least five pooled guts, but preferably ten. This is the first step towards a successful use of PCR-based methods to study natural feeding habits of species most likely contaminated on the body surface. When modified for field conditions, the results obtained by this method have a high potential to answer many questions about the animals feeding habits, and their functional role in the soil.     

Human health risk assessment associated with Co,Cr, Mn,Ni and V contents in agricultural soils from a Mediterranean site

Potentially toxic element contents in agricultural soils were assessed by comparison with levels recorded in the literature and evaluated using Index of Geoaccumulation (I_geo). The model recommended by United States Environment Protection Agency is applied for the health risk assessment from different exposure pathways. The median values of cobalt (Co), chromium (Cr) and nickel (Ni) exceeds about 2, 3 and 14 times, respectively, the corresponding values given by the Geochemical Atlas of Europe project, however, they present low potential ecological risk. The median values of manganese (Mn) and vanadium (V) are slightly lower than the corresponding values given by the Geochemical Atlas of Europe project. Risk assessment results present negligible health risk to children and adults due to manganese (Mn), nickel (Ni) and vanadium (V) exposure through ingestion of contaminated soil. Only the cobalt (Co) hazard quotient (HQ) and hazard index (HI) for children around two sampling sites exceed the acceptable safe risk level.     

Improving mineral nitrogen control by combining catch crops,fertilisation, and straw management in a clay loam soil

This experiment was conducted on a clay loam Cambisol and set out to determine the effects of combining catch crops, variable fertilisation levels, and straw management on the productivity of a spring barley-catch crop agrosystem, on the enrichment of soil with organic matter and nitrogen (N), and on soil mineral N control. Research was carried out in a spring barley (Hordeum vulgare L.) crop without catch crops, with undersown red clover (Trifolium pratense L.), and with post-crop white mustard (Sinapis alba L.). The barley was unfertilised, fertilised at moderate rates or at high rates. Straw was managed by either removing it from the field or chopping and spreading it. The quantity of organic matter and N incorporated into the soil depended on the fertilisation level of the barley crop. Soil mineral N stocks in the spring were reduced when straw was used together with red clover. When white mustard mass was incorporated alone in the autumn during ploughing, soil mineral N was reduced in the spring; however, when it was incorporated with straw, the effect was the opposite. Soil mineral N content is controllable when organic matter components are combined according to their decomposition rates, masses, and incorporation times.     

Multielement analysis of natural waters by neutron activation,group chemical separations,and gamma-ray spectrometric techniques

A multielement analytical technique of thermal neutron activation of frozen water samples has been developed and applied to the studies of natural waters. A rapid group chemical separation utilizing ion exchange resins and a precipitation step to reduce ²⁴Na and 42K interferences, followed by γ-ray analysis of the fractions with Ge (Li) and multiparameter NaI (TI) systems, permits the simultaneous measurement of a large number of trace constituents. Samples of river water, rain water, processed sewage water and Greenland ice were analyzed for 19 trace elements — Ag, As, Br, Cl, Co, Cs, Cr, Cu, Fe, Hg, K, Mn, Na, Rb, Sb, Se, Se, U, and Zn. These data have been used in studies of trace element concentration factors in aquatic biota, precipitation scavenging processes, and environmental pollution.     

氮、磷、钾肥配施对烤烟化学成分和致香物质含量的影响

田间试验以烤烟(Nicotiana.tabacum.L.)品种K236为材料,研究了氮、磷、钾肥配施对烤烟化学成分和致香物质含量的影响。结果表明,不施肥处理烟叶内在化学成分协调性差,致香物质总量及不同种类致香物质含量都较低;单施氮、磷、钾一种肥料或任意两种肥料配施可以不同程度改善烟叶化学成分,提高烟叶中类西柏烷类和类胡萝卜素类致香物质含量;而氮、磷、钾配施处理烟叶的化学成分协调,致香物质总量和不同种类致香物质含量高。表明平衡施肥是改善烟叶化学成分,提高烟叶香气质量的基础。