Cocoa-laden cadmium threatens human health and cacao economy: A critical view

Significant effects of bioavailable heavy metals on antibiotic resistome in paddy soils as revealed by metagenomic analysis

Heavy metals (HMs) act as a long-term selective pressure for the emergence and maintenance of antibiotic resistance genes (ARGs) in agricultural soils. However, the effects of HMs on ARG distributions in paddy soils and the underlying mechanisms remain unclear. In this study, 74 soil samples were collected from the paddy fields to explore the impact of HMs on ARG profiles. A total of 468 ARGs were detected in HM-contaminated soils. Variation partitioning analysis (VPA) and redundancy analysis (RDA) demonstrated that the bioavailable HMs contributed more significantly to ARG composition compared to the total HM content (8.59 % vs. 3.97 %). Structural equation models (SEMs) showed that bioavailable HMs affected ARGs mainly by negatively altering the microbial diversity. Furthermore, the co-occurrence analysis of ARGs and metal resistant genes (MRGs) was further performed at the metagenome-assembled genomes (MAGs) level. Consequently, 1145 MAGs that assigned to 29 bacterial phyla were found to concurrently harbor ARGs and MRGs, with the bacterial phyla Pseudomonadota being predominant ARG-MRG-carrying microbes for most coexistence types of ARGs and MRGs, i.e., multidrug-As, polymyxin-Cd, Quinolone-Cd, Beta-lactam-Pb, and multidrug-Zn. Our findings highlight that the extensive coexistence of ARG-MRG in microbial genomes is an important reason for the ARG pollution in HM-contaminated paddy soils.

Cadmium availability in rhizosphere and non-rhizosphere soils in cacao farms in Santander, Colombia

Current research has highlighted the need to understand the factors influencing cadmium (Cd) availability in cacao-growing soils to elucidate its presence in cacao beans (the raw material for chocolate). Although literature about this topic is increasing, few report the importance of rhizosphere soils on Cd dynamics. This study aimed to understand the changes in available Cd and its association with soil properties (pH, pseudo-total Cd, available Cd (Cd-DTPA), Ca, Mg, K, Na, soil organic carbon, P, Zn, urease activity, exchangeable acidity, and cation exchange capacity) considering rhizosphere and non-rhizosphere soils. Both soil types (51 samples of each, 102 in total) were collected from two Colombian cacao farms. The medians of pseudo-total Cd (1.86 mg kg-1) and Cd-DTPA (0.76 mg kg-1) were, respectively, about threefold and fourfold higher in rhizosphere compared to non-rhizosphere soils. Principal component analysis showed a clear distinction between rhizosphere and non-rhizosphere soils based on differences in soil properties, which explained the observed changes in available Cd when comparing both soil types. Soil organic carbon and Zn were important drivers of available Cd in rhizosphere soils. Spatial distribution analysis revealed a tendency of available Cd to cluster in rhizosphere soils, and indicated hotspots within each farm. These findings highlight the importance of rhizosphere soils for Cd diagnosis and monitoring, and for improving knowledge about Cd dynamics in the soil-Theobroma cacao L. system.

Dietary Risk Assessment of Cadmium Exposure Through Commonly Consumed Foodstuffs in Mexico

Cadmium (Cd) is a toxic heavy metal widely distributed in foodstuffs. In Mexico, few studies have evaluated Cd content in foods. This study aimed to determine Cd concentrations in foodstuffs that are highly consumed and bought in Mexico City to identify foods exceeding the Maximum Level (ML) and to assess the health risks of theoretical Cd intake from a diet following the Mexican Dietary Guidelines. A total of 143 foodstuffs were analyzed by atomic absorption spectrophotometry. Theoretical Cd intake was estimated in portions per week and compared with the Cd Tolerable Weekly Intake (TWI = 2.5 μg/kg per body weight). A total of 68.5% of the foodstuffs had detectable Cd concentrations. Higher concentrations were found in oyster mushrooms (0.575 mg/kg), romaine lettuce (0.335 mg/kg), and cocoa powder (0.289 mg/kg). Food groups with higher mean concentrations were vegetables (0.084 mg/kg) and snacks, sweets, and desserts (0.049 mg/kg). Ancho chili and romaine lettuce exceed the ML. The theoretical Cd intake estimation was 1.80, 2.05, and 3.82 μg/kg per body weight for adults, adolescents, and school-age children, respectively. This theoretical Cd intake represents a health risk only for school children exceeding the TWI by 53.2%. Our study confirms the presence and risk of Cd in Mexican foodstuffs and highlights the importance of monitoring programs.

Chemometric assessment of bioaccumulation and contamination pathways for toxic metals in diet and environment: implications for chronic kidney disease of unknown etiology (CKDu) in Sri Lankan agricultural regions

Prolonged consumption of foods containing toxic metals can elevate the risk of noncommunicable diseases, including chronic kidney disease of uncertain etiology (CKDu). Despite the increasing number of CKDu cases in Maradankulama and Mahakanadrawa Grama Niladhari Divisions (GN) in Sri Lanka, no prior studies have examined the accumulation of heavy metal(loid)s and their potential association with CKDu prevalence. Furthermore, there is an absence of comprehensive analyses using chemometric techniques such as PCA and hierarchical studies regarding CKDu and heavy metal contamination in Sri Lanka. This study aims to provide initial insights into the accumulation and potential pathways of toxic metals in staple foods within local diets and their subsequent presence in the agricultural environment of examined GNs. Cr, Cd, As, and Ni concentrations in analyzed foods were within permissible limits (MPLs), whereas Pb levels exceeded MPLs in rice (Oryza sativa), gotukola (Centella asiatica), lime (Citrus crenatifolia), and inland fish (Etroplus suratensis). High target hazard quotient (THQt) values in polished rice suggest possible health risks with prolonged intake. Hierarchical analysis suggested a common source of Pb accumulation. PCA and hierarchical clustering revealed the intricate connection between As and Cd, with their concurrent clustering in samples suggesting a potential common origin. This indicates that while individual concentrations comply with acceptable standards, the potential synergistic effects of Cd and As accumulation might pose elevated health risks. Further, the gut tissues of inland fish exhibited pronounced metal concentrations and significant (p < 0.05) positive correlations with toxic metals in the tank sediments suggesting a diet-based bioaccumulation pathway through sediments.

Occurrence of heavy metals coupled with elevated levels of essential elements in chocolates: Health risk assessment

The presence of contaminants in cacao-derived products, especially in chocolates, has raised concerns regarding food safety and human health. The study assessed the concentration variation of 16 elements in 155 chocolate samples from the US market by cacao content and country of geographic origin. The study further examined the potential health risks posed by toxic metals and determined the contribution of essential elements to the Daily Recommended Intake (DRI), estimated based on an ounce (∼28.4 g) of daily chocolate consumption. Dark chocolates with ≥50 % cacao exhibited consecutively increasing mean levels from 1.2 to 391 µg/kg for U, Tl, Th, As, Pb, Se, Cd, and Co. Similarly, Ni, Sr, Cu, Mn, Zn, Fe, Ca, and Mg had mean concentrations from 4.0 to 1890 mg/kg. Dark chocolates sourced from Central and South America exhibited the highest mean levels of Cd, and South America samples also contained elevated Pb, whereas those from West Africa and Asia had low Cd and Pb, respectively. Cacao contents showed increasingly strong association with Cd, Co, Mn, Sr, Ni, Cu, Zn, and Mg (r = 0.60-0.84), and moderately with Se, Fe, As, and Tl (r = 0.35-0.49), indicating these elements are primarily derived from cacao beans. Weak association of cacao contents with Pb, Th, and U levels (r < 0.25), indicates post-harvest contaminations. Hazard Quotient (HQ) > 1 was found only for Cd in 4 dark chocolates, and Hazard Index (HI) > 1 for cumulative risk of Cd, Pb, Ni, As, and U was found in 33 dark chocolates, indicating potential non-carcinogenic risks for 15 kg children but none for 70 kg adults. Dark chocolate also substantially contributed to 47-95 % of the DRI of Cu for children and 50 % for adults. Dark chocolates also provided notable Fe, Mn, Mg, and Zn contributions to the DRI. These essential elements are recognized to reduce the bioavailability of toxic metals such as Cd, Pb, or Ni, thereby potentially lowering associated health risks. This study informs consumers, food industries, and regulatory agencies to target cacao origins or chocolate brands with lower toxic metal contents for food safety and minimizing adverse health effects.

Environmental cadmium inhibits testicular testosterone synthesis via Parkin-dependent MFN1 degradation

Low testosterone (T) levels are associated with many common diseases, such as obesity, male infertility, depression, and cardiovascular disease. It is well known that environmental cadmium (Cd) exposure can induce T decline, but the exact mechanism remains unclear. We established a murine model in which Cd exposure induced testicular T decline. Based on the model, we found Cd caused mitochondrial fusion disorder and Parkin mitochondrial translocation in mouse testes. MFN1 overexpression confirmed that MFN1-dependent mitochondrial fusion disorder mediated the Cd-induced T synthesis suppression in Leydig cells. Further data confirmed Cd induced the decrease of MFN1 protein by increasing ubiquitin degradation. Testicular specific Parkin knockdown confirmed Cd induced the ubiquitin-dependent degradation of MFN1 protein through promoting Parkin mitochondrial translocation in mouse testes. Expectedly, testicular specific Parkin knockdown also mitigated testicular T decline. Mito-TEMPO, a targeted inhibitor for mitochondrial reactive oxygen species (mtROS), alleviated Cd-caused Parkin mitochondrial translocation and mitochondrial fusion disorder. As above, Parkin mitochondrial translocation induced mitochondrial fusion disorder and the following T synthesis repression in Cd-exposed Leydig cells. Collectively, our study elucidates a novel mechanism through which Cd induces T decline and provides a new treatment strategy for patients with androgen disorders.

Cardiovascular disease in low- and middle-income countries associated with environmental factors

There is a growing recognition that the profound environmental changes that have occurred over the past century pose threats to human health. Many of these environmental factors, including air pollution, noise pollution, as well as exposure to metals such as arsenic, cadmium, lead, and other metals, are particularly detrimental to the cardiovascular health of people living in low-to-middle income countries (LMICs). Low-to-middle income countries are likely to be disproportionally burdened by cardiovascular diseases provoked by environmental factors. Moreover, they have the least capacity to address the core drivers and consequences of this phenomenon. This review summarizes the impact of environmental factors such as climate change, air pollution, and metal exposure on the cardiovascular system, and how these specifically affect people living in LMICs. It also outlines how behaviour changes and interventions that reduce environmental pollution would have significant effects on the cardiovascular health of those from LMICs, and globally.

Stable Isotope Analyses Reveal Impact of Fe and Zn on Cd Uptake and Translocation by Theobroma cacao

High concentrations of toxic cadmium (Cd) in soils are problematic as the element accumulates in food crops such as rice and cacao. A mitigation strategy to minimise Cd accumulation is to enhance the competitive uptake of plant-essential metals. Theobroma cacao seedlings were grown hydroponically with added Cd. Eight different treatments were used, which included/excluded hydroponic or foliar zinc (Zn) and/or iron (Fe) for the final growth period. Analyses of Cd concentrations and natural stable isotope compositions by multiple collector ICP-MS were conducted. Cadmium uptake and translocation decreased when Fe was removed from the hydroponic solutions, while the application of foliar Zn-EDTA may enhance Cd translocation. No significant differences in isotope fractionation during uptake were found between treatments. Data from all treatments fit a single Cd isotope fractionation model associated with sequestration (seq) of isotopically light Cd in roots and unidirectional mobilisation (mob) of isotopically heavier Cd to the leaves (ε114Cdseq-mob = -0.13‱). This result is in excellent agreement with data from an investigation of 19 genetically diverse cacao clones. The different Cd dynamics exhibited by the clones and seen in response to different Fe availability may be linked to similar physiological processes, such as the regulation of specific transporter proteins.

Probabilistic health risk assessment of heavy metals (Cd, Pb, and As) in Cocoa powder (Theobroma cacao) in Tehran, Iran market

The concentrations of toxic elements were analyzed by using Flame Atomic Absorption Spectrophotometer (FAAS). Moreover, the human health risk was estimated by Total Target Hazard Quotient (TTHQ) and Cancer Risk (CR) in Monte Carlo Simulation (MCS) technique. The mean concentrations (mg/kg) of Cd (0.08 ± 0.08), Pb (0.23 ± 0.46), and As (0.06 ± 0.04), were in a good compliance with ISO (Iranian standard organization). TTHQ for adults and children was equal to 0.009 and 0.042, respectively and also mean CR in adults and children consumers was equal to 9.73E-7 and 9.08E-7, respectively. Consequently, the concentration of toxic elements (Cd, Pb, and As) in cocoa powder did not pose any safety concerns. Moreover, probabilistic health risk assessment revealed that both adults and children were not at considerable non-carcinogenic (THQ and/or TTHQ ≤ 1) and carcinogenic risk (CR ≤ 1E-6). Even though, seeking for mitigating solutions and applying them to suppress the dangers of food containing toxic elements is a critical subject.

The in vitro metabolism of GMDTC in liver microsomes of human, monkey, dog, rat and mouse: Metabolic stability assessment, metabolite identification and interspecies comparison

Sodium (S)- 2-(dithiocarboxylato((2 S,3 R,4 R,5 R)- 2,3,4,5,6-pentahydroxyhexyl)amino)- 4(methylthio)butanoate (GMDTC) is a compound that removes cadmium from kidney cells. This study aims to investigate the metabolic stability and metabolite identification of GMDTC in various liver microsomes, including those from human, monkey, dog, rat and mouse. The results show that the T1/2 values of GMDTC in human, monkey, dog, rat and mouse liver microsomes were 16.54, 18.14, 16.58, 15.16 and 16.00 min, respectively. While the hepatic extraction ratios (ERh) of GMDTC measured after 60 min incubation in these liver microsomes were 0.82, 0.70, 0.80, 0.75 and 0.79, respectively, indicating that GMDTC exhibits rapid hepatic metabolism and high hepatic clearance with no significant interspecies differences. Subsequent metabolite identification by high-resolution mass spectrometry revealed the presence of three metabolites, designated M1∼M3. The major metabolite products of GMDTC were found to be M1 and M2. The relative abundances of the hydrolysis products (M1 and M2) in human, monkey, dog, rat and mouse liver microsomes were found to be 97.18%, 97.99%, 95.94%, 96.31% and 93.43%, respectively, indicating that hydrolysis is the primary metabolic pathway of GMDTC in liver microsomes in vitro, and with no significant interspecies differences.

Cadmium up Taking and Allocation in Wood Species Associated to Cacao Agroforestry Systems and Its Potential Role for Phytoextraction

Trees in cacao Agroforestry systems (AFS) may present a high potential for cadmium (Cd) phytoextraction, helping to reduce Cd in cacao (Theobroma cacao L.) plants grown in contaminated soils. To assess this potential, four forest fine-woody species commonly found in cacao high-productive sites in Colombia (Tabebuia rosea, Terminalia superba, Albizia guachapele, and Cariniana pyriformis) were exposed to contrasting CdCl2 contamination levels (0, 6, and 12 ppm) on a hydroponic medium. Growth dynamics, tolerance index (TI), and Cd concentration and allocation in leaves, stems, and roots were evaluated for up to 90 days after initial exposure. T. superba, A. guachapele, and C. pyriformis were classified as moderately tolerant (TI > 0.6), and T. rosea was considered a sensitive species (TI < 0.35) under 12 ppm Cd contamination. Despite showing a high stem Cd concentration, C. pyriformis also showed the lowest relative growth rate. Among the evaluated forest species, A. guachapele exhibited the highest Cd accumulation capacity per plant (2.02 mg plant-1) but also exhibited a higher Cd allocation to leaves (4%) and a strong decrease in leaf and stem dry mass after 90 days of exposure (~75% and 50% respectively, compared to control treatments). Taking together all the favorable features exhibited by T. superba as compared to other CAFS tree species and recognized phytoextractor tree species in the literature, such as Cd hyperaccumulation, high tolerance index, low Cd concentration in leaves, and high Cd allocation to the stem (harvestable as wood), this species is considered to have a high potential for cadmium phytoextraction in cocoa agroforestry systems.

Electrochemical Evaluation of Cd, Cu, and Fe in Different Brands of Craft Beers from Quito, Ecuador

The presence of heavy metals in craft beers can endanger human health if the total metal content exceeds the exposure limits recommended by sanitary standards; in addition, they can cause damage to the quality of the beer. In this work, the concentration of Cd(II), Cu(II), and Fe(III) was determined in 13 brands of craft beer with the highest consumption in Quito, Ecuador, by differential pulse anodic stripping voltammetry (DPASV), using as boron-doped diamond (BDD) working electrode. The BDD electrode used has favorable morphological and electrochemical properties for the detection of metals such as Cd(II), Cu(II), and Fe(III). A granular morphology with microcrystals with an average size between 300 and 2000 nm could be verified for the BDD electrode using a scanning electron microscope. Double layer capacitance of the BDD electrode was 0.01412 μF cm^-2, a relatively low value; Ip_ox/Ip_red ratios were 0.99 for the potassium ferro-ferricyanide system in BDD, demonstrating that the redox process is quasi-reversible. The figures of merit for Cd(II), Cu(II), and Fe(III) were; DL of 6.31, 1.76, and 1.72 μg L^-1; QL of 21.04, 5.87, and 5.72 μg L^-1, repeatability of 1.06, 2.43, and 1.34%, reproducibility of 1.61, 2.94, and 1.83% and percentage of recovery of 98.18, 91.68, and 91.68%, respectively. It is concluded that the DPASV method on BDD has acceptable precision and accuracy for the quantification of Cd(II), Cu(II), and Fe(III), and it was verified that some beers did not comply with the permissible limits of food standards.

Quantitative Analysis and 2D/3D Elemental Imaging of Cocoa Beans Using X-ray Fluorescence Techniques

As an important raw material for the confectionery industry, the cocoa bean (Theobroma cacao L.) has to meet certain legal requirements in terms of food safety and maximum contaminant levels in order to enter the cocoa market. Understanding the enrichment and distribution of essential minerals but also toxic metals is of utmost importance for improving the nutritional quality of this economically important raw food material. We present three X-ray fluorescence (XRF) techniques for elemental bio-imaging of intact cocoa beans and one additional XRF technique for quantitative analysis of cocoa pellets. The interrelation of all the methods presented gives a detailed picture of the content and 3D-resolved distribution of elements in complete cocoa beans for the first time.

An investigation of zinc isotope fractionation in cacao (Theobroma cacao L.) and comparison of zinc and cadmium isotope compositions in hydroponic plant systems under high cadmium stress

This study aims to establish whether zinc (Zn) and cadmium (Cd) share similar physiological mechanisms for uptake and translocation in cacao plants (Theobroma cacao L.). Multiple-collector ICP-MS was used to determine the Zn stable isotope compositions in the roots, stems and leaves of 19 diverse cacao genotypes grown in hydroponics with 20 µmol L^-1 CdCl₂. Additional plants of one genotype were grown in hydroponic solutions containing lower Cd concentrations (0 and 5 µmol L^-1 added CdCl₂). Regardless of the Cd concentration used in the exposures, the Zn stable isotope compositions show the same systematic patterns in plant organs, with δ⁶⁶Zn_root > δ⁶⁶Zn_stem > δ⁶⁶Zn_leaf (δ⁶⁶Zn denotes relative differences in ⁶⁶Zn/⁶⁴Zn ratios in parts per thousand). The mean Zn stable isotope fractionation between the plants and the hydroponic solutions was ε⁶⁶Zn_uptake = -1.15 ± 0.36‰ (2SD), indicating preferential uptake of isotopically light Zn by plants from the hydroponic solution. The mean  stable isotope fractionation factor associated with translocation of Zn from roots to shoots, ε⁶⁶Zn_seq-mob =  + 0.52 ± 0.36‰ (2SD), shows that isotopically heavy Zn is preferentially sequestered in the cacao roots, whilst isotopically light Zn is mobilised to the leaves. A comparison with the Cd stable isotope compositions of the same plants shows that both isotopically light Zn and Cd are preferentially taken up by cacao plants. In contrast to Zn, however, the cacao roots retain isotopically light Cd and transfer isotopically heavy Cd to the leaves.

Foliar application of nanoceria attenuated cadmium stress in okra (Abelmoschus esculentus L.)

Foliar application of nanoparticles (NPs) as a means for ameliorating abiotic stress is increasingly employed in crop production. In this study, the potential of CeO₂-NPs as stress suppressants for cadmium (Cd)-stressed okra (Abelmoschus esculentus) plants was investigated, using two cycles of foliar application of CeO₂-NPs at 200, 400, and 600 mg/l. Compared to untreated stressed plants, Cd-stressed plants treated with CeO₂-NPs presented higher pigments (chlorophyll a and carotenoids). In contrast, foliar applications did not alter Cd root uptake and leaf bioaccumulation. Foliar CeO₂-NPs application modulated stress enzymes (APX, SOD, and GPx) in both roots and leaves of Cd-stressed plants, and led to decreases in Cd toxicity in plant's tissues. In addition, foliar application of CeO₂-NPs in Cd-stressed okra plants decreased fruit Cd contents, and improved fruit mineral elements and bioactive compounds. The infrared spectroscopic analysis of fruit tissues showed that foliar-applied CeO₂-NPs treatments did not induce chemical changes but induced conformational changes in fruit macromolecules. Additionally, CeO₂-NPs applications did not alter the eating quality indicator (Mg/K ratio) of okra fruits. Conclusively, the present study demonstrated that foliar application of CeO₂-NPs has the potential to ameliorate Cd toxicity in tissues and improve fruits of okra plants.

Implementation of pre-harvest techniques in emerging agroforestry systems to increase the yield of cocoa tree (Theobroma cacao L.)

Cocoa is one of the most important tropical fruits worldwide, its importance lies in its use in the food, cosmetic and pharmaceutical industries. Cocoa yield has been affected by different environmental, cultural and phytosanitary aspects. The emergence of new growing areas allows exploring the possibility of generating new economic and ecological systems that comply with current trends in organic farming. For them, pre-harvest practices such as pruning and soil fertilization are two necessary tools to control the productivity of cocoa agroecosystems. Therefore, the objective of this research was to analyses the implementation of pre-harvest techniques and the quality soil to increase the yield in a cocoa agroecosystem in an emerging zone in the Huasteca Potosina of Mexico. The work was carried out in an emerging zone in the cultivation of cocoa in three different zones delimited in 30 × 30 m. Thinning and pruning practices were carried out to keep the space clear and observe the influence on fruit yield. In addition, the quality of the soil was measured in terms of physical conditions and nutrient content. 25 kg/ha of nitrogen, 22 kg/ha of P2O5, 24 kg/ha of K2O and 4 kg/ha of magnesium were added following the recommendation of the fertilization laboratory. The physical properties of the pod were also analyzed, such as size, weight, number of grains and color. And some of the cocoa bean such as size, weight and hardness, all these parameters to measure the average yield of cocoa pods. The results show a clear influence of the soil quality and pre-harvest practices on the physical properties of the fruit and the total yield from 472.36 ± 52.01 to 520.06 ± 104.91 kg. However, other aspects are also modified, such as the increase in the size of the pod and the cocoa bean. Other aspects such as the color of the pod and the hardness of the grain do not present statistical difference. In conclusion, pre-harvest practices together with the application of fertilizers are factors that positively influence the yield of cocoa fruit. Some of the limitations of this research were the age of the plants and the local plant species.

Nano-selenium alleviates cadmium-induced cerebellar injury by activating metal regulatory transcription factor 1 mediated metal response

This study aims to investigate the role of metal regulatory transcription factor 1 (MTF1)-mediated metal response in cadmium (Cd)-induced cerebellar injury, and to evaluate the antagonistic effects of nano-selenium (Nano-Se) against Cd toxicity. A total of 80 chicks (1 d old, male, Hy-Line Variety White) were randomly allocated to 4 treatment groups for 3 months: the control group (fed with a basic diet, n = 20), the Nano-Se group (basic diet with 1 mg/kg nano-Se 1 mg/kg Nano-Se in basic diet, n = 20), the Nano-Se + Cd group (basic diet with 1 mg/kg Nano-Se and 140 mg/kg CdCl₂, n = 20) and the Cd group (basic diet with 140 mg/kg CdCl₂ , n = 20). The results of the experiment showed that the Purkinje cells were significantly decreased with their degradation and indistinct nucleoli after Cd exposure. Moreover, exposure to Cd caused a significant accumulation of Cd and cupper. However, the contents of Se, iron, and zinc were decreased, thereby disturbing the metal homeostasis in the cerebellum. The Cd exposure also resulted in high levels of malondialdehyde (MDA) and down regulation of selenoprotein transcriptome. Furthermore, the expressions of MTF1, metallothionein 1 (MT1), MT2, zinc transporter 3 (ZNT3), ZNT5, ZNT10, zrt, irt-like protein 8 (ZIP8), ZIP10, transferrin (TF), ferroportin 1 (FPN1), ATPase copper transporting beta (ATP7B), and copper uptake protein 1 (CTR1) were inhibited by Cd exposure. However, all these changes were significantly alleviated by the supplementation of Nano-Se. This study proved that Cd could disorder metal homeostasis and induce oxidative stress, whereas Nano-Se could relieve all these negative effects caused by Cd via activating the MTF1-mediated metal response in the cerebellum of chicken.

Fast Detection of Cadmium in Chocolate by Solid Sampling Electrothermal Vaporization Atomic Absorption Spectrometry and Its Application on Dietary Exposure Risk Assessment

In this work, a rapid detection method using solid sampling electrothermal vaporization atomic absorption spectrometry (SS-ETV-AAS) was established for cadmium in chocolate. The instrumental system includes a solid sampling ETV unit, a catalytic pyrolysis furnace, an AAS detector, and a gas supply system with only an air pump and a hydrogen generator. Herein, MgO material with 1.0−1.5 mm particle size was first employed to replace the kaolin filler previously used to further shorten the peak width and to thereby improve the sensitivity. With 350 mL/min of air, a chocolate sample was heated for 25 s from 435 to 464 °C to remove water and organic matrices; then, after supplying 240 mL/min hydrogen and turning down air to 120 mL/min, a N2/H2 mixture gas was formed to accelerate Cd vaporization from chocolate residue under 465 to 765 °C. Under the optimized conditions, the detection limit (LOD) was obviously lowered to 70 pg/g (vs. previous 150 pg/g) with R2 > 0.999; the relative standard deviations (RSD) of repeated measurements for real chocolate samples ranged from 1.5% to 6.4%, indicating a favorable precision; and the Cd recoveries were in the range of 93−107%, proving a satisfied accuracy. Thus, the total analysis time is less than 3 min without the sample digestion process. Thereafter, 78 chocolate samples with different brands from 9 producing countries in China market were collected and measured by this proposed method. Based on the measured Cd concentrations, a dietary exposure assessment was performed for Chinese residents, and the target hazard quotient (THQ) values are all less than 1, proving no significant health risk from intaking chocolate cadmium for Chinese residents.

Extraction Induced by Emulsion Breaking for Ca, Cu, Fe, Mn, Ni, and Zn Determination in Chocolate by Flame Atomic Absorption Spectrometry

Background

Chocolate is a rich source of essential and non-essential elements. A new liquid–liquid extraction (LLE) approach, extraction induced by emulsion breaking (EIEB), is proposed in which the analyzed elements are transferred from the organic phase to the aqueous phase before measurement by flame atomic absorption spectrometry (FAAS).

Objective

To compare EIEB to microwave digestion (MWD) for extraction of elements from chocolate prior to FAAS.

Methods

EIEB parameters were varied to optimize the procedure. EIEB-FAAS was then compared to MWD-FAAS for the analysis of Ca, Cu, Fe, Mn, Ni, and Zn in milk and dark chocolate samples. A certified reference material (NIST 2384, baking chocolate) was analyzed to determine the recoveries of Ca, Cu, Fe, Mn, and Zn by the two methods.

Results

The optimized EIEB extraction method involves dilution of tempered chocolate with toluene, ultrasonic emulsification with acidified Triton X-114, breaking the emulsion by heating, and centrifugation to produce two well-defined phases. Analysis of dark and milk chocolate samples showed similar repeatability by EIEB-FAAS (RSDr 0.3 to 6.6% in dark and 0.5 to 8.7% in milk) and MWD-FAAS (RSDr 0.5 to 5.4% in dark and 0.7 to 10.2% in milk), with no significant difference detected between the methods for analysis of Ca, Cu, Fe, Mn, Ni, and Zn based on Student’s t-test. Analysis of NIST 2384 baking chocolate certified reference material for Ca, Cu, Fe, Mn, and Zn demonstrated recoveries of 98.6 to 99.5% for EIEB-FAAS compared to 95.8 to 98.6% for MWD-FAAS.

Conclusion

EIEB-FAAS was shown to provide high recovery and excellent repeatability for accurate determination of Ca, Cu, Fe, Mn, Ni, and Zn from dark and milk chocolates.

Highlight

The EIEB-FAAS method is simpler and requires fewer reagents compared to other sample preparation methods and allows the calibration to be carried out using aqueous calibration solutions.

Pollution and health: a progress update

The Lancet Commission on pollution and health reported that pollution was responsible for 9 million premature deaths in 2015, making it the world's largest environmental risk factor for disease and premature death. We have now updated this estimate using data from the Global Burden of Diseases, Injuriaes, and Risk Factors Study 2019. We find that pollution remains responsible for approximately 9 million deaths per year, corresponding to one in six deaths worldwide. Reductions have occurred in the number of deaths attributable to the types of pollution associated with extreme poverty. However, these reductions in deaths from household air pollution and water pollution are offset by increased deaths attributable to ambient air pollution and toxic chemical pollution (ie, lead). Deaths from these modern pollution risk factors, which are the unintended consequence of industrialisation and urbanisation, have risen by 7% since 2015 and by over 66% since 2000. Despite ongoing efforts by UN agencies, committed groups, committed individuals, and some national governments (mostly in high-income countries), little real progress against pollution can be identified overall, particularly in the low-income and middle-income countries, where pollution is most severe. Urgent attention is needed to control pollution and prevent pollution-related disease, with an emphasis on air pollution and lead poisoning, and a stronger focus on hazardous chemical pollution. Pollution, climate change, and biodiversity loss are closely linked. Successful control of these conjoined threats requires a globally supported, formal science-policy interface to inform intervention, influence research, and guide funding. Pollution has typically been viewed as a local issue to be addressed through subnational and national regulation or, occasionally, using regional policy in higher-income countries. Now, however, it is increasingly clear that pollution is a planetary threat, and that its drivers, its dispersion, and its effects on health transcend local boundaries and demand a global response. Global action on all major modern pollutants is needed. Global efforts can synergise with other global environmental policy programmes, especially as a large-scale, rapid transition away from all fossil fuels to clean, renewable energy is an effective strategy for preventing pollution while also slowing down climate change, and thus achieves a double benefit for planetary health.

Reducing cadmium bioaccumulation in Theobroma cacao using biochar: basis for scaling-up to field

The intake of Cd-enriched food is the main Cd pathway for the nonsmoking population. In some cases, Cd bioaccumulates in edible plant parts which comprise risk to consumers, because of Cd is a harmful heavy metal that can cause potent environmental and health hazards. For instance, Cd enrichment of cacao seeds have led to Cd enrichment of cacao-based products. In Latin America and the Caribbean, Cd bioaccumulation in cacao seeds occurs in different regions with diverse edaphoclimatic conditions, which makes it difficult to select soil remediation alternatives. Limited resources require that potential amendments must be carefully investigated through laboratory and/or greenhouse conditions before scaling up to field experiments. In this study, we evaluated the effectiveness of four biochars: coffee-, quinoa-, and inoculated- and palm-biochar, derived from three feedstocks: coffee husk, quinoa straw, and oil palm residues, respectively. Biochars were applied in two rates (1 and 2% w/w) in two soils, one moderately acidic and one slightly alkaline (Cd-spiked and non-spiked). CCN-51 cacao plants were used for the greenhouse experiment. After 130 days, biometric parameters, the bioavailability of Cd in the soil, and the concentration of Cd and mineral nutrients in the plants were measured. Quinoa biochar at the 2% significantly decreased (P < 0.01), by ∼71%, bioavailable Cd in moderately acidic and slightly alkaline soils, and leaf-Cd by ∼48%. Soil pH, electrical conductivity, and effective cation exchange capacity were significantly (P < 0.01) correlated with bioavailable soil and leaf-Cd. Biochar characteristics, such as ash contents, basic cations content, and surface functional groups could be used as indicators for the selection of biochars to reduce Cd uptake by cacao. Additionally, application of quinoa derived biochar provided P and K, which could increase productivity to offset mitigation costs. Overall, incorporation of quinoa biochar at 2% rate is effective for lowering bioavailable Cd in different soil types which reduces leaf-Cd in cacao plants.

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Biochar ash content helps to increase soil pH and reduce Cd bioavailability.

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Quinoa biochar at 2% reduced up to 80% bioavailable Cd in moderately acidic and slightly alkaline soils.

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Quinoa biochar at 2% lowered, up to 48%, Cd concentration in cacao plants.

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Soil pH, CECe, and EC were significant and negative related to bioavailable and plant-Cd.

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Ash content could be used as a guide for selecting biochars for Cd remediation.

'From soil to chocolate bar': identifying critical steps in the journey of cadmium in a Colombian cacao plantation

Regulation of maximum levels of cadmium in chocolate is an issue for cacao exportation from many parts of Latin America, including Colombia. These limits are related to the final product, but buyers often request maximum levels of Cd in the beans. However, to date, there is neither a clear understanding of the relationship between the specified levels of Cd in chocolate and cocoa derivatives and levels in harvested beans or soil nor of the effect of post-harvest processes on the levels of Cd in the final product. To address this, the fate of Cd concentration from soil to chocolate bar was followed in a single farm in Santander district, Colombia. The concentration of Cd in soils was measured using ICP-OES and correlated with soil pH, soil organic matter (SOM), and the use of P-based fertilisers. Cd concentrations were also measured in unfermented seeds, fermented and dried beans, shell, nibs, and chocolate. SOM (2.93-3.78%), soil pH (4.7-4.9), soil P concentration (120-132 mg kg^-1) affect Cd availability. However, it is still unclear whether Cd concentration of P-based fertilisers (3-30 mg kg^-1) is important or not. While post-harvest treatments did not affect the Cd concentration of beans (4.17 ± 0.8 mg kg^-1 on average), the removal of the shell (6.57 mg kg^-1) from the nibs (3.28 mg kg^-1), as well as the percentage of cocoa mass used contributes to a reduction in Cd concentration in the chocolate bar (1.60 mg kg^-1). This study provides clear indications on where research into mitigation measures should be focussed, as well as indicating the importance of carrying out analyses for Cd in the nib or cacao mass, rather than the whole bean, reducing Cd concentration by up to 40%.

Drivers of cadmium accumulation in Theobroma cacao L. beans: A quantitative synthesis of soil-plant relationships across the Cacao Belt

Elevated cadmium (Cd) concentrations in cacao and cocoa-based products (e.g., chocolate) present a potentially serious human health risk. While recent regulatory changes have established a threshold of 0.8 mg kg-1 for Cd content of cocoa-based products, the biophysical factors (e.g., climatic or edaphic conditions) that determine the amount of soil-derived Cd in the cacao bean are poorly understood and have yet to be quantitatively assessed across diverse production contexts. To determine the primary drivers of cacao bean Cd, we used the scientific literature to systematically compile a database of climatic, edaphic, and plant data from across the Cacao Belt, which is approximately 20 degrees latitude on either side of the equator. From this compiled dataset, we then used boosted regression trees to quantitatively synthesize and evaluate these drivers of cacao bean Cd. Total soil Cd concentration, soil pH, and leaf Cd were the best predictors of bean Cd content. Notably, we found that both available soil Cd and soil organic carbon (SOC) content had negligible effects on bean Cd. However, soil pH and SOC decreased the degree of bioconcentration of total soil Cd in the bean Cd concentration. Thus, given the difficulty in remediating soil Cd enriched soils, our results suggest that Cd mitigation strategies targeting plant physiology-based approaches (e.g., breeding, rootstocks) have a higher probability of success than soil-based strategies (e.g., remediation).

Lowering the Toxicity of Cd to Theobroma cacao Using Soil Amendments Based on Commercial Charcoal and Lime

Carbonaceous and calcareous materials are commonly used as amendments to decrease the Cd mobility in contaminated soils. This study evaluated the effect of amendments applied to cocoa seedlings in the greenhouse, considering the mobilization of soil cadmium toward the seedlings as the main response. The experimental conditions considered soil artificially contaminated with Cd at a concentration of 50 mg Cd kg⁻¹ and applications of amendments in different treatments with the presence of charcoal dust and calcium carbonate. The charcoal was characterized by microscopy and by adsorption tests, and it proved to be a material with macropores, with a maximum capacity of 8.06 mg Cd g⁻¹ and favorable kinetic behavior according to the adjustment of the data obtained to the pseudo-second-order model. The results also showed that the application of liming decreased the mobility of Cd toward the seedlings, with the liming combined with charcoal leading to the absence of Cd in the cocoa seedlings, considering a residual concentration of Cd in the soil of 35 mg Cd kg⁻¹. The results, although limited to a small scale, demonstrated the possibility of applying low-cost and easy-to-handle amendments for the control of Cd in cocoa plantations.

Effect of soil characteristics on cadmium absorption and plant growth of Theobroma cacao L. seedlings

BACKGROUND

Cadmium uptake by cacao plants can affect plant growth, consumer health and commercialisation. To develop mitigation strategies, it is essential to identify the soil characteristics that could influence this absorption. To determine the relationships between cadmium absorption and the soil characteristics of cacao areas, the responses at concentrations of 0, 2, 5, 10 and 20 μg g^-1 of cadmium in three soils of these areas and an andisol were evaluated, using 120-day-old seedlings of four cultivars of Theobroma cacao L.

RESULTS

In the present study, several relationships were found between chemical and physical soil characteristics and available cadmium, such as real and bulk densities, as well as contents of iron, sand, magnesium, potassium, sodium and copper. Additionally, moderate to strong correlations between potassium (r²  = -0.56) and real density (r²  = 0.42), with foliar cadmium, were found. Moreover, a differential deleterious effect on cacao growth in variables such as biomass was corroborated in cadmium concentrations from 5 μg g^-1 in soils. There were no statistical differences between cultivars with respect to cadmium uptake or plant growth. Finally, a multiple linear regression model is proposed to estimate the foliar cadmium content (r²  = 0.878).

CONCLUSION

Some soil characteristics such as density, as well as sand, clay, aluminium, potassium and iron contents, should be considered before establishing cacao crops to avoid cadmium accumulation. The correlation between potassium with foliar cadmium indicated that potassium could be significant in cadmium uptake mitigation strategies. The high correlation between available cadmium and foliar cadmium indicates that the quantification methodology developed using ethylenediaminetetraacetic acid extractant may be a useful diagnostic tool. © 2021 Society of Chemical Industry.

Quality differentiation of cocoa beans: implications for geographical indications

Geographical indications may stimulate collective actions of governance for quality control, trade and marketing as well as innovation based on the use of local resources and regional biodiversity. Cocoa production, however, dominated by small family agriculture in tropical regions, has rarely made use of such strategies. This review is aimed at understanding major research interests and emerging technologies helpful for the origin differentiation of cocoa quality. Results from literature search and cited references of publications on cocoa research were imported into VOSviewer for data analysis, which aided in visualizing major research hotpots. Co-occurrence analysis yielded major research clusters which guided the discussion of this review. Observed was a consensus recognizing cocoa quality resulting from the interaction of genotype, fermentation variables and geographical origin. A classic view of cocoa genetics based on the dichotomy of 'fine versus bulk' has been reexamined by a broader perspective of human selection and cocoa genotype evolution. This new approach to cocoa genetic diversity, together with the understanding of complex microbiome interactions through fermentation, as well as quality reproducibility challenged by geographical conditions, have demonstrated the importance of terroir in the production of special attributes. Cocoa growing communities around the tropics have been clearly enabled by new omics and chemometrics to systematize producing conditions and practices in the designation of specifications for the differentiation of origin quality. © 2021 Society of Chemical Industry.

Heavy metal contamination and health risk assessment in grains and grain-based processed food in Arequipa region of Peru

Heavy metals (HMs) in crops and processed foods are a concern and pose a potential serious health hazard. This study investigated possible presence of HMs in grains and processed products in the Region of Arequipa in Peru. Concentrations of Cd, As, Sn, Pb, and Hg were determined for commonly consumed grains in 18 districts of the region and processed products from 3 popular markets of Arequipa city, using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and Cold Vapor Atomic Absorption Spectroscopy (CVAAS). HM concentrations above the Codex General Standard limits were found for As (0.17 mg kg^-1) and Cd (0.11 mg kg^-1) in cereal grains. Elevated Pb concentrations of 0.55, 0.75, and 5.08 mg kg^-1 were found for quinoa, maize, and rice products, respectively; and attributed to processing conditions. The Total Hazard Index (HI) for polished rice and rice products had values between 1 and 10, showing non-carcinogenic adverse effects. Total Target Cancer Risk (TR_T) and uncertainty analysis of percentile P_90% for polished rice and quinoa products gave values above permissible limit of 10^-4, indicating an unacceptable cancer risk. The Nemerow Composite Pollution Index method (NCPI) showed that processed products had a significant pollution level due to the presence of Pb. While most crops grains had acceptable low HM levels, this is the first report of concerning HM concentrations in some consumed grains and processed products in southern Peru and indicates the necessity to find ways to decrease certain toxic metals in foods.

Cadmium concentration and its typical input and output fluxes in agricultural soil downstream of a heavy metal sewage irrigation area

Heavy metal pollution of agricultural soils in sewage irrigation areas is a serious environmental issue. Many prior studies have demonstrated that soil around the irrigation area is polluted with heavy metals, even though they had not been irrigated by wastewater. In this study, a paddy field downstream of the Zhangshi Irrigation Area was selected as the study area. The Cd concentrations and their representative input and output fluxes to and from the topsoil were systematically studied. The results showed that 95.5% of soil samples exceeded the screening value of Cd concentration. The Cd input fluxes via irrigation water and atmospheric deposition, accounting for 56.95% and 42.53% of the total input flux, respectively, were the main sources of Cd in soil. Crop harvesting was the main output pathway, accounting for 89.63% of the total output flux. An estimation of the annual mass balance showed that Cd in the studied area was in a state of accumulation, and the annual increase in Cd concentration in topsoil would be 2.46 µg kg^-1 if the observed fluxes remain. These results will provide a reference for the development of strategies to control and reduce heavy metal contamination and diffusion in agricultural soils around irrigation areas.

Organic farming: Does it contribute to contaminant-free produce and ensure food safety?

Organic farming for higher ecological and human health benefits has been adopted in about 186 countries, covering a total area of 71.5 Mha worldwide. Because of the associated practices, the flows of several environmental pollutants into the organic products threaten food safety and human health. The contaminants that occur at higher concentrations in organic produce include persistent organic pollutants (61.3-436.9 ng g^-1 lamb meat, and 0.28 pg g^-1-2.75 ng g^-1 bovine meat), heavy metals (0.5-33.0 mg kg^-1 lettuce), organochlorine pesticides (11-199 μg g^-1 carrots), cyclodienes, hexachlorocyclohexanes, hexabromocyclododecane (2-3 times higher than in conventionally produced porcine meat), hexachlorobenzene (1.38-14.49 ng g^-1 fat in milk), and non-brominated flame retardants (1.3-3.2 times higher than in conventional produce of greenhouse-grown tomato and cucumber). Moreover, some pollutants like per- and polyfluoroalkyl substances with a longer half-life (1.50-9.10 yrs) are reported to occur in several organic products. In fact, several legacy persistent organic pollutants are known for their significant trophic magnification in an urban terrestrial ecosystem. In addition, many plant functionalities are adversely affected in organic farming. Therefore, the long-term usage of organic products containing such pollutants poses a significant threat to human health. The major limitation in organic livestock production is the severe shortage of organic feed. Several variable standards and technical regulations set by the government and private agencies are the major obstacles in the global marketing of organic products. The present review critically addresses the impact of organic farming on hidden risks due to the use of composts as the amendment resources that enhance the phytoaccumulation and trophic transfer of pollutants, the functional diversity of the ecosystems, and poor harmonization among the policies and regulations in different countries for organic farming. The future directions of research have been suggested to mitigate unintended flows of pollutants into the organic products.

The global research trend on cadmium in freshwater: a bibliometric review

Cadmium pollution turns out to be a global environmental problem. This study conducted a quantitative and qualitative bibliometric analysis based on 9188 research items from the Web of Science Core Collection published in the last 20 years (2000-2020), presenting an in-depth statistical investigation of global freshwater cadmium research progress and developing trend. Our results demonstrated that the researchers from China, the USA, and India contribute the most to this field. The primary sources of cadmium are mining, industry, wastewater, sedimentation, and agricultural activities. In developing countries, cadmium exposure occurs mainly through the air, freshwater, and food. Fish and vegetables are the main food sources of cadmium for humans because of their high accumulation capability. Source evaluation, detection, and remediation represent the main technologies used to clean up cadmium-contaminated sites. To mitigate the risk of cadmium contamination in freshwater, biomarker-based cadmium monitoring methods and integrated policies/strategies to reduce cadmium exposure merit further concern.

Bioactive compounds and techno-functional properties of high-fiber co-products of the cacao agro-industrial chain

The cacao shell (CS) and cacao pod husk (CPH), two of the most promising high-fiber co-products of the cacao agro-industrial chain, were evaluated to determine their potential incorporation into food products. This research determined bioactive compounds and techno-functional properties of CS and CPH, and was evaluated the enzymatic inactivation by thermal treatments in CPH. We found that CS is rich in protein, lipids, dietary fiber (48.1 ± 0.3 g 100 gdw -1), and antioxidant molecules such as epicatechin (1.10 ± 0.02 mg g-1) and isoquercetin (1.04 ± 0.09 mg g-1). Moreover, in CS a positive effect of hydration mechanism occur; in fact, it was observed a reduction of Lightness (L∗) value and a remarkable color difference (ΔE∗,18.8 ± 0.7) (CIEL∗a∗b∗ color space), between hydrated and dry CS samples; so, it could be used as a potential natural colorant in foods. CPH resulted equally rich in dietary fiber (35.3-37.4%) and flavonoids (2.9 ± 0.1 mg RE g-1); in this co-product, the rapid enzymatic inactivation by thermal treatments was essential to obtain the highest antioxidant activity and polyphenols content; regarding the techno-functional properties, it was found that CPH flour had high hydration capacity, so CPH can use it as a replacement for emulsifiers or water holding additives while incorporating the fiber and abundantly found antioxidants.

Cadmium Uptake in Native Cacao Trees in Agricultural Lands of Bagua, Peru

Cadmium (Cd) contamination threatens cocoa farming in the province of Bagua in Amazonas, Peru. This study reports our assessment of Cd concentrations in cocoa farm soils, and in cocoa roots, leaves, testa, and cotyledon, thus evaluating the magnitude of the problem caused by Cd exposure. For our analysis, we sampled agricultural soil, cocoa roots, leaves and pods at 29 farms in the province of Bagua. Concentrations of Cd in each of the samples were measured and correlated with selected variables at each sampling site. Within our collection of samples, Cd levels showed great variability. In soil, Cd concentrations ranged between 1.02 and 3.54 mg kg−1. Concentrations of this metal within cocoa trees measured from roots, leaves, testa, and cotyledon, Cd ranged from 0.49 mg kg−1 to 2.53 mg kg−1. The cocoa trees exhibited variable degrees of allocation Cd from the soil to their tissues and thus considerable variation among themselves. We found that Cd amounts in roots were up to five times more concentrated than Cd levels in the soils and 2.85 times [Cd] the amounts found in cotyledon. Soil pH is a key variable enabling the uptake of this metal. Most importantly, our evaluation determined that measurements from the majority of farms exceeded the maximum permissible limits established by Peruvian and European legislation.

Transforming Tropical Agroforestry towards High Socio-Ecological Standards

Growing demand for tropical commodities that are socially and environmentally more sustainable is changing the global market for agroforestry products such as coffee and cocoa. Transforming mass production of cash crops towards higher socio-ecological standards includes challenges, but also novel opportunities to protect ecosystem services and human health and well-being alike.