A feasible approach to measure metal concentrations in drill hole waters on site for mineral exploration

Variation in metal concentrations across a large contamination gradient is reflected in stream but not linked riparian food webs

Heavy metal concentrations in surface waters of Hurghada and environs, Red Sea Coast, Egypt, and their correlation with sediment distribution

Distribution of metals in different environmental compartments and oxidative stress biomarkers in Bryconops caudomaculatus (Osteichthyes: Characiformes) from a bauxite mining area in the Eastern Amazon

Submerged macrophytes have an ability to absorb metals and metalloids either from the sediments via the roots, from the water by the leaves, or from both sources. The objectives of this study were (1) to test the hypothesis that metal and metalloid concentrations in water and sediments from sampling sites with submerged macrophytes are significantly lower than those from sampling sites without submerged macrophytes, (2) to explore the accumulation potential for metals and metalloids of different submerged macrophyte species, and (3) to discuss the relationships among submerged macrophytes, water, and sediments in the Yunnan Plateau lakes. Twenty Yunnan Plateau lakes with different trophic levels were selected. Concentrations of 16 metals and metalloids (Al, As, Ba, Cd, Co, Cr, Cu, Fe, Li, Mn, Mo, Ni, Pb, Se, Sr, and Zn) in submerged macrophytes, water, and sediments were determined by using ICP-AES. Relationships among metal and metalloid concentrations in water, sediments, and submerged macrophytes were carried out by Pearson correlation analysis. The enrichment factor was calculated as the ratio between the concentration of metals and metalloids in a sediment sample and the soil background value. No significant differences were found in metal and metalloid concentrations in water and sediments between sampling sites with submerged macrophytes and sampling sites without submerged macrophytes. Moreover, lake water and sediments were mainly contaminated by As, Cr, and Pb. Potamogeton distinctus is a hyperaccumulator of Fe according to the threshold value for Fe hyperaccumulation. Many significantly positive correlations were found among metals and metalloids in submerged macrophytes due to co-accumulation. We found significant correlation between Cr in submerged macrophytes and Cr in water, and strong positive correlations between As, Cd, and Cu in submerged macrophytes and As, Cd, and Cu in corresponding sediments in the Yunnan Plateau lakes. Submerged macrophytes have no significant effects on metal and metalloid concentrations in sediments and water in all the 20 Yunnan Plateau lakes in the study. However, further studies are necessary to understand the interactions of metals and metalloids in submerged macrophytes, water, and sediments.

Lake Burullus is an important source of fish production in Egypt; it produces 20.5% of the Egyptian fisheries' production. There is intense controversy about the heavy metal pollution in Burullus water and its effects on fish health and safety for human consumption. Heavy metals represent a major concern for aquatic life and could negatively affect fish health. Agricultural and industrial water drainage represents a considerable part of the lake water supply. The present work was conducted to determine heavy metal concentrations in lake water and blue tilapia Oreochromis aureus musculature. Water samples were collected from six locations to determine cadmium, copper, lead, zinc and iron. Sixty O. aureus fish samples were also collected from the same sampling points to assess the prevalent parasites infesting fish and to determine the heavy metal (Cd, Cu, Pb, Zn and Fe) concentrations in fish musculature then study the relationship between heavy metals concentration and prevailing fish parasites. Results indicated that 53.34% of the examined fish were infested with encysted metacercaria. Centrocestus formosanus, Prohemistomum vivax, and Euclinostomum heterostomum were retrieved from gills, musculature, hepatopancreas and the posterior kidney. The parasitic intensity in fish tissues was between 1 and 9 cystg-1. Centrocestus formosanus was identified using the polymerase chain reaction in the gill tissues of 16 fish. The gill parasitic copepod Lamproglena monodi was identified in one fish. Degenerative changes such as thickening, corrugation, and destruction of gill filament are the most dominant pathological changes in infested fish gills. Heavy metal concentrations in water samples were at normal levels, except for copper and iron in the southern part of the lake. All heavy metals in fish musculature were below the permissible limits. The parasitic infestation was more dominant in the northern part of the lake than in the southern region; this could be due to elevated copper concentration in the southern part of the lake that could negatively affect the survival of the first intermediate host and parasite cercaria. In conclusion, captured fish from Lake Burullus were safe for human consumption, and heavy metal pollution in lake water does not represent a severe risk.

To investigate the changes in heavy metal content in the sub glacial water during the freezing and thawing process of seasonally frozen lakes, the Wuliangsuhai Lake in northern China was taken as the research object. The ice thickness, water depth, and heavy metal content at different depths of the lake were measured during the freezing and thawing periods. Based on a large amount of measured lake heavy metal data, MATLAB 2022b software is used to model data fitting and optimization identification, and wavelet analysis and 24 h sliding average method are used for verification analysis to describe the variation process of heavy metal concentration in ice water with depth and time. The results show that during the freezing and thawing periods of lakes, the water level is constantly changing, but the heavy metal content in the water below the ice follows the same distribution with water depth. During the freezing process, the heavy metal content in the water increases with the increase in ice thickness. A new numerical model describing the spatiotemporal distribution of heavy metals under the ice during the freezing period of the lake was obtained through calculation. The overall trend of the simulated contour lines is consistent with the measured values and has a small error. This study provides a reference for predicting the changes in heavy metal content under the ice cover during the freezing period in cold and arid regions. The model can be used to simulate the content values of heavy metals at different depths and times.

Anthropogenic activities influence the natural equilibrium of freshwater ecosystems resulting in negative ecological impacts. Differences in the infection variables of Lamproglena clariae in relation to variable water quality influenced by metal pollution were studied at six sites along the Vaal River, South Africa (March 2017 and October 2018). From each sampling site, in situ water quality parameters, water and sediment samples, and a minimum of 10 Clarias gariepinus were collected. Lamproglena clariae specimens collected from the gills of C. gariepinus were used to calculate the prevalence, mean intensity, and mean abundance of the parasite. Metal concentrations in water and sediment were analysed with inductively coupled plasma-optical emission spectrometry and inductively coupled plasma-mass spectrometry. Parasite intensity correlated negatively with some water quality parameters (conductivity, salinity, pH, total dissolved solids, and dissolved oxygen). Negative correlations were found between L. clariae (intensity and prevalence) and metal concentrations (Cu, Cr, Zn, Cd) in water. Parasite infections were influenced negatively at sites with high metal concentrations recorded in sediment and water and high levels of organic pollution. Sites that were found to be more polluted had lower mean intensity and mean abundance of L. clariae, indicating pollution affects the survival of this ectoparasite.

Heavy metals are potentially toxic to organisms causing lethal and sub lethal effects. Above threshold levels, these metals have been shown to adversely affect both aquatic and terrestrial organisms. Human health may also be impacted negatively through consumption of metal-contaminated foods and water. Lake Naivasha, Kenya, like many freshwater bodies in developing countries is a source of fish and water for human consumption in Naivasha town and its environs. Ironically, the lake receives untreated floricultural, agricultural and industrial effluents from its catchment area. In the recent past, there have been unconfirmed reports that fish from this lake are contaminated with heavy metals mainly Cu, Hg, Cd and Pb to levels that are harmful to humans. It is against this background that this study was conducted to determine the sources of the aforementioned heavy metals in the lake, their concentrations in water and sediments and in common carp (<em>Cyprinus carpio</em>) that constitutes a major portion of the Lake Naivasha fishery. Water, sediment and fish samples were collected from purposefully selected sites in six sampling occasions during both the dry and wet seasons. Analyses for heavy metals in fish, sediment and water samples were done using an Atomic Absorption Spectrophotometer (AAS). The study findings indicate that the heavy metal concentrations in the water and sediments collected from impacted sites were significantly higher (p<0.05) compared to those from unexpected sites. In spite of this, the metal concentrations in water were significantly lower than those recommended by the WHO and USEPA as drinking water guideline values. Metal concentrations in <em>C. carpio</em> were also significantly lower (p<0.05) than the World Health Organization (WHO) recommended levels for fish intended for human consumption. Based on these findings, it is safe to conclude that drinking water and fish collected from Lake Naivasha do not pose immediate health risks to human health. Despite this observation, we recommend continuous monitoring of heavy metal concentrations in water and sediment in the lake given their potential for bioaccumulation and biomagnifications and likely adverse effects on aquatic organisms and humans.

Water from 15 sampling stations in Tasik Chini (Chini Lake), Peninsular Malaysia were sampled for 12 months from September 2004 until August 2005 and analyzed for 11 metals including iron (Fe), aluminum (Al), manganese (Mn), barium (Ba), zinc (Zn), lead (Pb), copper (Cu), cadmium (Cd), nickel (Ni), chromium (Cr) and cobalt (Co). Results showed that the mean (min-max) metal concentrations (in micrograms per liter) in Tasik Chini waters for the 12 months sampling based on 15 sampling stations (in descending order) for Fe, Al, Mn, Ba, Zn, Pb, Cu and Cd were 794.84 (309.33-1609.07), 194.53 (62.37-665.93), 29.16 (16.68-79.85), 22.07 (15.64-29.71), 5.12 (2.224-6.553), 2.36 (1.165-4.240), 0.832 (0.362-1.443) and 0.421 (0.254-0.696) respectively. Concentration for three metals i.e. Ni, Cr and Co were too low and not detected by the graphite furnace Atomic Absorption Spectrophotometry (AAS). Comparison with various water quality standards showed that the mean metals concentration in surface water of Tasik Chini were low and within the range of natural background except for Fe and Al. In general, metal concentrations in Tasik Chini water varied temporally and spatially. The main factors influencing these metal concentrations in the water were the raining season and mining activities. Stations located at Tanjung Jerangking and Melai areas were the most effected due to those factors.

Heavy-metal pollution assessment in the coastal lagoons of Jacarepaguá, Rio de Janeiro, Brazil

Metal concentrations in water and sediments from tourist beaches of Acapulco, Mexico

Concentrations of Al, Fe, Cr, Cu, Ni, Pb and Zn in soils, sediments and water samples collected along the Oued Boufekrane river (Meknes, central Morocco) were determined. In soils, a homogeneous distribution of metal concentrations was observed throughout the study area except for Pb, which presents high enrichment at sites located at the vicinity of a main highway. In sediments, high enrichment, with respect to upstream sites, were observed downstream of the city of Meknes for Al, Cr, Fe and Ni and inside the city for Cu, Zn and Pb. In water samples, the metal contents showed to correlate with their homologues in sediments suggesting that the metal contents in water and sediments have identical origins. Descriptive statistics and multivariate analysis (principal factor method, PFM) were used to assist the interpretation of elemental data. This allowed the determination of the correlations between the metals and the identification of three main factor loadings controlling the metal variability in soils and sediments.

The Esmoriz-Paramos is a lagoon of great ecological significance located on the Northwest coast of Portugal. The quality of water and sediment within this ecosystem has been gradually degraded due to the discharges of mostly untreated industrial waste and domestic sewage. Contaminants include heavy metals that can be taken up by fish from water, food, sediments, and suspended particulate material. Fish inhabiting polluted water bodies tend to accumulate many chemicals in high concentrations, even when the environmental contamination levels are low (Colombo et al. 1995). The leaping grey mullet (Liza saliens) is one of a few dominant species living in this environment. This species may contact xenobiotics in the water column or, when feeding, in the sediments. Previous studies have analyzed heavy metal concentrations in the water and sediments of this lagoon, and evaluated their bioaccumulation in L. saliens (Fernandes et al. 2007a, b). According to these studies, the seasonal range of metal concentrations in surface water was 0.003–0.031 mg Cu L, 0.006–0.811 mg Zn L and 0.01–0.026 mg Pb L, all mainly found in particulate matter. The main metals found in sediments were Cu, Zn and Pb, respectively 83, 241 and 87 mg kgd.w. The Cu and Zn concentrations in L. saliens liver were 262 and 89 mg kgd.w. and below the detection limit for Pb (0.073 ppm), whereas these concentrations in the gill were 9 mg Cu kg d.w.; 114 mg Zn kg d.w. and 0.6 mg Pb kg d.w. Also, significant age-related increase of metal concentrations in tissues, were noted, for Zn in gill and for Cu in liver and gill (Fernandes et al. 2007a). The gill is particularly sensitive to physical and chemical changes in the aquatic environment and it is the main target organ in fish for toxic waterborne heavy metals (McDonald and Wood 1993). Effects of metals on ionoregulatory gill functions have been well demonstrated, including regulation of plasma electrolytes (Mazon et al. 2002; Grosell et al. 2003; Martinez et al. 2004). The histological effects of metals on fish gill have also been studied in several fish species (Arellano et al. 1999; De Boeck et al. 2001). The mechanisms of acute Cu toxicity include the osmoregulatory disturbances involving Na, Cl and K uptake by the gill (Mazon et al. 2002; Grosell et al. 2003). Although the mechanisms of heavy metals toxicity are well known in acute exposure, the process may differ in chronic exposure (Handy 2003). The objectives of this study were to evaluate the plasma electrolyte concentrations of wild Liza saliens from the Esmoriz-Paramos lagoon and to assess the osmoregulatory responses and branchial histopathological changes related to chronic heavy metal exposure in this habitat.

This study aimed to investigate nine heavy metal concentrations (As, Cd, Cr, Pb, Cu, Fe, Zn, Mn and Ni) in water, sediment and snakehead fish (Channa striata) and to identify abnormal chromosomes in C. striata from a reservoir near an industrial factory and a reference area. Heavy metal concentrations were measured by inductively coupled plasma optical emission spectrometry (ICP-OES). The metal concentrations in the water, sediment and C. striata samples did not exceed the standard limit of Thailand, except for Cr concentrations, which exceeded water quality standards. The concentrations of Cd, Fe, Mn and Ni in C. striata samples between the reservoir and the reference area were significantly different (p < 0.05). The diploid chromosome number of C. striata from both areas was (2n = 42). Eight types of abnormal chromosomes were identified and classified as a single-chromatid gap, a single-chromatid break, centric fragmentation, a centric gap (CG), fragmentation, deletion, single-chromatid decomposition and iso-arm fragmentation. The most frequent abnormal chromosome in the samples was CG. The percentages of abnormal chromosomes in the C. striata samples from the reservoir near the industrial factory and the reference area were significantly different (p < 0.05) at 8.44 and 1.20, respectively.

Suspended particles in rivers can act as carriers of potentially bioavailable metal species and are thus an emerging area of interest in river system monitoring. The delineation of bulk metals concentrations in river water into dissolved and particulate components is also important for risk assessment. Linear relationships between bulk metal concentrations in water (CW,tot) and total suspended solids (TSS) in water can be used to easily evaluate dissolved (CW, intercept) and particle-bound metal fluxes (CSUS, slope) in streams (CW,tot = CW + CSUS TSS). In this study, we apply this principle to catchments in Iran (Haraz) and Germany (Ammer, Goldersbach, and Steinlach) that show differences in geology, geochemistry, land use and hydrological characteristics. For each catchment, particle-bound and dissolved concentrations for a suite of metals in water were calculated based on linear regressions of total suspended solids and total metal concentrations. Results were replicable across sampling campaigns in different years and seasons (between 2013 and 2016) and could be reproduced in a laboratory sedimentation experiment. CSUS values generally showed little variability in different catchments and agree well with soil background values for some metals (e.g. lead and nickel) while other metals (e.g. copper) indicate anthropogenic influences. CW was elevated in the Haraz (Iran) catchment, indicating higher bioavailability and potential human and ecological health concerns (where higher values of CSUS/CW are considered as a risk indicator).