Contribution of cereals and cows' milk consumption to the exposure to mycotoxins: a study with Portuguese children.

The ubiquitous occurrence of mycotoxins in the environment results in unavoidable and repeated human exposure to mixtures of mycotoxins, the main exposure being through the consumption of contaminated foods, such as cereals and milk. Considering the frequency of contamination of these foods with mycotoxins, this study aimed to evaluate the risk of exposure to aflatoxins, ochratoxin A, deoxynivalenol and zearalenone in a Portuguese population under 17 years old through the consumption of these foods. To assess mycotoxin exposure, food contamination data was provided by the Official National Plan to Control Food and the food consumption information from the National Food, Nutrition, and Physical Activity Survey of the Portuguese General Population (2015-2016); risk assessment calculations were performed through the Monte Carlo probabilistic method. In view of the results obtained for aflatoxins, ochratoxin A, deoxynivalenol and zearalenone, and considering the legislation in force, the levels observed were below the maximum levels. However, there was a risk in deoxynivalenol exposure for children from 0 to 9 years old (average and high consumers), and for high consumers from 10 to 17 years old. Given the potential adverse effects of these mycotoxins, their co-existence in the same foods and being a priority issue defined by the European Food Safety Authority, tight control should be carried out, in addition to re-evaluation of the maximum levels of these mycotoxins.

NEUROTOXICITY OF METAL MIXTURES.

Environmental exposures and/or alterations in the homeostasis of essential transition metals (ETM), such as Fe, Cu, Zn or Mn, are known to contribute to neurodegenerative diseases (ND), such as Alzheimer's Disease (AD) and Parkinson's Disease (PD). Aberrant ETM homeostasis leads to altered distributions, as significant amounts may accumulate in specific brain areas, while causing metal deficiency in others. The disruption of processes reliant on the interplay between these ETM, may lead to loss of metal balance and the ensuing neurotoxicity via shared mechanisms, such as the induction of oxidative stress (OS). Both ETM imbalance and OS may play a role, via complex positive loop processes, in primary neuropathological signatures of AD, such as the accumulation of amyloid plaques and neurofibrillary tangles (NTF), and in PD, α-Syn aggregation and loss of dopamine(DA)rgic neurons. The association between ETM imbalance and ND is rarely approached under the view that metals such as Fe, Cu, Zn and Mn, can act as dangerous endogenous neurotoxic mixtures when their control mechanisms became disrupted. In fact, their presence as mixtures implies intricacies, which should be kept in mind when developing therapies for complex disorders of metal dyshomeostasis, which commonly occur in ND.

Biomarkers of exposure and effect in a working population exposed to lead, manganese and arsenic.

Lead (Pb), manganese (Mn) and arsenic (As) are among the major toxicants in mining environments. Miners are commonly and repeatedly exposed to this toxic mixture. Some adverse effects may appear at concentrations below environmental quality guidelines for individual mixture components. Further, Pb, Mn, and As induce common adverse outcomes, such as interferences in the cholinergic system and heme synthesis. It is thus vital to monitor miners through biomarkers (BM), such that subclinical effects may be identified at an early stage. The main objectives of this study were to evaluate the exposure of a mining population to these three metals and determine alterations in cholinergic and heme synthesis parameters. Blood and urine samples of workers (n = 60) were obtained from a Portuguese mining industry and compared with a control population (n = 80). The levels of the metals were determined in biological samples, as well as urinary heme precursor levels, delta aminolevulinic acid (ALA) and porphyrins, and blood acetylcholinesterase (AChE) activity. The miners exhibited significantly higher values of Pb and As in blood and urine compared to control. In the case of Mn near or slightly higher than limit values were found. Our data show that heme precursors may be used simultaneously with metal levels as BMs for multiple metal exposures on an individual basis, resulting in 94.3% and 95.7% accuracy, respectively, in blood and urine, for subjects correctly identified with respect to occupation. This study also revealed that biological monitoring of this working population regarding metal body burden and heme precursor accumulation is advisable.