Dynamic changes in radial oxygen loss and iron plaque formation and their effects on Cd and As accumulation in rice (Oryza sativa L.)

Temporal variations and correlations between radial oxygen loss (ROL), iron (Fe) plaque formation, cadmium (Cd) and arsenic (As) accumulation were investigated in two rice cultivars at four different growth stages based upon soil pot and deoxygenated solution experiments. The results showed that there were significant differences in ROL (1.1–16 μmol O₂ plant^?1 h^?1), Fe plaque formation (4,097–36,056 mg kg^?1), Cd and As in root tissues (Cd 77–162 mg kg^?1; As 49–199 mg kg^?1) and Fe plaque (Cd 0.4–24 mg kg^?1; As 185–1,396 mg kg^?1) between these growth stages. ROL and Fe plaque increased dramatically from tillering to ear emergence stages and then were much reduced at the grain-filling stage. Furthermore, significantly positive correlations were detected between ROL and concentrations of Fe, Cd and As in Fe plaque. Our study indicates that increased Fe plaque forms on rice roots at the ear emergence stage due to the increased ROL. This stage could therefore be an important period to limit the transfer and distribution of Cd and As in rice plants when growing in soils contaminated with these toxic elements.     

Elemental composition of Malawian rice

Widespread potential dietary deficiencies of calcium (Ca), iron (Fe), iodine (I), selenium (Se) and zinc (Zn) have been identified in Malawi. Several deficiencies are likely to be compounded by high phytic acid (PA) consumption. Rice (Oryza sativa) is commonly consumed in some Malawian populations, and its mineral micronutrient content is important for food security. The considerable irrigation requirements and flooded conditions of paddy soils can also introduce or mobilise potentially toxic elements including arsenic (As), cadmium (Cd) and lead (Pb). The aim of this study was to determine the mineral composition of rice sampled from farmers’ fields and markets in Malawi. Rice was sampled from 18 extension planning areas across Malawi with 21 white (i.e. polished) and 33 brown samples collected. Elemental composition was determined by inductively coupled plasma-mass spectrometry (ICP-MS). Arsenic speciation was performed using high-performance liquid chromatography (HPLC)-ICP-MS. Concentration of PA was determined using a PA-total phosphorus assay. Median total concentrations (mg kg^?1, dry weight) of elements important for human nutrition in brown and white rice, respectively, were: Ca = 66.5 and 37.8; Cu = 3.65 and 2.49; Fe = 22.1 and 7.2; I = 0.006 and <0.005; Mg = 1130 and 265; Mn = 18.2 and 9.6; Se = 0.025 and 0.028; and Zn = 17.0 and 14.4. In brown and white rice samples, respectively, median PA concentrations were 5438 and 1906 mg kg^?1, and median PA:Zn molar ratios were 29 and 13. Concentrations of potentially toxic elements (mg kg^?1, dry weight) in brown and white rice samples, respectively, were: As = 0.030 and 0.006; Cd  ≤ 0.002 and 0.006; Pb = 0.008 and 0.008. Approximately 95 % of As was found to be inorganic As, where this could be quantified. Malawian rice, like the more widely consumed staple grain maize, contains inadequate Ca, I, Se or Zn to meet dietary requirements. Biofortification strategies could significantly increase Se and Zn concentrations and require further investigation. Concentrations of Fe in rice grain varied greatly, and this was likely due to contamination of rice samples with soil. Risk of As, Cd or Pb toxicity due to rice consumption in Malawi appears to be minimal.     

Arsenic speciation in polychaetes (Annelida) and sediments from the intertidal mudflat of Sundarban mangrove wetland, India

This paper documents the concentration of total arsenic and individual arsenic species in four soft-bottom benthic polychaetes (Perenereis cultifera, Ganganereis sootai, Lumbrinereis notocirrata and Dendronereis arborifera) along with host sediments from Sundarban mangrove wetland, India. An additional six sites were considered exclusively for surface sediments for this purpose. Polychaetes were collected along with the host sediments and measured for their total arsenic content using inductively coupled plasma mass spectrometry. Arsenic concentrations in polychaete body tissues varied greatly, suggesting species-specific characteristics and inherent peculiarities in arsenic metabolism. Arsenic was generally present in polychaetes as arsenate (As^V ranges from 0.16 to 0.50 mg kg^?1) or arsenite (As^III ranges from 0.10 to 0.41 mg kg^?1) (30–53 % as inorganic As) and dimethylarsinic acid (DMA^V <1–25 %). Arsenobetaine (AB < 16 %), and PO₄-arsenoriboside (8–48 %) were also detected as minor constituents, whilst monomethylarsonic acid (MA^V) was not detected in any of the polychaetes. The highest total As (14.7 mg kg^?1 dry wt) was observed in the polychaete D. arborifera collected from the vicinity of a sewage outfall in which the majority of As was present as an uncharacterised compound (10.3 mg kg^?1 dry wt) eluted prior to AB. Host sediments ranged from 2.5 to 10.4 mg kg^?1 of total As. This work supports the importance of speciation analysis of As, because of the ubiquitous occurrence of this metalloid in the environment, and its variable toxicity depending on chemical form. It is also the first work to report the composition of As species in polychaetes from the Indian Sundarban wetlands.     

Contamination characteristics of trace metals in dust from different levels of roads of a heavily air-polluted city in north China

Concentrations of eight trace metals (TMs) in road dust (RD) (particles?<?25 μm) from urban areas of Xinxiang, China, were determined by inductively coupled plasma mass spectrometry. The geometric mean concentrations of Zn, Mn, Pb, As, Cu, Cr, Ni and Cd were 489, 350, 114, 101, 60.0, 39.7, 31.6, and 5.1 mg kg^?1, respectively. When compared with TM levels in background soil, the samples generally display elevated TM concentrations, except for Cr and Mn, and for Cd the enrichment value was 69.6. Spatial variations indicated TMs in RD from park path would have similar sources with main roads, collector streets and bypasses. Average daily exposure doses of the studied TMs were about three orders of magnitude higher for hand-to-mouth ingestion than dermal contact, and the exposure doses for children were 9.33 times higher than that for adults. The decreasing trend of calculated hazard indexes (HI) for the eight elements was As?>?Pb?>?Cr?>?Mn?>?Cd?>?Zn?>?Ni?>?Cu for both children and adults.     

Assessment of heavy metals in a soil contaminated by oil spill: a case study in Nigeria

Surface and subsurface soil samples contaminated with crude oils were collected from an impacted site at Bodo City in the Niger Delta, Nigeria, after a field reconnaissance survey. An uncontaminated soil sample collected 100 m from the impacted site, but within the same geographical area, was used as a control. Trace elements such as, As, Cu, Cr, Cd, Fe, Pb, Ba, Ni, V, Hg and cation-exchange capacity constituents of the contaminated and uncontaminated soils were determined by atomic absorption spectroscopy. Trace element concentrations were: Cu, 0.5–13.4 mg kg^{? 1}; Cr, 0.2–0.8 mg kg^{? 1}; Fe, 6.2–8.7 mg kg^{? 1}; Ba 80.0–108.0 mg kg^{? 1}; Ni, 0.6–4.8 mg kg^{? 1}; and V, 4.0–9.4 mg kg^{? 1}; cation-exchange capacity ranged from 43.6 to 57.2 mg kg^{? 1} in surface and subsurface soils. Results showed that eigenvalues for the two first principal components represent up to 49% of the total variance. A positive correlation of the first principal component with Cu, Cr and cation-exchange capacity shows pollution from oil spillage, while a positive correlation of the second principal component with Cr, Fe, V, and dissolved oxygen (DO) shows both oil pollution and allochthonous inputs.     

Assessment of heavy metals contamination in soils surrounding a gold mine: comparison of two digestion methods

This study investigated two digestion methods (USEPA 3051: microwave, HNO₃ or Hossner: hot plate, HF–H₂SO₄–HClO₄) for heavy metals analysis in contaminated soil surrounding Mahad AD'Dahab mine, Saudi Arabia. Moreover, contamination metal levels were estimated. The Hossner and USEPA 3051 methods showed, respectively, average total contents of 17.2 and 18.1 mg kg^?1 for Cd, 11.6 and 10.6 mg kg^?1 for Co, 45.7 and 34.7 mg kg^?1 for Cr, 1030 and 1100 mg kg^?1 for Cu, 33,300 and 27,400 mg kg^?1 for Fe, 963 and 872 mg kg^?1 for Mn, 33.2 and 22.8 mg kg^?1 for Ni, 791 and 782 mg kg^?1for Pb, and 6320 and 2870 mg kg^?1 for Zn. A lack of significant differences and a high correlation coefficient (>90%) for Cd, Pb and Cu between the two digestion methods suggest that the total-recoverable method (USEPA 3051) may be equivalent to the total-total digestion method (Hossner) for determining these metals in the studied soil. However, significantly higher concentrations of Cr, Fe, Ni and Zn were found by the Hossner method comapred with the USEPA 3051 method. The soil samples have very or extremely high levels of Zn, Cu, Cd and Pb contamination, indicating very high potential ecological risk.     

Purification of contaminated paddy fields by clean water irrigation over two decades

Paddy fields near a mining site in north part of Guangdong Province, PR China, were severely contaminated by heavy metals as a result of wastewater irrigation from the tailing pond. The following clean water irrigation for 2 decades produced marked rinsing effect, especially on Pb and Zn. Paddy fields continuously irrigated with wastewater ever since mining started (50 years) had 1,050.0 mg kg^?1 of Pb and 810.3 mg kg^?1 of Zn for upper 20 cm soil, in comparison with 215.9 mg kg^?1 of Pb and 525.4 mg kg^?1 of Zn, respectively, with clean water irrigation for 20 years. Rinsing effect mainly occurred to a depth of upper 40 cm, of which the soil contained highest metals. Copper and Cd in the farmlands were also reduced due to clean water irrigation. Higher availability of Pb might partly account for more Pb transferred from the tailing pond to the farmland and also more Pb removal from the farmland as a result of clean water irrigation. Neither rice in the paddy field nor dense weeds in the uncultivated field largely took up the metals. However, they might contribute to activate metals differently, leading to a different purification extent. Rotation of rice and weed reduced metal retention in the farmland soil, in comparison with sole rice growth. Harvesting of rice grain (and partially rice stalk) only contributed small fraction of total amount of removed metal. In summary, heavy metal in paddy field resulted from irrigation of mining wastewater could be largely removed by clean water irrigation for sufficient time.     

Population health risk via dietary exposure to trace elements (Cu,Zn, Pb,Cd, Hg,and As) in Qiqihar,Northeastern China

The estimated daily intakes (EDIs) of six trace elements (Cu, Zn, Pb, Cd, Hg, and As) in vegetables (leafy vegetable, i.e., bok choy, fruit vegetables, i.e., cucumber and tomato, and other categories, i.e., mushroom, kidney bean, and potato), cereals (rice and wheat flour), and meats (pork, mutton, and beef) most commonly consumed by adult inhabitants of Qiqihar, Northeastern China, were determined to assess the health status of local people. The average EDIs of Cu, Zn, Pb, Cd, Hg, and As were with 20.77 μg (kg bw)^?1 day^?1 of Cu, 288 μg (kg bw)^?1 day^?1 of Zn, 2.01 μg (kg bw)^?1 day^?1 of Pb, 0.41 μg (kg bw)^?1 day^?1 of Cd, 0.01 μg (kg bw)^?1 day^?1 of Hg, and 0.52 μg (kg bw)^?1 day^?1 of As, respectively, which are below the daily allowance recommended by FAO/WHO. However, the maximum EDIs of Pb and Cd were 4.56 μg (kg bw)^?1 day^?1 and 1.68 μg (kg bw)^?1 day^?1, respectively, which are above the recommended levels [i.e., 3.58 μg (kg bw)^?1 day^?1 for Pb and 1.0 μg (kg bw)^?1 day^?1 for Cd] by FAO/WHO. This finding indicates that the potential health risk induced by daily ingestion of Pb and Cd for the local residents should receive a significant concern. Similarly, we detected elevated Pb and Cd concentrations, i.e., with average of 13.58 and 0.60 mg kg^?1 dw, respectively, in the adult scalp hairs. Consumption of rice, potato, bok choy, and wheat flour contributed to 75 and 82% of Pb and Cd daily intake from foodstuffs. Nevertheless, human scalp hair is inappropriate biological material for determination of the nutritional status of trace elements in this region.     

Selenium speciation in wheat grain varies in the presence of nitrogen and sulphur fertilisers

This study investigated whether selenium species in wheat grains could be altered by exposure to different combinations of nitrogen (N) and sulphur (S) fertilisers in an agronomic biofortification experiment. Four Australian wheat cultivars (Mace, Janz, Emu Rock and Magenta) were grown in a glasshouse experiment and exposed to 3 mg Se kg^?1 soil as selenate (Se^VI). Plants were also exposed to 60 mg N kg^?1 soil as urea and 20 mg S kg^?1 soil as gypsum in a factorial design (N + S + Se; N + Se; S + Se; Se only). Plants were grown to maturity with grain analysed for total Se concentrations via ICP-MS and Se species determined via HPLC-ICP-MS. Grain Se concentrations ranged from 22 to 70 µg Se g^?1 grain (dry mass). Selenomethionine (SeMet), Se-methylselenocystine (MeSeCys), selenohomolanthionine (SeHLan), plus a large concentration of uncharacterised Se species were found in the extracts from grains. SeMet was the major Se species identified accounting for between 9 and 24 µg Se g^?1 grain. Exposure to different N and S fertiliser combinations altered the SeMet content of Mace, Janz and Emu Rock grain, but not that of Magenta. MeSeCys and SeHLan were found in far lower concentrations (<4 µg Se g^?1 grain). A large component of the total grain Se was uncharacterisable (>30 % of total grain Se) in all samples. When N fertiliser was applied (with or without S), the proportion of uncharacterisable Se increased between 60 and 70 % of the total grain Se. The data presented here indicate that it is possible to alter the content of individual Se species in wheat grains via biofortification combined with manipulation of N and S fertiliser regimes. This has potential significance in alleviating or combating both Se deficiency and Se toxicity effects in humans.     

Estimate of zearalenone exposure through the intake of white and brown rice in the Korean population

Rice samples (n = 482) harvested for 2010–2012 in South Korea were analyzed for zearalenone content by high-performance liquid chromatography and fluorescence detection. The exposure of the Korean populations was assessed by a deterministic approach. Because the proportion of non-detectable results was >80% in white rice but less than <60% in brown rice, the zearalenone levels for white rice were reported as 0.52 µg kg^?1 as lower bound and 2.54 µg kg^?1 as upper bound, while for brown rice the middle bound value was 13.9 µg kg^?1. The average dietary intake of zearalenone from white and brown rice by the Korean population was estimated to be 1.5 ng kg^?1 body weight (bw) day^?1 each. For heavy consumers, the average intakes were 18.5 and 10.1 ng kg^?1 bw day^?1, respectively. The age groups with the highest zearalenone intake were 1–2-year-old children for white rice and 3–6-year-old children for brown rice. Overall, the dietary exposure of the Korean population to zearalenone from white and brown rice was found to be lower than the provisional maximum tolerable daily intake of 0.5 μg kg^?1 bw day^?1.     

Long-term assessment of the environmental fate of heavy metals in agricultural soil after cessation of organic waste treatments

The current study examined the anthropogenic accumulation and natural decrease in metal concentrations in agricultural soils following organic waste application. Three common organic wastes, including municipal sewage sludge, alcohol fermentation processing sludge, and pig manure compost (PMC), were applied annually to an agricultural soil under field conditions over 7 years (1994–2000) at a rate of 12.5, 25, and 50 ton ha^?1 year^?1 and the soil accumulation of three metals of concern (Cu, Pb, and Zn) was monitored. Subsequently, organic waste amendments ceased and the experimental plots were managed using conventional fertilization for another 10 years (2001–2010) and the natural decrease in metal concentrations monitored. Although Cu and Zn concentrations in all experimental plots did not exceed the relevant guideline values (150 mg kg^?1 for Cu and 300 mg kg^?1 for Zn), significant increases in metal concentrations were observed from cumulative application of organic wastes over 7 years. For instance, PMC treatment resulted in an increase in Cu and Zn from 9.8 and 72 mg kg^?1 to 108.2 and 214.3 mg kg^?1, respectively. In addition, the natural decrease in Cu and Zn was not significant as soils amended with PMC showed only a 16 and 19 % decline in Cu and Zn concentrations, respectively, even 10 years after amendment ceased. This research suggested that more attention must be paid during production of organic waste-based amendments and at the application stage.     

Rare earth elements in street dust and associated health risk in a municipal industrial base of central China

The content levels, distribution characteristics, and health risks associated with 15 rare earth elements (REEs) in urban street dust from an industrial city, Zhuzhou, in central China were investigated. The total REE content (∑REE) ranged from 66.1 to 237.4 mg kg^?1, with an average of 115.9 mg kg^?1, which is lower than that of Chinese background soil and Yangtze river sediment. Average content of the individual REE in street dust decreased in the order Ce > La > Nd > Y > Pr > Sm > Gd > Dy > Er > Yb > Eu > Ho > Tb > Tm > Lu. The chondrite-normalized REE pattern indicated light REE (LREE) enrichment, a relatively steep LREE trend, heavy REE (HREE) depletion, a flat HREE trend, a Eu-negative anomaly and a Ce-positive anomaly. Foremost heavy local soil and to less degree anthropogenic pollution are the main sources of REE present in street dust. Health risk associated with the exposure of REE in street dust was assessed based on the carcinogenic and non-carcinogenic effect and lifetime average daily dose. The obtained cancer and non-cancer risk values prompt for no augmented health hazard. However, children had greater health risks than that of adults.     

Seasonal distribution and speciation of mercury in a gold mining area,north-west province,South Africa

The seasonal speciation of mercury (Hg) was determined in water, soil, and sediments from watersheds located in the North-West province of South Africa. The study area is known to have a long history of mining activities which also include the recovery of gold from old tailings. Both inorganic (IHg) and methyl mercury (MHg) were detected at high concentrations (up to 8480 μg IHg kg^?1 and 13 μg MHg kg^?1) in surface sediments during dry season. A considerable remobilization of Hg from bottom sediments was observed in water from dry to wet season as well as the migration of Hg away from pollution sources due to seasonal influences. Hg in sediments mostly has been speciated as Hg⁰. Enhancement of Hg methylation occurred mainly in deeper sediments at regions corresponding to the lowest redox potential, higher pH, and enrichment of IHg. Hg values in borehole waters were very high (up to 3310 ng L^?1) suggesting a serious contamination of the site groundwater which needs to be addressed urgently in order to minimize further impact that affects the Vaal River and other water systems located nearby.     

The influence of solid matrices on arsenic toxicity to Corophium orientale

In marine ecosystems, benthic organisms are really important because they are the first step in the transfer of contaminants from environment to biota. To this end, this study focused on biological assays with the amphipod Corophium orientale exposed to two different molecules of arsenic: arsenate (As^V), the most abundant form in sediments, and dimethyl-arsinate (DMA), expected to be moderately toxic as an intermediate in the process of detoxification. The toxicity of arsenic compounds was measured after exposure to three different matrices: water, spiked natural sediment and inert spiked quartz sand. LC₅₀ values were calculated for each exposure, and the results confirmed the highest toxicity of As^V, in addition to underlining the importance of matrix of exposure. Water exposure was the matrix which presented the highest toxicity for inorganic arsenic (As^V LC₅₀=3.51 mg L^?1 vs DMA LC₅₀=54.65 mg L^?1), spiked natural sediment demonstrated its capability to chelate arsenate toxicity (As^V LC₅₀=34.27 mg kg^?1 vs. DMA LC₅₀=52.19 mg kg^?1) and spiked quartz sand presented intermediate values for As^V (LC₅₀=25.26 mg kg^?1), whereas for DMA a lower toxicity was registered (LC₅₀=872.35 mg kg^?1). This study can provide some useful data linked with chemical speciation of arsenic and exposure matrix, for improving the correct management of contaminated sediment.     

Trace elements in surface sediments of the Hooghly (Ganges) estuary: distribution and contamination risk assessment

Our objective was to evaluate distribution and accumulation of trace elements (TEs) in surface sediments along the Hooghly (Ganges) River Estuary, India, and to assess the potential risk with view to human health. The TE concentrations (mg kg^?1 dry weight) exhibited a wide range in the following order: Al (31.801 ± 15.943) > Fe (23.337 ± 7584) > Mn (461 ± 147) > S (381 ± 235) > Zn (54 ± 18) > V (43 ± 14) > Cr (39 ± 15) > As (34 ± 15) > Cu (27 ± 11) > Ni (24 ± 9) > Se (17 ± 8) > Co (11 ± 3) > Mo (10 ± 2) > Hg (0.02 ± 0.01). Clay, silt, iron, manganese and sulphur were important for the accumulation of TE in the sediments as confirmed by factor analysis and Pearson correlation. The accumulation and dispersal of TEs were most likely to be governed by both tide-induced processes and anthropogenic inputs from point and non-point sources. Enrichment factor analysis and geoaccumulation index revealed serious contamination of the sediments with Se and As, while comparing the consensus-based sediment quality guidelines (SQGs), adverse biological effects to benthic fauna might be caused by As, Cu, Ni and Cr. This investigation may serve as a model study and recommends continuous monitoring of As, Se, Cu, Ni and Cr to ascertain that SQGs with respect to acceptable levels of TEs to safeguard geochemical health and ecology in the vicinity of this estuary.     

Phytotoxicity assessment of phenanthrene and pyrene in soil using two barley genotypes

This study investigated the toxicity extent of phenanthrene and pyrene to two cultivars (CM-72 and Gairdner) of barley (Hordeum vulgare). Germination of barley seeds was evaluated in 69-d aged soil, separately spiked with phenanthrene at extractable concentrations of 0.95, 6.3, 59, and 300 mg kg^?1 (dry soil) and pyrene at 1.0, 9.0, 73, and 400 mg kg^?1 (dry soil). Although germination was not inhibited, significant (P < 0.05) reduction in root and shoot length occurred at concentrations of phenanthrene ≥6.3 mg kg^?1 and pyrene ≥9.0 mg kg^?1 after both 72 and 240 h. Fresh and dry biomass of both cultivars reduced with increasing concentrations of both polycyclic aromatic hydrocarbons (PAHs). Barley cultivar CM-72 was more sensitive than Gairdner, and it can be considered suitable for toxicity assessment of PAH-contaminated soils.     

PAHs in organic film on glass window surfaces from central Shanghai,China: distribution,sources and risk assessment

Polycyclic aromatic hydrocarbons (PAHs) concentrations were analysed in the organic film on the glass surfaces of different functional areas in central Shanghai. Concentration levels of total PAHs in the organic film ranged from 1,348.5 to 4,007.9 ng m^?2. The concentration of PAHs was lowest in parks and green spaces (1,348.5 ng m^?2) and highest in traffic zones (4,007.9 ng m^?2). A concentration gradient of total PAHs was observed as follows: traffic zones > commercial areas > cultural and educational areas > parks and green spaces. The distribution of PAHs was characterised by 3–4 ring PAHs in the study areas. The most abundant PAHs were phenanthrene (20.5 %), fluorene (16.7 %), pyrene (12.4 %) and chrysene (Chry) (11.2 %). The mass of the bulk film was composed of organic and inorganic compounds and ranged from 246 to 1,288 mg m^?2. The bulk film thickness varied from 144 to 757 nm in the different functional areas. The ratios of An/178 and Fl/202 and principal component analysis suggested that PAHs came mainly from the mixed sources of fossil fuel, coal and incomplete combustion of biomass. Benzo[a]anthracene (BaA)/Chry is not suitable for use as a tracer for the transmission process of PAHs because of the rapid depletion of BaA in the organic film by photooxidation during daylight hours. The concentration of benzo[a]pyrene equivalent (BaPeq) varied from 21 to 701 ng g^?1, and the major carcinogenic contributors of the 16 PAHs were BaP, DahA, B[b/k]F and InP, accounting for 83 % of BaPeq.     

Spatial distribution of copper in relation to recreational boating in a California shallow-water basin

The overall effect of the number of boats on the copper (Cu) levels in the water column and sediment, along with their spatial variability within Shelter Island Yacht Basin (SIYB), San Diego Bay, California was examined. We identified a horizontal gradient of increasing dissolved Cu and Cu in sediment from outside to the head of SIYB which was coincident with the increasing number of boats. Spatial models of Cu distribution in water and sediment indicated the presence of ‘hotspots’ of Cu concentration. From outside to the head of SIYB, dissolved Cu ranged from 1.3 μ g L^?1 to 14.6 μ g L^?1 in surface water, and 2.0 μ g L^?1 to 10.2 μ g L^?1 in bottom water. Cu in sediment exceeded the Effect Range Low of 34 mg kg^?1 (i.e. where adverse effects to fauna may occur), with a peak concentration of 442 mg kg^?1 at the head of the basin. Free Cu⁺⁺ in surface water was several orders of magnitude higher than in sediment porewater. High-resolution data of Cu species together with probability maps presented in this paper will allow managers to easily visualise and localise areas of impaired quality and to prioritise which areas should be targeted to improve Cu-related conditions.