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The silver deposits located in the upper basin of the Felent Stream are currently the largest producing mine in the Türkiye. It is also significantly impacted by industrial, agricultural, and thermal spring-related waste in Kütahya Province. The main objectives of this study were to examine the spatiotemporal variations of 12 dissolved potentially toxic elements (PTEs) in the surface water of Felent Stream, to identify their possible sources, and to assess their probable risks. As a result of this study, among investigated PTEs, the highest mean concentrations of 3592-14,388 µg/L for Mg and the lowest of 0.15-0.19 µg/L for Cd were noted in Felent Stream water. The average concentrations of PTEs were found in the order of Mg > Ca > Na > As > Mn > B > Zn > Ni > Cu > Pb > Cr > Cd. Remarkably, during the dry season, there was a conspicuous escalation in the average PTEs contents of water, with an approximately multifold amplification. PTEs in stream water were evaluated for their potential ecotoxicological risks and possible sources. Based on ecological risk assessment indices, the stream exhibited low pollution levels during the wet season but displayed elevated pollution levels during the dry season, indicating a general shift towards heightened pollution conditions. The hazard index (HI) data for As exhibited significant potential noncarcinogenic risks across all monitoring stations. Conversely, the carcinogenic risk (CR) data underscored the imperative nature of addressing the health risks associated with As in the waters of the studied region. Mining activities were identified as the primary origin of PTEs based on principal component analysis (PCA). Moreover, upstream regions, proximal to the mining site, emerged as the most heavily contaminated areas according to cluster analysis (CA)., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Potentially toxic elements (PTEs), especially arsenic in drinking water, pose significant global health risks, including cancer. This study evaluates the groundwater quality in Giresun province on the Black Sea coast of Türkiye by analyzing twelve groundwater resources. The mean concentrations of macronutrients (mg/L) were: Ca (10.53 ± 6.63), Na (6.81 ± 3.47), Mg (3.39 ± 2.27), and K (2.05 ± 1.10). The mean levels of PTEs (µg/L) were: Al (40.02 ± 15.45), Fe (17.65 ± 14.35), Zn (5.63 ± 2.59), V (4.74 ± 5.85), Cu (1.57 ± 0.81), Mn (1.02 ± 0.76), As (0.93 ± 0.73), Cr (0.75 ± 0.57), Ni (0.41 ± 0.18), Pb (0.36 ± 0.23), and Cd (0.10 ± 0.05). All PTE levels complied with WHO drinking water safety guidelines, and overall water quality was excellent. The heavy metal evaluation index (HEI < 10) and heavy metal pollution index (HPI < 45) indicate low pollution levels across all stations. Irrigation water quality was largely adequate, as shown by the magnesium hazard (MH), sodium adsorption ratio (SAR), Na%, and Kelly's ratio (KR). The total hazard index (THI) values consistently remained below 1, indicating no non-carcinogenic health risks. However, at station 10 (city center), the cancer risk (CR) for adults due to arsenic was slightly above the threshold (1.44E-04). Using principal component analysis (PCA), positive matrix factorization (PMF), and geographic information system (GIS) mapping, the study determined that most PTEs originated from natural geological formations or a combination of natural and human sources, with minimal impact from human activities. These findings highlight the safety and reliability of the groundwater sources studied, emphasizing their potential as a long-term, safe water supply for nearby populations., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Water scarcity is a growing concern due to rapid urbanization and population growth. This study assesses spring water quality at 20 stations in Giresun province, Türkiye, focusing on potentially toxic elements and physicochemical parameters. The Water Quality Index rated most samples as "excellent" during the rainy season and "good" during the dry season, except at stations 4 (40° 35' 12″ North/38° 26' 34″ East) and 19 (40° 44' 28″ North/38° 06' 53″ West), indicating "poor" quality. Mean macro-element concentrations (mg/L) were: Ca (34.27), Na (10.36), Mg (8.26), and K (1.48). Mean trace element values (μg/L) were: Al (1093), Zn (110.54), Fe (67.45), Mn (23.03), Cu (9.79), As (3.75), Ni (3.00), Cr (2.84), Pb (2.70), Co (1.93), and Cd (0.76). Health risk assessments showed minimal non-carcinogenic risks, while carcinogenic risk from arsenic slightly exceeded safe limits (CR = 1.75E-04). Higher arsenic concentrations during the rainy season were due to increased recharge, arsenic-laden surface runoff, and human activities. Statistical analyses (PCA, PCC, HCA) suggested that metals and physico-chemical parameters originated from lithogenic, anthropogenic, or mixed sources. Regular monitoring of spring water is recommended to mitigate potential public health risks from waterborne contaminants., (© 2024. The Author(s).)

This study investigates potentially toxic elements (PTEs) in the surface sediments of the Abdal River system, a critical water source for Samsun province, Türkiye, due to the presence of the Çakmak Dam. PTE concentrations, measured in mg/kg, show significant variability: Hg (0.03) < Cd (0.26) < As (10.98) < Pb (13.88) < Cu (48.61) < Ni (62.45) < Zn (70.97) < Cr (96.28) < Mn (1015) < Fe (38357). Seasonal variations were observed, in particular increased concentrations of As, Cd and Pb in summer (p < 0.05). Contamination and ecological risk indices (mHQ, EF, I geo , CF, PLI, E r i , mCd, NPI, PERI, MPI, and TRI) indicate moderate to low levels of contamination, suggesting potential ecological effects. Health risk assessments suggest minimal risks to human health from sediment PTEs. Statistical analyses (PCC, PCA and HCA) improve the understanding of the sediment environment and contamination sources, while the coefficient of variation assists in source identification., Competing Interests: Declaration of competing interest The authors confirm that they have no disclosed competing financial interests or personal relationships that could have influenced the research presented in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

This study examines the levels and patterns of potentially toxic elements (PTEs) in surface sediment of Almus Dam Lake (ADL), a key fish breeding site in Türkiye. PTE concentrations in sediment were ranked: Hg (0.05 ± 0.01) < Cd (0.16 ± 0.01) < Pb (9.34 ± 1.42) < As (18.75 ± 15.65) < Cu (63.30 ± 15.17) < Ni (72.64 ± 20.54) < Zn (86.66 ± 11.95) < Cr (108.35 ± 36.40) < Mn (1008 ± 151) < Fe (53,998 ± 6468), with no significant seasonal or spatial differences. Ecological risk indices (mHQ, EF, I geo , CF, PLI, E r i , mCd, NPI, PERI, MPI, and TRI) showed low contamination levels. Health risk assessments, including LCR, HQ, and THI, indicated minimal risks to humans from sediment PTEs. Statistical analyses (PCA, HCA, SCC) identified natural, transportation, and anthropogenic PTE sources, with slight impacts from agriculture and fish farming. This research underlines contamination status of ADL and emphasizes the need for targeted management strategies, offering critical insights for environmental safeguarding., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Potentially hazardous elements (PHEs) are non-biodegradable and accumulate in places like water, soil, and plants where they endanger environmental health. There are a considerable number of wetlands having both national and worldwide importance in Türkiye. Regarding PHE accumulation, sediments and Ceratophyllum demersum were examined in the Miliç Wetland (MW), situated in a basin with intense hazelnut and rice farming, which is next to the international highway on the Central Black Sea Coast of Türkiye. The quantification of PHEs in the study subjects was undertaken using a validated inductively coupled plasma-mass spectrometry (ICP-MS) method, and mean concentrations (mg/kg) of PHEs in the sediments were in the order of Al (13,133) > Fe (10,790) > Mn (205.84) > Cu (17.95) > Cr (16.40) > Zn (15.55) > Ni (11.74) > Pb (9.17) > Co (6.30) > As (2.07) > Cd (0.19). The ecotoxicological risk was assessed using sediment quality guidelines (SQGs) and certain geological indices, indicating mostly low ecological risk, low pollution, and no hazardous risk. Based on the modified hazard quotient (mHQ) classification of values, Ni showed low contamination, while Cd, Pb, As, and Cu displayed very low contamination, and Zn presented minor contamination. The findings of total lifetime cancer risk (LCR), hazard quotient (HQ), and hazard index (HI) identified that exposure of adults or children to sediments containing PHEs would not represent a major health risk. As a recommendation, it is necessary to avoid the direct entrance of agricultural pesticides and fertilizers to enhance the sediment quality of the MW. Since the highway was constructed close to MW, this is considered a significant source of human-caused pollution. Consequently, all PHEs analyzed, except for Cd, displayed a bioconcentration factor (BCF) value of more than 1000, indicating that Ceratophyllum demersum is a promising plant for phytoremediation in PHE-polluted ecological systems involving wetlands, and it can efficiently be employed as an indicator species in biological screening investigations., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The objective of this paper was to stress the possible potential toxic element (PTE) accumulation in the surface sediments of the Çavuşlu Stream (ÇS), as well as examining the source identification of whether or not any association between garbage disposal facility (GDF) and ecotoxicity or human health risk in Giresun, Turkey. The sediment specimens were analyzed by inductively coupled plasma mass spectroscopy (ICP-MS) followed by microwave digestion. The descending order of metals (mg/kg) in sediments were as follows: Fe (38,791 ± 3269) > Al (27,753 ± 4051) > Mn (730.90 ± 114.60) > Cr (233.39 ± 53.32) > V (176.40 ± 19.66) > Cu (85.22 ± 6.06) > Ni (72.87 ± 11.50) > Zn (46.45 ± 3.68) > Co (21.96 ± 3.33) > Pb (12.17 ± 1.97) > As (3.12 ± 1.45) > Sb (0.22 ± 0.06) > Cd (0.17 ± 0.02) > Hg (0.04 ± 0.01). Among these elements, certain metals (V, Cr, Cu, and Ni) in the sediments were above the average shale. Cr and Ni levels were above their corresponding threshold effect level (TEL) and probable effect level (PEL) values while Cu concentration exceeding its TEL, indicating that benthic organisms in the sediment of ÇS have likely toxic responses. Based on the results from contamination factor (CF), enrichment factor (EF), and geo-accumulation factor (I geo ) values of PTEs, the sediment was frequently classified into moderate contamination, moderate enrichment, and unpolluted to moderately polluted group. Pollution load index (PLI), integrated pollution index (IPI), and ecological risk index (E r i ) indicated low pollution or low potential ecological risk. Toxicity risk index (TRI) and toxic unit analysis (TUs) suggested moderate toxicity. The outcomes of hazard quotient (HQ), total hazard index (THI), and lifetime cancer risk (LCR) stressed out that PTEs would not pose a significant health risk when adults are exposed to sediments in ÇS. However, a non-cancerogenic health risk for children was considered as the collective effect of 14 PTE (THI = 1.47 > 1). Multivariate statistical analysis (principal component analysis (PCA), Pearson's correlation coefficient (PCC), and hierarchical cluster analysis (HCA)) outlined that the metallic accumulation in the sediments of ÇS was related to lithological, geological, and anthropogenic impacts. Therefore, the GDF is likely a major reason in terms of anthropogenic pollution in the sediments of the ÇS., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

In this study, the phytoremediation capacity of Azolla filiculoides Lam. for the water resources contaminated with petroleum hydrocarbons was investigated. The plants were grown in nitrogen-free Hoagland nutrient solution containing 0.005%, 0.01%, 0.05%, 0.1%, 0.2%, 0.3%, 0.4%, and 0.5% crude oil under greenhouse conditions for 15 days. Although the growth rate of the plants were not negatively influenced by the presence of crude oil in the media for the concentration of 0.005% and 0.01% v/v, a gradual impeding effect of crude oil in the growth media has been observed at concentrations 0.05-0.1%. More than 0.1% crude oil in the growth medium ostensibly retarded the growth. For example, 0.2% oil in the media reduced growth approximately 50% relative to the control, and the presence of crude oil at concentrations 0.3% or more were lethal. The data about the percentage of plant growth, fresh weight increase and root growth clearly indicated that the tolerance level of A. filiculoides plants to crude oil ranges between 0.1% and 0.2%. In comparison to control samples, the biodegradation rate of total aliphatic and aromatic (phenathrene) hydrocarbons at 0.05-0.2% oil concentrations, was 94-73% and 81-77%, respectively. On the other hand, in case of further increases in oil concentration in media, i.e.; 0.3-0.5%, the biodegradation rate was still higher in the experimental samples, respectively 71-63% and 75-71%. The high biodegradation rates of petroleum hydrocarbons in the experimental samples suggested that A. filiculoides plants could be a promising candidate to be used for the phytoremediation of low crude oil contaminated precious freshwater resources.