A benchmark dose analysis for sodium monofluoroacetate (1080) using dichotomous toxicity data

The carcinogenic PAHs in breads, amount, analytical method and mitigation strategy, a systematic review study

Bread is one of the most consumed foods all over the world. Several contaminants are identified in bread. Polycyclic aromatic hydrocarbons (PAHs) is one of these contaminants. This systematic study evaluates the amount of four carcinogenic PAHs (PAH4) in various types of breads. To conduct this study, a comprehensive search was carried out using keywords of polycyclic aromatic hydrocarbons, PAHs, PAH4, and bread, with no time limitations. 17 articles were selected and fully evaluated. The observed range of PAH4 concentrations in bread varied from non-detected (ND) to 20.66 µg/kg. In the sample preparation process for analysis, an ultrasonic bath was predominantly utilized. Most chromatographic methods are able to measure PAHs in food, but the GC-MS method has been used more. To mitigate PAH levels in bread, it is suggested to incorporate antioxidants during the bread-making process. Furthermore, the type of bread, the type of fuel used to bake the bread, the temperature and the cooking time were some of the factors affecting the amount of PAH. Restricting these factors could significantly reduce PAH content. Regarding the risk assessment conducted in the manuscript, it was determined that industrial breads are usually considered safe. However, some traditional breads may pose risks in terms of their potential PAH content.

Potential impact of pollutant emitted by generator-powered telecommunication masts on air quality of Oja Oba in Akure metropolis

The main aim of this study is to simulate the concentrations of three major air pollutants, namely carbon monoxide (CO), nitrogen oxide (NOx), and particulate matter of diameter less or equal to 10 μm (PM₁₀), commonly emitted from base station of telecommunication masts powered by a generator running on diesel and evaluated the simulated pollutants in terms of health risks they pose to people living at close proximity to the telecommunication masts. In this study, we engaged the AERMOD model to simulate the concentrations of pollutants emanating from the use of generators in powering telecommunication base stations around a major busy market place in Akure, Nigeria, a tropical location. The simulation of pollutants was carried out for both dry months (January, February, and March) and wet months (June, July, and August) of 2018. Results showed that CO has the 1-h highest simulated concentration of 1013.4 μg/m³, and it was found during wet seasons, while NOx has 1-h highest concentration of 78.8 μg/m³, and the corresponding value of PM₁₀ was 58.7 μg/m³. While highest concentrations of CO and NOx occurred during the wet season, PM₁₀ highest concentration occurred during the dry season. Measured concentrations of the pollutants also showed similar pattern; however, the measured concentrations are higher than their corresponding simulated values. This difference between measured and simulated is accounted for as background concentration from other sources of pollution. The risks posed to human health by these pollutants were evaluated using hazard quotient (HQ) against some air quality related such as asthma, aggravated asthma, eye irritation, and reproductive and developmental toxicity. CO posed greater human health risks in both wet and dry seasons having HQ greater unity, while PM₁₀ human health risk is noticeable during the dry season. NOx do not pose a human health risk due to very minor content of nitrogen compound emitted by the generators. It is has been demonstrated that the use of a generator to power electrical need of telecommunication base stations has a high impact on air quality within the vicinity of these stations. The hazard could be escalated where many base stations are co-located close public places. Renewable sources of energy could be used in place of generators in the base stations to reduce the impact on air quality and safeguard human health.

High-Throughput Quantification of Monofluoroacetate (1080) in Milk as a Response to an Extortion Threat

As a food defense measure against an extortion threat to poison infant formula with monofluoroacetate, a robust methodology for monofluoroacetate analysis in fluid milk and powdered dairy products was developed and optimized. Critical challenges posed by this situation required that the analytical methodology provide (i) high specificity, (ii) high throughput capable of analyzing thousands of samples of fluid milk per day, and (iii) trace-level detection of 1 ng/g or lower to achieve the maximum residue limit. Solid-phase extraction-purified acetone extracts of fluid milk were derivatized with aniline, and after ultrahigh-performance liquid chromatography using a Kinetex-C18 column packed with 1.3-μm shell particles, the resulting N-phenyl 2-fluoroacetamide could be determined by liquid chromatography-tandem mass spectrometry in a highly specific manner and with a limit of quantification of 0.5 ng/ml. By using 4-(4-chlorophenoxy)aniline as a derivatizing agent, the method could be extended to powdered dairy products with the same limit of quantification. Between January and July 2015, some 136,000 fluid milk samples were tested using this method. This analytical testing of fluid milk formed one element in a larger program of work by multiple agencies to ensure that consumers could continue to have confidence in the safety of New Zealand milk and dairy products.

The Impact of Model Uncertainty on Benchmark Dose Estimation

We study the popular benchmark dose (BMD) approach for estimation of low exposure levels in toxicological risk assessment, focusing on dose-response experiments with quantal data. In such settings, representations of the risk are traditionally based on a specified, parametric, dose-response model. It is a well-known concern, however, that uncertainty can exist in specification and selection of the model. If the chosen parametric form is in fact misspecified, this can lead to inaccurate, and possibly unsafe, lowdose inferences. We study the effects of model selection and possible misspecification on the BMD, on its corresponding lower confidence limit (BMDL), and on the associated extra risks achieved at these values, via large-scale Monte Carlo simulation. It is seen that an uncomfortably high percentage of instances can occur where the true extra risk at the BMDL under a misspecified or incorrectly selected model can surpass the target BMR, exposing potential dangers of traditional strategies for model selection when calculating BMDs and BMDLs.

Simultaneous Confidence Bands for Abbott-Adjusted Quantal Response Models

We study use of a Scheffé-style simultaneous confidence band as applied to low-dose risk estimation with quantal response data. We consider two formulations for the dose-response risk function, an Abbott-adjusted Weibull model and an Abbott-adjusted log-logistic model. Using the simultaneous construction, we derive methods for estimating upper confidence limits on predicted extra risk and, by inverting the upper bands on risk, lower bounds on the benchmark dose, or BMD, at which a specific level of 'benchmark risk' is attained. Monte Carlo evaluations explore the operating characteristics of the simultaneous limits.

The use of myocardial and testicular end points as a basis for estimating a proposed tolerable daily intake for sodium monofluoroacetate (1080)

This paper presents the development of a tolerable daily intake (TDI) for sodium monofluoroacetate (1080) using the quantal myocardial and testicular toxicity end points derived from the traditional NOAEL and newer benchmark dose (BMD) methods. 1080 is a highly toxic vertebrate pesticide that has been proven to be effective in controlling possums and other pests. By convention, the TDIs are derived using the traditional no-observed-adverse-effect-level (NOAEL) and applying appropriate default uncertainty factors (UF). In addition to the default UF, a statistically derived UF was also employed in deriving the TDI. The TDIs derived from the NOAEL and BMD approach, 0.075 and 0.10 mg/kg bw/day, respectively, were compared. The resulting TDI estimates using the BMDL, a statistical lower confidence bound on the BMD, were generally consistently slightly higher than those derived using the NOAEL approach. Based on the best fit of modelled dose-response data, a TDI of 0.03 micro g/kg bw/day is proposed for human health risk assessment of 1080.