Qualidade da água do manancial subterrâneo em áreas urbanas de Feira de Santana (BA)

Physicochemical, microbiological and parasitological analysis of water for human consumption in a quilombola community in Alagoas

Water is the indispensable natural resource for all living beings. For human consumption, it must be potable, so as not to pose a risk to health, and can be used for ingestion, food preparation and personal hygiene. Knowing this importance, this study aimed to carry out physical-chemical, microbiological and parasitological analyzes of water for human consumption in a quilombola community of Santa Luzia do Norte in Alagoas. A cross-sectional, experimental and quantitative study was carried out between January and December 2019. The physical-chemical parameters of residual chlorine, turbidity, fluoride, fluoridation, color and pH were analyzed, microbiological analyses were based on the research of total and thermotolerant coliforms (E. coli) and parasitological analyses were performed based on the research of protozoa and intestinal helminths. Some physical-chemical parameters (turbidity and pH) were observed outside the limits required by the Ministry of Health, and the presence of total coliforms in some of the analyzed samples (17.85%), characterizing this community at risk related to waterborne diseases. The samples analyzed did not present infecting forms of parasitic species. Regarding the variables evaluated, the results found showed that the lack of adequate basic sanitation affects the quality of water used for human consumption by the quilombola population of Santa Luzia do Norte-AL.

An integrated assessment of water quality in a land reform settlement in northern Rio de Janeiro state, Brazil

The Zumbi dos Palmares land reform settlement lacks modern facilities for water and sewage treatment. Local farmers often use shallow wells as alternative source of water supply, because the water table is reasonably high in the region. This work presents a multivariate analysis assessment of physicochemical and bacteriological parameters and pesticide residues in water samples collected from these shallow wells. The physicochemical parameters analyzed were: conductivity, pH, DOC (dissolved organic carbon), nitrate, turbidity, and bacteriological analysis measuring total and fecal coliforms. The results show non-compliance with Brazilian legal standards in most samples where low pH values were found, characterizing the presence of acidic waters. Another example of non-compliance is the presence of total and fecal coliforms in for drinking water in most of the samples and, in some cases, very high values (2,400 CFU). Some wells showed high conductivity values, probably associated with a history of oceanic intrusion. Analyses determining the contamination by pesticides show the presence of ametrine, atrazine, methyl parathion, carbaryl and hexazinone. The concentration for these compounds ranged from 0.14 to 1.17 μg/L. Ordinance No 2914/2011 from the Brazilian Ministry of Health establishes the acceptable limits for atrazine and methyl parathion as 9 μg L⁻¹ and 2 μg L⁻¹. None of these exceeded the allowable Brazilian and European limits. However, for the other two pesticides, the European Legislation (Council Directive) recommends the maximum allowable concentration of 0.1 μg L⁻¹ and, 0.5 μg L⁻¹ for total pesticides. Our samples that were above the quantifiable limit of 50 ng L⁻¹, were also above the European limit values. Our results therefore suggest that water gathered from shallow wells at the Zumbi dos Palmares settlement is not proper for consumption without proper disinfection treatments.

Toxicological aspects of trihalomethanes: a systematic review

Chlorine is considered the most used chemical agent for water disinfection worldwide. However, water chlorination can lead to by-product generation which can be toxic to humans. The present study aimed to perform a systematic review on the toxicity of trihalomethanes (THMs) through bioindicators of cytotoxicity, genotoxicity, and mutagenicity. The results showed that studies on the effects of THMs on DNA are a current research concern for evaluating the toxicity of the pure compounds and real samples involving several types including water for recreational use, reused water, and drinking water. THMs deleterious effects have been assessed using several biosystems, where the Ames test along with experimental animal models were the most cited. A wide range of THM concentrations have been tested. Nevertheless, DNA damage was demonstrated, highlighting the potential human health risk. Among the studied THMs, chloroform presented a different action mechanism when compared with brominated THMs, with the former being cytotoxic while brominated THMs (bromodichloromethane, bromoform, and dibromochloromethane) were cytotoxic, genotoxic, and mutagenic. The described evidence in this research highlights the relevance of this topic as a human health issue. Nevertheless, research aimed to represent THMs current exposure conditions in a more accurate way would be needed to understand the real impact on human health.

The use of bacterial bioremediation of metals in aquatic environments in the twenty-first century: a systematic review

Metal pollution is a current environmental issue as a consequence of unregulated anthropic activiy. A wide range of bioremediation strategies have been successfully implemented to recover contaminated areas. Among them, bacterial bioremediation stands out as a promising tool to confront these types of concerns. This study aimed to compare and discuss worldwide scientific evolution of bacterial potential for metal bioremediation in aquatic ecosystems. The study consisted of a systematic review, elaborated through a conceptual hypothesis model, during the period from 2000 to 2016, using PubMed, MEDLINE, and SciELO databases as data resources. The countries with the largest number of reports included in this work were India and the USA. Industrial wastewater discharge was the main subject associated to metal contamination/pollution and where bacterial bioremediations have mostly been applied. Biosorption is the main bioremediation mechanism described. Bacterial adaptation to metal presence was discussed in all the selected studies, and chromium was the most researched bioremedied substrate. Gram-negative Pseudomonas aeruginosas and the Gram-positive Bacillus subtilis bacteria were microorganisms with the greatest applicability for metal bioremediation. Most reports involved the study of genes and/or proteins related to metal metabolism and/or resistence, and Chromobacterium violaceum was the most studied. The present work shows the relevance of metal bacterial bioremediation through the high number of studies aimed at understanding the microbiological mechanisms involved. Moreover, the developed processes applied in removal and/or reducing the resulting environmental metal contaminant/pollutant load have become a current and increasingly biotechnological issue for recovering impacted areas.

Padrão físico-químico e microbiológico da água de nascentes e poços rasos de propriedades rurais da região sudoeste do Paraná

Este trabalho avalia a qualidade da água em propriedades rurais do município de Dois Vizinhos, Paraná, por meio de analises físico-químicas e microbiológicas. Foram analisadas 90 amostras, sendo 45 provenientes de nascentes e 45 de poços rasos, quanto aos parâmetros pH, temperatura, turbidez, coliformes totais e termotolerantes. Das 90 amostras analisadas, 23 atenderam à legislação vigente, enquanto que 67 estavam em desacordo, logo, inapropriadas para o consumo humano e animal, representando fator de risco à saúde.

Simultaneous adsorption of iron and manganese from aqueous solutions employing an adsorbent coal

In this work, an adsorbent coal was characterized and its sorption properties for the removal of iron and manganese from aqueous solutions were determined. Energy dispersive X-ray (EDX) analysis and X-ray diffraction (XRD) identified the presence of quartz, magnetite and manganese oxide in the adsorbent coal. The results of the adsorption isotherms verified the adsorption of iron and manganese by adsorbent coal showing a linear behaviour and indicated that chemisorption and physisorption occurred. The kinetic results were best adjusted to the pseudo-second order model with a 0.999 correlation coefficient. The results showed that the adsorbent coal could be used efficiently for the removal of iron and manganese from aqueous solutions.

Microbiological quality of drinking rainwater in the inland region of Pajeú, Pernambuco, Northeast Brazil

Despite all efforts to store and reduce its consumption, water is becoming less inexhaustible and its quality is falling faster. Considering that water is essential to animal life, it is necessary to adopt measures to ensure its sanitary conditions in order to be fit for consumption. The aim of this study was to analyze the microbiological quality of drinking rainwater used by rural communities of Tuparetama, a small town located in Northeast Brazil. The study covered seven rural communities, totaling 66 households. In each household two samples were collected, one from a tank and the other from a clay pot located inside the home, resulting in 132 samples (tank plus clay pot). Approximately 90% of samples were below the standard recommended by the current legislation, being considered unfit for human consumption. Part of this high microbiological contamination of drinking rainwater could be related to the lack of sanitary education and of an adequate sewerage sanitation system.