Potentially toxic elements (PTEs) in seawater and sediments may be amplified along the aquatic food chain, posing a health threat to humans. This study comprehensively analyzed the concentrations, ...distribution, potential sources, and health risk of 7 PTEs in multimedia (seawater, sediment and organism) in typical subtropical bays in southern China. The results indicated that Zn was the most abundant element in seawater, and the average concentration of Cd in sediment was 3.93 times higher than the background value. Except for As, the seasonal differences in surface seawater were not significant. The content of Zn in fishes, crustacea, and shellfish was the highest, while the contents of Hg and Cd were relatively low. Bioaccumulation factor indicated that Zn was a strongly bioaccumulated element in seawater, while Cd was more highly enriched by aquatic organisms in sediment. According to principal component analysis (PCA), and positive matrix factorization (PMF), the main sources of PTEs in Quanzhou Bay were of natural derivation, industrial sewage discharge, and agricultural inputs, each contributing 40.4 %, 24.2 %, and 35.4 %, respectively. This study provides fundamental and significant information for the prevention of PTEs contamination in subtropical bays, the promotion of ecological safety, and the assessment of human health risk from PTEs in seafood.
Display omitted
•Potentially toxic elements in the seawater, sediment and organism were monitored.•Sediment was moderately polluted by PTEs, especially for Cd.•Most abundant element in marine organisms is Zn, and highest excess rate was As.•The sources of PTEs were natural sources, industrial and agricultural activities.
The study aimed to determine the effect of different slope positions on selected chemical properties of Pseudogley in the vineyard. The study was conducted in Zagreb, central Croatia. A total of 15 ...top-soil samples (0-30 cm) were collected from a hilltop, backslope, and footslope and analysed for pH, hydrolytic acidity (Hy), soil organic carbon (SOC) content, P2O5, K2O, and potentially toxic elements (As, Cu, Ni, Pb, and Zn). A slight increase in mean pH value from the hilltop to the footslope and a decrease in Hy were observed, although differences were not statistically significant. The SOC content was low and uniform along the entire slope. A significantly higher concentration of P2O5 at the footslope compared to the hilltop was established (10.4 and 3.4 mg/100 g of soil, respectively). The K2O concentration at the footslope (29.7 mg/100 g of soil) was significantly higher than at the backslope (21.2 mg/100 g of soil). The Cu, Pb, and Zn concentrations were significantly affected by slope positions in terms of download accumulation. The studied soil was contaminated by As, Ni, and Zn at the hilltop and the footslope and partly at the backslope, according to the Ordinance on the Protection of Agricultural Land from Pollution. The Cu concentrations exceeded the maximum allowed concentrations only on the backslope and footslope. The minor differences in studied soil properties between slope positions can be attributed to a short length, low and uneven inclination, and relatively short-term anthropogenic influence.
In the current study, we conducted a field experiment using the test plant, Brassica chinesis L. (pak choi), to investigate the effect of sugarcane bagasse-derived biochar on the bioavailability of ...cadmium (Cd), copper (Cu) and lead (Pb), and the health of soil microbiota in a contaminated soil. Biochar application significantly (P < 0.05) increased pak choi yield. Bioavailability of heavy metals to plant shoots and roots decreased with increasing biochar application rates (at 0, 1.5, 2.25 and 3.0 t ha−1). Sequential extraction of the biochar-treated and -untreated soil revealed that exchangeable Cd reduced whereas organically-bound fraction increased with increasing biochar rate. The labile fractions of Cu and Pb decreased, but the residual fraction increased in biochar-treated soils compared to the control. Urease, catalase and invertase activities, and the populations of bacteria and actinomycetes were significantly enhanced, whereas fungi population declined in biochar-treated soils. This study highlights that sugarcane bagasse biochar has the potential to support the remediation of soils contaminated with heavy metals, and as such can improve the yield and quality of agricultural crops.
•Sugarcane bagasse biochar amendment reduced availability of Cd, Cu and Pb in soils.•Heavy metals were less labile in the biochar-treated soils.•Biochar amendment induced an increase in soil enzyme and microbial activity.•Edible part of pak choi was safer for human consumption after biochar amendment.
Municipal solid waste incineration (MSWI) fly ash is considered as a hazardous waste that requires specific treatment before disposal. The principal treatments encompass thermal treatment, ...stabilization/solidification, and resource recovery. To maximize environmental, social, and economic benefits, the development of low-carbon and sustainable treatment technologies for MSWI fly ash has attracted extensive interests in recent years. This paper critically reviewed the state-of-the-art treatment technologies and novel resource utilization approaches for the MSWI fly ash. Innovative technologies and future perspectives of MSWI fly ash management were highlighted. Moreover, the latest understanding of immobilization mechanisms and the use of advanced characterization technologies were elaborated to foster future design of treatment technologies and the actualization of sustainable management for MSWI fly ash.
Display omitted
•Review the state-of-the-art treatment technologies and recycling approaches for MSWI fly ash.•Compare the merits and demerits of various technologies for MSWI fly ash treatment.•Elaborate the latest immobilization mechanisms based on advanced characterization techniques.•Provide future perspectives for sustainable management of MSWI fly ash.
Biochar has received extensive attention because of its multi-functionality for agricultural and environmental applications. Despite its many benefits, there are concerns related to the long-term ...safety and implications of its application, mainly because the mechanisms affecting soil and organism health are poorly quantified and understood. This work reviews 259 sources and summarises existing knowledge on biochar's adverse effects on soil from a multiangle perspective, including the physicochemical changes in soil, reduced efficiency of agrochemicals, potentially toxic substances in biochar, and effects on soil biota. Suggestions are made for mitigation measures. Mixed findings are often reported; however, the results suggest that high doses of biochar in clay soils are likely to decrease available water content, and surface application of biochar to sandy soils likely increases erosion and particulate matter emissions. Furthermore, biochar may increase the likelihood of excessive soil salinity and decreased soil fertility because of an increase in the pH of alkaline soils causing nutrient precipitation. Regarding the impact of biochar on (agro)chemicals and the role of biochar-borne toxic substances, these factors cannot be neglected because of their apparent undesirable effects on target and non-target organisms, respectively. Concerning non-target biota, adverse effects on reproduction, growth, and DNA integrity of earthworms have been reported along with effects on soil microbiome such as a shift in the fungi-to-bacteria ratio. Given the diversity of effects that biochar may induce in soil, guidelines for future biochar use should adopt a structured and holistic approach that considers all positive and negative effects of biochar.
Display omitted
•The review summarises the possible adverse biochar effects considering 259 studies.•Adverse effects may arise due to changes in soil properties upon biochar addition.•Soil organisms, mostly earthworms, suffer from biological adverse effects of biochar.•Several unfavourable soil-biochar combinations were identified.•A holistic approach is needed to reveal all possible, long-term adverse effects.
Rapid industrialization and urbanization have accelerated the contamination of paddy soils with potentially toxic elements (PTEs). However, the status and the key factors responsible for the ...geographical variation in PTE concentrations in rice remain poorly understood. Here, a total of 113 pairs of soil and rice plant samples were collected from 19 provinces in four major rice producing areas of China to assess the geographical variation in total arsenic (As), cadmium (Cd) and lead (Pb) concentrations in the soil-rice system. Average total concentrations of As, Cd and Pb were 11.8, 0.45 and 25.7 mg kg−1, respectively, in the soils and 0.089, 0.087 and 0.036 mg kg−1 in the polished rice. The national maximum allowable concentrations of total soil As and Cd were exceeded in 6.19 and 33.6% of soils and that of Cd was exceeded in 7.96% of polished rice and no polished rice exceed the Pb limit. The As, Cd and Pb concentrations of rice were significantly and positively correlated (p < 0.05) with their corresponding soil available concentrations rather than with their soil total concentrations. Due to the combined effects of local rice varieties, cultivation of varieties with high Cd translocation factors and high Cd availability in acid soils, the highest rice Cd risk occurred in south China. The Cd concentrations in polished rice exceeded the maximum allowable by 4.0 and 15.8% in uncontaminated and contaminated soils, respectively. Results from 113 fixed samples may represent the actual current As, Cd and Pb status of rice in the main rice production areas nationally as they were very consistent with 574 random samples. In view of the high Cd contamination risk in acid soils of south China, countermeasures are needed to minimize Cd accumulation in rice crops in this region.
Display omitted
•113 paired paddy soil and rice samples collected from 19 Chinese provinces•High geographical variation in soil and rice PTEs (As, Cd and Pb) concentrations•Rice grown in acid unpolluted soils in south China at risk of Cd contamination•Soil properties, PTEs availabilities and rice genotypes influenced plant PTEs uptake.
The utilization of Cd-contaminated soil in vegetable crop production can lighten the food crisis and improve the soil environmental resilience. Intercropping is a reliable technology in safety ...production from contaminated soil. A field-scale experiment was carried out to unravel how plant species and pattern affect the growth and Cd uptake of Chinese cabbage from Cd contaminated land. Among all the intercropping systems designed in this study, one row of Chinese cabbage intercropping with one row of Solanum nigrum L. is the best planting mode (high yields (2.78 kg/m2) and low Cd accumulation (0.02 mg/kg) of Chinese cabbage). Combined with the in-depth joint analysis of diverse soil physicochemical features (soil nutrient characteristics and microbial community structure), biomass yield and quality, and soil microbiological properties, we elaborated that two measures (screening hyperaccumulation types and controlling planting strip width) were the major factors in determining the growth of the aboveground and underground parts of Chinese cabbage respectively, thus directly regulating the application effectiveness of intercropping technology. The intertwined mechanisms (interspecific and intraspecific relationship) of different intercropping systems are summarized, which include better utilization of space, light and other resources in the aboveground part, bioavailability of nutrient, drive of soil bacteria and alleviated soil Cd stress in the underground part, etc. Our research outputs indicate the effectiveness and feasibility of intercropping can be improved by optimizing the streamline configuration and plant mode, which provide theory of reference and practical evidence for warranting the food safety and agricultural soil remediation simultaneously.
Display omitted
•Intercropping can be used as a safe utilization technology for polluted farmland.•Intercropping can realize "remediate while production" at a field scale.•Screening planting species and strip widths can tune intercropping effect.•The internal mechanisms of above/underground on the intercropping were discussed.
Tea (Camellia sinensis) is a popular beverage that is consumed globally. However, a better understanding of potentially toxic elements (PTEs) content in tea leaves and infusion is necessary to ...minimize risk on human health. Therefore, 249 tea samples (grown in different areas) covering six types of tea were collected in China to investigate the PTEs contents, identify their potential source and assess the health risk associated with drinking tea. PTE contents in tea leaves across six tea types were ND–0.900 (Cd), 0.005–2.133 (As), ND–5.679 (Pb), ND–13.86 (Cr), 1.601–22.93 (Ni), ND–2.048 (Se), 0.109–622.4 (F), 13.02–269.9 (Rb), 1.845–50.88 (Sr), and 2.796–53.23 (Ba) mg/kg. The result of tea infusion showed that 14.3 %–44.1 % (green tea), 14.5 %–46.7 % (black tea), 10.5 %–25.3 % (dark tea), 13.6 %–34.2 % (oolong tea), 16.9 %–40.7 % (yellow tea), and 19.9 %–35.1 % (white tea) of F were released. All tea types, except green tea, exhibited comparatively low leachability of Cd, As, Pb and Cr in tea infusion. The source apportionment revealed that PTEs in tea leaves mainly originated from soil parental materials, while industrial activities, fertilizer application, and manufacturing processes may contribute to exogenous Se, Cd, As, and Cr accumulation. Health risk assessment indicated that F in tea infusion dominated the health risk. Humans may be exposed to a higher health risk by drinking green tea compared to that of other tea types. Nevertheless, the long-term tea consumption is less likely to contribute to pronounced non-carcinogenic and carcinogenic risks. This study confirmed that tea consumption is an important and direct pathway of PTEs uptake in humans. The health risk associated with drinking tea should be of concern.
Display omitted
•The contents of potentially toxic elements in teas across China are low.•Anthropogenic activities contribute to exogenous As, Cd, Cr and Se accumulation in teas.•Potentially toxic elements in teas tend to be predominantly released in the first infusion.•Health risk associated with drinking tea is acceptable for the tested Chinese teas.
In the past few decades, contamination of urban children's parks (UCPs) with potentially toxic elements (PTEs) has been attracting more and more interest; however, assessment of eco-environmental and ...child exposure risks particularly in developing countries remains limited. The current study investigated PTE (Cr, Ni, Zn, As, Cd, and Pb) concentrations, potential sources, and their health risk assessment in UCP soils of 12 major cities in Pakistan. The results showed that the mean concentration of Ni exceeded the SEPA-permissible limit in all UCP sites, while other PTEs were found to be within acceptable limits. The soil properties such as pH, electrical conductivity, organic matter, and soil particles size were determined in UCPs soils. The contamination factor and pollution load index results indicated low to moderate pollution levels (CF < 3) and (PLI<1) for all PTEs except Ni in some of the selected cities. Quantile–quantile (Q-Q) plotting determined the normal distribution line for all PTEs in the UCPs. Principal component analysis showed the mixed sources of contamination from industrial emissions, fossil fuel combustion, vehicular emissions, wastewater irrigation, as well as solid waste disposal and natural sources of soil parent materials in all park sites. ANOVA results showed that all the PTEs except Cd had moderate to higher contamination values than the reference site. The risk assessment study revealed that children had high exposure to the selected PTEs via all exposure pathways. The hazard index (HI) mean value (1.82E+00) of Ni for all exposure pathways was greater than 1, while total risk value of Cr (1.00E-03) had exceeded USEPA limit, indicating cancer risk. Consequently, the study of UCPs soils revealed PTEs contamination that could pose a potential health risk to the local population in the studied UCPs regions of Pakistan. Thus, the present study recommends that the influx of PTEs originating from natural and anthropogenic sources should be mitigated and government should implement strict enforcement of environmental regulations and proper management, as well as air quality monitoring guidelines for public health should be strictly adopted to reduce traffic- and industrial emission-related to PTEs in metropolitan areas.
Display omitted
•Nickel had the highest prevalent contamination in UCPs soils among PTEs.•Vehicular and industrial emissions are the main driving factors influencing PTEs.•Children were relatively more susceptible than the adults to PTEs exposure in all.•UCPs soils.•Monitoring strategies should be implemented to mitigate PTEs pollution.
To determine the status and sources of contamination and phytoremediation capability of Typha latifolia L. in the Bahmanshir River of Iran, the concentration of eight potentially toxic elements (As, ...Cd, Cr, Cu, Mn, Ni, Pb, and Zn) in sediment and plant tissues from ten sampling sites were measured. Mean concentrations of Cd, Cr, Cu, Pb, and Zn in the sediment exceeded those of local background. PCA-MLR receptor analysis suggested that the sediment contamination was due to municipal wastewater/vehicular pollution and weathering/industrial/agricultural activities, with contributions of 66% and 34%, respectively. Average enrichment factor (EF) and modified hazard quotient (mHQ) for Pb and Cu were categorized as moderate. Modified pollution index (MPI) and modified ecological risk index (MRI) values suggested moderate to heavy pollution and low ecological risk, respectively. The values of sediment quality guidelines (SQGs), ecological contamination index (ECI), contamination severity index (CSI), and toxic risk index (TRI) were all similar, reflecting low to moderate contamination and toxicity. Typha latifolia L. showed good phytostabilization capability for Cd, Cu, and Pb, and phytoextraction capacity for Zn. Using the metal accumulation index (MAI) and the comprehensive bioconcentration index (CBCI), Typha latifolia L. was shown to have acceptable performance in the accumulation of Cd, Cu, Pb, and Zn and thus, can be considered a good candidate for bioaccumulation of these elements in the study area. Overall, this study suggests that phytoremediation using Typha latifolia L. could be a practical method for uptake and remove of potentially toxic elements from aquatic environments.
Display omitted
•Mean concentrations of Cd, Cr, Cu, Pb, and Zn exceeded the local background concentration.•Moderated level of enrichment was observed for Cu and Pb.•Index-based approach for the overall assessment of the sediment quality indicated moderate contamination and toxicity.•Municipal wastewater and vehicular pollution were found as the main sources of pollution.•Typha latifolia L. represented phytoremediation capability for Cd, Cu, Pb, and Zn.
