Effect of the irrigation method and genotype on the bioaccumulation of toxic and trace elements in rice

The Reaction of Rice Growth to the Arsenic Contamination under Various Irrigation Methods

Several studies have explored how arsenic (As) is absorbed and transported in plants, but less attention has been paid to its impact on rice growth and yield in relation to water management. We aimed to assess how arsenic affects plant development under different irrigation methods. The growth and yield parameters of four rice varieties ('M 488', 'Janka', 'Szellő', and 'Nembo') in two greenhouse experiments were analyzed in 2021 and 2022 under different irrigation methods (flooded (F), intermittent (I), and aerobic (A)). Three different As concentrations were set up in the soil: 43 mg kg-1, 24 mg kg-1, and 4 mg kg-1. Our results showed that the high As treatment caused severe damage to the plants including leaf yellowing as well as reduced growth and decreased yield parameters. Alternative water management practices such as I and A irrigation could reduce the negative effects of As. At the high level of As stress (43 mg kg-1), the I irrigation had the most favorable effect on the yield of 'Janka' among the tested cultivars compared to the F irrigation (in F: 1.64 ± 1.13 g; in I: 5.45 ± 3.69 g). However, the use of fully aerobic conditions increased the likelihood of drought stress.

Illegal products containing selective androgen receptor modulators purchased online from Italy: health risks for consumers

Background

Selective androgen receptor modulators (SARMs) are small synthetic drug molecules that are still not approved as medicine in Europe or the United States but are sold on illegal websites to improve sport performance, particularly bodybuilding.

Aim

To address the quality issues of illegal SARM products and their increasing diffusion in Italy with their potential health risks for consumers.

Methods

Web-based tools were used to investigate retail websites, trending searches, and information exchange via social media. Thirteen SARM products, purchased on retail websites accessible from Italy, were subject to visual inspection and chemical analysis by mass spectrometry and quantitative nuclear magnetic resonance.

Outcomes

The primary outcome was demonstration of additional health risks due to the illicit presence of other active ingredients, contamination, and misdosage in SARM products sold on the internet. The secondary outcome was to show the increasing trend of interest in Italy for these products.

Results

Most websites reported misleading information; specifically, the statement "for research only" was reported notwithstanding indications on dosage and training phases. The trending search showed that interest toward SARMs increased in Italy in the last years. The use of these products is clearly encouraged by the emerging phenomenon of "broscience" as revealed in socials. Visual inspection evidenced nonconform labeling. Qualitative analysis confirmed the presence of the stated SARM in about 70% of samples. In 23% of samples, the expected SARM was not detected but a different one instead, and in 1 sample, no SARMs were detected. Other undeclared pharmaceutical substances (tamoxifen, clomifene, testosterone, epimethandienone, tadalafil) were measured in 30% of samples. The copresence of >1 active substance was observed in >60% of samples. Quantitative nuclear magnetic resonance data showed nonuniform content ranging from 30% to 90% of the label claim.

Clinical Implications

The use of SARMs, in the presence of unexpected life-threatening reactions in persons using the products to increase sport performance, should be assessed.

Strengths and Limitations

This investigation involved an integrated approach to study SARM products and related sociologic aspects. The main shortcomings are the limited number of samples and retail websites in the clear web investigated.

Conclusion

SARMs sold online as food supplement-like products represent a health hazard due to the presence of unapproved and undeclared active substances. The presence of contaminants clearly indicates the absence of good manufacturing practices in the production, which increases the health risks.

Effects of elevation and geomorphology on cadmium, lead and chromium enrichment in paddy soil and rice: A case study in the Xiangtan basin of China

The distributions of heavy metals in paddy fields and rice along river valleys were studied to explore the key factors affecting the accumulation of heavy metals in the upstream terraces and downstream plains. Results from 975 sampling sites showed that elevation, growing season and soil organic matter (OM) had significant effects on the content of Cd and Pb in topsoil and rice. The content of Cd (0.47-0.66 mg kg-1) and Pb (49.9-68.6 mg kg-1) in paddy fields with low elevation (30-60 m) in the downstream plains was significantly higher than the content of Cd (0.29-0.38 mg kg-1) and Pb (43.9-56.3 mg kg-1) in the upstream terraces with high altitude (60-90 m). In the double-rice production area, late rice generally produced grains with higher Cd and Pb content than early rice. Soil Cd was positively increased with the content of OM, especially in the downstream plains. When elevation was used for principal component analysis, plains with low elevation were grouped together with high content of total and soluble Cd, OM and Pb in soil, as well as high content of Cd and Pb in late rice. Altitude is one of the key factors affecting Cd content in rice. Although content of Cr (93.7-138.0 mg kg-1) was significantly higher than that of Cd and Pb in soil, content of Cr was lower than that of Cd in rice. These results indicate that paddy fields with elevation of 30-60 m in the downstream plains had high risk to produce late rice with Cd and Pb content exceeding the food safety standard 0.2 mg kg-1, which may be resulted from the driving force of runoff on soil soluble Cd and Pb from terraces to alluvial plains in river valleys.

Heavy Metals in Agricultural Soils: Sources, Influencing Factors, and Remediation Strategies

Soil heavy metal pollution is a global environmental challenge, posing significant threats to eco-environment, agricultural development, and human health. In recent years, advanced and effective remediation strategies for heavy metal-contaminated soils have developed rapidly, and a systematical summarization of this progress is important. In this review paper, first, the anthropogenic sources of heavy metals in agricultural soils, including atmospheric deposition, animal manure, mineral fertilizers, and pesticides, are summarized. Second, the accumulation of heavy metals in crops as influenced by the plant characteristics and soil factors is analyzed. Then, the reducing strategies, including low-metal cultivar selection/breeding, physiological blocking, water management, and soil amendment are evaluated. Finally, the phytoremediation in terms of remediation efficiency and applicability is discussed. Therefore, this review provides helpful guidance for better selection and development of the control/remediation technologies for heavy metal-contaminated agricultural soils.

Effects of fresh and field-aged holm-oak biochar on As, Cd and Pb bioaccumulation in different rice growing environments

Arsenic, Cd, and Pb environmental fate is influenced when the traditional permanent flooding rice production systems are replaced by water-saving and soil conservation practices, urging for additional strategies that avoid their bioaccumulation in rice grain. The aim of this two-years field study was to evaluate the effects of fresh and field-aged biochar on As, Cd, and Pb bioaccumulation, and on As speciation, in rice grain produced in different growing environments (flooding versus sprinkler and conventional tillage versus direct seeding). Biochar produced from holm-oak pruning residues (pyrolysis at 550 °C, 48 h), in a single application (28 Mg ha^-1), reduced As bioaccumulation in rice grain in the permanent flooding system to non-quantifiable concentrations (e.g., from 0.178 mg kg^-1 to <0.04 mg kg^-1, for inorganic-As, respectively), an effect which remained under field-aging conditions, increasing rice commercial value. When adopting sprinkler irrigation, the undesirable increase in Cd bioaccumulation in rice, relatively to the anaerobic system, was counteracted by biochar application, reducing its bioaccumulation in kernels between 32 and 80 %, allowing a simultaneous control of metals and metalloids bioaccumulation in rice. The bioaccumulation of Pb was also prevented with biochar application, with a reduction in its concentration four- to 13-times, in all the management systems, relatively to the non-amended plots, under fresh biochar effects. However, Pb immobilization decreased with biochar field-aging, indicating that the biochar application may have to be repeated to maintain the same beneficial effect. Therefore, the present study shows that the implementation of sprinkler irrigation with holm-oak biochar could reduce the risk of heavy metals(loids) bioaccumulation in rice grains and, thereby, ensuring food safety aspects, particularly under fresh biochar effects.

Medium-Term Effects of Sprinkler Irrigation Combined with a Single Compost Application on Water and Rice Productivity and Food Safety

Traditional rice (Oryza sativa L.) management (tillage and flooding) is unsustainable due to soil degradation and the large amount of irrigation water used, an issue which is exacerbated in the Mediterranean region. Therefore, there is a need to explore rice management strategies in order to improve water-use efficiency and ensure its sustainability. Thus, field experiments were conducted to determine the medium-term effects of different irrigation and tillage methods combined with a single compost application on water and rice productivity, as well as food safety in a semiarid Mediterranean region. The management systems evaluated were: sprinkler irrigation in combination with no-tillage (SNT), sprinkler irrigation in combination with conventional tillage (ST), which were implemented in 2015, and flooding irrigation in combination with conventional tillage (FT), and their homologues (SNT-C, ST-C, and FT-C) with single compost application in 2015. In reference to rice grain yield, the highest values were observed under ST treatment with 10 307 and 11 625 kg ha^-1 in 2018 and 2019 respectively; whereas between FT and SNT there were no significant differences, with 8 140 kg ha^-1 as mean value through the study. Nevertheless, sprinkler irrigation allowed saving 55% of the total amount of water applied in reference to flooding irrigation. Furthermore, the highest arsenic concentration in grains was found under FT but it decreased with compost application (FT-C) and especially with sprinkler irrigation, regardless of tillage management systems. However, sprinkler irrigation favors the cadmium uptake by plants, although this process was reduced under SNT in reference to ST, and especially under amended compost treatments. Therefore, our results suggested that a combination of sprinkler irrigation and compost application, regardless of the tillage system, could be an excellent strategy for rice management for the Mediterranean environment in terms of water and crop productivity as well as food safety.

Effects and oxygen-regulated mechanisms of water management on cadmium (Cd) accumulation in rice (Oryza sativa)

Irrigation has been considered an effective approach for decreasing cadmium (Cd) uptake and accumulation in rice (Oryza sativa), but increasing evidence shows that the effects of different water management strategies on Cd accumulation in rice are contradictory in different studies, and the detailed regulatory mechanisms remain unconfirmed. Most previous studies have shown that irrigation regulates Cd accumulation in rice mainly by affecting Cd bioavailability, pH and redox potential (Eh) in soil, and few reports have focused on the function of oxygen (O₂) in regulating the physiological mechanisms of rice on Cd tolerance or accumulation. Here, we concluded that irrigation affects Cd bioavailability, pH and Eh in soil mainly by regulating O₂ content. In addition, recent studies have also shown that irrigation-regulated O₂ also affects Cd accumulation in rice by affecting iron plaque (IP), the radial oxygen loss (ROL) barrier, the cell wall and mass flow in rice roots. All these results indicate that O₂ is the key factor in irrigation-regulated Cd accumulation in rice, and dramatic result variations from different irrigation experiments are due to the different rhizosphere O₂ conditions. This review will help clarify the effects and regulatory mechanisms of irrigation on Cd accumulation in rice and reveal the roles of O₂ in this process.

Influence of irrigation methods on arsenic speciation in rice grain

Although the bioaccumulation of arsenic (As) in rice grains is a global health issue, its speciation is not less worrying. Despite the ascertained effectiveness of the intermittent irrigation methods in minimizing the amount of total As in rice, knowledge of its influence on the As speciation has been insufficient so far. Hence, this contribution was aimed to measure the concentrations of As(III), As(V), dimethylarsinic acid (DMA), and monomethylarsonic acid (MMA) in grains from twenty-six different rice genotypes irrigated either with continuous flooding (CF), periodic saturation (SA) or sprinkler irrigation (SP). In CF-irrigated rice, As(III) and DMA prevailed in roughly equal amounts, only As(III) was found in SA-irrigated rice, whereas As(V) was largely predominant on As(III) in SP-irrigated rice. Organoarsenic species were below the limits of detection (LoD) in rice irrigated by intermittent methods. Principal component analysis (PCA) explained the influence of the irrigation method on the total amount of As, its chemical species, and their correlation. Furthermore, PCA showed also significant differences in As speciation as a function of the rice genotype, whereas no differences were found among Indica and Japonica subspecies.

Arsenic accumulation in rice: Alternative irrigation regimes produce rice safe from arsenic contamination

The natural occurrence of arsenic (As) in groundwater & soils and its bioaccumulation in rice grains is a major health concern worldwide. To combat the problem, best combination of irrigation management and suitable rice variety altering As content in grains must be ensured. With this aim, a field trial was conducted with two rice varieties and water management including alternate wetting and drying (AWD) and continuous flooding (CF) irrigation regimes with As contaminated groundwater (AsW) and temporarily stored groundwater (TSG) and river water for only CF (as control). Results revealed that As content in different portions of paddy plant was significantly different (P < 0.001) with irrigation practices and rice varieties. AWD irrigation with TSG accumulated lower As in rice grains compared with CF-AsW for both varieties. Data showed that AWD-TSG practice led to 61.37% and 60.34% grain As reduction for BRRI dhan28 and BRRI dhan29, respectively, compared with CF-AsW. For Principle Component Analysis (PCA), first principle component (PC1) explained 91.7% of the variability and irrigation water As, soil total and available As, straw As, root As and husk As were the dominating parameters. With significant (P < 0.05) variation in yields between the genotypes, AWD increased grain yield by 29.25% in BRRI dhan29 Compared with CF. However, translocation factor (TF) and bioconcentration factor (BCF) for both varieties were less than one for all the treatments. The addition of this study to our knowledge base is that, AWD-TSG with BRRI dhan29 can be an As-safe practice without compromising yields.

Human health impact due to arsenic contaminated rice and vegetables consumption in naturally arsenic endemic regions

Rice and vegetables cultivated in naturally arsenic (As) endemic areas are the substantial source of As body loading for persons using safe drinking water. However, tracing As intake, particularly from rice and vegetables by biomarker analysis, has been poorly addressed. This field investigation was conducted to trace the As transfer pathway and measure health risk associated with consuming As enriched rice and vegetables. Purposively selected 100 farmers from five sub-districts of Chandpur, Bangladesh fulfilling specific requirements constituted the subjects of this study. A total of 100 Irrigation water, soils, rice, and vegetable samples were collected from those farmers' who donated scalp hair. Socio-demographic and food consumption data were collected face to face through questionnaire administration. The mean As level in irrigation water, soils, rice, vegetables, and scalp hairs exceeded the acceptable limit, while As content was significant at 0.1%, 5%, 0.1%, 1%, and 0.1% probability levels, respectively, in all five locations. Arsenic in scalp hair is significantly (p ≤ 0.01) correlated with that in rice and vegetables. The bioconcentration factor (BCF) for rice and vegetables is less than one and significant at a 1% probability level. The average daily intake (ADI) is higher than the RfD limit for As. Both grains and vegetables have an HQ (hazard quotient) > 1. Maximum incremental lifetime cancer risk (ILCR) showed 2.8 per 100 people and 1.6 per 1000 people are at considerable and threshold risk, respectively. However, proteinaceous and nutritious food consumption might have kept the participants asymptomatic. The PCA analysis showed that the first principle component (PC1) explains 91.1% of the total variance dominated by As in irrigation water, grain, and vegetables. The dendrogram shows greater variations in similarity in rice and vegetables As, while the latter has been found to contribute more to human body loading compared to grain As.

Combined use of olive mill waste compost and sprinkler irrigation to decrease the risk of As and Cd accumulation in rice grain

Sprinkler irrigation has been successfully introduced in rice production as an alternative to the traditional flooding system, allowing water savings and the reduction of As accumulation in the grain. However, the same conditions can increase Cd mobility and grain accumulation, an effect that needs to be countered. A 3-year field experiment was set-up in a Mediterranean region (Extremadura, Spain), to evaluate how the application of compost from olive mill waste (single application, 80 t ha^-1), influences the accumulation of As and Cd in the grain under different irrigation regimes. Accumulation of As in the grain was always lower in the sprinkler irrigation when compared with the flooding irrigation, reaching a 5-fold difference in the third year. Compost application did not evidence a clear effect on the As accumulation in the rice grain, but highly significant negative correlations (p < 0.001) were obtained between As content in the grain (total, inorganic, and organic) and the humification parameters in the soil, evidencing the importance of using a mature and stable organic amendment to avoid As accumulation in the grain. Cadmium accumulation in the rice grain decreased in each treatment where compost was applied, relatively to the non-treated counterpart (e.g., from 0.080 to <0.010 mg kg^-1, in direct seeding with sprinkler irrigation, in the third year). There were no significant differences in the total inorganic As between treatments with or without compost application, but it was possible to observe an increase in the predominance of the organic As over the more toxic inorganic As, when compost was applied, allowing a decrease in the risk associated to As accumulation. Therefore, the aerobic cultivation of rice, with the simultaneous application of an adequate source of organic matter, can be considered a good solution to cope with the risk of accumulation of As and Cd in the rice grain.

Multi-Elemental Analysis as a Tool to Ascertain the Safety and the Origin of Beehive Products: Development, Validation, and Application of an ICP-MS Method on Four Unifloral Honeys Produced in Sardinia, Italy

Despite unifloral honeys from Sardinia, Italy, being appreciated worldwide for their peculiar organoleptic features, their elemental signature has only partly been investigated. Hence, the principal aim of this study was to measure the concentration of trace and toxic elements (i.e., Ag, As, Ba, Be, Bi, Cd, Co, Cr, Cu, Fe, Hg, Li, Mn, Mo, Ni, Pb, Sb, Sn, Sr, Te, Tl, V, and Zn) in four unifloral honeys produced in Sardinia. For this purpose, an original ICP-MS method was developed, fully validated, and applied on unifloral honeys from asphodel, eucalyptus, strawberry tree, and thistle. Particular attention was paid to the method’s development: factorial design was applied for the optimization of the acid microwave digestion, whereas the instrumental parameters were tuned to minimize the polyatomic interferences. Most of the analytes’ concentration ranged between the relevant LoDs and few mg kg⁻¹, while toxic elements were present in negligible amounts. The elemental signatures of asphodel and thistle honeys were measured for the first time, whereas those of eucalyptus and strawberry tree honeys suggested a geographical differentiation if compared with the literature. Chemometric analysis allowed for the botanical discrimination of honeys through their elemental signature, whereas linear discriminant analysis provided an accuracy level of 87.1%.

Assessment and validation of ICP-MS and IC-ICP-MS methods for the determination of total, extracted and speciated arsenic. Application to samples from a soil-rice system at varying the irrigation method

Food is the major route of arsenic (As) intake for humans, and rice is the staple food for more than half of the world's population. Unfortunately, rice bioaccumulates large amounts of As from the paddy field, and the toxicity of this element in the kernel is closely linked to its chemical form. Therefore, it is of the utmost importance to have access to an integrated set of analytical methods, capable of measuring the concentration of As in its various chemical forms in soil and rice. Hence, the principal aim of this study was to assess and validate a group of inductively coupled plasma - mass spectrometry (ICP-MS) and IC-ICP-MS (IC, Ionic Chromatography) methods designed to measure the amount of the total or extracted As and its main chemical species (As(III), As(V), monomethylarsonic acid, MMA, and dimethylarsinic acid, DMA) in flours of rice grain and in soils. Great attention has been given to the assessment and the optimization of extraction methods of As species from these matrices. No appreciable interconversion among As species has been observed using an aqueous solution 1 mol dm^-3 of phosphoric acid and 0.5 mol dm^-3 of L (+)-ascorbic acid for the extraction from soils, and an aqueous solution 0.2% (w/v) of nitric acid for the extraction from rice flour. Validation has been successfully accomplished in terms of limit of detection, limit of quantification, linearity and accuracy. In addition to many certified reference materials, these methods have been tested on real samples of soils and rice grains of the Aleramo genotype obtained through traditional or intermittent irrigation methods. Data obtained revealed the critical role of the intermittent irrigation methods in determining the nature and the amount of the As chemical species in rice grains as well as in soils. As(V) is the only species found in soil irrigated by sprinkling, while the most toxic As(III) dominates in soil irrigated by continuous flooding. On the other hand, the most abundant species found in continuously flooded Aleramo rice grains are As(III) and - mostly - DMA, whereas As(V), less toxic than As(III), represents 60% of the total inorganic compounds measured in sprinkler-irrigated rice. Lastly, the total amount of As measured in this rice is 3.8% of that measured in rice irrigated by continuous flooding.

Effects of optimized water management on the uptake and translocation of cadmium and arsenic in Oryza sativa L. in two contaminated soils

Water management has opposite effects on the bioavailability of Cd and As in soil. In order to identify the most efficient water management strategy for reducing Cd and As accumulations and amino acid (AA) synthesis in rice in two soils with different Cd and As contents, a pot experiments were conducted in greenhouse. A treatment consisting of 5 days of flooding followed by 3 days of drainage (F5D3, repeated every 8 days) was identified as the most effective treatment for simultaneously decreasing Cd and As in grains, with reductions of grain Cd and As contents of more than 80.0% and 73.1%, respectively, compared with either a drained treatment or a flooded treatment alone; this is probably related to the high efficiency of the F5D3 treatment in reducing dissolved Cd and As according to its minimum "trade-off value" (an index for evaluating the degree of trade-off between soil solution As and Cd concentrations in water management condition), due to the variations in grain Cd and As contents which were significantly correlated with the variations in soil solution Cd (R2=0.98) and As (R2=0.92, P=0.0001) concentrations. Additionally, grain Cd content was also significantly related to the organs Cd contents (especially root Cd content, R2=0.99) and the root-to-shoot Cd translocation factors (R2=0.99), whereas grain As content was significantly related to soil Eh (R2=-0.82, P=0.003) and pH (R2=0.88, P=0.0008). The AA contents in organs under the F5D3 treatment were lower than those under the flooded and drained treatments. These results indicated that the F5D3 treatment was the most effective water management strategy for simultaneously reducing grain Cd and As contents and AA synthesis in rice, which was probably due to there being no need for rice to synthesize abundant AAs to chelate metal ions.

ICP-MS Determination of 23 Elements of Potential Health Concern in Liquids of e-Cigarettes. Method Development, Validation, and Application to 37 Real Samples

The lack of interest in the determination of toxic elements in liquids for electronic cigarettes (e-liquids) has so far been reflected in the scarce number of accurate and validated analytical methods devoted to this aim. Since the strong matrix effects observed for e-liquids constitute an exciting analytical challenge, the main goal of this study was to develop and validate an ICP-MS method aimed to quantify 23 elements in 37 e-liquids of different flavors. Great attention has been paid to the critical phases of sample pre-treatment, as well as to the optimization of the ICP-MS conditions for each element and of the quantification. All samples exhibited a very low amount of the elements under investigation. Indeed, the sum of their average concentration was of ca. 0.6 mg kg-1. Toxic elements were always below a few tens of a μg per kg-1 and, very often, their amount was below the relevant quantification limits. Tobacco and tonic flavors showed the highest and the lowest concentration of elements, respectively. The most abundant elements came frequently from propylene glycol and vegetal glycerin, as confirmed by PCA. A proper choice of these substances could further decrease the elemental concentration in e-liquids, which are probably barely involved as potential sources of toxic elements inhaled by vapers.

Sprinkler irrigation in the production of safe rice by soils heavily polluted by arsenic and cadmium

Among the factors affecting the bioaccumulation of As and Cd in rice, a key role is played by the irrigation methods. The sprinkler irrigation (SP), optimized for rice in Sardinia, Italy, applied to several rice genotypes over many years has produced no differences in yields in comparison to what observed using the traditional continuous flooding irrigation method (CF). Because all the previous SP trials have been performed just on one, unpolluted soil, the principal aim of this study is to ascertain the effectiveness of SP to simultaneously minimize the bioaccumulation of As and Cd in rice grain even in soils severely polluted by As and/or Cd. Hence, a Carnise rice genotype was cultivated in an open field in: i) an unpolluted soil; ii) a soil polluted with 55 mg kg^-1 of As; iii) a soil polluted with 40 mg kg^-1 of Cd; iv) a soil polluted with 50 mg kg^-1 of As and 50 mg kg^-1 of Cd. In the worst condition of pollution, the amounts of total As and Cd measured in the kernels using a fully validated ICP-MS method is 90 ± 10 μg kg^-1 and 50 ± 20 μg kg^-1, respectively, i.e. less than 50% and the 25% of the maximum concentration set for these elements in rice by the European Community (200 μg kg^-1 for the inorganic As and the total amount of Cd, respectively). SP might represent a simple and valuable tool able to produce safe rice also from soils where the traditional irrigation might produce inedible rice only.