Comprehensive estimate of the theoretical maximum daily intake of pesticide residues for chronic dietary risk assessment in Argentina

Probabilistic risk assessment of endocrine disrupting pesticides in Iran

The chronic dietary risk assessment for 34 pesticides suspected of acting as endocrine disrupters in Iran was assessed by comparing TMDI with the Acceptable Daily Intakes (ADI). Of 34 investigated endocrine-disrupting pesticides (EDPs), 6 had TMDI > ADI. In addition, potential non-carcinogenic and carcinogenic health risk assessments were evaluated using Monte Carlo simulation. HQ in wheat was 17.40 and 20.29 in adults and children, respectively. Due to dimethoate residue in wheat, HQ was 2.78, and for fenitrothion residue, 3.22. HI was 21.22 for adults and 24.76 for children in wheat, more than 1. Total Carcinogenic risk (TCR) due to EDPs residues was 6.40 × 10-5 in apples, in citrus fruits 5.97 × 10-5, 3.33 × 10-5 in cucumber, 5.30 × 10-5 in lettuce, in potato was 2.36 × 10-5, in rice was 1.61 × 10-5, 1.78 × 10-5 in tomato, and due to epoxiconazole residues in wheat was 3.18 × 10-5, more than acceptable limit 1.0 × 10-6. Therefore, consumers were at significant risk of carcinogenesis.Abbreviations: PCBs: polychlorinated biphenyls; BPA: Bisphenol A; ED: Endocrine Disrupting; EDCs: Endocrine Disrupting Chemicals; EDPs: Endocrine Disrupting Pesticides; ADI: Acceptable Daily Intake; TMDI: Theoretical Maximum Daily Intake; FAO: Food and Agriculture Organization; WHO: World Health Organization; MRL: Maximum Residue Limit; HQ: Hazard Quotient; HI: Hazard Index; CR: Cancer Risk; TCR: Total Cancer Risk; PPP: plant protection products.

Immunomodulatory effect of imidacloprid on macrophage RAW 264.7 cells

The neonicotinoid imidacloprid was promoted in the market because of widespread resistance to other insecticides, plus its low mammalian impact and higher specific toxicity towards insects. This study aimed to evaluate the immunomodulatory effect of imidacloprid on macrophages. RAW 264.7 cells were incubated to 0-4000mg/L of imidacloprid for 24 and 96h. Imidacloprid presented a concentration-dependent cytotoxicity after 24h and 96h incubation for MTT reduction (3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyltetrazolium bromide) (EC₅₀ 519.6 and 324.6mg/L, respectively) and Neutral Red (3-amino-7-dimethylamino-2-methylphenazine hydrochloride) assays (EC₅₀ 1139.0 and 324.2mg/L, respectively). Moreover, imidacloprid decreased the cells' inflammatory response and promoted a mitochondrial depolarization. The complex II and succinate dehydrogenase (SDH) activities in RAW 264.7 cells incubated with imidacloprid increased more at 24h. These results suggest that imidacloprid exerts an immunomodulatory effect and mitochondria can act as regulator of innate immune responses in the cytotoxicity mediated by the insecticide in RAW 264.7 cells.

Effects of pyrethroids on the cerebellum and related mechanisms: a narrative review

Pyrethroids (PYRs) are a group of synthetic organic chemicals that mimic natural pyrethrins. Due to their low toxicity and persistence in mammals, they are widely used today. PYRs exhibit higher lipophilicity than other insecticides, which allows them to easily penetrate the blood-brain barrier and directly induce toxic effects on the central nervous system. Several studies have shown that the cerebellum appears to be one of the regions with the largest changes in biomarkers. The cerebellum, which is extremely responsive to PYRs, functions as a crucial region for storing motor learning memories. Exposure to low doses of various types of PYRs during rat development resulted in diverse long-term effects on motor activity and coordination functions. Reduced motor activity may result from developmental exposure to PYRs in rats, as indicated by delayed cerebellar morphogenesis and maturation. PYRs also caused adverse histopathological and biochemical changes in the cerebellum of mothers and their offspring. By some studies, PYRs may affect granule cells and Purkinje cells, causing damage to cerebellar structures. Destruction of cerebellar structures and morphological defects in Purkinje cells are known to be directly related to functional impairment of motor coordination. Although numerous data support that PYRs cause damage to cerebellar structures, function and development, the mechanisms are not completely understood and require further in-depth studies. This paper reviews the available evidence on the relationship between the use of PYRs and cerebellar damage and discusses the mechanisms of PYRs.

National probabilistic risk assessment of newly registered pesticides in agricultural products to propose maximum residue limit (MRL)

Following the EPA recommended method, a chronic diet risk assessment for pesticides was recently performed for adults and children in the Iranian population. The National Theoretical Maximum Daily Intake (NTMDI) for 32 pesticides was computed using the theoretical maximum residue limits (MRLs) of food consumption regulations and data from the comprehensive database of the Iranian Research Institute of Plant Protection (IRIPP). The risk was assessed by comparing TMDI with the acceptable daily intakes (ADI) evaluated by FAO. From 32 investigated pesticides, 10 pesticides had TMDI > 65% of the ADI. Some of these ADI-exceeding compounds (spirodiclofen, abamectin, trifloxystrobin, spiromesifen, fipronil, difenoconazole, tetraconazole) were found in citrus, cucumber, grapes, tomato, and potato as the foods that have played the most roles in the consumption of these pesticides. Furthermore, a probabilistic risk assessment was performed to estimate the contingency of extravagance of the ADI. In the current research, only cyazofamid in potato for children consumers exceeded the 1 of the HQ. However, carcinogenic risk (CR) due to spirodiclofen in citrus fruit and difenoconazole in tomato was higher than the 1E-6 value; therefore, consumers were at considerable carcinogenic risk in these commodities. This scrutiny is essential for improving the activities' risk assessment, regulation, and surveillance.

In vivo mutagenic effects and oxidative stress parameters evaluation of cypermethrin and benzoate of emamectin and their mixtures in female mice

We evaluated the biological effects of ingestion by gavage, for 28 days, of the pesticides cypermethrin (CP) and emamectin benzoate (EB) and their mixtures in female Swiss mice. The groups were Control (water); CP; EB and three distinct concentrations of CP and EB mixture expressed in mg/kg/day. The biological effects were analyzed in the complete blood count and plasma (alkaline phosphatase (ALP), alanine aminotransferase (ALT) and creatinine); the biochemical parameters of oxidative stress (substances reactive to thiobarbituric acid (TBARS); reduced glutathione (GSH); catalase (CAT), superoxide dismutase (SOD) and glutathione-S-transferase (GST)), and bone marrow cells obtained from the femur for the micronucleus (MN) test. In the heart, there was a reduction in GSH in the groups (0.5 + 0.67 and 2.5 + 3.37), although in the brain this effect appeared for the other groups, except EB. Brain TBARS increased in CP and in the group (2.5 + 3.37) and platelets increased in the group (12.5 + 16.87). Genotoxic/mutagenic effects, showing a consistent increase dose-dependent effect on micronucleus counting for in the female mice. After 28 days of treatment, we can observe that the pesticide mixtures promoted genotoxic damage and oxidative brain damage in female mice, which can damage the health of these animals and possibly their future offspring.

Estimation of chronic dietary intake of pesticide residues

OBJECTIVE

To estimate the maximum theoretical daily intake of pesticides potentially consumed, chronically, by the Brazilian population.

METHOD

By using data from the food consumption section of the 2008-2009 Household Budget Survey to characterize the population diet, a database was built to group the foods based on the NOVA classification. Considering the maximum residue limit values of each pesticide authorized in the country until 2016, the limits of all consumed foods were added and multiplied by the amount consumed, resulting in the maximum theoretical intake index, which was compared with the acceptable daily intake.

RESULTS

The results show that, of the 283 pesticides considered in the database, 71 (25%) compounds had estimates of zero intake, 144 compounds (50.8%) reached acceptable daily intake values and 68 compounds (24%) showed median intake that exceeded the acceptable daily value. The pesticide intake estimation according to the different regions of the country showed a variation in the amount of compounds that exceeded the acceptable daily intake (48 to 69 substances) due to the different consumption patterns. The categories of products that most exceeded the limits were the insecticides, herbicides and fungicides.

CONCLUSION

The application of this methodology is valid for the first step in risk assessment, but the resulting values may be different from the actual exposure since they do not include other factors, such as the combined use of pesticides or unauthorized products. The importance of developing research on specific national food consumption data in a systematic way is emphasized, which generates data and analyses that allow a detailed risk assessment.

Effect of oral administration of a mixture of pyrethroids at doses relevant to human exposure on the general and male reproductive physiology in the rat

Studies on the effects of unintentional intake of pyrethroid pesticides that are akin to actual human exposure settings are very rare. Such an exposure is primarily by consuming the food products as routine diet that contain residual levels of pyrethroids. In this study, rats were orally administered for 15 months with a mixture of pyrethroids at a dose that is one-fifth (high dose; HD) or one-twenty fifth (low dose; LD) of the residual levels commonly present in the average amount of rice and vegetables consumed by Indian population. Lipid profile, kidney and liver function were assessed. Lipid peroxidation, nitric oxide, antioxidant enzyme activities and histopathological changes were analyzed in the liver, lung, kidney, pancreas, testes, caput, cauda and prostate. The effect on the male reproductive system as a function of sperm count, enzyme activity of 3β-HSD and 17β-HSD and the expression profile of genes involved in spermatogenesis, steroidogenesis, genetic reprogramming and apoptosis of male gametes were evaluated. Significant increase in the relative organ weight, perturbations in the activities of antioxidant enzymes, lipid profile and liver function were observed in both LD and HD groups. Damage to the anatomical architecture was evident in all the tissues due to pyrethroid toxicity. Exposure to LD and HD of pyrethroid mixture resulted in decreased sperm count, activities of 3β-HSD and 17β-HSD, impaired capacitation and acrosome reaction and perturbations in the expression of genes that govern male gamete production. Results of our study indicate that exposure to pyrethroids for longer durations even at doses that are far below the residual levels present in the food consumed will result in severe damage to general physiological processes as well as reproductive function.

Immunomodulatory effect of mancozeb, chlorothalonil, and thiophanate methyl pesticides on macrophage cells

Mancozeb (MZ), chlorothalonil (CT), and thiophanate methyl (TM) are pesticides commonly used in agriculture due to their efficacy, low acute toxicity to mammals, and short environmental persistence. Although the toxic effects of these pesticides have been previously reported, studies regarding their influence on the immune system are limited. As such, this study focused on the immunomodulatory effect of MZ, CT, and TM pesticides on macrophage cells. RAW 264.7 cells were exposed to a range of concentrations (0.1-100 μg/mL) of these pesticides. CT exposure promoted an increase in reactive oxygen species (ROS) and nitric oxide (NO) levels. The MTT and ds-DNA assay results demonstrated that MZ, CT, and TM exposure induced macrophage proliferation. Moreover, MZ, CT, and TM promoted cell cycle arrest at S phase, strongly suggesting macrophage proliferation. The levels of pro-inflammatory cytokines (IL-1β, IL-6, TNF-α, and IFN-γ) and caspases (caspase 1, 3, and 8) in macrophages exposed to MZ, CT, and TM pesticides increased, whereas the anti-inflammatory cytokine levels decreased. These results suggest that MZ, CT, and TM exert an immunomodulatory effect on the immune system, inducing macrophage activation and enhancing the inflammatory response.

Evaluation of regulatory variation and theoretical health risk for pesticide maximum residue limits in food

To evaluate whether pesticide maximum residue limits (MRLs) can protect public health, a deterministic dietary risk assessment of maximum pesticide legal exposure was conducted to convert global MRLs to theoretical maximum dose intake (TMDI) values by estimating the average food intake rate and human body weight for each country. A total of 114 nations (58% of the total nations in the world) and two international organizations, including the European Union (EU) and Codex (WHO) have regulated at least one of the most currently used pesticides in at least one of the most consumed agricultural commodities. In this study, 14 of the most commonly used pesticides and 12 of the most commonly consumed agricultural commodities were identified and selected for analysis. A health risk analysis indicated that nearly 30% of the computed pesticide TMDI values were greater than the acceptable daily intake (ADI) values; however, many nations lack common pesticide MRLs in many commonly consumed foods and other human exposure pathways, such as soil, water, and air were not considered. Normality tests of the TMDI values set indicated that all distributions had a right skewness due to large TMDI clusters at the low end of the distribution, which were caused by some strict pesticide MRLs regulated by the EU (normally a default MRL of 0.01 mg/kg when essential data are missing). The Box-Cox transformation and optimal lambda (λ) were applied to these TMDI distributions, and normality tests of the transformed data set indicated that the power transformed TMDI values of at least eight pesticides presented a normal distribution. It was concluded that unifying strict pesticide MRLs by nations worldwide could significantly skew the distribution of TMDI values to the right, lower the legal exposure to pesticide, and effectively control human health risks.

National short-term dietary exposure assessment of a selected group of pesticides in Argentina

An evaluation of acute dietary exposure to pesticide residues, applying deterministic and stochastic methods, was performed for a selected group of pesticides in two representative age groups from Argentina. Thus, 28 active ingredients (a.i.) and 75 food items were evaluated for the group of 2-5-year-old children, while 9 a.i. and 59 food items were considered for the 10-49-year-old women group. A deterministic assessment was conducting following the Food and Agriculture Organization (FAO) and World Health Organization (WHO) procedure but using the national maximum residue limits (MRLs) as pesticide residue concentration data, while in the stochastic approach, a theoretical distribution modeled with the available information was used. Food consumption data were obtained from the 2004-2005 comprehensive national nutrition and health survey. The risk was estimated by comparing the short-term dietary exposure with the acute reference dose (ARfD) values for each pesticide-food combination evaluated. In the deterministic assessment, 173 (39.1%) and 40 (31.3%) combinations exceeded the ARfD thresholds for the 2-5-year-old children and 10-49-year-old women groups, respectively. This conservative study generated relevant information as a first stage of acute dietary risk assessment in Argentina.