Multi-elemental exposure assessment through concentrations in hair of free-ranging capybaras (Hydrochoerus hydrochaeris Linnaeus, 1766) in the Atlantic Forest remnants, Northeast of Brazil

Mineral profile and histopathological findings in the liver of white-lipped frog (Leptodactylidae) from the morphoclimatic domain of the Caatingas, Brazil

This study aimed to investigate the mineral profile and histopathological findings in the liver of Leptodactylus macrosternum (white-lipped frog) and to assess the association between melanomacrophage areas and hepatic fungal granuloma with several factors such as weight, snout-cloacal length, sex, hepatosomatic index, season (dry and rainy), and condition factor K. A total of 135 frogs of different ages were collected from three areas in the city of Petrolina, Pernambuco, with varying land use (conventional agriculture, organic agriculture, and Caatinga stricto sensu). The liver of all specimens exhibited changes such as granulomatous lesions, inflammatory cell infiltrate, blood vessel congestion, and sinusoid dilation. The melanomacrophage areas were influenced by weight, snout-cloacal length, and hepatosomatic index. Our findings revealed a positive correlation between body size (weight and snout-cloacal length) and melanomacrophage/hepatic granuloma, while the hepatosomatic index showed a negative relationship. For the condition factor K, only age presents relationship. Eleven elements were quantified for the mineral profile, with aluminum (Al), iron (Fe), and zinc (Zn) being the most abundant in both liver and muscle. Although the histopathological findings and mineral profile of the liver and muscle in this study indicate an effect on the health of L. macrosternum in different collection areas, confirming the relationship between environmental characteristics and these findings requires future studies. Furthermore, long-term studies would be necessary to allow the monitoring of all stages of development of these populations, from tadpoles to adults, for a better evaluation of these effects in L. macrosternum.

Concentrations of iron and chromium in free-ranging common marmosets (Callithrix jacchus) from Pernambuco, Brazil

Common marmosets (Callithrix jacchus) are widely distributed in Northeast Brazil and often inhabit urban and peri-urban forest areas close to human settlements. Given its wide territorial distribution, its proximity to human populations, and its exposure to environmental degradations originating from urbanization, common marmosets have a high potential for environmental biomonitoring. The concentrations of iron (Fe) and chromium (Cr) were quantified in the liver, hair, and bone of 22 free-ranging common marmosets' bodies from nine cities from Pernambuco State, Brazil, using inductively coupled plasma optical emission spectrometry (ICP OES). The liver showed the highest concentrations of Fe and Cr (3773.2 ± 3715.8 mg/kg and 19.4 ± 41.6 mg/kg, respectively); the lowest concentration of Fe was detected in the bone (111.6 ± 97.6 mg/kg) and of Cr in the hair (3.3 ± 1.5 mg/kg). There was a moderate positive correlation between Fe and Cr in the liver (r = 0.64) and a high negative correlation for Cr between bone and hair (r = -0.65). This study demonstrated the bioaccumulation of Fe and Cr in hair, liver, and bone in common marmosets. The highest average concentration of Fe and Cr occurred in animals from Recife, Jaboatão dos Guararapes, and Paulista, respectively, the 1^st, the 2^nd, and the 5^th most populated cities in the state of Pernambuco. The presence of high concentrations of metals in animals from Recife and nearby cities can indicate alarming levels of environmental pollution in these locations.

Biomonitoring metals and metalloids in wild mammals: invasive versus non-invasive sampling

Heavy metal and metalloid pollution is a matter of concern in animal, human and environmental health (One Health) and also in wildlife conservation worldwide. Studying wild mammals in toxicology has been contributing significantly to our knowledge, namely to find out the most critical regions, to understand bioaccumulation and biomagnification phenomena or to evaluate their toxic effects. However, not all the animal tissues and organs provide the same information or should be interpreted in the same way. The best sample to use will depend on the objectives and conditions of the study. This review aims to compare invasive and non-invasive samples to biomonitor heavy metals, providing a brief resume of their advantages, limitations and examples of use. Further research, using a wider range of mammalian species, is required to establish what information can be obtained in biomonitoring studies that use non-invasive samples (such as hair, faeces and parasites) and/or invasive samples (such as blood, liver, kidney, bone and other organs).

Clay Nanotube Immobilization on Animal Hair for Sustained Anti-Lice Protection

Topical administration of drugs is required for the treatment of parasitic diseases and insect infestations; therefore, fabrication of nanoscale drug carriers for effective insecticide topical delivery is needed. Here we report the enhanced immobilization of halloysite tubule nanoclay onto semiaquatic capybaras which have hydrophobic hair surfaces as compared to their close relatives, land-dwelling guinea pigs, and other agricultural livestock. The hair surface of mammals varies in hydrophobicity having a cortex surrounded by cuticles. Spontaneous 1-2 µm thick halloysite hair coverages on the semi-aquatic rodent capybara, non-aquatic rodent guinea pig, and farm goats were compared. The best coating was found for capybara due to the elevated 5 wt% wax content. As a result, we suggest hair pretreatment with diluted wax for enhanced nanoclay adsorption. The formation of a stable goat hair coverage with a 2-3 µm halloysite layer loaded with permethrin insecticide allowed for long-lasting anti-parasitic protection, enduring multiple rain wettings and washings. We expect that our technology will find applications in animal parasitosis protection and may be extended to prolonged human anti-lice treatment.

Quantification of Some Heavy Metals in Hair of Dairy Cows Housed in Different Areas from Sicily as a Bioindicator of Environmental Exposure-A Preliminary Study

The objective of this preliminary study was to evaluate the levels of selected heavy metals in hair samples of Holstein dairy cows reared on agricultural soils characterized by grassland subjected to anthropogenic impacts. Ninety Holstein-Friesian cows were enrolled in the study and divided into six groups according to farm origin. From each animal, hair samples were collected in order to determine the content of aluminum, chromium, iron, copper, zinc, arsenic, cadmium, and lead. One-way analysis of variance was applied to assess statistically significant differences in the studied heavy metals among the six groups. A significant effect of groups (p < 0.05) on all tested heavy metals was observed. In this study, the low concentration of heavy metals in the hair of the studied animals led us to think that the cows were subjected to low levels of these compounds, preventing them from bioaccumulating. Although the current study provides only preliminary results, it highlights the importance of investigating the concentration of heavy metals in cow hair to improve the health and welfare of both humans and animals.