Human and animal health risk assessments of chemicals in the food chain: comparative aspects and future perspectives

Application of a generic PBK model for beef cattle: Tissue/fluid correlations of paracetamol and NSAIDs

Nonsteroidal Anti-Inflammatory Drugs (NSAIDs) and paracetamol can be administered off-label to cattle. Since the use of these veterinary medicines in cattle may pose a public health risk after meat consumption, it is important to translate measured concentrations in urine and tissues into concentrations in meat for human consumption. A generic physiologically-based kinetic (PBK) model for cattle can enable this translation. In this work, a beef cattle PBK model was applied to calculate the relationships between concentrations in different bovine tissues and those were compared to measured concentrations in different matrices. Sixty-seven kidney samples, the corresponding urine and meat samples, and available 19 serum samples were analysed. Overall, 70% of the PBK model predictions are within a 2-fold factor and relationships for kidney/meat, urine/meat, and plasma/meat ratios were established. The conversions of measured kidney concentrations into meat concentrations were mostly within a factor two, while those based on plasma and urine were underpredicted. Based on these ratios, plasma and urine could be used as an appropriate surrogate matrix for a fast, simple in vivo sample screening test under field conditions, such as in local farms and slaughterhouses, to predict a maximum residue level exceedance in meat, reducing the number of test samples.

Review of the Terminology, Approaches, and Formulations Used in the Guidelines on Quantitative Risk Assessment of Chemical Hazards in Food

This paper reviews the published terminology, mathematical models, and the possible approaches used to characterise the risk of foodborne chemical hazards, particularly pesticides, metals, mycotoxins, acrylamide, and polycyclic aromatic hydrocarbons (PAHs). The results confirmed the wide variability of the nomenclature used, e.g., 28 different ways of referencing exposure, 13 of cancer risk, or 9 of slope factor. On the other hand, a total of 16 equations were identified to formulate all the risk characterisation parameters of interest. Therefore, the present study proposes a terminology and formulation for some risk characterisation parameters based on the guidelines of international organisations and the literature review. The mathematical model used for non-genotoxic hazards is a ratio in all cases. However, the authors used the probability of cancer or different ratios, such as the margin of exposure (MOE) for genotoxic hazards. For each effect studied per hazard, the non-genotoxic effect was mostly studied in pesticides (79.73%), the genotoxic effect was mostly studied in PAHs (71.15%), and both effects were mainly studied in metals (59.4%). The authors of the works reviewed generally opted for a deterministic approach, although most of those who assessed the risk for mycotoxins or the ratio and risk for acrylamide used the probabilistic approach.

Assessing the health risks of dermal exposure to heavy metals dust among nail salon technicians

BACKGROUND

Nail salon technicians are susceptible to potential exposure to a diverse array of hazardous chemicals in the form of dust or vapors. One of the main routes of exposure is dermal contact.

OBJECTIVE

The aim of present study was to health risk assessment of dermal exposure to dust containing heavy metals in nail salon technicians.

METHODS

Dust sampling was done on the work surface of 20 available nail salon technicians. The concentration of five metals including cadmium, lead, chromium, nickel, and manganese were determined using ICP-MS. Afterwards, the United States Environmental Protection Agency (USEPA) guideline was used to estimate the potential health risks, including carcinogenic and non-carcinogenic risks, associated with the analyzed metals.

RESULTS

Results indicated the mean concentrations of Pb, Cd, Ni, Cr and Mn were 0.7953±0.4373, 0.0952±0.0264, 0.7666±0.8629, 0.4900±0.5994 and 1.134±0.4736, respectively. The hazard quotient (HQ) of all metals was within the permissible value, while hazard index (HI) was greater than 1. The probability of cancer risk (CR) resulting from dermal exposure to Ni, Cd and Cr exceeded the acceptable risk levels (10-6-10-4), but CR calculated for Pb was less than allowable value.

CONCLUSION

Implementation of engineering controls such as downdraft vented nail tables and portable source capture systems is necessary. Besides, the use of personal protective equipment such as disposable nitrile gloves, N95 respirator masks, and ensuring proper training on safe work practices is recommended.

Machine-learning-facilitated prediction of heavy metal contamination in distiller's dried grains with solubles

Excessive heavy metal contamination often occurs in feed due to natural or anthropogenic activity, leading to poisoning and other health problems in animals. In this study, a visible/near-infrared hyperspectral imaging system (Vis/NIR HIS) was used to reveal the different characteristics of spectral reflectance of Distillers Dried Grains with Solubles (DDGS) doped with various heavy metals and to effectively predict metal concentrations. Two types of sample treatment were used, namely tablet and bulk. Three quantitative analysis models were constructed based on the full wavelength, and through comparison the support vector regression (SVR) model was found to show the best performance. As typical heavy metal contaminants, copper (Cu) and zinc (Zn) were used for modeling and prediction. The prediction set accuracy of the tablet samples doped with Cu and Zn was 94.9% and 86.2%, respectively. In addition, a novel characteristic wavelength selection model based on SVR (SVR-CWS) was proposed to filter characteristic wavelengths, which improved the detection performance. The regression accuracy of the SVR model on the prediction set of tableted samples with different Cu and Zn concentrations was 94.7% and 85.9%, respectively. The accuracy of bulk samples with different Cu and Zn concentrations was 81.3% and 80.3%, respectively, which indicated that the detection method can reduce the pretreatment steps and verify its practicability. The overall results suggested the potential of Vis/NIR-HIS in the detection of feed safety and quality.

Quantitative exposure assessment and risk characterization for fipronil residues in laying hen eggs

Poultry production is linked to veterinary drug use to treat diseases. Few ectoparasitic compounds are approved for poultry. Fipronil is a pesticide widely used in agriculture. It is also a drug authorized to control ectoparasites in small animals and, in some countries, in cattle. There has been evidence of fipronil extra-label use in laying hens, mainly to control the red mite Dermanyssus gallinae. Fipronil's popularity is due to its high toxicity to invertebrates. It could be metabolized to more toxic metabolites that potentially damage human health. In the present study, we carry out a quantitative exposure assessment and risk characterization for fipronil residues in laying hen eggs for local consumption in five cities of Buenos Aires province in Argentina, namely, Azul, Balcarce, Juarez, Chaves, and Tandil. Consumption surveys and egg sampling were conducted for three summer periods. Eggs were analyzed by UFLC-MS-MS. Fipronil prevalence, residue concentrations, residue stability to cooking methods, egg consumption, among the most important variables were modeled. The results indicated that 20.7% of samples contained fipronil residues. The highest residue was fipronil sulfone metabolite. Fipronil concentrations quantified ranged between 10 and 2510 ppb (median value = 150 ppb). When eggs were cooked, fipronil residues were stable. The exposure assessment and risk characterization revealed that the highest probability of consuming eggs with fipronil residues above the admissible limits was for young adults (20.8%), followed by babies (16.9%), young children (16.4%), children (13.4%), teenagers (10.3%), older adults (9.41%), and adults (8.65%). These results suggest an unacceptable risk associated with egg consumption with fipronil residues for all age groups. PRACTICAL APPLICATION: Fipronil is widely used as an extra-label way on laying hens since its use is prohibited in poultry production both in Argentina and in most countries. This molecule has been classified as Class II, a moderately hazardous pesticide because it could damage various human organs. Fipronil residues in eggs could be one of the exposure pathways for consumers. Monitoring residual levels and carrying out the health risk assessment in eggs are thus in an urge.

Fipronil and fipronil sulfone in chicken: From in vitro experiments to in vivo PBK model predictions

In 2017 a large-scale fipronil contamination in eggs occurred in several European countries. Fipronil and its metabolites have the potential to be transferred into the eggs of laying hens, thereby entering the human food chain. Here, first the metabolism of fipronil was measured in vitro using chicken liver S9. The results show that fipronil is mainly metabolised into fipronil sulfone and the clearance obtained in vitro was extrapolated to in vivo liver clearance. In a second step a physiologically based kinetic model was developed with a focus on fipronil and its major sulfone metabolite and the model outcome was compared to available in vivo data in eggs from the literature. The experimentally obtained clearance was used as model input to evaluate whether such an in vitro-based model can be used in an early phase of a contamination incident to predict the time-concentration curves. Overall, all model predictions were within a 10-fold difference and the estimated elimination half-life for fipronil equivalents was 14 days. In vitro experiments are definitely recommended compared to in vivo studies, since they provide a fast first insight into the behaviour of a chemical in an organism.

Health Risk Assessment of Essential and Toxic Metals in Canned/Pouched Food on Kitten and Adult Cats: an Animal Health Risk Assessment Adaptation Assay

The main aim of this study was to determine the levels of Al, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, and Zn in commercial canned and pouched cat foods (salmon, tuna, liver, fish, and other aquatic products) and assess the potential health risks to kitten (≤ 1 years old) and adult cats (≥ 1 years old) associated with the recommended average consumption rate of labels. The study was also aimed to adapt the health risk assessment method to animal health and to support clinical prevention and diagnosis. The detected levels of the metals were below the data from other studies, except the mean Fe in all and Pb levels in salmon and kitten foods. Target hazard quotient (THQ) and total target hazard quotient (TTHQ) values did not exceed 1. That means the studied metals do not pose a health risk for adult cats and kittens. Dietary Hg and Cd should also be considered in the differential diagnosis of cases with clinical or postmortem findings, especially regarding neurological, kidney, and liver tissues. In conclusion, although canned/pouched consumption does not pose a health risk with regard to metals, further studies of health risk assessment for other pollutants by this first adaptation method will be necessary.

Attenuating effect of Prosopis cineraria against paraquat-induced toxicity in prepubertal mice, Mus musculus

Several herbicides, especially paraquat, are persistent organic pollutants which cause damage to humans and animals through reactive oxygen and nitrogen species. Prosopis cineraria (L.) Druce exhibits antioxidant activity and can effectively manage tremors. Therefore, the present research assessed the preventive effect of Prosopis cineraria (L.) Druce ethanolic extract (PCDE) against paraquat-induced toxicity in prepubertal mice. The plant extract was chemically characterized by a high-performance liquid chromatography-diode array detector (HPLC-DAD). The PCDE was orally administered to prepubertal mice for continuous 21 days, 2 h before paraquat exposure (2 mg/kg for consecutive 3 days per week for 3 weeks). The changes in behavior, motor coordination, memory, muscle movement, anxiety, and neurotransmitter levels in the brain were assessed. Histopathology and estimation of oxidative stress parameters in the brain, liver, kidney, and heart tissues were also carried out. HPLC-DAD analysis showed a high amount of quercetin, kaempferol, and ellagic acid derivatives in the plant extract. The PCDE showed improved muscle coordination, muscle movement and memory, and reduced anxiety in prepubertal mice. Moreover, levels of dopamine and noradrenaline were increased in the brain. It successfully ameliorated the oxidative stress in different organs by increasing the level of glutathione and superoxide dismutase and by reducing malondialdehyde. The histopathological assessment showed the plant extract effectively mitigated paraquat-induced pathological lesions in the neurons, neuroglia, hepatocytes, and kidney tissues. It is concluded from the present study that the treatment with PCDE had prevented the paraquat-induced toxicity in the brain, liver, kidney, and heart through the reduction of oxidative stress possibly due to the presence of phenolic compounds and flavonoids.

In Silico Methods for Environmental Risk Assessment: Principles, Tiered Approaches, Applications, and Future Perspectives

This chapter aims to introduce the reader to the basic principles of environmental risk assessment of chemicals and highlights the usefulness of tiered approaches within weight of evidence approaches in relation to problem formulation i.e., data availability, time and resource availability. In silico models are then introduced and include quantitative structure-activity relationship (QSAR) models, which support filling data gaps when no chemical property or ecotoxicological data are available. In addition, biologically-based models can be applied in more data rich situations and these include generic or species-specific models such as toxicokinetic-toxicodynamic models, dynamic energy budget models, physiologically based models, and models for ecosystem hazard assessment i.e. species sensitivity distributions and ultimately for landscape assessment i.e. landscape-based modeling approaches. Throughout this chapter, particular attention is given to provide practical examples supporting the application of such in silico models in real-world settings. Future perspectives are discussed to address environmental risk assessment in a more holistic manner particularly for relevant complex questions, such as the risk assessment of multiple stressors and the development of harmonized approaches to ultimately quantify the relative contribution and impact of single chemicals, multiple chemicals and multiple stressors on living organisms.

Sustainable use of CRISPR/Cas in fish aquaculture: the biosafety perspective

Aquaculture is becoming the primary source of seafood for human diets, and farmed fish aquaculture is one of its fastest growing sectors. The industry currently faces several challenges including infectious and parasitic diseases, reduced viability, fertility reduction, slow growth, escapee fish and environmental pollution. The commercialization of the growth-enhanced AquAdvantage salmon and the CRISPR/Cas9-developed tilapia (Oreochromis niloticus) proffers genetic engineering and genome editing tools, e.g. CRISPR/Cas, as potential solutions to these challenges. Future traits being developed in different fish species include disease resistance, sterility, and enhanced growth. Despite these notable advances, off-target effect and non-clarification of trait-related genes among other technical challenges hinder full realization of CRISPR/Cas potentials in fish breeding. In addition, current regulatory and risk assessment frameworks are not fit-for purpose regarding the challenges of CRISPR/Cas notwithstanding that public and regulatory acceptance are key to commercialization of products of the new technology. In this study, we discuss how CRISPR/Cas can be used to overcome some of these limitations focusing on diseases and environmental release in farmed fish aquaculture. We further present technical limitations, regulatory and risk assessment challenges of the use of CRISPR/Cas, and proffer research strategies that will provide much-needed data for regulatory decisions, risk assessments, increased public awareness and sustainable applications of CRISPR/Cas in fish aquaculture with emphasis on Atlantic salmon (Salmo salar) breeding.

Antioxidative Molecules in Human Milk and Environmental Contaminants

Breastfeeding provides overall beneficial health to the mother-child dyad and is universally recognized as the preferred feeding mode for infants up to 6-months and beyond. Human milk provides immuno-protection and supplies nutrients and bioactive compounds whose concentrations vary with lactation stage. Environmental and dietary factors potentially lead to excessive chemical exposure in critical windows of development such as neonatal life, including lactation. This review discusses current knowledge on these environmental and dietary contaminants and summarizes the known effects of these chemicals in human milk, taking into account the protective presence of antioxidative molecules. Particular attention is given to short- and long-term effects of these contaminants, considering their role as endocrine disruptors and potential epigenetic modulators. Finally, we identify knowledge gaps and indicate potential future research directions.

Creating conditions for critical trust - How an uncertainty-based risk perspective relates to dimensions and types of trust

Although some disagreement about the strength of the relationship, it is generally agreed within risk research, that trust plays a central role in shaping risk perception and risk responses. Over recent decades, risk managing institutions have experienced what by many has been described as a decline in public trust. Strategies like stakeholder involvement and communication of scientific uncertainties are increasingly implemented to rebuild levels of trust but often prove less effective. Also, trust-related research mainly revolves around the relation between regulators and authorities, on one hand, and the public, on the other, with less attention given to the role of the scientific risk assessor. In this paper, we argue that assessors can act to improve conditions of trust by adopting an understanding of risk, stressing uncertainty and knowledge aspects when conceptualizing and characterizing risk. While 'full' trust commonly is seen as an ideal situation and distrust as a state of affairs to be prevented, this approach involves recognizing distrust as a resource. Based on an example regarding the authorization and regulation of a feed additive and the Social Amplification of Risk Framework, we show how such a perspective affects trust, both as a filter for processing, interpreting and responding to risk-related information and as an impact following such processes. Drawing on a typology of trust, we also illustrate how this relates to different dimensions and forms of trust.

Integrated In Silico Models for the Prediction of No-Observed-(Adverse)-Effect Levels and Lowest-Observed-(Adverse)-Effect Levels in Rats for Sub-chronic Repeated-Dose Toxicity

Repeated-dose toxicity (RDT) is a critical endpoint for hazard characterization of chemicals and is assessed to derive safe levels of exposure for human health. Here we present the first attempt to model simultaneously no-observed-(adverse)-effect level (NO(A)EL) and lowest-observed-(adverse)-effect level (LO(A)EL). Classification and regression models were derived based on rat sub-chronic repeated dose toxicity data for 327 compounds from the Fraunhofer RepDose database. Multi-category classification models were built for both NO(A)EL and LO(A)EL though a consensus of statistics- and fragment-based algorithms, while regression models were based on quantitative relationships between the endpoints and SMILES-based attributes. NO(A)EL and LO(A)EL models were integrated, and predictions were compared to exclude inconsistent values. This strategy improved the performance of single models, leading to R² greater than 0.70, root-mean-square error (RMSE) lower than 0.60 (for regression models), and accuracy of 0.61-0.73 (for classification models) on the validation set, based on the endpoint and the threshold applied for selecting predictions. This study confirms the effectiveness of the modeling strategy presented here for assessing RDT of chemicals using in silico models.

An open source physiologically based kinetic model for the chicken (Gallus gallus domesticus): Calibration and validation for the prediction residues in tissues and eggs

Xenobiotics from anthropogenic and natural origin enter animal feed and human food as regulated compounds, environmental contaminants or as part of components of the diet. After dietary exposure, a chemical is absorbed and distributed systematically to a range of organs and tissues, metabolised, and excreted. Physiologically based kinetic (PBK) models have been developed to estimate internal concentrations from external doses. In this study, a generic multi-compartment PBK model was developed for chicken. The PBK model was implemented for seven compounds (with log K_ow range -1.37-6.2) to quantitatively link external dose and internal dose for risk assessment of chemicals. Global sensitivity analysis was performed for a hydrophilic and a lipophilic compound to identify the most sensitive parameters in the PBK model. Model predictions were compared to measured data according to dataset-specific exposure scenarios. Globally, 71% of the model predictions were within a 3-fold change of the measured data for chicken and only 7% of the PBK predictions were outside a 10-fold change. While most model input parameters still rely on in vivo experiments, in vitro data were also used as model input to predict internal concentration of the coccidiostat monensin. Future developments of generic PBK models in chicken and other species of relevance to animal health risk assessment are discussed.

Occurrence and level of emerging organic contaminant in fish and mollusk from Klang River estuary, Malaysia and assessment on human health risk

The occurrence, level, and distribution of multiclass emerging organic contaminants (EOCs) in fish and mollusks from the Klang River estuary were examined. The targeted EOCs for this assessment were phenolic endocrine disrupting compounds (bisphenol A, 4-OP, and 4-NP), organophosphorous pesticides (quinalphos, chlorpyrifos, and diazinon), estrogenic hormones (E2, E1, and EE2), and pharmaceutically active chemicals (primidone, sulfamethoxazole, dexamethasone, diclofenac, amoxicillin, progesterone, and testosterone). Results from this study showed that the prevalent contamination of the Klang River estuary by EOCs with diclofenac, bisphenol A, progesterone, and amoxicillin were predominantly detected in fish and mollusks. Among the EOCs, diclofenac and progesterone had the highest concentrations in fish and mollusk samples, respectively. The concentrations of diclofenac and progesterone in fish and mollusk samples range from 1.42 ng/g to 10.76 ng/g and from 0.73 ng/g to 9.57 ng/g, respectively. Bisphenol A should also be highlighted because of its significant presence in both fish and mollusks. The concentration of bisphenol A in both matrices range from 0.92 ng/g to 5.79 ng/g. The calculated hazard quotient (HQ) for diclofenac, bisphenol A, and progesterone without consideration to their degradation byproduct were less than one, thus suggesting that the consumption of fish and mollusks from the Klang River estuary will unlikely pose any health risk to consumers on the basis of the current assessment. Nonetheless, this preliminary result is an important finding for pollution studies in Malaysian tropical coastal ecosystems, particularly for organic micropollutant EOCs, and can serve as a baseline database for future reference.

Quantification and feed to food transfer of total and inorganic arsenic from a commercial seaweed feed

Seaweed has a long-associated history of use as a supplemented livestock feed, providing nutrients and vitamins essential to maintaining animal health. Some species of seaweed, particularly the fucoids, are well-known accumulators of the metalloid arsenic (As). Arsenic toxicity to humans is well established even at low exposure levels and is considered a class 1 human carcinogen. As mankind's appetite for livestock produce continues to grow unabated, there is a concern that consumption of livestock produce reared on a diet supplemented with seaweed animal feed (SAF) may pose a threat to the human population due to potentially high levels of As present in seaweed. To address this concern and provide end users, including industry, consumers, policymakers and regulators with information on the exposure associated with As in commercial seaweed animal feed, the estimated daily intake (EDI) of As was calculated to evaluate potential human exposure levels. Using As data from a commercially available seaweed meal over a five-year period (2012-2017) a population exposure assessment was carried out. A Monte Carlo simulation model was developed to characterise the feed to food transfer of As from animal feed to animal produce such as beef, milk, chicken, and eggs. The model examined initial levels in seaweed, inclusion rate in animal feed, animal feeding rates and potential transfer to food produced from a supplemented diet of SAF. The analysis of seaweed animal feed showed that inorganic As was a small fraction of the total As found in seaweed meal (80:1). Statistical analysis found significant differences in the concentration of As in seaweed animal feed depending on the grain size (p < 0.001), with higher As concentrations in smaller sized grain fractions. Due to several detoxification steps and subsequent rapid excretion from the bodies of livestock, a very low carryover rate of As compounds from seaweed animal feed into livestock produce was observed. The EDI calculated in this study for the livestock produce evaluated at the 95th confidence interval was <0.01% of suggested safe levels of inorganic As intake. The threat to the general population as a result of consumption of livestock products reared on a diet consisting of SAF is found to be negligible.

Determination of plasma concentrations of organochlorine pesticides and polychlorinated biphenyls in pet cats and dogs

The aim of this study was the determination of plasma concentrations of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in cats and dogs and evaluation of their prevalence and possible effects. The concentrations of nine OCPs, such as α-hexachlorocyclohexane (HCH), β-HCH, γ-HCH, hexachlorobenzene (HCB), aldrin, 2,4′-dichlorodiphenyltrichloroethane (2,4′-DDT), 4,4′-DDT, 2,4′-dichlorodiphenyldichloroethylene (2,4′-DDE) and 4,4′-DDE and 16 PCBs (PCB-28, -52, -70, -74, -81, -99, -101, -118, -138, -153, -156, -170, -180, -183, -187 and -208) were evaluated in the plasma samples of pet cats ( n = 15) and dogs ( n = 21). The concentrations of OCPs ranged from 1.12 ng g−1 lipid weight (lw) to 7.65 ng g−1 lw in cats and from 1.25 ng g−1 lw to 6.79 ng g−1 lw in dogs. In addition, mean PCB levels were 0.58–5.66 and 0.52–6.62 ng g−1 lw in cats and dogs, respectively. β-HCH, γ-HCH and PCB-138 levels were significantly higher in dogs ( p < 0.05). As far as could be determined, OCPs and PCBs were detected in the plasma samples of domestic cats and dogs in Turkey for the first time. Their concentrations were similar to those reported in earlier studies abroad. However, in contrast to other research, the levels of some OCPs were higher in dogs than in cats. It is concluded that, because of their high prevalence and potential health effects in animals and humans, OCP and PCB levels should be monitored systematically in domestic cats and dogs.

Overview of the activities of the European Food Safety Authority on mycotoxins in food and feed

Mycotoxins are widely occurring in foods and feeds and dietary exposure to them can induce various types of adverse health effects in humans and animals. Since its establishment in 2002, the European Food Safety Authority (EFSA) has assessed risks of dietary exposure to mycotoxins for public health and for the health of farm and companion animals on the request of the European Commission and has assessed safety and efficacy of feed additives for the reduction of contamination of feed by mycotoxins within the European Union authorisation process for feed additives. Over 40 scientific opinions on risks of mycotoxins for human and animal health and other reports on mycotoxins have been issued by the authority for the use of the European risk managers. Mycotoxins belong to one of the important areas of the EFSA work. Occurrence data on mycotoxins submitted to EFSA by the European national food safety bodies and research institutions have been collected in the EFSA databases and have informed its scientific opinions and reports on mycotoxins. Similarly, many EFSA-funded projects conducted by the European research organisations, not only to generate data on occurrence, but also data on toxicity of mycotoxins, have provided valuable information for the risk assessments of EFSA. Aflatoxin and deoxynivalenol are the mycotoxins, for which EFSA has delivered most of its scientific mycotoxin opinions. Very recently also modified forms of mycotoxins have been included in the EFSA risk assessments. In this review paper an overview of many different EFSA activities on mycotoxins is given. It also includes a brief description how EFSA develops its scientific opinions and works.

Accumulation and depletion of indospicine in calves (Bos taurus) fed creeping indigo (Indigofera spicata)

Prolonged consumption of Indigofera pasture plants can cause both hepatotoxicosis and reproductive losses in grazing animals with the responsible toxin indospicine forming persistent tissue residues. Separate accumulation and depletion feeding trials were undertaken in calves fed Indigofera spicata (3 mg indospicine/kg bodyweight) to ascertain the appearance and elimination of indospicine from various tissues. In the accumulation trial indospicine concentrations increased throughout the 42-day feeding period with maximum levels of 15 mg/L in plasma and 19 and 33 mg/kg in liver and muscle, respectively. In the depletion trial, calves were fed I. spicata for 35 days, after which the plant was withdrawn from the diet. The rate of elimination was relatively slow with estimates of half-life being 31, 25 and 20 days for muscle, liver and plasma, respectively. Indospicine levels measured in bovine tissues in this trial are comparable with levels in horsemeat and camel meat reported to cause fatal hepatoxicity in dogs, a species known to be susceptible to this toxin. The persistence of indospicine residues in bovine tissues and the widespread distribution of Indigofera species in tropical and sub-tropical grazing lands warrant further investigation, as indospicine has been established as causing reproductive losses and likely contributes to calf losses in these regions.

An accurate and robust LC-MS/MS method for the quantification of chlorfenvinphos, ethion and linuron in liver samples

A method for the determination of chlorfenvinphos, ethion and linuron in liver samples by LC-MS/MS is described. Sample treatment was performed by using Sola™ polymeric reverse phase SPE cartridges after protein precipitation. Gradient elution using 10 mM ammonium formate in methanol (A) and 10 mM ammonium formate in water (B) was used for chromatographic separation of analytes on a Hypersil™ end-capped Gold PFP reverse phase column (100 mm × 2.1 mm, 3 μm). All analytes were quantified without interference, in positive ionization mode using multiple reaction monitoring (MRM) with chlorfenvinphos-d10 as internal standard. The whole procedure was validated according to the FDA guidelines for bioanalytical methods. The calibration curves for chlorfenvinphos, linuron and ethion compounds were linear over the concentration range of 0.005-2 μM (i.e. 0.0018-0.720 μg/mL, 0.0019-0.770 μg/mL and 0.0012-0.500 μg/mL respectively) with coefficients of determination higher than 0.998. A Lower limit of quantification of 0.005 μM was achieved for all analytes, i.e. 5.76, 6.08 and 3.84 μg/kg of liver for chlorfenvinphos, ethion and linuron respectively. Compounds extraction recovery rates ranged from 92.9 to 99.5% with a RSD of 2.3%. Intra- and inter-day accuracies were within 90.9 and 100%, and imprecision varied from 0.8 to 8.2%. Stability tests proved all analytes were stable in liver extracts during instrumental analysis (+12 °C in autosampler tray for 72 h) at the end of three successive freeze-thaw cycles and at -20 °C for up to 9 months. This accurate and robust analytical method is therefore suitable for contamination or metabolism studies.

Emerging Fusarium and Alternaria Mycotoxins: Occurrence, Toxicity and Toxicokinetics

Emerging Fusarium and Alternaria mycotoxins gain more and more interest due to their frequent contamination of food and feed, although in vivo toxicity and toxicokinetic data are limited. Whereas the Fusarium mycotoxins beauvericin, moniliformin and enniatins particularly contaminate grain and grain-based products, Alternaria mycotoxins are also detected in fruits, vegetables and wines. Although contamination levels are usually low (µg/kg range), higher contamination levels of enniatins and tenuazonic acid may occasionally occur. In vitro studies suggest genotoxic effects of enniatins A, A1 and B1, beauvericin, moniliformin, alternariol, alternariol monomethyl ether, altertoxins and stemphyltoxin-III. Furthermore, in vitro studies suggest immunomodulating effects of most emerging toxins and a reproductive health hazard of alternariol, beauvericin and enniatin B. More in vivo toxicity data on the individual and combined effects of these contaminants on reproductive and immune system in both humans and animals is needed to update the risk evaluation by the European Food Safety Authority. Taking into account new occurrence data for tenuazonic acid, the complete oral bioavailability, the low total body clearance in pigs and broiler chickens and the limited toxicity data, a health risk cannot be completely excluded. Besides, some less known Alternaria toxins, especially the genotoxic altertoxins and stemphyltoxin III, should be incorporated in risk evaluation as well.

Predicting acute contact toxicity of pesticides in honeybees (Apis mellifera) through a k-nearest neighbor model

Ecological risk assessment of plant protection products (PPPs) requires an understanding of both the toxicity and the extent of exposure to assess risks for a range of taxa of ecological importance including target and non-target species. Non-target species such as honey bees (Apis mellifera), solitary bees and bumble bees are of utmost importance because of their vital ecological services as pollinators of wild plants and crops. To improve risk assessment of PPPs in bee species, computational models predicting the acute and chronic toxicity of a range of PPPs and contaminants can play a major role in providing structural and physico-chemical properties for the prioritisation of compounds of concern and future risk assessments. Over the last three decades, scientific advisory bodies and the research community have developed toxicological databases and quantitative structure-activity relationship (QSAR) models that are proving invaluable to predict toxicity using historical data and reduce animal testing. This paper describes the development and validation of a k-Nearest Neighbor (k-NN) model using in-house software for the prediction of acute contact toxicity of pesticides on honey bees. Acute contact toxicity data were collected from different sources for 256 pesticides, which were divided into training and test sets. The k-NN models were validated with good prediction, with an accuracy of 70% for all compounds and of 65% for highly toxic compounds, suggesting that they might reliably predict the toxicity of structurally diverse pesticides and could be used to screen and prioritise new pesticides.

Towards eco-friendly crop protection: natural deep eutectic solvents and defensive secondary metabolites

With mounting concerns over health and environmental effects of pesticides, the search for environmentally acceptable substitutes has amplified. Plant secondary metabolites appear in the horizon as an attractive solution for green crop protection. This paper reviews the need for changes in the techniques and compounds that, until recently, have been the mainstay for dealing with pest insects. Here we describe and discuss main strategies for selecting plant-derived metabolites as candidates for sustainable agriculture. The second part surveys ten important insecticidal compounds, with special emphasis on those involved in human health. Many of these insecticidal metabolites, however, are crystalline solids with limited solubility which might potentially hamper commercial formulation. As such, we introduce the concept of natural deep eutectic solvents for enhancing solubility and stability of such compounds. The concept, principles and examples of green pest control discussed here offer a new suite of environmental-friendly tools designed to promote and adopt sustainable agriculture.

Mycotoxin in the food supply chain-implications for public health program

Mycotoxins are a group of naturally occurring toxic chemical substances, produced mainly by microscopic filamentous fungal species. Regarding potential synergisms or even mitigating effects between toxic elements, mycotoxin contamination will continue to be an area of concern for producers, manufacturers, regulatory agencies, researchers, and consumers in the future. In Serbia, recent drought and then flooding confirmed that mycotoxins are one of the foodborne hazards most susceptible to climate change. In this article, we review key aspects of mycotoxin contamination of the food supply chain and implications for public health from the Serbian perspective.

Heavy Metals in Seafood and Farm Produce from Uyo, Nigeria: Levels and health implications

OBJECTIVES

This study aimed to obtain representative data on the levels of heavy metals in seafood and farm produce consumed by the general population in Uyo, Akwa Ibom State, Nigeria, a region known for the exploration and exploitation of crude oil.

METHODS

In May 2012, 25 food items, including common types of seafood, cereals, root crops and vegetables, were purchased in Uyo or collected from farmland in the region. Dried samples were ground, digested and centrifuged. Levels of heavy metals (lead, cadmium, nickel, cobalt and chromium) were analysed using an atomic absorption spectrophotometer. Average daily intake and target hazard quotients (THQ) were estimated.

RESULTS

Eight food items (millet, maize, periwinkle, crayfish, stock fish, sabina fish, bonga fish and pumpkin leaf) had THQ values over 1.0 for cadmium, indicating a potential health risk in their consumption. All other heavy metals had THQ values below 1.0, indicating insignificant health risks. The total THQ for the heavy metals ranged from 0.389 to 2.986. There were 14 items with total THQ values greater than 1.0, indicating potential health risks in their consumption.

CONCLUSION

The regular consumption of certain types of farm produce and seafood available in Uyo, Akwa Ibom State, Nigeria, is likely adding to the body burden of heavy metals among those living in this region.

Assessing health in agriculture--towards a common research framework for soils, plants, animals, humans and ecosystems

In agriculture and food systems, health-related research includes a vast diversity of topics. Nutritional, toxicological, pharmacological, epidemiological, behavioural, sociological, economic and political methods are used to study health in the five domains of soils, plants, livestock, humans and ecosystems. An idea developed in the early founding days of organic agriculture stated that the health of all domains is one and indivisible. Here we show that recent research reveals the existence and complex nature of such health links among domains. However, studies of health aspects in agriculture are often separated by disciplinary boundaries. This restrains the understanding of health in agricultural systems. Therefore we explore the opportunities and limitations of bringing perspectives together from the different domains. We review current approaches to define and assess health in agricultural contexts, comparing the state of the art of commonly used approaches and bringing together the presently disconnected debates in soil science, plant science, veterinary science and human medicine. Based on a qualitative literature analysis, we suggest that many health criteria fall into two paradigms: (1) the Growth Paradigm, where terms are primarily oriented towards continued growth; (2) the Boundary Paradigm, where terms focus on maintaining or coming back to a status quo, recognising system boundaries. Scientific health assessments in agricultural and food systems need to be explicit in terms of their position on the continuum between Growth Paradigm and Boundary Paradigm. Finally, we identify areas and concepts for a future direction of health assessment and research in agricultural and food systems.

Occurrence of deoxynivalenol and zearalenone in commercial fish feed: an initial study

The control of mycotoxins is a global challenge not only in human consumption but also in nutrition of farm animals including aquatic species. Fusarium toxins, such as deoxynivalenol (DON) and zearalenone (ZEN), are common contaminants of animal feed but no study reported the occurrence of both mycotoxins in fish feed so far. Here, we report for the first time the occurrence of DON and ZEN in samples of commercial fish feed designed for nutrition of cyprinids collected from central Europe. A maximal DON concentration of 825 μg kg(-1) feed was found in one feed whereas average values of 289 μg kg(-1) feed were noted. ZEN was the more prevalent mycotoxin but the concentrations were lower showing an average level of 67.9 μg kg(-1) feed.