Toxics, Volume 7, Issue 4 (December 2019) – 17 articles

Among marine mammals, gray and bowhead whales contain large amounts of fat and thereby constitute crucial dietary components of the traditional diet of indigenous peoples of the Eastern Arctic. Despite the high nutritional and cultural value of gray and bowhead whales, there is a risk of persistent organic pollutant (POP) intake by indigenous individuals who use marine mammals as their main source of fat. POPs are lipophilic pollutants and are known to accumulate and magnify along the marine food web. Consumption of foods contaminated by POPs can perturb the endocrine, reproductive, and immune systems, and can potentially cause cancer. Moderate to relatively high concentrations of POPs have indeed been reported in the edible tissues of gray and bowhead whales consumed by indigenous peoples of the North Pacific Ocean. Even though their consumption is potentially harmful, there is no regular monitoring of eco-toxicants in the foods consumed by the indigenous peoples of the Eastern Arctic. In our view, the routine analyses of consumable parts of whales and of comparable nutritional items need to be included in the Russian Arctic Biomonitoring Programme. Full article

Anthropogenic debris is an environmental problem that affects beaches and coastlines worldwide. The abundance of beach debris is often documented with the use of public volunteers. To date, such community participations have been largely confined to the marine environment, but the presence and impact of anthropogenic debris on freshwater shorelines has been increasingly recognized. Our study presents the first such information from the African Great Lakes, specifically Lake Malawi. A total of 490,064 items of anthropogenic litter were collected by over 2000 volunteers in a clean-up campaign that took place annually between 2015 and 2018. Approximately 80% of the anthropogenic debris was comprised of plastic litter, with plastic carrier bags being the most common item. The dominance of plastic litter, and in particular the presence of plastic bags, which have subjected to bans in some African countries, is discussed. The broader implications of citizen science in the African Great Lakes area is also discussed. Full article

The decontamination of chemical warfare agents is important for the elimination or reduction of the effects of these substances on persons. Solid decontamination (degradation) sorbents that decompose dangerous substances belong among modern decontamination substances. The aim of the study was to design a procedure for monitoring the degradation of chemical warfare agents using such sorbents. The degradation of soman, VX [O-ethyl-S-(diisopropylaminoethyl)methylphosphonothioate] and sulphur mustard (chemical warfare agents) was monitored using FTIR spectrometry with the attenuated total reflection (ATR) technique. During the development and validation of this process, bonds were found in the substance molecule that decomposed and the positions of the absorbance bands corresponded to the vibration of these bonds. The evaluation of the degradation efficiency procedure for sorbents on chemical warfare agents was designed based on this study. We present the result of the measurements graphically as the time dependence of the distributed chemical warfare agent ratio, and the reaction times required to decompose 50% and 90% of the original amount of the substance. Full article

To enhance crop productivity and economic profit, farmers often use pesticides that modulate plant growth and prevent disease. However, contamination of ecosystems with agricultural pesticides may impair the health of resident biota. Paclobutrazol (PBZ), an aromatic-containing triazole, is widely applied to many crops in order to promote flowering and fruit setting, while also regulating plant growth and preventing fungus-related diseases. Due to its high mobility, high stability and potential for bioaccumulation, the risks of PBZ to the health of organisms and ecological systems have become a serious concern. In previous studies, we documented the toxicity of PBZ on developing heart, eyes, liver, pancreas and intestine of zebrafish. In this study, we sought to further understand the developmental stage-specific impacts of PBZ on digestive organs and other tissues. Zebrafish were exposed to PBZ beginning at different embryonic stages, and the toxic effects on organs were evaluated at 120 hpf (hours post-fertilization) by in situ hybridization staining with tissue-specific marker genes, such as liver, intestine and pancreas. Unsurprisingly, early-stage embryos exhibited higher sensitivity to PBZ-induced death and developmental hypoplasia of digestive organs. Interestingly, the developing liver and pancreas were more sensitive to PBZ than intestine when embryos were exposed at early stages, but these tissues showed lower sensitivity at later stages. Our delineation of the differential toxic effects of PBZ on developing organs at different exposure timings can serve as a powerful reference for further studies into the mechanisms of PBZ organ toxicity. Full article

The number and popularity of electronic nicotine delivery systems (ENDS) and especially e-cigarettes (e-cigs) have been increasing in the last decade. Although ENDS owe their popularity to excluding the harmful chemicals that are present in tobacco smoke, there is a debate whether they are safe, regulated, and as harmless as they are assumed to be and have potential unknown long-term effects. Involvement of cigarette smoking to the progression of periodontal diseases, other adverse oral health outcomes, and its detrimental effects to oral health are well-described. ENDS producer companies claim that these products can improve oral health by providing alternatives to smoking. However, the effect of e-cigs on oral health is not fully understood and is still debated among many scientists and clinicians. The number of studies addressing the potential toxic effect of ENDS or e-cig aerosol on oral cells is limited along with the clinical studies which are still preliminary, and their sample size is limited. The long-term effects of inhaled aerosols and the potential synergistic effect of the e-cigs components are not known. It is essential and of utmost importance to determine whether exposure to ENDS aerosol contributes to the progression of periodontal diseases and how it affects periodontal ligament and gingival cells which are believed to be its first targets. This review briefly summarizes the available evidence about the effects of e-cigs on periodontal health including several pathophysiological events, such as oxidative stress, DNA damage, inflammation, cellular senescence, dysregulated repair, and periodontal diseases. Full article

In this study, we used anion supramolecular solvent (SUPRAS) prepared from a mixture of an anionic surfactant, sodium dodecyl sulfate (SDS), and a cationic surfactant, tetrabutylammonium bromide (TBABr), as the extraction solvent in liquid phase microextraction (LPME) of paraquat (PQ) and diquat (DQ). The enriched PQ and DQ in the SUPRAS phase were simultaneously analyzed by ion-pairing reversed-phase high performance liquid chromatography. PQ and DQ were successfully extracted by LPME via electrostatic interaction between the positive charge of the quats and the negative charge of SUPRAS. PQ, DQ, and ethyl viologen (the internal standard) were separated within 15 min on a C18 column, with the mobile phase containing 1-dodecanesulfonic acid and triethylamine, via UV detection. The optimized conditions for the extraction of 10 mL aqueous solution are 50 μL of SUPRAS prepared from a mixture of SDS and TBABr at a mole ratio of 1:0.5, vortexed for 10 s at 1800 rpm, and centrifugation for 1 min at 3500 rpm. The obtained enrichment factors were 22 and 26 with limits of detection of 1.5 and 2.8 µg L⁻¹ for DQ and PQ, respectively. The precision was good with relative standard deviations less than 3.86%. The proposed method was successfully applied for the determination of PQ and DQ in vegetable samples and recoveries were found in the range of 75.0% to 106.7%. Full article

The present study aims to evaluate the impact of e-cig second-hand aerosol on indoor air quality in terms of ultrafine particles (UFPs) and potential inhalation exposure levels of passive bystanders. E-cig second-hand aerosol characteristics in terms of UFPs number concentration and size distribution exhaled by two volunteers vaping 15 different e-liquids inside a 49 m³ room and comparison with tobacco smoke are discussed. High temporal resolution measurements were performed under natural ventilation conditions to simulate a realistic exposure scenario. Results showed a systematic increase in UFPs number concentration (part cm⁻³) related to a 20-min vaping session (from 6.56 × 10³ to 4.01 × 10⁴ part cm⁻³), although this was one up to two order of magnitude lower than that produced by one tobacco cigarette consumption (from 1.12 × 10⁵ to 1.46 × 10⁵ part cm⁻³). E-cig second-hand aerosol size distribution exhibits a bimodal behavior with modes at 10.8 and 29.4 nm in contrast with the unimodal typical size distribution of tobacco smoke with peak mode at 100 nm. In the size range 6–26 nm, particles concentration in e-cig second-hand aerosol were from 2- (Dp = 25.5 nm) to 3800-fold (Dp = 9.31 nm) higher than in tobacco smoke highlighting that particles exhaled by users and potentially inhaled by bystanders are nano-sized with high penetration capacity into human airways. Full article

The purpose of this study was to investigate the toxicity and the distribution of mercury (Hg) in the main tissues of freshwater fish (Oreochromis niloticus) after being exposed to water containing Hg(II). A sample group of 10 fish, of mean weight 80–100 g wet weight, were exposed to different concentrations of Hg (0.0012; 0.0049; 0.0141; 0.0524; 0.1126; and 0.5110 mg-HgII/L) for 72 h under controlled conditions using the static method in ponds. A control medium was also prepared in two replications. Mortality of fish was closely monitored, and the test was repeated three times. For the toxicity test, observations were based on behavior, mortality, and anatomical pathology. The methodology was based on the OECD guidelines for testing of chemicals and lethal concentration (LC₅₀) and particularly using the probit method. Thus, the mean value was obtained from two replications and then further calculated by a software (MiniTab® 16 version). Prior to analysis, samples were first lyophilized. The total concentration of Hg accumulation in the fish organs was analyzed using heat-vaporization atomic absorption spectrometry (HV-AAS) and a MA2000 automatic mercury analyzer. Results showed that toxicity (LC₅₀) of freshwater fish was 0.1435 mg-Hg(II)/L. The internal organs showed some pathological changes including pale gills, anemic eyes, and a whitish body color after the exposure. Furthermore, histopathologically, exposure to mercury might also affect other organs, such as gills, liver, and hepatopancreas. Mercury was found in trace amounts, and its accumulation was found to be at least in the gills. Meanwhile, the highest accumulation was found in the muscle tissue with approximately 5.7183 µg/g dry weight. If they are put in order, the mercury accumulation in the tissue organs was varied from the highest to lowest one: Muscle > eye > bone > head > gill. Finally, it can be concluded that the Hg exposure could affect the histopathological condition of the tested fish. Full article

In order to assess the human exposure risks from the release of contaminants from water pipes made of polyvinyl chloride (PVC), experiments were carried out by subjecting the PVC pipe material to burning and leaching conditions followed by analysis of the emission and leachate samples. The emissions of burning pipes were analyzed by both infrared spectrometry and gas chromatography-mass spectrometry (GC-MS). The emission test results indicate the presence of chlorinated components including chlorine dioxide, methyl chloride, methylene chloride, allyl chloride, vinyl chloride, ethyl chloride, 1-chlorobutane, tetrachloroethylene, chlorobenzene, and hydrogen chloride were detected in the emissions of burning PVC pipes. Furthermore, the concentrations of benzene, 1,3-butadiene, methyl methacrylate, carbon monoxide, acrolein, and formaldehyde were found at levels capable of affecting human health adversely. The analysis of PVC pipe leachates using GC-MS shows that there are 40–60 tentatively identified compounds, mostly long-chain hydrocarbons such as tetradecane, hexadecane, octadecane, and docosane, were released when the burned PVC materials were soaked in deionized water for one week. Quantitative analysis shows that 2-butoxyethanol, 2-ethyl-1-hexanol, and diethyl phthalate were found in the burned PVC polymer at the average levels of 2.7, 14.0, and 3.1 micrograms per gram (μg/g) of pipe material. This study has significant implications for understanding the benzene contamination of drinking water in the aftermath of wildfires that burned polymer pipes in California. Full article

Methylmercury (MeHg) has conventionally been investigated for effects on nervous system development. As such, epigenetic modifications have become an attractive mechanistic target, and research on MeHg and epigenetics has rapidly expanded in the past decade. Although, these inquiries are a recent advance in the field, much has been learned in regards to MeHg-induced epigenetic modifications, particularly in the brain. In vitro and in vivo controlled exposure studies illustrate that MeHg effects microRNA (miRNA) expression, histone modifications, and DNA methylation both globally and at individual genes. Moreover, some effects are transgenerationally inherited, as organisms not directly exposed to MeHg exhibited biological and behavioral alterations. miRNA expression generally appears to be downregulated consequent to exposure. Further, global histone acetylation also seems to be reduced, persist at distinct gene promoters, and is contemporaneous with enhanced histone methylation. Moreover, global DNA methylation appears to decrease in brain-derived tissues, but not in the liver; however, selected individual genes in the brain are hypermethylated. Human epidemiological studies have also identified hypo- or hypermethylated individual genes, which correlated with MeHg exposure in distinct populations. Intriguingly, several observed epigenetic modifications can be correlated with known mechanisms of MeHg toxicity. Despite this knowledge, however, the functional consequences of these modifications are not entirely evident. Additional research will be necessary to fully comprehend MeHg-induced epigenetic modifications and the impact on the toxic response. Full article

In theory, the identification of the source of excreted cadmium (Cd) might elucidate the pathogenesis of Cd-induced chronic kidney disease (CKD). With that possibility in mind, we studied Thai subjects with low, moderate, and high Cd exposure. We measured urine concentrations of Cd, ([Cd]_u); N-acetyl-β-d-glucosaminidase, a marker of cellular damage ([NAG]_u); and β₂-microglobulin, an indicator of reabsorptive dysfunction ([β₂MG]_u). To relate excretion rates of these substances to existing nephron mass, we normalized the rates to creatinine clearance, an approximation of the glomerular filtration rate (GFR) (E_Cd/C_cr, E_NAG/C_cr, and E_β2MG/C_cr). To link the loss of intact nephrons to Cd-induced tubular injury, we examined linear and quadratic regressions of estimated GFR (eGFR) on E_Cd/C_cr, eGFR on E_NAG/C_cr, and E_NAG/C_cr on E_Cd/C_cr. Estimated GFR varied inversely with both ratios, and E_NAG/C_cr varied directly with E_Cd/C_cr. Linear and quadratic regressions of E_β2MG/C_cr on E_Cd/C_cr and E_NAG/C_cr were significant in moderate and high Cd-exposure groups. The association of E_NAG/C_cr with E_Cd/C_cr implies that both ratios depicted cellular damage per surviving nephron. Consequently, we infer that excreted Cd emanated from injured tubular cells, and we attribute the reduction of eGFR to the injury. We suggest that E_Cd/C_cr, E_NAG/C_cr, and eGFR were associated with one another because each parameter was determined by the tubular burden of Cd. Full article

The present study explored environmental and behavioral factors associated with elevated blood lead (Pb) levels in 311 children (151 girls and 160 boys), aged 3–7 years, who lived in a coastal fishing community of the Pakpoon Municipality, Nakhon Si Thammarat, Thailand. The geometric mean for blood Pb was 2.81 µg/dL, ranging between 0.03 and 26.40 µg/dL. The percentage of high blood Pb levels, defined as blood Pb ≥ 5 µg/dL, was 10.0% in boys and 13.9% in girls. Parental occupation in producing fishing nets with lead weights was associated with a marked increase in the prevalence odds ratio (POR) for high blood Pb (POR 17.54, 95%; CI: 7.093, 43.390; p < 0.001), while milk consumption was associated with 61% reduction in the POR for high blood Pb (POR 0.393, 95%; CI: 0.166, 0.931; p = 0.034). High blood Pb was associated with an increased risk for abnormal growth (POR 2.042, 95%; CI: 0.999, 4.174; p = 0.050). In contrast, milk consumption was associated with a 43% reduction in POR for abnormal growth (POR 0.573, 95%; CI: 0.337, 0.976; p = 0.040). After adjustment for age, the mean (standard error of mean, SE) values for blood Pb were 6.22 (0.50) μg/dL in boys and 6.72 (0.49) μg/dL in girls of parents with an occupation in making fishing nets with lead weights. These mean blood Pb values were respectively 2.3 and 2.5 times higher than similarly aged boys and girls of parents with other occupations. These data are essential for setting surveillance and programmes to prevent toxic Pb exposure, especially in children of coastal fishing communities in southern Thailand. Full article

We know little about the potential health risks from exposure to diisoheptyl phthalate (DiHpP), a plasticizer used in commercial applications. The production of DiHpP ended in the United States in 2010, but DiHpP may still be present in phthalate diester mixtures. To investigate human exposure to DiHpP, we used three oxidative metabolites of DiHpP: Monohydroxyheptyl phthalate (MHHpP), mono-oxoheptylphthalate (MOHpP), and monocarboxyhexyl phthalate (MCHxP) as exposure biomarkers. We analyzed urine collected anonymously in 2000 (N = 144) and 2018–2019 (N = 205) from convenience groups of U.S. adults using high-performance liquid chromatography coupled with isotope-dilution high-resolution mass spectrometry. We detected MCHxP in all the samples tested in 2000 (GM = 2.01 ng/mL) and 2018–2019 (GM = 1.31 ng/mL). MHHpP was also detected in 100% of the 2018–2019 samples (GM = 0.59 ng/mL) and 96% of the 2000 urine samples analyzed (GM = 0.38 ng/mL). MOHpP was detected in 57% (2018–2019, GM = 0.03 ng/mL) and 92% (2000, GM = 0.19 ng/mL) of samples. The presence of MHHpP, MOHpP, and MCHxP in the 2018–2019 samples suggests recent exposure to DiHpP. Intercorrelations between metabolite concentrations were more significant in samples collected in 2000 than in samples collected in 2018–2019. The differences in urinary metabolite profiles and intercorrelations from samples collected during 2000 and 2018–2019 likely reflects changes in the composition of commercial DiHpP formulations before and after 2010. Full article

Since 1998, a monitoring program is periodically performed to assess the environmental and human health impact of air chemicals potentially emitted by a hazardous waste incinerator (HWI) located in Constantí (Catalonia, Spain). In 2017, samples of hair were collected from 94 schoolchildren (aged 10–13 years) living nearby and the levels of 11 trace elements (As, Be, Cd, Cr, Hg, Mn, Ni, Pb, Sn, Tl and V) were determined. The concentrations showed the following descending order: Pb > Hg > Ni > Sn > Mn > Cr. In turn, As, Be and Tl were not detected, while Cd and V were found only in a few samples. Some metal levels were significantly, positively correlated. Some significant differences were also noticed according to the gender and the specific zone of residence. Finally, the levels of trace elements showed fluctuations through time. Cr and Pb showed a significant decrease in comparison to the concentrations obtained in the baseline study (1998). According to the current results, metal emissions from the HWI are not relevant in terms of human health impact since their levels were similar and even lower than those reported in other contaminated areas. Full article

The objective of this work was to characterize the toxicological profile of a newly developed sunscreen formulation based on polymeric nanocapsules (NCs) loading benzophenone-3 (BZP3). NCs composed of poly(ε-caprolactone) carrot oil and Pluronic^® F68 were produced by emulsification-diffusion method. Their mean particle size (Z-Ave) ranged from 280 to 420 nm, polydispersity index (PDI) was below 0.37, while zeta potential (ZP) reached about |+11 mV|. No cytotoxic effects were observed in L929 fibroblast cell line for the blank (i.e., non-loaded) NCs and BZP3-loaded NCs (BZP3-NCs). The semi-solid sunscreen formulation was stable over time (centrifugation testing) and exhibited non-Newtonian pseudoplastic behavior, which is typical of products for topical application onto the skin. The sun protection factor (SPF) value reached 8.84, when incorporating BZP3-NCs (SPF of 8.64) into the semi-solid formulation. A synergistic effect was also observed when combining the formulation ingredients of nanocapsules, i.e., SPF of carrot oil was 6.82, blank NCs was 6.84, and BZP3-loaded NCs was 8.64. From the hen’s egg-chorioallantoic membrane test (HET-CAM) test, the non-irritation profile of the developed formulations could also be confirmed. The obtained results show a promising use of poly(ε-caprolactone) nanocapsules to be loaded with lipophilic sunscreens as benzophenone-3. Full article

Recent studies suggest that organophosphates and carbamates affect human fetal development, resulting in neurological and growth impairment. However, these studies are conflicting and the extent of adverse effects due to pesticide exposure warrants further investigation. In the present study, we examined the impact of the carbamate insecticide propoxur on zebrafish development. We found that propoxur exposure delays embryonic development, resulting in three distinct developmental stages: no delay, mild delay, or severe delay. Interestingly, the delayed embryos all physically recovered 5 days after exposure, but behavioral analysis revealed persistent cognitive deficits at later stages. Microarray analysis identified 59 genes significantly changed by propoxur treatment, and Ingenuity Pathway Analysis revealed that these genes are involved in cancer, organismal abnormalities, neurological disease, and hematological system development. We further examined hspb9 and hspb11 due to their potential roles in zebrafish development and found that propoxur increases expression of these small heat shock proteins in all of the exposed animals. However, we discovered that less significant increases were associated with the more severely delayed phenotype. This raises the possibility that a decreased ability to upregulate these small heat shock proteins in response to propoxur exposure may cause embryos to be more severely delayed. Full article

Cork quality is crucial for the fabrication of corks intended to be used to seal wine bottles. This work has focused on the determination of chloroanisoles (CAs)—exogenous compounds with a low perception threshold—in cork. The identification and quantification of these compounds was carried out with Bond Elut-ENV solid phase extraction and gas chromatography with mass spectrometry detection. Cork samples were obtained from oaks from Catalonia, Extremadura and Italy, and the presence of CAs was evaluated. Moreover, cork affected by the presence of yellow stains (a defect present in cork, mainly originated from the growth of the fungus Armillaria mellea) was analysed separately. The results obtained from cork macerates revealed the presence of trichloroanisole (TCA) in Catalan and Italian cork. Furthermore, TCA concentration was not statistically different when comparing cork affected and non-affected by the growth of A. mellea. Other chlorinated compounds were identified by comparison of their mass spectra with the data from the NIST library. Full article