This study aimed to verify the linear associations between the physical, chemical and microbiological variables of spring water. The research was developed from two seasons of spring water sample collections and evaluated physical–chemical variables such as temperature, pH, turbidity, electrical conductivity, total alkalinity, total hardness, total ammonia, nitrite, nitrate, true and apparent colors, total phosphorus, fluoride and total iron, and microbiological variables—total coliforms and Escherichia coli. The variables’ total alkalinity, total hardness, and electrical conductivity have a strong positive correlation among them (r > 0.50), which is similar to what occurs with the variables’ turbidity, apparent color, true color, and total iron, between nitrite and total iron, and between the turbidity and total coliforms. These correlations occur as a function of the interaction that water has with the soil and the compounds found, thus altering the quality. The springs do not have masonry protection, they only have plant protection. Moreover, this water is exposed and accessible to animals in these areas. In addition, the result of the surface and sub-surface flow effect of spring water must be considered.

Há variações nas composições químicas, físicas e na anatomia da madeira, entre espécies e também dentro da mesma espécie, as quais variam significativamente com a altura do tronco e na direção da medula até a casca. O objetivo do presente trabalho foi analisar a composição química da madeira de Cordia trichotoma. Foram analisadas três árvores, coletadas na Região Noroeste do Estado do Rio Grande do Sul, das quais foi retirado um disco de madeira localizado próximo da base. Quantificou-se o teor de cinzas e de extrativos pela norma TAPPI e o óleo essencial foi extraído usando o método por arraste de vapor. Também foram determinados os elementos químicos presentes nas amostras de madeira, na sua forma natural, e moída, por espectrometria de fluorescência de raios-X por energia dispersiva –EDXRF. A madeira de Cordia trichotoma apresentou teores médios de cinzas e de extrativos totais de 1,39% e 28,22%, respectivamente. Na composição química do óleo essencial foi possível a identificação de dois principais componentes do óleo o α-cadinol e do α-muurolol. Os elementos minerais mais abundantes foram o potássio, cálcio, magnésio, fósforo, enxofre e silício. O ferro foi o elemento com menor concentração encontrado na madeira pela técnica de análise utilizada.

Wood is a renewable material considered eco-friendly and used for various purposes. While wood treated with chromated copper arsenate (CCA) does not deteriorate, its final disposal may entail risks due to the concentration and toxicity of the components. The removal of CCA from wood can be achieved in different ways. This study focuses on the reduction of the concentrations of Cu, Cr, and As chemical species by the electro-removal technique, aiming to obtain biomass with low deleterious potential that would allow multiple uses or safe disposal in landfills. The analytical results showed reductions of 79.5, 87.4, and 81.3% in the mean concentrations of Cu, Cr, and As, respectively. It is worth mentioning the occurrence of the fungus Xylaria sp. after treatment 6 (60 min, 5 g, and 25 V), further suggesting that the method was effective. Samples of these fungi were identified from isolates by culture in medium, DNA extraction, and sequencing of the Internal Transcribed Spacer (ITS) region.

Fish farming is commonplace worldwide, especially in Asian countries. World aquatic animals’ production was approximately 178 million tons in 2020, and from this total, around 89% was destined for human consumption (FAO, 2022 Food and Agriculture Organization of the United Nations – FAO, 2022. The state of world fisheries and aquaculture [online]. Rome. Retrieved in 2023, March 20, from https://www.fao.org/3/cc0461en/online/cc0461en.html https://www.fao.org/3/cc0461en/online/cc... ). The demand for animal protein increases the consumption of fish and its derivatives, and therefore reflects on the increase in fish farming (El-Hack et al., 2022 El-Hack, M.E.A., El-Saadony, M.T., Nader, M.M., Salem, H.M., El-Tahan, A.M., Soliman, S.M., & Khafaga, A.F., 2022. Effect of environmental factors on growth performance of Nile tilapia (Oreochromis niloticus). Int. J. Biometeorol. 66(11), 2183-2194. PMid:36044083. http://dx.doi.org/10.1007/s00484-022-02347-6. http://dx.doi.org/10.1007/s00484-022-023... ). In Brazil, this activity has been developing at a fast rate, mainly due to the demand of the domestic consumer market (Embrapa, 2020 Empresa Brasileira de Pesquisa Agropecuária – Embrapa, 2020. O mercado de peixes da piscicultura no Brasil: estudo do segmento de supermercados. Palmas: Embrapa Pesca e Aquicultura, 38 p., Boletim de Pesquisa e Desenvolvimento, no. 25. ). Nile tilapia (Oreochromis niloticus) is the most cultivated species in Brazil (IBGE, 2019 Instituto Brasileiro de Geografia e Estatística – IBGE, 2019. Pecuária. Retrieved in 2021, March 20, from https://cidades.ibge.gov.br/brasil/pesquisa/18/16459?ano=2019 https://cidades.ibge.gov.br/brasil/pesqu... ), and widely used in aquaculture worldwide (FAO, 2023 Food and Agriculture Organization of the United Nations – FAO, 2023. Oreochromis niloticus [online]. Rome: Fisheries and Aquaculture. Retrieved in 2023, March 20, from https://www.fao.org/fishery/en/introsp/3399/en https://www.fao.org/fishery/en/introsp/3... ).

This study aimed to evaluate the potability of drinking water in ten municipalities of Rio Grande do Sul State, Brazil, distributed in rural and urban areas, with three different sources: springs, shallow wells, and deep wells. The water quality parameters analyzed from 2017 to 2019 were: pH, temperature, apparent and true color, turbidity, electrical conductivity, total alkalinity, total hardness, nitrate, total phosphorus, total iron, fluoride, biochemical oxygen demand, total coliforms, and Escherichia coli. A macroscopic analysis was also conducted in the surrounding of sampling points. According to the Brazilian and the WHO (World Health Organization) guidelines, some of the analyzed variables, in some sampling points, were in disagreement with the current both guidelines, which are pH, apparent color, turbidity, total iron, total coliforms, and Escherichia coli. The surveillance showed that the deeper the water is abstracted the less are natural and anthropogenic interferences in physical, chemical, and microbiological characteristics of the water; and the protection of the location where the water is abstracted improves its quality. Nonetheless, for the sampled waters it is necessary a disinfection process for posterior human consumption.