Importance of background values in assessing the impact of heavy metals in river ecosystems: case study of Tisza River, Serbia

Temporal assessment of water and soil quality near Barapukuria coal mine, Bangladesh

This study assessed the water suitability for various purposes, evaluated heavy metal contamination and soil fertility, and investigated seasonal variations in water and soil parameters near the Barapukuria coal mine in Bangladesh. A total of nine sampling locations were selected, resulting in 18 samples (12 water and 6 soil) collected during the summer and winter seasons. The water samples were analyzed at the Environmental Engineering Laboratory, while the soil samples were analyzed at the Soil Resource Development Institute (SRDI). The suitability of drinking water was evaluated using the Water Quality Index (WQI), and heavy metal contamination was assessed using the geo-accumulation index. The findings indicate that surface water is generally suitable for irrigation due to several positive attributes, with slight to moderate seasonal variations. However, treatment is required for high turbidity and chemical oxygen demand (COD). On the other hand, wastewater quality exhibits elevated levels of turbidity, total suspended solids, and chemical oxygen demand, although most parameters are within acceptable limits. The assessment of drinking water quality using the WQI reveals that both hand and deep tubewells are generally unfit for consumption. The WQI values peak at 441.84 in summer and 202.79 in winter for the hand tubewell, and 129.66 in summer and 95.88 in winter for the deep tubewell. This finding emphasizes the need for effective treatment and continuous monitoring. The soil analysis indicates that most heavy metals are not present in significant amounts, except for cadmium, which shows uncontaminated to moderately contaminated conditions during the summer. Moreover, the soil treated with coal water exhibits significantly higher levels of organic matter, micronutrients, and macronutrients compared to the normal field soil. Further analysis of the coal water treated soil shows a shift from a slightly acidic pH in summer (6.30) to a neutral pH in winter (7.10). The organic matter content remains consistently high, and nutrient analysis shows high to very high levels of Zn, Cu, K, Ca, Mg, Mn, and Fe, while phosphorus remains low. Seasonal analysis reveals increased levels of zinc, potassium, and phosphorus in winter, whereas other nutrients generally decrease. The primary novel contribution of this study is the detailed seasonal analysis of water and soil quality near the coal mining area, capturing changes across summer and winter. Additionally, it compares coal water treated soil with normal field soil, revealing significant improvements in soil quality and fertility.

Origin, spatial distribution, sediment contamination, ecological and health risk evaluation of trace metals in sediments of ship breaking area of Bangladesh

Eleven trace metals (Cd, Cr, Fe, Mn, Cu, Ni, Co, Zn, As, Pb, and Ag) in sediments of Bangladesh's ship breaking area were measured by an atomic absorption spectrometer to determine origin, contamination extent, spatial distributions, and associated ecological and human health hazards. This study found considerable quantities of Pb, Cd, Mn, Zn, and Cu when compared with standards and high levels of Pb, Cd, Zn, Cu, As, and Ag contamination according to pollution evaluation indices. Different indices indicate most of the sampling sites were highly polluted. However, spatial distribution maps indicate that trace metals were predominantly deposited in the northern and southern region. The ecological risk index revealed that Cd has the highest while Pb and As had moderate risk. Based on the health index values, Zn for both adults and children were higher than the safe limit while Mn, Pb, Cr, As, Fe, Cu, Ni, and Co for children were close to the threshold. The mean total carcinogenic risk values of Cr, As, and Ni for children and Ni for adults exceeded the permissible threshold. The cancer risk possibilities were further assessed using Monte Carlo simulation. Most trace metals have anthropogenic origins, which were attributed to ship breaking activities.

Distribution of potentially toxic elements in soils and sediments in Pearl River Delta, China: Natural versus anthropogenic source discrimination

Although anthropogenic contamination has been regarded as the most important source of potentially toxic elements (PTEs) in soils of large river delta plains, the extent to which human activities affect PTEs in soils is worth exploring. This study used high density geochemical data to distinguish source patterns of PTEs in soils of the Pearl River Delta Economic Zone, a large industrialized and urbanized area in China. Enrichment factor, discriminant analysis, principal components analysis, cumulative distribution function, and positive matrix factorization were used to identify sources of PTEs in soils. The results indicated that parent material was the most significant factor affecting geochemical characteristics of PTEs in soils. Median concentrations of Cd, Cr, Cu, Hg, Pb, and Zn were 0.400, 88.5, 40.5, 0.143, 43.0, and 116.0 mg/kg for stream sediments, 0.333, 75.7, 39.0, 0.121, 42.6, and 98.5 mg/kg for deep soils, and 0.365, 74.0, 45.1, 0.143, 44.6, and 119.5 mg/kg for surface soils, respectively, all of which exceed relevant reference standards. Compared with stream sediments and deep soils, surface soils exhibit substantial concentrations of PTEs. Chemical weathering and erosion of parent materials distributed in the Pearl River Delta were the main sources of PTEs in soils. Diffuse contamination and many small local contamination sources distributed throughout the study area were the most significant anthropogenic sources of PTEs in surface soils. Intensive human activities failed to change the soil geochemical characteristics derived from the parent material at the regional scale. However, it could induce non-point source pollution and local severe PTEs pollution in surface soils.

Improved Method of Background Value Determination for Sb and Cd in Freshwater Sediment-Insights from Controlling Factors on Spatial Variability

Variability in the distribution of natural total Sb and Cd in freshwater sediments leads to difficulties in background value (BV) determination. This study aimed to establish a method to determine BV more accurately by investigating the vertical distribution of Sb and Cd in sediment cores collected from a typical river in alluvial plain in China and revealed the factors that control the variation of Sb and Cd BV, which has not been studied in alluvial freshwater sediment. The results suggested that uncontaminated samples for BV calculation should be determined by statistical analysis as human and natural disturbance led to high variation in contamination depth, from <5 cm to >55 cm. The sequential chemical extraction method showed a considerable amount of non-residual fractions of Sb and Cd, which accounted for 48% and 43% of the total, respectively. Acid extractable Cd (16%) was associated to the limestone geology in the area. Fine particles which governed by sedimentary environment contained more natural Sb and Cd, as strong positive correlation was found between clay content and Sb concentration (r = 0.89, p < 0.01), as well as Cd concentration (r = 0.54, p < 0.01). Based on these findings, a method combined with standard deviation and geochemical method was established to calculate the BV of Sb and Cd, and counter maps were made to cover the variation of BV in the Taipu river sediment. The pollution level has been evaluated by the geoaccumulation index more accurately.

Levels and ecological risk of heavy metals in the surface sediments of tidal flats along the North Jiangsu coast, China

We investigated the contamination levels of nine heavy metals (Mn, Pb, V, Cr, Co, Ni, Cu, Zn, and As) in 153 surface sediment samples collected along five tidal flats on the North Jiangsu coast, China. The spatial distributions of most heavy metals gradually decreased from the northern Sheyang region to the southern Jianggang region, while slightly increasing in the Rudong region. Principal component analysis indicated that Co, Ni, Cu, Zn, and As were mainly derived from the natural environment, V and Cr were mainly derived from human activities. Additionally, Mn and Pb influenced by both natural and human sources. The geo-accumulation index and the contamination factor indicated that heavy metal contamination in the sediments exhibited little to no pollution levels. The potential ecological risk index exhibiting low ecological risks. Meanwhile, the mean probable effect level quotient values indicating slight toxicity. Cr and Ni were the major contributors to toxicity.

Distribution and provenance of heavy metals in sediments of the Vrbas River, Bosnia and Herzegovina

Heavy metals are naturally occurring elements, but they are regarded as significant environmental pollutants due to their high density and high toxicity even at low concentrations. The aim of this paper is the evaluation of the pollution level of heavy metals in the river and riverbank sediments, as well as the estimation of their origin and spatial differences along the course of the Vrbas River through Banja Luka. The concentrations of metals have been assessed using the Inductively coupled plasma ? optical emission spectrometry and Advanced mercury analyzer for mercury determination. The anthropogenic impact on heavy metal concentration in sediments was estimated by the calculating of pollution indices: geoaccumulation index (Igeo), contamination factor (Cf), pollution load index (PLI) and potential ecological risk index (Er). Obtained results indicate that there is no statistically significant spatial difference in metal concentration, indicating that heavy metals in sediments have a constant source. The anthropogenic impact expressed by the values of pollution indices showed that sites are generally uncontaminated by Co, Cr and V and moderately contaminated by Zn, Cu and Ni. On the contrary, lead, mercury and cadmium pose the highest ecological risk. The anthropogenic source of Pb, Hg and Cd is industry, municipal waste and the combustion of fossil fuels. The obtained results demonstrate the high ecological risk and the need for environ-mental monitoring, with the aim to support an efficient strategy to reduce local pollution and contamination of the investigated system.

The contents of the potentially harmful elements in the arable soils of southern Poland, with the assessment of ecological and health risks: a case study

Agricultural soil samples were collected from the areas where edible plants had been cultivated in southern Poland. The PHE content decreased in proportion to the median value specified in brackets (mg/kg d.m.) as follows: Zn (192) > Pb (47.1) > Cr (19.6) > Cu (18.8) > Ni (9.91) > As (5.73) > Co (4.63) > Sb (0.85) > Tl (0.04) > Cd (0.03) > Hg (0.001) > Se (< LOQ). No PHE concentrations exceeded the permissible levels defined in the Polish law. The PHE solubility (extracted with CaCl2) in the total concentration ranged in the following order: Fe (3.3%) > Cd (2.50%) > Ni (0.75%) > Zn (0.48%) > Cu (0.19%) > Pb (0.10%) > Cr (0.03%). The soil contamination indices revealed moderate contamination with Zn, ranging from uncontaminated to moderately contaminated with Pb, and, practically, no contamination with other PHEs was identified. The ecological risk indices revealed that soils ranged from uncontaminated to slightly contaminated with Zn, Pb, As, Cu, and Ni. The PCA indicated natural sources of origin of Co, Cu, Hg, Sb, Zn, Cr, and Pb, as well as anthropogenic sources of origin of Cd, Ni, As, and Tl. The human health risk assessment (HHRA) for adults and children decreased in the following order of exposure pathways: ingestion > dermal contact > inhalation of soil particles. The total carcinogenic risk values for both adults and children were at the acceptable level under residential (1.62E-05 and 6.39E-05) and recreational scenario (5.41E-06 and 2.46E-05), respectively, as well as for adults in agricultural scenario (1.45E-05). The total non-carcinogenic risk values for both adults and children under residential scenario (1.63E-01 and 4.55E-01, respectively), under recreational scenario (2.88E-01 and 6.69E-01, respectively) and for adults (1.03E-01) under agricultural scenario indicated that adverse health effects were not likely to be observed. Investigated soils were fully suitable for edible plant cultivation.

Assessment of heavy metal contamination in surface sediments along the Mediterranean coast of Morocco

In this paper, heavy metal contamination in surface sediments along the Mediterranean coast of Morocco was investigated. Determining pollution degree as well as heavy metal origins were the main objectives of this investigation. For this reason, concentrations of nine heavy metals (Cd, Cu, Cr, Ni, Pb, Zn, Hg, Fe, and Mn) were analyzed at ten stations sampled during three different periods. The obtained concentrations showed significant variation between sampling periods, which was controlled by several environmental and chemical processes. According to contamination indices results using pollution load index (PLI), modified contamination degree (mC_d), geoaccumulation index (I_geo), enrichment factor (EF), and potential ecological risk index (RI), sampling stations were classified between uncontaminated and strongly contaminated without detecting any intense heavy metal pollution in surface sediment. Likewise, the EF values were comprised between no enrichment and moderate to severe enrichment. According to sediment quality guidelines, the calculated M-ERM-Q indicated that heavy metal mixtures have between 9 and 49% probability for being toxic. This result revealed lowest to medium-low potential of adverse effects to biota populations. Regarding heavy metal origins, multivariate statistical investigation showed that Cd, Cu, Hg, Pb, and Zn are derived mainly from anthropogenic activities, while Fe, Mn, Cr, and Ni were derived from natural sources. Despite Cd is considered as a typical anthropogenic metal, the very low concentrations obtained in this study support the involvement of natural factor in the enrichment with this metal. Therefore, the surface sediments contamination along the Mediterranean coasts of Morocco is particularly caused by a combination of anthropogenic and natural factors. As a result, the study area can be considered as not significantly enriched by human activities.

Water Quality in Surface Water: A Preliminary Assessment of Heavy Metal Contamination of the Mashavera River, Georgia

Water quality contamination by heavy metal pollution has severe effects on public health. In the Mashavera River Basin, an important agricultural area for the national food system in Georgia (e.g., vegetable, dairy and wine production), water contamination has multiple influences on the regional and country-wide health. With new industrial activities in the region, sediment extraction, and discharge of untreated wastewater into the river, its tributaries and irrigation canals, a comprehensive study of water quality was greatly needed. This study examined sediment and water samples from 17 sampling sites in the Mashavera River Basin during the high and low precipitation seasons. The results were characterized utilizing the Geo-accumulation Index (I_geo), Enrichment Factor (EF), Pollution Load index (PLI), Contamination Factor (CF) and Metal Index (MI). According to the CFs, Cu > Cd > Zn > Pb > Fe > Mn > Ni > Cr > Hg is the descending order for the content of all observed heavy metals in sediments collected in both seasons. Fe and As were additionally examined in water samples. Overall, As, Cd and Pb, all highly toxic elements, were found in high concentrations in downstream sample sites. According to these results, comprehensive monitoring with narrow intervals between sampling dates, more sample sites along all waterways, and proximate observation of multiple trace metal elements are highly recommended. Moreover, as the part of the water quality governance system, an immediate and sustainable collective action by all stakeholders to control the pollution level is highly recommended, as this issue is linked to the security of the national food system and poses a local public health risk.