Assessment of trace element pollution and ecological risks in a river basin impacted by mining in Colombia

Trace element pollution in rivers by anthropogenic activities is an increasing problem worldwide. In this study, the contamination and ecological risk by several trace elements were evaluated along a 100-km stretch of the San Jorge River in Colombia, impacted by different mining activities. The increase of average concentration levels and range of trace elements in sediments (in μg/g) was as follows: Cu 6656 (454–69,702) > Cd 1159 (0.061–16,227) > Zn 1064 (102–13,483) > Ni 105 (31–686) > Pb 7.2 (5.1–11.7) > As 1.8 (1.0–3.2) > Hg 0.31 (0.12–1.37). Results showed that surface sediments could be classified as very high ecological risk index (RI > 600), associated with high contamination of Hg, Cd, and Cu, in stations close mining activities. Values for pollution load index indicate an environmental deterioration (PLI > 1), and sediment quality guidelines (SQGs) suggested that Cu, Ni, Zn, and Hg caused adverse biological effects. We further used pollution indices such as contamination factor (CF), enrichment factor (EF), and geoaccumulation index (Igeo) to assess the extent of contamination. According to these indices, discharges of hazardous chemicals over many years have resulted in a high degree of pollution for Cu, Pb, and Cd, with critical values in stations receiving wastes from mining activities. Multivariate statistical analysis suggested that Hg, Cd, Cu, and Zn derived from gold and coal mining, Ni and As were related from the mining of ferronickel and coal, respectively, whereas the high Pb load was attributed to diffuse source of pollution. In sum, our study provided the first detailed database on metal concentration and ecological risks to organisms in sediments of the San Jorge River Basin, and the current results also suggested future research for public health action.

     

Distribution,Sources, and Possible Adverse Biological Effects of Trace Metals in Surface Sediments of a Tropical Estuary

Metal (Cu, Zn, Pb, Cd, Ni, Co, and Fe) contamination in sediments from a tropical estuary (Ébrié Lagoon, Ivory Coast) was assessed using pollution indices, multivariate analyses and sediment quality guidelines (SQGs). The results demonstrate that increased input of the studied metals occurred over the past 6 years compared to that from 20 years ago, due to rapid population growth, along with the increase of industrial and agricultural activities in the vicinity of the estuary. Ébrié Lagoon was also found to be one of the most contaminated tropical coastal estuaries. Very high average total organic carbon (TOC) content was found (1.9–3.70%) with significant spatial variation as a result of the influence of anthropogenic activities. This study also found that TOC plays an important role in the distribution of Cu, Zn, Co, and Cd in the Ébrié Lagoon sediments. Moderate to high sediment contamination was observed for Cd and Cu, moderate contamination was observed for Zn and Pb, while low contamination was observed for Ni, Co, and Fe. Cluster analysis (CA) and principal component analysis (PCA) investigation revealed that Cu, Zn, Cd, and Co result mainly from anthropogenic sources while Pb, Ni, and Fe may be of natural origin. The pollution-loading index (PLI) indicated that all of the sites close to wastewater discharges were highly polluted. The sediments are likely to be an occasional threat to aquatic organisms due to Cu, Zn, Pb, Cd, and Ni contents, based on the SQGs approach.     

Fractionation and extractability of sulfur, iron and trace elements in sulfidic sediments

This study describes iron and sulfur fractionation, and the related extractability of selected trace elements (As, Cd, Cr, Cu, Ni, Pb and Zn) in estuarine sediments. The sediments were sulfidic, with moderately high concentrations of pore-water sulfide (200-600 micromol l(-1)) and acid-volatile sulfide (AVS; 9.9-129 micromol g(-1)). Pyrite-S concentrations increased with depth, with 63-251 micromol g(-1) at site W1 and 312-669 micromol g(-1) at site W2. The degree of sulfidisation was generally high (>80%), indicating that Fe may be limiting pyrite accumulation. The ratios of AVS to pyrite-S increased with sediment depth, as expected for the pyritisation of solid-phase AVS. Cadmium, Pb and Zn extractability in 1M HCl indicated that these elements are not significantly sequestered during pyritisation, whereas sequestration may be important for As, Cu and possibly Ni. Extractability trends for Cr suggest that diagenesis in sulfidic sediments may enhance Cr reactivity. Overall, replacement of AVS by pyrite during diagenesis may enhance the reactivity of Cd, Cr, Pb and Zn, whereas As, Cu and possibly Ni may be rendered less reactive.     

Trace element contamination of Norwegian Lake sediments

Concentrations of Sb, Hg, Bi, Cd, Mo, As, Co, Ni, Cr, Cu, V, Pb and Zn in surface and preindustrial sediments from 210 lakes in Norway were used for studying modern atmospheric depositions of these elements. Surface sediments had considerably higher concentrations of Sb, Hg, Bi, Cd, As, Pb than preindustrial sediments. The differences decreased with latitude and altitude. A multivariate analysis including the trace elements and the major constituents (organic matter, Si, Al, Fe and Mn) of surface sediments suggested the following relationships: Sb, Hg, Bi, As, and Pb formed a group with strong associations to organic matter. Ni, Cr and Cu formed a second group, weakly associated to the inorganic sediment fraction (Si and Al). Zn and Cd formed a third group with weak associations to organic matter. Co was associated to Mn, whereas Mo and V showed no important covariations with any other trace elements or major components.     

Metal accumulation in the greentail prawn, Metapenaeus bennettae, in Sydney and Port Hacking estuaries, Australia

Metal concentrations of the inshore greentail prawn, Metapenaeus bennettae, and surface sediments from locations within Sydney estuary and Port Hacking (Australia) were assessed for bioaccumulation and contamination. The current study aimed to assess metal concentrations in prawn tissue (tail muscle, exoskeleton, hepatopancreas and gills), relate whole body prawn tissue metal concentrations to sediment metal concentrations and animal size, as well as assess prawn consumption as a risk to human health. Metal concentrations were highest in sediment and prawns from contaminated locations (Iron Cove, Hen and Chicken Bay and Lane Cove) in Sydney estuary compared with the reference estuary (Port Hacking). Concentrations in sediments varied considerably between sites and between metals (As, Cd, Cr, Cu, Ni, Pb and Zn), and although concentrations exceeded Interim Sediment Quality Guideline-Low values, metals (As, Cd, Cr, Cu, Ni, Pb and Zn) were below Australian National Health and Medical Research Council human consumption guidelines in prawn tail muscle tissue. Metal concentrations in prawn tail muscle tissue were significantly different (p?≤?0.05) amongst locations for Pb, Zn and Cd, and metal concentrations were generally highest in gills tissue, followed by the hepatopancreas, exoskeleton and tail muscle. The exoskeleton contained the highest Sr concentration; the hepatopancreas contained the highest As, Cu and Mo concentrations; and the gills contained the highest Al, Cr, Fe and Pb concentrations. Concentrations of Pb, As and Sr were significantly different (p?≤?0.05) between size groups amongst locations.     

Mobility of heavy metals from polluted sediments of a semi-enclosed basin: in situ benthic chamber experiments in Taranto’s Mar Piccolo (Ionian Sea,Southern Italy)

In situ benthic flux experiments were conducted at two stations in the Mar Piccolo of Taranto (Italy), one of the most industrialised and contaminated coastal areas of the Mediterranean. Sediments of the two stations are notably different in their trace metal content, with a station closer to a Navy harbour showing higher mean concentrations of almost all investigated metals (Al, As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, V and Zn). Conversely, both stations are characterised by significant Hg contamination, compared to the local baseline. Results of a sequential extraction scheme on surface sediments suggest a relatively scarce mobility of the examined metals (Zn > Ni > Cr > As > Cu > Pb). A Hg-specific extraction procedure showed that most of the element (93.1 %) occurs in a fraction comprising Hg bound to Fe/Mn oxi-hydroxides. Reduction of these oxides may affect Hg remobilisation and redistribution. Porewater profiles of dissolved trace metals were quite similar in the two sites, although significant differences could be observed for Al, Cu, Fe and Hg. The highest diffusive fluxes were observed for As, Fe and Mn. Mobility rates of several trace elements (Al, As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, V and Zn) were directly measured at the sediment–water interface. Results from benthic in situ incubation experiments showed increasing dissolved metal concentrations with time, resulting in higher fluxes for Cu, Fe, Hg, V and Zn in the most contaminated site. Conversely, fluxes of Mn, Ni and Pb were comparable between the two stations. The estimated flux of Hg (97 μg m^?2 day^?1) was the highest observed among similar experiments conducted in other highly contaminated Mediterranean coastal environments. Benthic fluxes could be partially explained by considering rates of organic matter remineralisation, dissolution of Fe/Mn oxy-hydroxides and metal speciation in sediments. Seasonal and spatial variation of biogeochemical parameters can influence metal remobilisation in the Mar Piccolo area. In particular, metals could be promptly remobilised as a consequence of oxygen depletion, posing a serious concern for the widespread fishing and mussel farming activities in the area.     

Trace metal contamination of sediments in an e-waste processing village in China

This study examined trace metal contamination of sediments in Guiyu, China where primitive e-waste processing activities have been carried out. It was found that some river sediments in Guiyu were contaminated with Cd (n.d.-10.3mg/kg), Cu (17.0-4540mg/kg), Ni (12.4-543mg/kg), Pb (28.6-590mg/kg), and Zn (51.3-324mg/kg). The (206)Pb/(207)Pb and (208)Pb/(207)Pb ratios of the Pb-contaminated sediments of Lianjiang (1.1787+/-0.0057 and 2.4531+/-0.0095, respectively) were lower than those of Nanyang River (1.1996+/-0.0059 and 2.4855+/-0.0082, respectively), indicating a significant input of non-indigenous Pb with low (206)Pb/(207)Pb and (208)Pb/(207)Pb ratios. Copper, Pb and Zn in the non-residual fractions noticeably increased in the contaminated sediments compared to those in the uncontaminated sediments. A genuine concern is associated with potential transport of the contaminated sediments downstream and enhanced solubility and mobility of trace metals in the non-residual fractions.     

Contamination status and potential release of trace metals in a mangrove forest sediment in Ho Chi Minh City,Vietnam

Can Gio district is located in the coastal area of Ho Chi Minh City, southern Vietnam. Discharge of wastewater from Ho Chi Minh City and neighboring provinces to the rivers of Can Gio has led to concerns about the accumulation of trace metals (As, Cu, Cr, Ni, Pb, and Zn) in the coastal sediments. The main objective of this study was to assess the distribution of As, Cu, Cr, Ni, Pb, and Zn in surface and core sediments and to evaluate the contamination status in relation to local background values, as well as the potential release of these selected trace metals from sediments to the water environment. Sediment characteristization, including determination of fine fraction, pH, organic matter, and major elements (Al, Fe, Ca, K, Mg, and S), was carried out to investigate which parameters affect the trace metal enrichment. Fine fraction and Al contents were found to be the controlling proxies affecting the distribution of trace metals while other sediment characteristics did not show any clear influence on trace metals’ distribution. Although As concentrations in the sediments were much higher compared to its reference value in other areas, the enrichment factor based on local background values suggests minor contamination of this element as well as for Cr, Cu, and Pb. Risk assessment suggested a medium to very high risk of Mn, Zn, and Ni under acidification. Of importance is also that trace metals in sediments were not easily mobilized by organic complexation based on their low extractabilities by ammonium-EDTA extraction.

     

Geochemical behavior of metals and metalloids in an estuary affected by acid mine drainage (AMD)

The Tinto and Odiel rivers in southwest Spain drain the world’s largest sulfide mineral formation: the Iberian Pyrite Belt which has been worked since 2,500 BC. The Tinto and Odiel estuarine zones include both an extensive area of salt marsh and an intensively industrialized urban area. As a consequence of pyrite oxidation, the Tinto and Odiel rivers are strongly acidic (pH?<?3) with unusually high and quite variable metal concentrations. In this study, seasonally varying concentrations of dissolved major and trace elements were determined in the acid mine drainage affected estuary of the Ría de Huelva. During estuarine mixing, ore-derived metal concentrations exhibit excellent correlations with pH as the main controlling parameter. As pH increases, concentrations of dissolved ore-associated elements are attenuated, and this process is enhanced during the summer months. The decrease in Fe and Al concentrations ranged from 80 to 100 % as these elements are converted from dissolved to sediment-associated forms in the estuary. Coprecipitation/adsorption processes also removed between 60 and 90 % of the originally dissolved Co, Cu, Mn, Pb, Zn, and Th; however, Cd and Ni exhibited a greater propensity to remain in solution, with an average removal of approximately 60 %. On the other hand, As and U exhibited a different behavior; it is likely that these elements remain in dissolved forms because of the formation of U carbonates and soluble As species. Concentrations of As remain at elevated levels in the outer estuary (average?=?48 μg L^?1) which exceeds concentrations present in the Tinto River. Nevertheless, the estuary has recently witnessed improvements in water quality, as compared to results of several previous studies reported in the 1990s.     

Occurrence,speciation, and risks of trace metals in soils of greenhouse vegetable production from the vicinity of industrial areas in the Yangtze River Delta,China

The effect of industrial activities on trace metals in farmland of rapidly industrializing regions in developing countries has increasingly been a concern to the public. Here, soils were collected from 13 greenhouse vegetable production (GVP) farms or bases near industrial areas in the Yangtze River Delta of China to investigate the occurrence, speciation, and risks of Cr, Cu, Zn, Cd, Ni, and Pb in GVP soil. The results revealed that the main metal elements causing GVP soil pollution were Cd, Zn, Ni, and Cu, of which contamination levels were generally unpolluted to moderately polluted. Zinc pollution was mainly attributed to heavy fertilization, while Cd, Ni, and Cu pollution may be greatly ascribed to industrial effluents and coal combustion. Metal speciation studies showed that most of Cr, Ni, Cu, and Zn was present in residual fraction while more than half of Cd and Pb was present in non-residual fractions. Additionally, pollution of Cd, Cu, Ni, and Zn in GVP soil increased their corresponding mobile fractions. Risk assessment using potential ecological risk index and risk assessment code showed that Cd was the major risk contributor. Specifically, Cd generally posed moderate or considerable ecological risk as well as displayed medium or high mobility risk in GVP soil. Thus, great attention should be paid to the contribution of both industrial discharges and intensive farming to soil pollution by trace metals, especially Cd, because of its high mobility risk.

     

Analysis of essential and non-essential trace elements in the organs of a mother–fetus pair of spotted seals (Phoca largha) from the Sea of Japan

Environmental Science and Pollution Research - Concentrations of 22 essential and non-essential trace elements (Be, Al, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Mo, Ag, Cd, Sb, Ba, Tl, Pb, Th, U, and...     

Heavy metals in sediments,soils, and aquatic plants from a secondary anabranch of the three gorges reservoir region,China

We investigated the occurrence of cadmium (Cd), copper (Cu), chromium (Cr), nickel (Ni), lead (Pb), Znic (Zn), iron (Fe), manganese (Mn), and magnesium (Mg) in sediments, as well as in related soils and aquatic plants in the Liangtan River, a typical secondary anabranch of the Yangtze River in the Three Gorges Reservoir Region (TGRR) of China. We found that sediments accumulated more metals than soils and aquatic plants. Concentrations of the nine metals in sediments and soils followed the same sequence, while their concentrations in aquatic plants followed a different sequence. Potential adverse effects of contaminated sediments on benthic fauna were evaluated, and the results showed that the toxic effect on benthic organisms followed the sequence Zn?>?Ni?>?Cr?>?Cu?>?Cd?>?Pb. The potential ecological risk index analysis indicated that Cd in sediments had considerable ecological risk, whereas Cr, Cu, Zn, Ni, and Pb had low ecological risk. The potential ecological risk index (RI) of the heavy metals in sediments of the Liangtan River was 174.9, indicating moderate ecological risk. The transfer factor trend of metals for aquatic plants showed that Cd and Ni had the most and least accumulation, respectively. For Cu, Cd, Mg, Pb, and Cr, a significant positive correlation of the metal concentrations was observed between sediments and soils, but no correlations (excluding Cr) were detected between sediments and aquatic plants. Our study indicated that anthropogenic input may be the primary source of metal contamination in the Liangtan River, and that Zn and Cd pollution in the Liangtan River should be further explored.     

Dissolved trace element biogeochemistry of a tropical river, Southwestern India

River Swarna, a small tropical river originating in Western Ghats (at an altitude of 1,160 m above mean sea level) and flowing in the southwest coast of India discharges an average of 54 m³s^?1 of water into the Arabian Sea, of which significant part is being discharged during the monsoon. No studies have been made yet on the water chemistry of the Swarna River basin, even as half a million people of Udupi district use it for domestic and irrigational purposes. As large community in this region depends on the freshwater of Swarna River, there is an urgent need to study the trace element geochemistry of this west flowing river for better water management and sustainable development. The paper presents the results on the biogeochemistry of dissolved trace elements in the Swarna River for a period of 1 year. The results obtained on the trace elements show seasonal effect on the concentrations as well as behavior and thus forming two groups, discharge driven (Li, Be, Al, V, Cr, Ni, Zr, In, Pb, Bi and U) and base flow driven (groundwater input; Mn, Fe, Co, Cu, Ga, Zn, As, Se, Rb, Sr, Ag, Cd, Cs, Ba and Tl) trace elements in Swarna River. The biogeochemical processes explained through Hierarchical Cluster Analysis show complexation of Fe, Ga and Ba with dissolved organic carbon, redox control over Mn and Tl and biological control over V and Ni. Also, the water quality of Swarna River remains within the permissible limits of drinking water standards.     

Evaluation of the anthropogenic influx of metal and metalloid contaminants into the Moulay Bousselham lagoon, Morocco, using chemometric methods coupled to geographical information systems

Superficial and cored sediment samples from the Moulay Bousselham lagoon and sub-watershed were analyzed for Al, Fe, Cu, Zn, Pb, Mn, Ni, Cr, As, Hg, and Cd. The temporal and spatial distributions of the main contamination sources of heavy metals were identified and described using chemometric and geographic information system (GIS) methods. Sediments from coastal lagoons near urban and agricultural areas are commonly contaminated with heavy metals, and the concentrations found in surface sediments are significantly higher than those from 50–100 years ago. The concentrations of these elements decrease sharply with depth in the sediment column, and the elements are preferentially enriched in the <2-μm-sized fraction of the sediment. The zones of enhanced risk of heavy metals were detected by means of GIS-based geostatistical modeling. According to sediment pollution indices and statistical analysis, heavy metals (Pb, Cu, Ni, Zn, Cr, and Hg) that pose a risk have become largely enriched in the lagoon sediments during the recent period of agricultural intensification.     

Pollution status and risk assessment of trace elements in Portuguese water,soils, sediments,and associated biota: a trend analysis from the 80s to 2021

Pollution of water bodies and sediments/soils by trace elements remains a global threat and a serious environmental hazard to biodiversity and human’s health. Globalization and industrialization resulted in the increase and availability of these substances in the environment posing unpredictable adverse effects to living organisms. To determine pollution status and risk contamination by trace elements, data available in the literature of the last 40 years on trace elements occurrence in three environmental matrices (water bodies, sediments/soils, and biota) from Continental Portugal were collected (about 90 studies). Data were compared to water and sediment quality guidelines to assess potential ecological risks. Most environmentally relevant hazardous elements include Zn, Cu, Cd, Pb, and As. Various studies found trace elements at levels higher than those considered safe by environmental guidelines. In surface waters, Al, Zn, Se, and Ag were found above aquatic life limits in about 60% of the reviewed papers, while Cu, Zn, and As exceed those values in more than 60% of mining waters. Hg and Cd in sediments from mining areas exceeded aquatic life limits and potential ecological risk showed extremely high risk for most of the elements. The data compiled in this review is very heterogenous, varying in terms of sampling schemes, trace elements analysed, and spatiotemporal settings. This heterogenicity leads to data differences that make meaningful comparisons difficult. Nevertheless, the compilation of scattered environmental spatial and temporal trace elements data, of either natural sources or human activity as well as the ultimate effect on biological systems, is of the upmost importance to broaden its knowledge, risk assessment, and implementation of mitigation measures.

     

Metal accumulation in the smooth toadfish, Tetractenos glaber, in estuaries around Sydney, Australia

This study determined the metal levels in sediments and tissues of a common estuarine fish, Tetractenos glaber (smooth toadfish), from two metal contaminated and two reference estuaries near Sydney, Australia. Metal levels were highest in sediments and fish from contaminated estuaries. Gonads contained the highest metal levels followed by muscle, gill and liver. Metal accumulation was gender-dependant (e.g. male gonads were >20 times higher in As than females; female gills were >30 times higher than males for Pb). Cadmium, Pb and Ni levels in fish tissues reflected sediment levels, indicating sediment and/or dietary metal uptake. Levels of As, Co, Cd & Pb in gills showed similar patterns to other tissues, suggesting that metals may have been taken up by gills through contaminated water. Similar metal patterns in tissues and sediments suggest more than one uptake pathway. This study indicates that multiple factors influence metal accumulation in fish.     

Analytical methods and validation for determining trace elements in red wines

The objective of this work is to quantify As, Hg, Cd, Ni and Pb in Portuguese red wines. First, the methods for the quantification of trace elements in red wines were validated. Several pre-treatments were compared, namely a pre-digestion process with HNO₃, a pre-oxidation step with H₂O₂, and a spiking step of wine samples with a known concentration of the trace elements analyzed. Except for As, it was determined that the quantification of the trace elements does not require a pre-digestion process with HNO₃. For all of the trace elements analyzed, a pre-oxidation step with H₂O₂ may enable an accurate quantification. The techniques chosen for the quantification of trace elements were hydride generation atomic absorption spectrometry (HGAAS) for As and Hg, electrothermal atomic absorption spectrometry (ETAAS) for Cd, and flame atomic absorption spectrometry (FAAS) for Ni and Pb. In the second stage of this work, 25 Portuguese red wines spanning all of the red wine-producing regions were analyzed for all of the five trace elements referred to above. Only Cd and Pb have shown concentrations above the limit values defined by the “Organization Internationale de la Vigne et du Vin.” The Target Hazard Quotient (THQ) equation was used to determine in which wine-producing regions that wine consumption can be a problem for public health in terms of the concentrations of the five trace elements analyzed. THQ values have indicated that for the universe of the 25 red wines analyzed no region produces wines that can pose problems for public health, when the Portuguese red wine standard consumption is considered.     

Heavy metal concentrations in molluscs from the Atlantic coast of southern Spain

Trace metals were determined in the two most abundant species of bivalve molluscs along the Atlantic coast of southern Spain (Donax trunculus and Chamelea gallina) and in the sediments where they live. The results show that the area near the mouth of the Huelva estuary is where the highest metal concentrations are found in sediments and in the two bivalve species. This is not surprising, considering that the Huelva estuary is the mouth of the Tinto and Odiel rivers, which have one of the highest levels of metal pollution of all the rivers of Europe. The two species of bivalves have different amounts of metals in their tissues. The concentrations of Cr, Cu, Pb, Zn, As and Hg in D. trunculus were significantly higher (p < 0.05) than in C. gallina; however, C. gallina contained more Ni and Cd. In both species the most abundant elements were Cu and Zn, while Hg showed the lowest values. There is a significant correlation (p < 0.05) for concentrations of Cu, Pb, Zn and Hg in D. trunculus and C. gallina relative to their concentrations in surface sediments.     

Trace element contaminants in mineral fertilizers used in Iran

The application of mineral fertilizers which have contaminants of trace elements may impose concern regarding the entry and toxic accumulation of these elements in agro-ecosystems. In this study, 57 mineral fertilizers (nitrogen, potassium, phosphate, and compound fertilizers) distributed in Iran were analyzed for their contents of Cd, Co, Cr, Cu, Mn, Ni, Pb, Zn, and Fe. The results revealed that the contents of these trace elements varied considerably depending on the type of the element and the fertilizer. Among these elements, Fe displayed the highest average content, whereas Cd showed the lowest. Generally, the trace element contents in P-containing fertilizers were higher than those in nitrogen and potassium fertilizers. The mean values of trace elements (mg kg^?1) in P-containing fertilizers were 4.0 (Cd), 5.5 (Co), 35.7 (Cr), 24.4 (Cu), 272 (Mn), 14.3 (Ni), 6.0 (Pb), 226 (Zn), and 2532 (Fe). Comparing trace element contents to limit values set by the German Fertilizer Ordinance showed that the mean contents of potentially toxic trace elements, such as Cd and Pb, were lower than their limit values in all groups of fertilizers. On the other hand, while a number of fertilizers contained a high content of some essential trace elements, particularly Fe, they were not labeled as such.