High Levels Of Cu Research Articles

Copper and Zn distribution in humic substances of soil after 10 years of pig manure application in south of Santa Catarina, Brazil.

This study aims to evaluate available Cu and Zn levels in soil and related in soil organic matter (SOM) fractions (fulvic acids-FA, humic acids-HA, and humins-HU) after 10years of application of pig slurry (PS) and pig deep litter (PL). Soil samples were collected from an experiment with black oat/corn succession under no-tillage in southern Brazil. The treatments consisted of fertilization of 90 and 180kgNha-1 applied as PS and PL from 2002 to 2012 and a control treatment without any fertilization. SOM chemical fractionation was performed in air-dried samples. Copper and Zn concentrations were analyzed in soil (total, EDTA- and CaCl2-extracted) and in SOM fractions. The amount of Cu and Zn (in mol) related to each fraction of SOM (Cu/C and Zn/C molar ratios) was established. The applications of PS and PL promoted the accumulation of total and available Cu and Zn, especially in the PL180 treatment. The highest amount of Zn was found with HU, while for Cu both HA and HU were important retention compartments. The highest Cu/CFA, Cu/CHA and Cu/CHU ratios were found with the addition of PL. Increases in Zn/C ratio were found mainly in FA fraction. The high levels of Cu and Zn obtained in the HCl-extracted SOM fraction suggest that a considerable part is bound to SOM and clay minerals with low energy. However, the SOM is an important source of metal adsorption in soils with swine manure application.

Act now before its too late: Copper exposure drives chemo-ecology of predator-prey dynamics of freshwater common spiny loach, Lepidocephalichthys thermalis (Valenciennes, 1846)

Due to the extensive use of copper (Cu) in various commercial products, its existence in aquatic bodies (freshwater and marine) is not unusual. Cu is well known for its effect on the olfactory physiology of fish. However, there are limited studies on the effect of Cu on important ecological functions in fish (predator-prey dynamics) that are primarily influenced by olfaction. In a series of experiments, we studied the effect of Cu exposure on the chemoreceptive behavior of the prey fish, Lepidocephalichthys thermalis. Prey fishes were exposed to an environmentally relevant concentration (5 μg/L) of Cu for 3 h and the anti-predator responses against native (Channa gachua) and alien predatory fish (tilapia) were quantified using an ethological assay. Cu exposed prey fishes did not recognize the native predator and had a lower survival rate than control (unexposed) fishes in predation trials. Cu exposed prey fishes have failed to learn associatively to detect a non-native predator resulting in higher mortality in prey population in direct encounters with tilapia. However, such a lack of predator recognition was found to be short-term and the treated prey fishes recovered anti-predator responses within 72 h. In addition, Cu inactivated the alarm cue which acts as a signal for the presence of predators and ensures associative learning and therefore it was considered to be an ‘info-disruptor’ in the present study. These outcomes together demonstrate that even at low concentration, Cu influences ecological decisions and survival against predators. Owing to the ubiquitous occurrence of Cu in water bodies, the present investigation will contribute to the knowledge of how environmental stressors alter the crucial ecological decisions of prey individuals in aquatic ecosystems. In addition, we suggest that freshwater reservoirs containing high levels of Cu could be unsuitable for the long-term survival of prey fishes and freshwater biodiversity.

Effects of copper and zinc sources and inclusion levels of copper on weanling pig performance and intestinal microbiota.

A 42-d experiment was conducted to evaluate the effect of Cu and Zn source and Cu level on pig performance, mineral status, bacterial modulation, and the presence of antimicrobial-resistant genes in isolates of Enterococcus spp. At weaning, 528 pigs (5.9 ± 0.50 kg) were allotted to 48 pens of a randomized complete block design in a 2 × 2 factorial arrangement with two Cu and Zn sources (SF: sulfate and HCl: hydroxychloride) and two Cu levels (15 and 160 mg/kg). As a challenge, the pigs were reared in dirty pens used by a previous commercial batch. Two-phase diets were offered: the pre-starter (PS) phase from day 1 to 14 and the starter phase (ST) from day 14 to 42. At days 14 and 42, pigs were individually weighed and blood samples from one pig per pen were taken. At the end of the experiment, one pig per pen was euthanized to collect the samples. Feeding high levels of Cu increased body weight (BW) from 16.6 to 17.7 kg (P < 0.001). Furthermore, average daily gain, gain to feed (G:F) ratio, average daily feed intake (ADFI), and mineral status were enhanced with Cu at 160 mg/kg (P < 0.05) compared with Cu at 15 mg/kg. There was no effect of the interaction between source × level on any of the growth performance responses except for ADFI (P = 0.004) and G:F (P = 0.029) at the end of the ST period and for G:F (P = 0.006) for entire nursery period (day 0 to 42). At the end of the ST period, pigs fed Cu at 160 mg/kg as HCl had not only higher ADFI but also lower G:F than those fed Cu as SF at 160 mg/kg. Meanwhile, for the entire nursery period, G:F did not differ between pigs fed Cu at 160 mg/kg as HCl or SF. In colonic digesta, the relative abundance of Streptococcus, Enterobacter, Escherichia, among others, decreased (P-adjust < 0.05), while Lachnospira and Roseburia tended (P-adjust < 0.10) to increase in pigs fed Cu at 160 mg/kg as HCl compared with those fed Cu SF at 160 mg/kg. An increase (P-adjust < 0.05) in Methanosphaera and Roseburia was observed in pigs fed Cu at 160 mg/kg. From colon digesta, Enterococcus spp. was isolated in 40 samples, being E. faecalis the most dominating (65%) regardless of the experimental diet. Genes of ermB (7.5%) and tetM (5%) were identified. No genes for Cu (tcrB) or vancomycin (vanA, vanB, vanC1, and vanC2) were detected. In conclusion, European Union permissible levels of Cu (160 mg/kg), of both sources, were able to increase performance, mineral status, and bacterial modulation compared with nutritional level. Different effects on growth performance, mineral tissue content, and microbial modulation were observed between Cu and Zn sources.

A Cd/Zn Co-hyperaccumulator and Pb accumulator, Sedum alfredii, is of high Cu tolerance

High sensitivity towards Cu toxicity is problematic when using some hyperaccumulator plants for phytoremediation of soils with mixed contamination of Cu. Sedum alfredii, a Cd/Zn co-hyperaccumulator and Pb accumulator, is widely used for remediation of Cd, Zn, and Pb co-contaminated soils in China. In this paper, the tolerance and accumulation ability of S. alfredii towards Cu stress and its potential for phytoremediation of multi-metal polluted soils have been studied. Both the hyperaccumulating ecotype (HE) and non-hyperaccumulating ecotype (NHE) of S. alfredii accumulated high Cu in the roots and translocated minimal Cu to the shoots, and Cu in the stems and leaves mostly restricted in the vascular tissues (phloem zone). The HE plants, however, exhibited high Cu resistance with stimulated lateral root growth and increased chlorophyll content under 10 μM Cu treatment. XANES analysis showed that Cu in HE roots comprised Cu2+ (46.7%), Cu-histidine (35.2%) and Cu-cell wall (18.1%). The NHE under Cu stress showed decreased biomass, reduced leaf chlorophyll content, altered root architecture, and higher Cu localized to root cell wall as compared with the HEs. Potted HE plants thrived six months in multi-metal contaminated soils including 3897 mg kg−1 available Cu. In conclusion, HE S alfredii is highly tolerant toward Cu due to metal homeostasis in root cells. Therefore, this plant has great potential to remediate Zn, Cd, and Pb contaminated soils those also contain high levels of Cu.

Heavy metal pollution status, spatial distribution and associated ecological risks within sediments of Yundang Lagoon catchment in Xiamen, China, after 30 years continuous ecological rehabilitation and management

This study aims to assess the pollution status and spatial distribution of heavy metals, including Chromium (Cr), Manganese (Mn), Nickel (Ni), Copper (Cu), Zinc (Zn), Arsenic (As), Cadmium (Cd), and Lead (Pb), in sediments from the Yundang Lagoon catchment, and to determine the risk from such metals and associated possible sources. Results show considerable spatial variations in total concentrations of heavy metals within sediment samples. The Geo-accumulation index indicates that sediment is not contaminated with Cr, Mn, Ni, and As, but moderate to high levels of Cu, Zn, Cd, and Pb are present. The potential ecological risk is low for Cr, Mn, Ni, Cu, Zn, As, and Pb, but Cd in lagoon sediments poses a considerable ecological risk to biota. A high positive correlation was found between Zn, Cu, and Cd (r > 0.8), while Zn, Cd, and Cu (r > 0.7) were positively correlated with total organic carbon. Principal component analysis indicated that Cr, Ni, Mn, and As was mainly from the lithogenic origin and Zn, Cu, Cd, and Pb were influenced by anthropogenic contamination. We identified evidence of point source and runoff are the main contributors to enhanced heavy metals levels.

Reconstruction of anthropogenic activities in legacy sediments from the Eure River, a major tributary of the Seine Estuary (France)

Most rivers worldwide are contaminated by various trace metals from different origins, which may be stored for considerable periods of time in depositional areas. Most of these studies are focused on the main river of a watershed and the tributaries are often neglected which can be important sources of contamination. The aim of this study was to reconstruct the anthropogenic activities that occurred in the Eure River, tributary of the Seine Estuary, since the 1940s using “legacy sediments”. The results showed that the temporal trends of trace metals were not related to detrital inputs and TOC variations but with the industrial history of the Eure River watershed. The high levels of Zn, Cu, and Ni during the 1950s and the 1960s, and the decrease with the decline of the probable main source of release showed the watershed reactivity to anthropogenic activities. The high levels of Pb during the 1990s and the 2000s showed that the watershed reacted immediately to anthropogenic pressures. The Pb levels remained important after the cease of industrial activity, showing that a resilience period is necessary for the system, and that interactions between human activities and the environment go beyond of the activities themselves.

Using pXRF to assess the accumulation, sources, and potential ecological risk of potentially toxic elements in soil under two greenhouse vegetable production systems in North China.

Intensive greenhouse vegetable production (GVP) has increased the pollution risk of potentially toxic elements (PTEs) in soils. This study examined the accumulation, sources, and potential ecological risk of six PTEs (Cu, Zn, As, Ni, Pb, and Cr) in soil under two GVP (solar greenhouse (SG) and round-arched plastic greenhouse (RAPG)) systems by portable X-ray fluorescence spectroscopy (pXRF) and conventional laboratory analysis. The results indicated that all PTE concentrations were lower than their corresponding thresholds in GVP soils, presenting a low potential ecological risk in both GVP soils according to risk indices (RI ≤ 40.67). As, Ni, Pb, and Cr were not significantly accumulated in both GVP soils. Although Cu and Zn accumulated in both GVP soils, their accumulation extents in SG soil were both greater than that in RAPG soil. Cu and Zn were mainly originated from anthropogenic activities based on multivariate statistical analysis, which were greatly associated with excessive manure application. Overall, pXRF can identify the accumulation difference of PTEs between the two GVP soils, which is generally consistent with conventional laboratory analysis. Hence, pXRF can be a promising alternative to conventional laboratory analysis for rapid assessment of PTEs accumulation, sources, and the potential ecological risk in the two GVP soils. Although PTEs had a low ecological risk, Cu and Zn accumulation in SG soil was increased with the planting years. Therefore, rational application of livestock manure containing high levels of Cu and Zn should inspire strategies to mitigate the environmental risk in GVP soils, especially in SG soil.

Direct Solid Sample Analysis of Medicinal Herbs for Determination of Ba, Cu, Ni, V and Zn by EDXRF

In this work, an analytical method for determination of Ba, Cu, Ni, V, and Zn, in medicinal herbs, through direct solid sample analysis by energy dispersive X-ray fluorescence spectrometry (EDXRF), was applied. Accuracy and precision (intra and inter day) of the analytical method were confirmed through analysis of certified reference material, tomato leaves (CRM NIST 1573a). Principal component analysis (PCA) and hierarchical cluster analysis (HCA) allowed to observe the formation of two groups. Group I was composed by highest levels of Cu and Zn, and the group II with highest concentrations of Ba, V, and Zn. Group I also was subdivided into two subgroups. The concentration of Ni in some samples exceeded the maximum allowed limit. In all samples, Cu and Zn concentration were below the maximum limit allowed by Brazilian legislation. However, for Ba and V, the evaluation was not possible, because there are no maximum limits in legislation.

Heavy Metals Contents of Municipal Solid Waste Dumpsites in Potiskum, Yobe State Nigeria

The concentrations of As, Cd, Cr, Cu, Ni, Pb, Fe and Zn in selected dumpsites in Potiskum were determined with Buck Scientific 210VGB Atomic Absorption Spectrometer (AAS) AVG 210. One-way ANOVA was deployed at p ·kg-1) of studied heavy metals in Potiskum dumpsites ranged from 0.108 ± 0.02 - 262.536 ± 0.68 with pattern of accumulation Pb (262.536 ± 0.02) > Zn (183.369 ± 0.58) > Fe (159.453 ± 0.50) > Cu (111.382 ± 0.62) > Cr (43.523 ± 0.36) > Ni (6.419 ± 0.26) > Cd (0.679 ± 0.01) > As (0.108 ± 0.02) mg·kg-1. The concentrations of As, Cr, Ni, Fe and Zn fell below the WHO standards while those of Pb, Cd and Cu were above set limits by WHO. High acidity corresponds markedly with high levels of Cd, Cu, Cr and Zn and requires urgent attention as this trend is capable of groundwater contamination that will cause public health concern in affected areas.

Geochemical patterns of Cu, Au, Pb and Zn in stream sediments from Tongling of East China: Compositional and geostatistical insights

Geochemical patterns of elements in surficial sediments are of significance in deciphering processes and locating mineral resources. Stream sediment geochemical data of four ore-forming elements (Cu, Au, Pb and Zn) and fourteen associated elements (Ag, As, Bi, Cd, La, Mn, Mo, Nb, Sb, Th, U, W, Y and Zr) from the Tongling Ore Cluster District (TOCD), East China were analyzed by compositional multivariate and geostatistical approaches. It is shown that the median values of the four ore-forming and main associated elements including Ag, As, Bi, Cd and Sb are at least two times larger than those in stream sediments of China, indicating that there was a noteworthy addition of such ore minerals as (gold-rich) chalcopyrite and pyrite, galena and sphalerite into the sediments. The first three factors that explain 71.4% of the total variance could represent the dominant geology in the TOCD including the felsic intrusive rocks by F1 (−) (Zr-Th-Nb-Y-La) and F2 (−) (U-Y-Th-Nb-La), Pb and Zn-bearing strata and related mineralization by F1 (+) (Pb-Cd-Ag-Mn-Sb-Zn), skarn Cu mineralization by F2 (+) (Bi- Cu-Au-As) and porphyry Cu mineralization by F3 (−) (MoW). Simultaneously, regression analysis exhibited a closer relationship of Cu in the stream sediments with the skarn-type Cu mineralization than the porphyry counterpart. The geostatistical semivariogram modeling reflected that the greatest continuity of Cu, Au, Pb and Zn is at NE4°, SE95°, NE50° and NE42°, respectively. Moreover, the factor score and balance maps from factor analysis and sequential binary partition (SBP) illustrated the geochemical patterns of the elements. According to the modeling and spatial patterns, not only the possible sources (geogenic vs. anthropogenic), but also the controlling factors have determined. High levels of Cu, Bi, Mo and W are dominated by the felsic intrusives and related mineralization. That of Au, however, is governed by combined effect of the basement fault system and felsic intrusives. In contrast, high concentrations of Pb and Zn and such associated elements as Cd and Sb are controlled by the Permian and Triassic strata and associated PbZn mineralization. Exploration suggestions and targets were proposed accordingly. It demonstrates that compositional and geostatistical analyses are effective to characterize geochemical patterns of elements.

Heavy metals in iron ore tailings and floodplain soils affected by the Samarco dam collapse in Brazil

In November 2015, the Fundão Dam collapsed releasing about 35 million m−3 of iron ore tailings into the environment, which covered approximately 15 km2 of floodplain soils. Four years later, there is still great concern and controversy regarding contamination by heavy metals in the affected areas. Thus, the present study sought to evaluate the heavy metal contents and its distribution in tailings and non-affected soils. Tailings samples were collected in the stretch between Bento Rodrigues and the Candonga hydroelectric plant, in addition to a sample inside the Fundão Dam. Non-affected soils and river sediments from the same region were also collected as a control group. The heavy metal contents in the tailings were lower than in non-affected samples from the same area, discarding the hypothesis of contamination by the tailings mud. The non-affected samples presented high levels of As, Ba, Co, Cr, Cu, Ni and Zn, with at least one sample exceeding the quality reference values (QRV's) established for Minas Gerais state, which indicated a scenario of pre-disaster contamination for the Doce River watershed. Most of the elements (As, Cr, Cu, Ni, V and Zn) were extracted in the residual fraction of the BCR sequential extraction, presenting low risk of release in nature. The health risk assessment for As estimated that all the non-affected soils and sediments from Gualaxo do Norte, Carmo and Doce rivers have carcinogenic risk higher than the acceptable value for children. From our results, it is more likely to conclude that the deposited tailings are not a time-bomb for heavy metals contamination in the region.

Distribution of arsenic, silver, cadmium, lead and other trace elements in water, sediment and macrophytes in the Kenyan part of Lake Victoria: spatial, temporal and bioindicative aspects

This is the first detailed report on the distribution of Ni, As, Sr and Ag in water, sediments and macrophytes from Lake Victoria, complemented with recent data on the heavy metals Cr, Cu, Zn, Cd and Pb. The study was conducted over an 11-month period at five sites in the Kenyan part of Lake Victoria: four sites in the Winam Gulf influenced by various anthropogenic pressures including a site near Kisumu City, and one in the main lake, perceived to have lesser direct anthropogenic influence. Compared with the main lake site, the water in Winam Gulf had significantly higher values for electrical conductivity and concentrations of dissolved components: organic carbon and bound nitrogen, as well as major and most trace elements. This contamination is also evident in surface sediments, which contained significantly higher levels of Cr, Zn, As, Ag, Cd and Pb compared with the main lake site. The mean levels of Cr, Cu, Zn, Ag and Pb exceeded probable effect levels at least at one of the gulf sites. The sediments at the Kisumu City site were classified as severely polluted with Cu (up to 259 mg/kg dw) and Pb (up to 1188 mg/kg dw). The sediment cores showed significantly higher levels of Cu, Zn, Ag, Cd and Pb in the surface (0–3 cm) versus subsurface (22–25 cm) layer at the Kisumu City site, indicating increasing pollution by these elements within the last 15 years. This is also the first report on trace elements in the emergent water plant Vossia cuspidata and submerged plant Ceratophyllum demersum from this lake. Even though the accumulation of most elements is comparable between C. demersum (whole plant) and V. cuspidata roots, the latter shows a better bioindicative potential. Contamination of the gulf with Ni, Cu, Zn, Ag, Cd and Pb is well mirrored in V. cuspidata roots. V. cuspidata strongly restricts the acropetal transport of trace elements, and hence using the shoots as fodder does not pose a risk to livestock.

Determination of HeaDetermination of Some Heavy Metals in Three Fish Species from Duhok City Markets in Kurdistan of Iraq

In this study, the concentrations of some heavy metals including Al, Cu, Fe, Mn, Zn, Cd, Co, Cr, Ni and Pb were determined in the muscles of three commercial fish species available in Duhok city markets in two seasons, using inductively coupled plasma-optical emission spectrometry (ICP-OES), after the wet digestion process. Lowest and highest mean values of metals in µg/g (dry weight) were as follows: Al: Under Detection Limit (UDL)-3.71, Cu: UDL-4.00, Fe: 5.40-21.44, Mn: UDL-3.45, Zn: 13.38-140.11, while Cd, Co, Cr, Ni, and Pb were not detected. The highest levels of Al, Fe and Zn were recorded in Shukhat fish species, and the highest levels of Cu and Mn were recorded in Shabout in the winter season. The highest level of all metals was recorded for Zn (172.8 µg/g) with the highest mean value of (140.11 µg/g) in Shukhat species during winter. Most heavy metal concentrations were below the international permissible limits for fish, however, some of the maximum and mean values of metals were above the international standards. Fe concentrations were above the maximum allowable limits set by WHO (1999). Zn concentrations were above the maximum permissible limits set by joint FAO/WHO (1989) and FAO (2012).

Active-site environment of Cu bound amyloid β and amylin peptides.

Alzheimer's disease (AD) and Type 2 Diabetes mellitus (T2Dm), two of the most common amyloidogenic diseases. They share a common pathological symptom, i.e., the formation of amyloid deposits comprised of amyloid β and amylin peptides, respectively. Autopsy of brains of AD-affected patients shows the presence of abnormally high concentrations of Cu in the deposited amyloid β plaques, while a significantly higher level of Cu is found in the serum of patients suffering from T2Dm. These invoke that Cu might play a crucial role in the onset of both AD and T2Dm. In fact, Cu is found to bind amyloid β as well as amylin relevant to AD and T2Dm, respectively. Cu-Aβ and Cu-amylin in their reduced states can generate partially reduced oxygen species (PROS) on reaction with O2 which leads to oxidative stress in the brain and in the pancreas, respectively. However, the pathway of O2 reduction is quite different for the two complexes. Moreover, the use of various spectroscopic techniques such as absorption, EPR, and CD involving native and site-directed mutants of the peptides show that their active-site environments are also dissimilar. Here, we have discussed the different aspects of Cu-Aβ and Cu-amylin complexes including their pH-dependent coordination environments and their reactivity towards O2 which may be responsible for the oxidative stress associated with the two diseases. This depicts the significance of the Cu bound peptide complexes in the context of AD and T2Dm. Graphic abstract.

First Trimester Serum Copper or Zinc Levels, and Risk of Pregnancy-Induced Hypertension.

Early identification of women at risk of developing pregnancy-induced hypertension (PIH) is very important. The involvement of copper (Cu) and zinc (Zn) in the oxidative balance suggests the possibility of their association with this disease, in which oxidative stress plays a key role. However, it has not been established so far whether the microelement levels in early pregnancy may be risk markers of the disease, as prospective studies are limited in number. In our innovative single-center study, we identified from a prospective cohort of healthy women in the 10–14th week of a single pregnancy: women subsequently developing pregnancy-induced hypertension (n = 121) and matched women remaining normotensive (n = 363). We measured the concentrations of microelements in the serum from 10–14 week, using the inductively coupled plasma mass spectrometry (ICP-MS). The odds ratios of the disease (and 95% confidence intervals) were assessed in logistic regression. In the whole cohort, the odds ratio (OR) of PIH was 1.52 (p = 0.174) for women in the lowest (Q1) quartile of Cu (≤1540.58 µg/L) compared with women in the highest (Q4) quartile (>1937.46 µg/L), but adjusted odds ratio (AOR) was 2.17 (p = 0.019) after adjusted for pre-pregnancy body mass index (BMI) and gestational age at recruitment. The higher levels of Cu in the subgroup of BMI ≥ 25 kg/m2 compared to normal BMI were found (1847.64 vs. 1673.36 µg/L; p < 0.0001). In the subgroup of women with the normal pre-pregnancy BMI, the adjusted odds ratio of PIH was AOR = 2.95 (p = 0.040) for Q1 vs. Q4 quartile. Our results suggest that lower Cu levels in early pregnancy may be connected with higher risk of PIH, but BMI affected estimated odds ratios. Zinc levels had no effect on the risk.

Elevated trace elements in sediments and seagrasses at CO2 seeps

Seagrasses often occur around shallow marine CO2 seeps, allowing assessment of trace metal accumulation. Here, we measured Cd, Cu, Hg, Ni, Pb and Zn levels at six CO2 seeps and six reference sites in the Mediterranean. Some seep sediments had elevated metal concentrations; an extreme example was Cd which was 43x more concentrated at a seep site than its corresponding reference site. Three seeps had metal levels that were predicted to adversely affect marine biota, namely Vulcano (for Hg), Ischia (for Cu) and Paleochori (for Cd and Ni). There were higher-than-sediment levels of Zn and Ni in Posidonia oceanica and of Zn in Cymodocea nodosa, particularly in roots. High levels of Cu were found in Ischia seep sediments, yet seagrass was abundant there, and the plants contained low levels of Cu. Differences in bioavailability and toxicity of trace elements helps explain why seagrasses can be abundant at some CO2 seeps but not at others.

Simultaneous removal of As(III) and Cu(II) from real bottom ash leachates by manganese-oxidizing aerobic granular sludge: Performance and mechanisms

Manganese-oxidizing aerobic granular sludge (Mn-AGS) is a novel extension of AGS technology to treat arsenic (As) in organic wastewater. In this study, Mn-AGS was first applied to treat real wastewater (bottom ash leachates) containing high levels of As(III) and Cu(II) in a sequencing batch reactor (SBR) for 91 days. Influent and effluent As(III), As(V), Cu(II), as well as pH and chemical oxygen demand (COD) were monitored daily, and sludge was collected regularly for morphological observation, chemical characterization, and microbial analysis. The results indicated that As(III) and Cu(II) could be efficiently removed from wastewater (∼83% and ∼100%, respectively), but the performance was sensitive to pH variation, especially for As(III). The removed As and Cu were mostly bound to carbonates (60.2 ± 2.0% and 70.0 ± 0.6%, respectively) and Fe/Mn oxides (28.2 ± 1.6% and 14.6 ± 0.5%, respectively) in the final sludge. Influent As(III) was partially oxidized into As(V), and high fractions of As(V) were obtained in the Fe/Mn oxide-bound phase. Unexpectedly, microbial analysis revealed that community richness was only slightly changed when the influent was acidized (pH 4.0) but greatly reduced after the influent pH back to 6.0. It could be explained by that acid-fast bacteria rapidly grew after pH recovery and eliminated non-acid-fast bacteria. This work further supported the practical application of Mn-AGS to treat As(III)-containing organic wastewaters.

Risk for Indo-Pacific humpback dolphins (Sousa chinensis) and human health related to the heavy metal levels in fish from the Pearl River Estuary, China

Cetaceans and humans shared the same route of exposure to many anthropogenic contaminants via fish consumption. To assess the health risks associated with heavy metal levels in fishes from the Pearl River Estuary (PRE) and the seasonal dynamics, 13 fish species (n = 675) consumed by the Indo-Pacific humpback dolphins (Sousa chinensis) and humans were analyzed for concentrations of nine heavy metals. Heavy metal levels vary significantly by species and by season in the PRE fishes. The two eel goby species were the most contaminated fish species, which had the highest levels of Cu, Pb, Hg, Mn and Se. Levels of non-essential metals (As and Pb) in many different fish species were all found significantly higher in dry season than in wet season, which may reflect the dilution effect on contaminant levels in the PRE waters in rainy season. For essential metals, Cu, Cr and Se in many fish species were significantly higher in dry season compared to wet season, while Se and Mn in the other fish species showed an opposite pattern, since essential metal accumulation could be influenced by several physiological processes in life. Risk assessment for dolphins showed that inorganic-As levels in all fishes exceeded the safe limits, whereas a more conservative approach indicated that the levels of all metals in all fish samples had toxic effects on dolphins, except for Hg. Human health risk analysis showed that inorganic-As levels in tonguesole (all year) and sillago (dry season) and Cr levels in pomfret (dry season) exceeded the acceptable values.

Urinary Metal Concentrations and the Incidence of Hypertension Among Adult Residents Along the Yangtze River, China.

Metals from the natural environment have potential hypertension effects. However, relevant studies on this topic are few. A total of 1358 adults aged 18-74years from Chizhou, Maanshan, and Tongling of Anhui Province participated in the baseline study from 2014 to 2015. The follow-up study was performed from 2016 to 2017. Inductively coupled plasma optical emission spectrometry (7000DV) was used to measure urinary Cr, Mn, Fe, Cu, and Zn of residents. Urinary concentrations of Cd determined via TAS-900 atomic absorption spectrophotometry at 228.8nm wavelength. A total of 275 hypertension cases were identified. After adjusting for sociodemographic factors and risk factors for hypertension, four metals (Cd, Cr, Cu, and Mn) were significantly associated with hypertension in the single-metal model. Upon including all metals in the same model, the hazard ratios of the highest quartiles Cd and Cu compared with the reference group were 1.42 (95% confidence interval [CI] 1.09-2.02) and 1.56 (95% CI 1.16-2.09) for cases of hypertension. Our findings suggested that high levels of Cd and Cu might increase the incidence of hypertension. Further studies involving larger population should be conducted to confirm these findings.

Changes in the total content and speciation patterns of metals in the dredged sediments after ocean dumping: Taiwan continental slope

The aim of this study was to understand the changes in heavy metals and speciation patterns in the dredged sediments after ocean dumping by a five-step sequential extraction procedure. The potential mobility and bioavailability of heavy metals in the sediments were also assessed. The results showed that the average contents of heavy metals, Cu, Zn, Ni, Cd, Cr, and Pb, in the dredged sediment of Kaohsiung Harbor are 120, 403, 33, 0.46, 112, and 40 mg/kg dw, respectively. The Cd and Zn basically bound in the carbonate fractions of the dredged sediments, which accounts for 36% and 45% of their total content on average. The highest level of Cu was present in the organic-matter fraction (92%), Cr and Pb were present in the Fe–Mn oxides fraction (59% and 52%) of the dredged sediments, and the most of Ni (52%) was found in the residual fraction of sediments. Except for Ni, the total amount of all heavy metals in the dredged sediments of Kaohsiung Harbor was about 1.5–4 times higher than the surface sediment of the ocean disposal site. The speciation patterns of heavy metals in the surface sediments of disposal site were similar to those of the reference site, whereas were distinctly different with the dredged sediments. The observation implies that the dredged sediments after dumping in the ocean disposal site, their heavy metals could be diluted by the physical and chemical effects in the marine environment and eventually to the stable state.