Blood levels of 21 metals and metalloids in riverside villagers of the Brazilian Amazon: A human biomonitoring study with associations with sociodemographic, dietary, and lifestyle factors.

Human biomonitoring of toxic and essential trace elements is critically important for public health protection. Amazonian riverine communities exhibit distinctive dietary patterns, heavily reliant on locally sourced fish, fruits, and vegetables. These habits may result in unique exposure profiles compared to urban populations. However, comprehensive assessments of their exposure to toxic and essential metals are lacking, representing a critical gap in understanding the health risks faced by these communities. This study aimed to establish baseline levels of 21 metals and metalloids in human blood and explore the influence of sociodemographic factors, dietary habits, and lifestyle choices as potential sources of exposure to these elements. A cross-sectional biomonitoring investigation was conducted with 1,024 individuals from 13 communities in the Tapajós and Amazon Basins (Pará, Brazil). Most of the elements in study was determined for the first time in the region. Blood samples were analyzed using inductively coupled plasma mass spectrometry (ICP-MS). The levels of all elements were summarized by quantiles and compared with cutoff values from other Brazilian populations. Multiple linear regression was used to assess possible associations between element concentrations and sociodemographic characteristics, dietary habits, and lifestyle choices. High detection rates (64%-100%) were observed, indicating the widespread presence of these elements. Elevated blood concentrations were found for mercury (median 21.1 µg.L-1, interquartile range: 12-34 µg.L-1), selenium (median 166 µg.L-1, interquartile range: 137-208 µg.L-1), and lead (median 34 µg.L-1, interquartile range: 20.8-64 µg.L-1). Regression analysis revealed a positive association between mercury levels and fish consumption, while manioc flour intake showed no relationship to lead levels. In conclusion, our findings emphasize the need for continued monitoring and public policy development for these vulnerable populations. Further studies should assess long-term trends and investigate the health implications of prolonged exposure to diverse chemicals in Amazonian riverside communities.

Levels and health risk assessment of twenty-one current-use pesticides in urban and riverside waters of the Brazilian Amazon Basin.

In Brazil, the favorable weather conditions and abundant land contribute to the thriving agricultural production. Brazilian crops extensively employ pesticides due to their high efficacy, cost-effectiveness, and permissive regulatory framework. However, pesticide use also endangers water resources, animal organisms, and human health. Due to the lack of data on pesticide use in the Amazonas forest-based Brazil, the present study aimed to assess the levels of twenty-one current-use pesticides (CUPs) from five different classes in river waters collected from urban and riverside areas in this region. Moreover, the non-carcinogenic risks associated with water consumption were also characterized. Thirteen CUPs were detected in concentrations above the limit of detection (LOD) in at least one of the water samples, and most pesticides were detected in riverside areas. In contrast, only 18% of the analyzed samples were considered "clean," with only one compound detected. Fenitrothion showed the highest concentration, with a mean value of 4.86 ng/mL (0.30-14.3 ng/mL). Up to 33% of the samples showed levels of fipronil above the LOD, an issue of environmental and human health concern, mainly because of the adverse effects observed in honeybees. Despite this, the human health risk assessment showed a target hazard quotient below one (HQ < 1) in adults for all substances, suggesting that pesticide exposure through water consumption should not mean risk for the riverside populations. Taking into account the large extension of Brazil, as well as its different agricultural practices throughout the country, it would be of great importance to conduct extensive research in other areas. It would help to gain knowledge in this field and to promote eco-friendly alternatives to mitigate pesticide use and, consequently, to reduce their potential adverse effects on human health and the ecosystems.

Human exposure to elements through consumption of raw and cooked fish in an urban region of the central Brazilian Amazon biome: Health risks.

Fish is an important source of animal protein for local communities in the Amazon basin, whose food safety must be assured. However, certain potential toxicants elements, can bioaccumulate in fish species, which inhabit anthropogenically polluted waters, ultimately posing a risk to human health. In the present study, the concentrations of nine elements (Al, As, Cd, Cr, Cu, Hg, Ni, Pb and Zn) were determined in raw and cooked samples of eight fish species consumed in Santarém (northern Brazil, Amazon biome). The potential for non- carcinogenic human health risks linked to the consumption of cooked fish were evaluated for adults and children in two different scenarios. Four carnivores, three omnivores and one detritivore, all of them regularly marketed and consumed by the Santarém population, were the target species. The safety reference values set by national and international guidelines for humans, in both raw and cooked preparations, were used. In most cases, the cooking process showed a trend to increase elements concentrations compared to raw samples, however the differences were not significant. Moreover, the risk assessment showed danger for children in relation to Hg from the consumption of fish, in both scenarios evaluated. For adults, in one of the scenarios, there was a health risk associated to Hg as a result of carnivorous fish consumption. In a context of combined exposure to all elements, children were at risk when consuming fish, especially carnivorous and omnivorous species. For adults, the mixture of elements posed a risk to health human only for carnivorous fish consumption. The results reveal an environmental scenario of Hg contamination, which requires monitoring actions to preserve the aquatic biodiversity and human health in the Brazilian Amazon biome.

Levels of organic pollutants and metals/metalloids in infant formula marketed in Brazil: Risks to early-life health.

Infant formula intake is recommended to ensure comprehensive nutritional and caloric fulfillment when exclusive breastfeeding is not possible. However, similarly to breast milk, infant formulas may also contain pollutants capable of inducing endocrine-disrupting and neurotoxic effects. Thus, considering the sensitivity of their developing physiological systems and that infants have heightened susceptibility to environmental influences, this study was aimed at assessing the contents of essential elements, and inorganic and organic pollutants in infant formulas marketed in Brazil. Additionally, health risk assessments for selected contaminants were also performed. Measured contents of essential elements (Ca, Fe, Mg, Mn, Cu, Se, and Zn) were congruent with label information. Nevertheless, some toxic elements (Pb, Cd, As, Ni, and Al) were also detected. Notably, in the upper-bound scenario, Pb and Cd surpassed established threshold values when comparing the estimated daily intake (EDI) and tolerable daily intake (TDI - 3.57 and 0.36 µg/kg bw, respectively). Bisphenol P (BPP) and benzyl butyl phthalate (BBP) were frequently detected (84 % detection rate both) with elevated contents (BPP median = 4.28 ng/g and BBP median = 0.24 ng/g). Furthermore, a positive correlation (0.41) was observed between BPP and BBP, implying a potential co-occurrence within packaging materials. Methyl-paraben also correlated positively with BBP (0.57), showing a detection rate of 53 %. The cumulative PBDE contents ranged from 0.33 to 1.62 ng/g, with BDE-154 and BDE-47 the dominant congeners. When comparing EDI values with TDIs, all organic pollutants remained below the thresholds across all exposure scenarios. Moreover, non-carcinogenic risks were below the threshold (HQ > 1) when dividing the EDIs by the respective reference doses for chronic exposure. While the current findings may suggest that infant formula intake poses no immediate risk in terms of the evaluated chemicals, it remains imperative to conduct further research to safeguard the health of infants considering other chemicals, as well as their potential cumulative effects.

Association between urinary concentrations of toxic metals/metalloids and oxidative stress in Brazilians living in areas affected by the Fundão dam failure.

The Fundão Dam failure has been the most significant environmental disaster in Brazil. The catastrophe released large amounts of mining waste into the environment, including toxic metals/metalloids, which are recognized to induce carcinogenic effects. The urinary levels of 8-hydroxy-2'-deoxyguanosine (8OHdG), a widely accepted oxidative stress and carcinogenesis biomarker, provide a potential tool for assessing the disaster's health implications. This study investigated the association between urinary levels of some toxic metals/metalloids and 8OHdG in Brazilian individuals living in areas affected by the Fundão dam failure. Urinary concentrations of arsenic (As), cadmium (Cd), mercury (Hg), nickel (Ni), and lead (Pb) were determined using inductively coupled plasma mass spectrometry, while 8OHdG was analyzed by liquid chromatography-tandem mass spectrometry. Non-parametric bootstrap regression was used to estimate the associations between the urinary levels of toxic elements and 8OHdG. The results showed that except for Hg, urinary concentrations of all metals/metalloids analyzed here exceeded the reference ranges for the Brazilian population. The regression analysis revealed that As (0.337; CI 95%: 0.203; 0.474), Cd (0.268; CI 95%: 0.036; 0.520), and Ni (0.296; CI 950.108; 0.469) were positively associated with creatinine-adjusted urinary 8OHdG levels. Associations were not found for Hg (0.0122; CI 95%: -0.155; 0.183) and Pb (0.201; CI 95%: -0.040; 0.498). The current findings suggest that high exposure to toxic metals/metalloids might increase 8OHdG levels with potential adverse health effects. This study is the first one in which the relationship between toxic metals/metalloids and oxidative stress biomarkers is investigated in populations affected by environmental disasters. Further prospective studies are necessary to monitor exposure levels and explore additional health impacts.

Recent trends in pesticides in crops: A critical review of the duality of risks-benefits and the Brazilian legislation issue.

Due to the increasing population worldwide, in recent years, an exponential increase in agricultural practices has occurred in order to attend to the growing demand for food. Unfortunately, this increase is not associated with the supply of foodstuffs free of environmental pollutants. In Brazil, agriculture is one of the most important economic pillars, making the country one of the largest consumers of pesticides around the world. The intense use of pesticides, mainly glyphosate, 2,4-D, and atrazine, constitutes an essential factor in the viability of this great agricultural productivity. Sugarcane, corn, soybean, and citrus crops consume around 66% of the total pesticides worldwide, representing 76% of the planted area. Pesticide residues have been frequently detected in food and the environment, becoming a significant concern for human health. Monitoring programs for pesticide use are essential to reduce the potential negative impacts on the environment and improve the overall efficiency and sustainability of their use. However, in Brazil, the approval status of pesticide-active ingredients is very discrepant compared to other agricultural countries. Moreover, the duality of benefits and risks of pesticide application creates an economic and toxicological conflict. In this paper, we have critically reviewed the duality of risks-benefits of the use of pesticides in agriculture and the current Brazilian legislation issues. We have also compared this flawed legislation with other countries with high economic potential. Due to the negative environmental impacts on soil and water by the high levels of pesticides, remediation techniques, sustainable agriculture, and the development of new technologies can be considered some viable alternatives to reduce the levels in these compartments. Besides, this paper includes some recommendations that can be included in the coming years.

Non-regulated aromatic amines in clothing purchased in Spain and Brazil: Screening-level exposure and health impact assessment.

The staggering amount of chemicals in clothes and their harmful effects on human health and the environment have attracted the attention of regulatory agencies and the scientific community worldwide. Azo dyes are synthetic dyestuffs with widespread use in textile industries, currently classified as emerging pollutants of great health concern to consumers. These compounds may release one or more aromatic amines (AAs) after reductive cleavage of their azo bounds. Twenty-two AAs have already been regulated due to their carcinogenic effects. However, since information on their potential toxicity is not currently available, several AAs have not been still regulated by the European Union. Considering this gap, the present study aimed to assess the levels of forty non-regulated AAs in 240 clothing items from Spain and Brazil. The potential impact on the health of vulnerable population groups after dermal exposure to those garments was also evaluated. In Brazil, at least one AA was detected in the clothes, while in samples obtained in Spain, only two of them showed values below the limit of detection for AAs. In 75 clothes, at least one of the measured AAs was higher than the hazardous threshold (30 mg/kg), which can mean risks to human health since these compounds are suspected to be mutagenic. Aniline, the most common AA, showed a high detection rate (82%) in clothes, with significantly higher concentrations in items commercialized in Brazil (0.35 vs. 0.17 mg/kg; p = 0.032). Moreover, o-aminobenzenesulfonic and p-phenylenediamine, suspected mutagenic, were found at relevant concentrations in several clothes, mainly made of synthetic fibers. In this study, the hazard index associated with exposure to AAs through clothing was low (0.006-0.13) for all the population groups of both countries in the medium-bound scenario. However, its value was close to 1 for Brazilian pregnant women (0.998) when the maximum concentration value was considered under an upper-bound scenario. The risk of exposure to non-regulated AAs may be underestimated since only dermal exposure was considered for risk assessment. Moreover, the co-occurrence of other carcinogenic and non-carcinogenic substances present in skin-contact clothes should mean an additional source of potential risk.

High occurrence of heavy metal tolerance genes in bacteria isolated from wastewater: A new concern?

Some heavy metals have antimicrobial activity and are considered as potential alternatives to traditional antibiotic therapy. However, heavy metal tolerance genes (HMTG) have been already detected and coding different tolerance mechanisms. Considering that certain metals are promising for antimicrobial therapy, evaluation of HMTG dissemination in bacteria from sewage is essential to understand the evolution of these bacteria and to predict antimicrobial use and control. The present study aimed to evaluate the occurrence of bacteria carrying HMTG in samples of hospital wastewater and from urban wastewater treatment plant (WWTP). The acquired HMTG were investigated by PCR in bacterial collection previously characterized for antibiotic resistant genes (ARGs). HMTG searched include arsB (arsenic efflux pump), czcA (cadmium, zinc and cobalt efflux pump), merA (mercuric reductase), pcoD (copper efflux pump), silA (silver efflux pump) and terF (tellurite resistance protein). Among 45 isolates, 82% of them carried at last one HMTG, in which the silA and pcoD tolerance genes were the most prevalent. A very strong positive correlation was found between these genes (r = 0.91, p < 0.0001). Tolerance genes merA, arsB, czcA and terF were detected in 47%, 13%, 13% and 7% of the isolates, respectively. It was found that 15 isolates co-harbored ARGs (ß-lactamase encoding genes). HMTG are probably more dispersed than ARGs in bacteria, representing a new concern for heavy metals use as effective antimicrobials. To the best of our knowledge, this is the first study on the HMTG searched in Hafnia alvei, Serratia fonticola and Serratia liquefaciens. Hospital wastewater treatment implementation and additional technologies for treatment in WWTP can reduce the impacts on water resources and HMTG spread, ensureing the environmental and human health safety.

Essential and toxic elements in human milk concentrate with human milk lyophilizate: A preclinical study.

Concentrated human milk (HM-concentrate) can be obtained from the simple and inexpensive method of donated breast milk direct lyophilization. A previous study reported that HM-concentrate contains the adequate amount of main macro- and micronutrients for use as a nutritional resource for preterm infants with very low birth weight admitted to neonatal intensive care units. However, further details need to be elucidated about HM-concentrate composition, particularly its content of essential and potentially toxic trace elements. Therefore, this study aimed to determine the concentration of essential and toxic elements in human milk considered baseline (HM-baseline) and HM-concentrate, as well as to quantify changes in concentration of these elements after the HM concentration process. The concentration of Aluminum, Arsenic, Cadmium, Chromium, Iron, Mercury, Manganese, Nickel, Lead, Selenium, Tin, and Thallium was analyzed by inductively coupled plasma-mass spectrometry (ICP-MS). Moreover, Bayesian linear mixed effect models were applied to estimate the mean difference between HM-baseline and HM-concentrate samples. After comparison (HM-concentrate versus HM-baseline), a significant increase in concentration was observed only for Manganese (0.80 µg/L; 95% CrI [0.16; 1.43]) and Selenium (6.74 µg/L; 95% CrI [4.66; 8.86]), while Lead concentration (-6.13 µg/L; 95% CrI [-8.63; -3.61]) decreased. This study provides latest and reliable information about HM composition. After milk concentration by lyophilization, there was a significant increase only in the essential elements Manganese and Selenium. The essential micronutrient content in HM-concentrate was similar or higher than that in preterm mothers' milk, which suggests it is viable for nutritional support of preterm infants. In addition, the low concentrations of potentially toxic elements in HM-concentrate indicates that it is safe for consumption by premature newborns.

Metals risk assessment for children's health in water and particulate matter in a southeastern Brazilian city.

Ribeirão Preto City is supplied by the Guarani Aquifer System and suffers with intense environmental degradation due to growth of the vehicle fleet, burning of cane fields and also with water contamination by agricultural products, such as pesticides and fertilizers. The aim of the present study was to assess the human health risk derived from the exposure to metals through water and air (PM10) for two population groups (adults and children) of the municipality of Ribeirão Preto during the dry and wet seasons. Seasonal and spatial assessments of the metal concentrations in supply wells and household waters and the concentrations of PM10 and its metals were also performed. Element concentrations were determined by inductively coupled plasma spectrometry. Environmental exposure to metals were assessed under a residential scenario and estimated considering the three main routes of exposure: ingestion, dermal contact and inhalation. The results showed a higher concentration of PM10 during the dry season, which may be due to the lower precipitation and higher number of burns in this period. Copper in household waters presented a great increase when compared with the concentrations of the supply wells, probably related to the contamination during the route from its source until the residences supply. Although presenting levels in accordance with the national legislation, household waters in the municipality of Ribeirão Preto may be a concern for human exposure to metals for children during the wet season as well as the levels found for the carcinogenic risk (ELCR).

Health risks of environmental exposure to metals and herbicides in the Pardo River, Brazil.

Mixture of metals and herbicides in rivers may pose relevant risks for the health of surrounding communities. Humans may be exposed to river pollution through intake of contaminated water and fish, as well as irrigated agricultural products. The aim of this study was to assess the human health risks of environmental exposure to metals and herbicides through water and fish intake in the Pardo River. Metals (Al, As, Be, Cd, Cr, Cu, Pb, Mn, Hg, Ni, Tl, Sn, V, and Zn) were analyzed in river water and in edible fish. Herbicides (ametryn, atrazine, diuron, hexazinone, simazine, and tebuthiuron) were analyzed in river water. Seasonal variances were also studied. Aluminum, Cd, Cu, Mn, Pb, and Zn levels in river water were higher than the USEPA benchmarks. Non-carcinogenic risks due to pollutants mixture exposure were above the limit, and carcinogenic risks of As exposure were >10-6 in the sampling points during the rainy season. Metal levels in fish were lower than the Brazilian legislation and do not pose a threat to public health. Herbicides were detected in four sampling points, with atrazine concentrations (range 0.16-0.32 µg/L) below the Brazilian standard (2.0 µg/L), but above the European Union standard (0.1 µg/L). Considering the water supply needs of cities located in the Pardo River Basin and the persistence of metals and herbicides, the present study indicated that there was a seasonal influence on non-carcinogenic and carcinogenic risks to human health, especially in the rainy season. Studies for water treatment plants implantation should consider the risks of exposure to persistent substances, in order to protect the population.

Integrating three tools for the environmental assessment of the Pardo River, Brazil.

There is a growing need for strategic assessment of environmental conditions in river basins around the world. In spite of the considerable water resources, Brazil has been suffering from water quality decrease in recent years. Pardo River runs through Minas Gerais and São Paulo, two of the most economically important states in Brazil, and is being currently promoted as a future drinking water source. This study aimed at integrating three different tools to conduct a hydromorphological assessment focused on the spatial complexity, connectivity, and dynamism of the Pardo River, Brazil. Twelve sampling stretches were evaluated in four sampling campaigns, in dry and rainy seasons. In each stretch, permanent preservation areas (PPAs), hydromorphological integrity by rapid assessment protocol (RAP), and physicochemical parameters were qualified. The kappa coefficient was used to assess statistical agreement among monitoring tools. The PPA analysis showed that in all stretches, the vegetation was modified. RAP results revealed environmental deterioration in stretches located near human activities and less variability of substrates available for aquatic fauna and sediment deposition as well. Low values for dissolved oxygen in the river mouth were noted in the rainy season. Electrical conductivity was higher in stretches near sugarcane crops. The poor agreement (k<0.35) between the RAP and physicochemical parameters indicates that the tools generate different and complementary information, while they are not replaceable. Potential changes of the hydromorphological characteristics and variations in physicochemical indicators must be related to extensive PPA modification.

Traffic-related air pollution biomonitoring with Tradescantia pallida (Rose) Hunt. cv. purpurea Boom in Brazil.

This study aimed to verify the capacity of Tradescantia pallida in the biomonitoring of air pollution in urban areas with different traffic intensities and under varying environmental conditions. Experiments were carried out in Ribeirão Preto, in the Southeastern Brazil, with more than 660,000 inhabitants and a fleet of more than 485,000 motor vehicles. Ten seedlings of T. pallida were exposed in three areas in the city, differing in traffic vehicle flow, in two seasons (wet and dry). At the end of each sampling period, which lasted 4 months, samples of leaves were collected, and the content of As, Ba, Ca, Cd, Cr, Cu, Fe, Hg, Mg, Mn, P, Pb, S, and Zn was determined by inductively coupled plasma mass spectroscopy (ICP-MS). The same elements were determined in soil samples for a seasonal characterization in conjunction with secondary data of environmental parameters. Additionally, micronucleus assay with early pollen tetrad cells of Tradescantia (Trad-MN) was conducted by collecting flower buds and analyzing the micronuclei frequencies in pollen mother cells. Although pollutant levels in air were below the Brazilian legal limits, plants exposed in the high-traffic flow area presented higher concentrations of elements related to vehicle emissions, especially under dry conditions, and higher micronuclei frequency in pollen mother cells. These results show the sensitivity of T. pallida to low-level urban air pollution and its suitability as bioindicator for trace elements. This alternative tool for biomonitoring can serve as a support methodology for the adoption of more restrictive public environmental policies in Brazil and extendible to other developing countries.

Metal concentrations in surface water and sediments from Pardo River, Brazil: human health risks.

Pardo River (Brazil) is suffering from an important anthropogenic impact due to the pressure of highly populated areas and the influence of sugarcane cultivation. The objective of the present study was to determine the levels of 13 trace elements (As, Be, Cd, Cr, Cu, Pb, Mn, Hg, Ni, Tl, Sn, V and Zn) in samples of surface water and sediments from the Pardo River. Furthermore, the human health risks associated with exposure to those metals through oral intake and dermal absorption were also evaluated. Spatial and seasonal trends of the data were closely analyzed from a probabilistic approach. Manganese showed the highest mean concentrations in both water and sediments, remarking the incidence of the agricultural activity and the geological characteristics within the basin. Thallium and arsenic were identified as two priority pollutants, being the most important contributors to the Hazard Index (HI). Since non-carcinogenic risks due to thallium exposure slightly exceeded international guidelines (HI>1), a special effort should be made on this trace element. However, the current concentrations of arsenic, a carcinogenic element, were in accordance to acceptable lifetime risks. Nowadays, there is a clear increasing growth in human population and economic activities in the Pardo River, whose waters have become a serious strategic alternative for the potential supply of drinking water. Therefore, environmental monitoring studies are required not only to assure that the current state of pollution of Pardo River does not mean a risk for the riverside population, but also to assess the potential trends in the environmental levels of those elements.

Concentration profiles of metals in breast milk, drinking water, and soil: relationship between matrices.

The concentrations of Cd, Cr, Cu, Hg, Mn, Ni, Pb, Sn, and Zn were determined in breast milk of women living in Conceição das Alagoas, Minas Gerais, Brazil. The potential relationships between metal levels in samples of breast milk, drinking water, and soils collected in the study area were also established. Metal levels in breast milk, except Cr, were lower in comparison to WHO reference concentrations. Zinc was the predominant element in breast milk and drinking water samples, with a median level of 46.2 and 82.2 µg · L(-1), respectively. Soils presented a different pattern of metal concentrations with respect to those found in breast milk and drinking water, Chromium showed the highest median levels (148 mg · kg(-1)), while a certain predominance of Zn and Cu was also observed (47.0 and 43.0 mg · kg(-1), respectively). Similar profiles were observed when comparing metal concentrations in drinking water and breast milk (chi-square χ(2) = 14.36; p < 0.05). In contrast, breast milk-soil and drinking water-soil metal concentration profiles showed significant differences (χ(2) = 635.05 and χ(2) = 721.78, respectively; p < 0.05). These results indicate that drinking water is an important exposure pathway for metals to newborns through breast milk. Further studies should be aimed at assessing the body burdens of metals in that population and at evaluating the potential relationships in the concentrations in biological and environmental matrices as well as at estimating the contribution of dietary intake of metals. In addition, the presence of other chemical pollutants in breast milk should be also studied in order to assess the combined newborn exposure to other contaminants.

Water quality analysis in rivers with non-parametric probability distributions and fuzzy inference systems: application to the Cauca River, Colombia.

The integration of water quality monitoring variables is essential in environmental decision making. Nowadays, advanced techniques to manage subjectivity, imprecision, uncertainty, vagueness, and variability are required in such complex evaluation process. We here propose a probabilistic fuzzy hybrid model to assess river water quality. Fuzzy logic reasoning has been used to compute a water quality integrative index. By applying a Monte Carlo technique, based on non-parametric probability distributions, the randomness of model inputs was estimated. Annual histograms of nine water quality variables were built with monitoring data systematically collected in the Colombian Cauca River, and probability density estimations using the kernel smoothing method were applied to fit data. Several years were assessed, and river sectors upstream and downstream the city of Santiago de Cali, a big city with basic wastewater treatment and high industrial activity, were analyzed. The probabilistic fuzzy water quality index was able to explain the reduction in water quality, as the river receives a larger number of agriculture, domestic, and industrial effluents. The results of the hybrid model were compared to traditional water quality indexes. The main advantage of the proposed method is that it considers flexible boundaries between the linguistic qualifiers used to define the water status, being the belongingness of water quality to the diverse output fuzzy sets or classes provided with percentiles and histograms, which allows classify better the real water condition. The results of this study show that fuzzy inference systems integrated to stochastic non-parametric techniques may be used as complementary tools in water quality indexing methodologies.

Behavior of metals, pathogen parasites, and indicator bacteria in sewage effluents during biological treatment by activated sludge.

The purpose of this study was to evaluate the behavior of metals, pathogen parasites, and indicator bacteria in sewage effluents during biological treatment by activated sludge in a wastewater treatment plant in Ribeirão Preto (WTP-RP), Sao Paulo, Brazil. The evaluation was done during a period of 1 year. Results showed that metal concentrations in treated effluents decreased, reaching concentrations according to those established by national regulations. The activated sludge process at the WTP-RP promoted a partial removal of parasites considered as possible indicators according to the WHO guidelines. Reduction factors varied between 18.2% and 100% for agents such as Endolimax nana, Entamoeba coli, Entamoeba hystolitica, Giardia sp., Ancylostoma sp., Ascaris sp., Fasciola hepatica, and Strongyloides stercoralis. A removal was also observed in total and fecal coliforms quantification. The present study represents an initial evaluation of the chemical and microbiological removal capacity of the WTP-RP. The results should be of interest for the authorities responsible for the environmental health at municipal, regional, national, and international levels.

Analysis of bacteria, parasites, and heavy metals in lettuce (Lactuca sativa) and rocket salad (Eruca sativa L.) irrigated with treated effluent from a biological wastewater treatment plant.

This study aimed to evaluate the viability of using treated residuary water from the Biological Wastewater Treatment Plant of Ribeirão Preto to grow vegetables, through the characterization and quantification of parasites, coliforms, and heavy metals. Three equal cultivation areas were prepared. The first was irrigated with treated/chlorinated (0.2 mg L(-1)) wastewater, the second one with treated wastewater without chlorination, and the third site with potable water, which was the control group. The presence of Hymenolepis nana, Enterobius vermicularis, nematode larvae, and Entamoeba coli was verified in lettuce (Lactuca sativa) samples. Although nematode larvae were observed in rocket salad (Eruca sativa L.), no significant differences were found between the number of parasites and type of irrigation water used. No significant differences were found between the number of fecal coliforms in vegetables and the different types of irrigation. However, the vegetables irrigated with treated effluent without chlorination showed higher levels of fecal coliforms. The risk of pathogens is reduced with bleach addition to the treated effluent at 0.2 mg/L. Concentration of heavy metals in vegetables does not mean significant risks to human health, according with the parameters recommended by the World Health Organization.

Aluminum concentrations in water of elderly people's houses and retirement homes and its relation with elderly health.

The purpose of this study was to determine the concentrations of aluminum (Al) and other metals in water samples from elderly people's houses and retirement homes. Forty-six duplicate water samples from kitchen taps were collected in Ribeirão Preto/SP, Brazil. Metal levels were measured by atomic absorption spectrophotometer. Aluminum concentration exceeded the maximum allowed values in 26% of samples according to the Decree 518/2004 of the Brazilian Health Ministry. It was noted that 11% of elderly living at monitored houses, as well as 19% living at retirement homes presented Alzheimer disease diagnostic. These results suggest taking into account Al risks among vulnerable elderly population groups.

Heavy metals in untreated/treated urban effluent and sludge from a biological wastewater treatment plant.

BACKGROUND, AIM AND SCOPE: The presence of heavy metals in wastewater is one of the main causes of water and soil pollution. The aim of the present study was to investigate the removal of Cd, Cu, Pb, Hg, Mn, Cr and Zn in urban effluent by a biological wastewater treatment, as well as to quantify the levels of As, Be, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Sn, Tl, V and Zn in dewatering sludge from the Biological Wastewater Treatment Plant of Ribeirão Preto (RPBWTP), Brazil. MATERIALS AND METHODS: Concentrations of Cd, Cr, Cu, Mn and Pb in wastewater and those of Ni in sludge were determined by atomic absorption spectrophotometry with graphite furnace atomization. Mercury concentrations in wastewater were measured by hydride generation atomic spectrophotometry, and Zn levels were determined by atomic absorption spectrophotometry using acetylene flame. In sludge, the levels of As, Be, Cd, Cr, Cu, Fe, Hg, Mn, Pb, Sn, TI, V and Zn were determined by inductively coupled plasma-mass spectrometry. Results. The percentages of removal efficiency (RE) were the following: Hg 61.5%, Cd 60.0%, Zn 44.9%, Cu 44.2%, Pb 39.7%, Cr 16,5% and Mn 10.4%. In turn, the mean concentrations (mg/kg) of metals in dewatering sludge followed this increasing order: Tl (< 0.03), Hg (0.31), Be (0.43), As (1.14), Cd (1.34), V (59.2), Pb (132.1), Sn (166.1), Cr (195.0), Mn (208.1), Ni (239.4), Cu (391.7), Zn (864.4) and Fe (20537). DISCUSSION: The relationship between metal levels in untreated wastewater, as well as the removal efficiency are in agreement with previous data from various investigators. It is important to note that metal removal efficiency is not only affected by metal ion species and concentration, but also by other conditions such as operating parameters, physical, chemical, and biological factors. CONCLUSIONS: Metal values recorded for treated wastewater and sludge were within the maximum permitted levels established by the Environmental Sanitation Company (CETESB), São Paulo, Brazil. RECOMMENDATIONS: There is an urgent need for the authorities who are responsible for legislation on sludge uses in agriculture of establishing safety levels for As, Be, Hg, Sn, Tl and V. PERSPECTIVES: According to the current metal levels, RP-BWTP sludge might be used for agriculture purposes. However, for an environmentally safe use of sewage sludge, further studies including systematic monitoring are recommended. Annual metal concentrations and predicted variations of those elements in the sludge should be monitored.