Heavy metal bioaccumulation and risk assessment in fishery resources from the Gulf of Thailand.

The muscle tissues of 19 fish species, two crab species, and one shrimp species collected from the Gulf of Thailand (GoT) were analyzed to determine the levels of heavy metals, including Cu, Zn, Fe, Mn, Ni, Pb, Cd, and Hg. The results revealed that the mean concentrations of the heavy metals, in descending order, were Zn > Cu > Fe > Cd > Hg > Mn > Pb > Ni. Among the examined metals, zinc was found to be the most prevalent in fish tissues. Based on the risk assessment indices, the estimated average daily doses (ADD) of the heavy metals were found to be below the provisional tolerable daily intake (PTDI) recommended by the joint Committee of the Food and Agriculture Organization (FAO) and the World Health Organization (WHO) on food contaminants. The results of the target cancer risk analysis revealed no related cancer risk from the consumption of the fishes considered for the study. However, the target hazard quotient (THQ) values exceeded the threshold of 1 (THQ > 1) specifically for mercury in Gymnothorax spp. and Terapon spp. Furthermore, the calculated hazard index (HI) values for fish muscles were all below 1, indicating that there is no significant health risk for humans at the current consumption rates, except in Terapon species for both normal and habitual consumers. Notably, habitual consumers of Gymnothorax species showed the highest HI value (>1), suggesting potential long-term effects on human health when consuming larger quantities of these fishes.

The Research Status, Potential Hazards and Toxicological Mechanisms of Fluoroquinolone Antibiotics in the Environment.

Fluoroquinolone antibiotics are widely used in human and veterinary medicine and are ubiquitous in the environment worldwide. This paper recapitulates the occurrence, fate, and ecotoxicity of fluoroquinolone antibiotics in various environmental media. The toxicity effect is reviewed based on in vitro and in vivo experiments referring to many organisms, such as microorganisms, cells, higher plants, and land and aquatic animals. Furthermore, a comparison of the various toxicology mechanisms of fluoroquinolone antibiotic residues on environmental organisms is made. This study identifies gaps in the investigation of the toxic effects of fluoroquinolone antibiotics and mixtures of multiple fluoroquinolone antibiotics on target and nontarget organisms. The study of the process of natural transformation toward drug-resistant bacteria is also recognized as a knowledge gap. This review also details the combined toxicity effect of fluoroquinolone antibiotics and other chemicals on organisms and the adsorption capacity in various environmental matrices, and the scarcity of data on the ecological toxicology evaluation system of fluoroquinolone antibiotics is identified. The present study entails a critical review of the literature providing guidelines for the government to control the discharge of pollutants into the environment and formulate policy coordination. Future study work should focus on developing a standardized research methodology for fluoroquinolone antibiotics to guide enterprises in the design and production of drugs with high environmental biocompatibility.

Microplastics in canned, salt-dried, and instant sea cucumbers sold for human consumption.

Determining the amount of microplastics (MPs) in food is key to clarifying their potential toxicity to humans. Here, we collected canned, instant, and salt-dried sea cucumbers Apostichopus japonicus, the most valued sea cucumbers, from Chinese markets to determine their content of MPs. Sea cucumbers contained MPs in the range of 0-4 MP individual-1, an average of 1.44 MP individual-1, and 0.081 MP g-1. Accordingly, consuming 3 g of sea cucumbers could result in an exposure risk of an average of 0.51 MPs, 0.135 MPs, and 0.078 MPs day-1 for canned, instant, and salt-dried sea cucumbers, respectively. MPs were in size range of 12-575 µm, and fibrous shape was dominant. Furthermore, among the five polymers identified, polypropylene showed the highest energy binding with two catalysts engaged in organic chemical oxidation. This study extends the knowledge regarding MPs occurrence in food and provides a theoretical basis for MPs toxicity in humans.

Assessment of trace metal bioaccumulation on the shells of edible gastropod Chicoreus ramosus and Hemifusus pugilinus.

The current study aimed to examine how some gastropods absorbed trace metals (Chicoreus ramosus and Hemifusus pugilinus). The existence of 17 elements, including aluminium, arsenic, boron, calcium, cadmium, cobalt, chromium, copper, iron, potassium, lithium, manganese, sodium, nickel, phosphorus, lead, and zinc (Al, As, B, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mn, Na, Ni, P, Pb, and Zn), was confirmed by inductively coupled plasma-mass spectroscopy (ICP-MS) analysis of trace metals. According to the ICP-MS results, C. ramosus (Al: 1.97 ± 0.2 µg/g, Fe: 1.93 ± 0.2 µg/g, and As: 1.52 ± 0.4 µg/g) and H. pugilinus (Al: 1.85 ± 0.7 µg/g, Fe: 1.68 ± 0.6 µg/g, and As: 1.37 ± 0.6 µg/g) both had significant amounts of aluminium, iron, and arsenic, respectively. Zinc concentrations of 0.58 to 0.7 µg/g (C. ramosus) and 0.67 to 0.2 µg/g were recorded (H. pugilinus). The elemental composition of the surface of the sample was confirmed by scanning electron microscopy-energy-dispersive X-ray spectroscopy (SEM-EDX) micrographs, which also showed the degree of trace metal absorption in the chosen gastropod species.

Release characteristics and toxicity assessment of micro/nanoplastics from food-grade nonwoven bags.

Micro/nanoplastic (M/NP) contamination in food has become a global concern. Food-grade polypropylene (PP) nonwoven bags, which are widely used to filter food residues, are considered environmentally friendly and nontoxic. However, the emergence of M/NPs has forced us to re-examine the use of nonwoven bags in cooking as plastic contact with hot water leads to M/NP release. To evaluate the release characteristics of M/NPs, three food-grade PP nonwoven bags of different sizes were boiled in 500 mL water for 1 h. Micro-Fourier transform infrared spectroscopy and Raman spectrometer confirmed that the leachates were released from the nonwoven bags. After boiling once, a food-grade nonwoven bag can release 0.12-0.33 million MPs (>1 µm) and 17.6-30.6 billion NPs (<1 µm), equivalent to a mass of 2.25 - 6.47 mg. Number of M/NPs released is independent of nonwoven bag size; however, it decreases with increasing cooking times. M/NPs are primarily produced from easily breakable PP fibers, and they are not released into the water at once. Adult zebrafish (Danio rerio) were cultured in filtered distilled water without released M/NPs and in water containing 14.4 ± 0.8 mg L-1 released M/NPs for 2 and 14 days, respectively. To evaluate the toxicity of the released M/NPs on the gills and liver of zebrafish, several oxidative stress biomarkers (i.e., reactive oxygen species, glutathione, superoxide dismutase, catalase, and malonaldehyde) were measured. The ingestion of the released M/NPs by zebrafish induces oxidative stress in the gills and liver, depending on the exposure time. Food-grade plastics, such as nonwoven bags, should be used with caution in daily cooking because they release large amounts of M/NPs when heated, which can threaten human health.

Mercury bioaccumulation in thresher sharks from the eastern tropical Pacific: Influences of body size, maturation stage, and feeding habitat.

Sharks, as top order predators, provide a guidance on how contaminants such as mercury bioaccumulate in marine environments. This study assessed the bioaccumulation of mercury (total mercury, THg) in the muscle, liver, red blood cells (RBC), and plasma of pelagic and bigeye thresher sharks (Alopias pelagicus and A. superciliosus) from eastern tropical Pacific. Additionally, the concentration of methylmercury (MeHg) in muscle was also determined to assess risks for human consumption. For both species, muscle THg concentrations (4.05 ± 2.15 and 4.12 ± 1.84 µg g-1 dry weight for pelagic and bigeye thresher shark) were higher than that in other tissues. THg concentrations for all tissues were significantly correlated with precaudal length, with higher accumulation rates after maturity in pelagic than bigeye thresher sharks, suggesting an associated dietary shift at maturation. Correlations among tissues in both species suggested similar transportation and distribution patterns in internal tissues. The δ13C values in muscle, RBC and plasma suggested that habitat shifts influenced Hg accumulation, whereas trophic position, estimated by δ15N values, had limited effects on patterns of Hg bioaccumulation. Diet shifts towards prey more cephalopods that content higher Hg than small fishes (large fishes: 1.77 µg g-1; cephalopods: 0.66 µg g-1 and small fishes 0.48 µg g-1, dry weight) increased Hg accumulation rates in adult pelagic thresher sharks. Concentrations of MeHg in the muscle of both thresher shark (3.42 ± 1.68 µg g-1 in A. pelagicus and 3.78 ± 2.13 µg g-1 in A. superciliosus) exceeded the recommended levels for human consumption. This research provides insight into the factors influencing mercury bioaccumulation in thresher sharks, which are essential for the management and conservation of these species.

A review of microplastic pollution in commercial fish for human consumption.

Today microplastics (MPs) have received worldwide attention as an emerging environmental pollution which is one of the four major global environmental threat and health hazard to human as well. Unfortunately, MPs have been founded in the all environments and media include air, water resources, sediments, and soil. It should not be forgotten MPs have also been detected in food and processing products like tuna. MPs can be ingested by marine organisms such as zooplankton, fish and birds. Accumulation and distribution of MPs by commercially important aquatic organisms is expected to lead to greater exposure risk for human populations with possible adverse effects over time. The aim of this work was to review the published literature regarding the contamination of commercial fish muscle for human consumption. Furthermore, a short revision of the environmental contamination and human health effects by MPs are included. We also estimated human daily intake considering the worldwide contamination of commercial fish muscle ranged from 0.016 items/g muscle of fish to 6.06 items/g muscle of fish. MPs have been found in 56.5% of the commercial fish samples analysed here. As fish is used in human food table across the word, they constitute a long-term exposure route for all humans and raise the concern about the potential public health risk.

Chlorine Dioxide: Friend or Foe for Cell Biomolecules? A Chemical Approach.

This review examines the role of chlorine dioxide (ClO2) on inorganic compounds and cell biomolecules. As a disinfectant also present in drinking water, ClO2 helps to destroy bacteria, viruses, and some parasites. The Environmental Protection Agency EPA regulates the maximum concentration of chlorine dioxide in drinking water to be no more than 0.8 ppm. In any case, human consumption must be strictly regulated since, given its highly reactive nature, it can react with and oxidize many of the inorganic compounds found in natural waters. Simultaneously, chlorine dioxide reacts with natural organic matter in water, including humic and fulvic acids, forming oxidized organic compounds such as aldehydes and carboxylic acids, and rapidly oxidizes phenolic compounds, amines, amino acids, peptides, and proteins, as well as the nicotinamide adenine dinucleotide NADH, responsible for electron and proton exchange and energy production in all cells. The influence of ClO2 on biomolecules is derived from its interference with redox processes, modifying the electrochemical balances in mitochondrial and cell membranes. This discourages its use on an individual basis and without specialized monitoring by health professionals.

Microbiome characterization of alpine water springs for human consumption reveals site- and usage-specific microbial signatures.

The microbiome of water springs is gaining increasing interest, especially in water intended for human consumption. However, the knowledge about large-scale patterns in water springs microbiome is still incomplete. The presence of bacteria in water sources used for human consumption is a major concern for health authorities; nonetheless, the standard microbiological quality checks are focused only on pathogenic species and total microbial load. Using 16S rRNA high throughput sequencing, we characterized the microbiome from 38 water springs in Trentino (Northern Italy) for 2 consecutive years in order to gain precious insights on the microbiome composition of these unexplored yet hardly exploited environments. The microbiological studies were integrated with standard measurements of physico-chemical parameters performed by the Provincial Office for Environmental Monitoring in order to highlight some of the dynamics influencing the microbial communities of these waters. We found that alpha diversity showed consistent patterns of variation overtime, and showed a strong positive correlation with the water nitrate concentration and negatively with fixed residue, electrical conductivity, and calcium concentration. Surprisingly, alpha diversity did not show any significant correlation with neither pH nor temperature. We found that despite their remarkable stability, different water springs display different coefficients of variation in alpha diversity, and that springs used for similar purposes showed similar microbiomes. Furthermore, the springs could be grouped according to the number of shared species into three major groups: low, mid, and high number of shared taxa, and those three groups of springs were consistent with the spring usage. Species belonging to the phyla Planctomycetes and Verrucomicrobia were prevalent and at relatively high abundance in springs classified as low number of shared species, whereas the phylum Lentisphaerae and the Candidate Phyla radiation were prevalent at higher abundance in the mineral and potable springs. The present study constitutes an example for standard water spring monitoring integrated with microbial community composition on a regional scale, and provides information which could be useful in the design and application of future water management policies in Trentino.

Human health risk assessment of pesticide residues in vegetable and fruit samples in Gujarat State, India.

The present study was initiated with the purpose to evaluate possible health risks associated with pesticide residues through consumption of vegetables and fruits by general population of Gujarat, India. A total of 1075 samples comprising of twelve different varieties of commonly consumed food commodities were collected from twenty-five divergent locations in Gujarat. The collected samples were extracted using QuEChERS method and analyzed for the presence of organophosphorus (OPs), organochlorine (OCs) and synthetic pyrethroids (SPs) pesticides using UHPLC-HR/MS, GC-µECD and GC-MS/SIM. The results indicated that 2.3% of vegetable and fruit samples showed the presence of pesticide residues exceeding maximum residue limits (MRLs). The results suggested that, detected residue levels in samples were within safe limits and their consumption will not pose any significant health risk to human. The outcomes present significant information regarding the status of vegetable and fruit contamination and pointed out the prerequisite for further studies with reference to monitoring of pesticides and other toxic contaminants in different samples for assessing cumulative health risk.

Determination of the internal dose due to the intake of 226Ra and 210Pb in drinking water from deep wells in the Metropolitan Region of Recife-Brazil.

The Metropolitan Region of Recife, the capital of the state of Pernambuco in northeastern Brazil, has a high demographic density and developed under a region of marine phosphorus with high concentrations of phosphate that naturally contains uranium ore, producing ionizing radiation from descendants of the radioisotope 238U where 226Ra and 210Pb are of great importance in verifying the probable harmful effects on human health due to environmental radioactivity. The supply of drinking water is the responsibility of the state-owned company COMPESA which uses wells of great depth to complete the supply of drinking water for the entire population. COMPESA and the RAE Group of the Federal University of Pernambuco developed a joint project to assess the concentrations of 226Ra and 210Pb and estimate the equivalent and effective doses caused by ingesting these radiation sources. According to the above, this research aimed to evaluate concentrations of 226Ra and 210Pb in drinking water samples from 110 deep wells in Recife. The activities of 226Ra and 210Pb ranged from 1.4 ± 0.3 to 119.3 ± 12.9 and from 25.6 ± 3.3 to 563.2 ± 45.6 mBq.L-1, with arithmetic means of 48.1 ± 3.8 and 231.1 ± 20 mBq.L-1, respectively. The equivalent doses average in bone tissue due to 226Ra and 210Pb were 0.45 ± 0.04 and 3.9 ± 0.37 mSv.y-1, and the annual average effective doses were 0.01 ± 0.00 and 0.13 ± 0.01 mSv.y-1, respectively.

Microplastics in take-out food: Are we over taking it?

Take-out food has become increasingly prevalent due to the fast pace of people's life. However, few study has been done on microplastics in take-out food. Contacting with disposable plastic containers, take-out food may be contaminated with microplastics. In the present study, abundance and characteristics of microplastics in total of 146 take-out food samples including solid food samples and beverage samples (bubble tea and coffee) were determined and identified. The mean abundance of microplastics in take-out food was 639 items kg-1, with the highest value in rice and the lowest value in coffee. Fragments shape, transparent color and sizes ≤ 500 µm were the main characteristics of microplastics in those food, and polyethylene was the main polymer type. Our results indicated that microplastics in take-out food was influenced by food categories and cooking methods, as well as food packaging materials. Approximately 170-638 items of microplastics may be consumed by people who order take-out food 1-2 times weekly.

Ecological traits influence the bioaccumulation of microplastics in commercially important estuarine crabs from the southeastern Gulf of Mexico.

We assessed microplastics (MPs) contamination in water, sediments, and tissues (gills, digestive tract, and muscle) of two intertidal crab species with different ecological traits and commercial importance (Menippe mercenaria and Callinectes sapidus), from a coastal lagoon in the southeastern Gulf of Mexico. There were significant differences between MP abundances in the abiotic matrices and between crab species. The burrower, sedentary and carnivorous M. mercenaria bioaccumulates 50 % more MPs than the free-swimming, omnivorous C. sapidus. However, no differences were observed between species' tissues. Fragments were the predominant shape in the tissues of both species, with the exception in the digestive tract of M. mercenaria. We identified polyethylene, and polyethylene terephthalate in water samples and Silopren® in sediment. In both crab species, Silopren and polyethylene predominated. Differences in ecological traits resulted in different bioaccumulation patterns in intertidal crabs.

Heavy metal concentrations in the Pacific sharpnose shark Rhizoprionodon longurio from the Santa Rosalia mining zone, Baja California Sur, Mexico.

Rhizoprionodon longurio is an important commercial species captured in an area with heavy metal presence due to the mining waste from Santa Rosalia, Gulf of California, and levels of heavy metals in its muscle remain unknown. This study aimed to investigate whether contamination levels are below the limits allowed for human consumption and to prevent health damage. Concentrations of essential (Cu, Fe, Mn, and Zn) and non-essential (Ag, Cd, and Pb) trace elements were determined in fifty-seven muscle samples of R. longurio. The average concentrations of Fe > Zn > Cu > Mn > Cd > Ag did not exceed the permissible limits for human consumption established by the Mexican norm, WHO, and FAO. The mineral daily ingestion was 0.10 to 0.53 % × 100 g of muscle, and the percentage of weekly consumption was 2.5 % to <12 % concerning corporal weight. The meat from this shark can be consumed due to its low toxic potential for human health.

Common Single-Use Consumer Plastic Products Release Trillions of Sub-100 nm Nanoparticles per Liter into Water during Normal Use.

This study demonstrates that commonly used consumer products such as single-use food grade nylon bags and hot beverage cups lined with low-density polyethylene release nanometer-sized plastic particles at number densities >1012 L-1 when exposed to water. The number of particles released was a function of the initial water temperature (high temperature vs ambient) for each of the tested materials. Mean particle diameters were between 30 and 80 nm with few particles >200 nm. The number of particles released into hot water from food grade nylon was 7 times higher when compared to single-use beverage cups. On a particle number density basis, particles released into water from a single 300 mL hot beverage cup equate to one particle for every seven cells in the human body in a size range available for cellular uptake.

Muscle proximate composition of various food fish species and their nutritional significance: A review.

Today, there is a growing awareness about the importance of eating nutritious foods and fish is gaining momentum as a result of its unique nutritional benefits. Fish are considered as nutritionally valuable part of the human diet because of the presence of both macronutrients (proteins, lipids and ash) and micronutrients (vitamins and minerals). These nutrients are indispensable in human nutrition and have proven to be involved in several metabolic functions. The nutritional content can be used to rank different fish species based on their nutritional and functional benefits, allowing consumers to make better decisions according to their requirements. Proximate composition of fish includes determination of moisture, protein, fat and ash contents, which constitutes about 96%-98% of the total constituents of the fish body. The study of these components gives us a clear understanding in assessing the energy value of the fishes. In the present study, an attempt has been made to provide a concise review about the proximate composition of various fish species from different parts of the world in order to evaluate the high-protein, low-fat food with excellent nutritional values and to enlighten the different exogenous and endogenous factors that are actually responsible for their variation. The review also provides an insight into the characteristics of the chemical composition of various fish species, which are gaining importance for the sector involving fish and fishery products for domestic and foreign trade and for appreciating as animal feed all over the world.

Hormones residues in bovine animals: Sampling, analysis and health risk assessment.

The use of hormones for breeding animal livestock has been banned since 1981 under the Council Directive 81/602/EC. So far, each country should monitor the use of anabolic hormones in animal production to protect the consumer's health against these unwanted residues. This paper presents the research results on steroid and non-steroid hormones residues carried out in Lebanon from 2018 to 2020. Using a newly developed and validated LC-MS/MS method, the detection and the quantification of hormones in bovine matrices were done. The targeted matrices were muscle, liver, kidney, and bile. A total of two-hundred and forty-seven samples were collected from different slaughterhouses located in six different cities in Lebanon. Interestingly, only four hormones were found: testosterone, progesterone, epitestosterone, and 6 propyl 2thiouracil. Based on the obtained data, the estimated daily intake, hazard quotient, and hazard index were calculated to evaluate an exposure assessment.

Existence of microplastics in the edible part of the sea cucumber Apostichopus japonicus.

Microplastics (MPs; ≤ 5 mm) have become a potential threat to human health due to the widespread detection of MPs in foods consumed by humans. Here, we investigated the potential of MP occurrence in the main edible part of the most valuable species of sea cucumbers (Apostichopus japonicus). Laboratory experiments showed that fluorescent MPs and microfibers (MFs) could transfer into the body wall of the sea cucumber. The evidence revealed that these MPs enter the body wall via the outer surface. Although these MPs decreased after the sea cucumbers were transferred to clean water, traces of MPs (at least one MP particle) were found up to 60 d post-transfer. To validate these laboratory observations, sea cucumber samples were collected from the field. MPs were found in 86% of live and processed sea cucumber samples. The MP abundances in the field samples ranged from 0-15 MPs animal-1 and 0-2 MP g-1. The isolated MPs were mainly MFs, constituting 81% of MPs, followed by fragments, films, and beads. Fourier transform infrared spectroscopy revealed that the polymer composition of the isolated MPs mainly included rayon, followed by polyester and chlorinated polyethylene. The findings of this study demonstrated that the body walls of farmed and processed sea cucumbers contain MPs, thus highlighting the need to control MP pollution during the farming and processing of sea cucumbers.

Uso do coagulante/floculante emergente à base de moringa no tratamento de água com verificação da composição e toxicidade do lodo produzido: tratamento de água com Moringa e toxicidade do lodo / Use of emergent moringa-based coagulant/flocculant for water treatment with verification of composition and toxicity of the produced sludge: water treatment with Moringa and toxicity of the sludge

RESUMO O presente estudo consistiu em avaliar a eficiência dos processos de tratamento convencional de água, por meio do coagulante natural Moringa oleifera Lam, com e sem casca, para o tratamento de água bruta captada do Rio Poxim, Aracaju, SE, Brasil. Após essa avaliação, realizou-se a análise da composição química e da toxicidade do lodo. As etapas de coagulação/floculação e decantação (30 e 60 minutos) foram realizadas em jar test com o coagulante, seguidas de filtração rápida descendente. A eficácia dos coagulantes foi analisada por meio da caracterização da água nas dosagens de 100, 200, 300 e 400 mg.L-1, por meio de análises físico-químicas, englobando os parâmetros pH, cor aparente e turbidez. O lodo proveniente do tratamento, em ambas as situações em estudo, foi caracterizado em relação à composição de proteína, amido e lipídio, além de ter sido verificada a toxicidade do resíduo por intermédio do crescimento e da germinação da Lactuca sativa. Como resultado, a moringa demonstrou potencial no tratamento de água pra consumo humano, principalmente o extrato de moringa com casca, tendo como dosagem ótima 300 mg.L-1 tanto para os parâmetros de cor quanto para a turbidez. Em relação ao pH, constatou-se que os tratamentos não promoveram variação significativa em relação aos valores da água bruta. Quanto à caracterização do lodo, foi possível verificar que em sua constituição há presença tanto de lipídio quanto de proteínas e ausência de amido; além disso, seu resíduo apresentou-se como atóxico para o meio ambiente.

ABSTRACT The present study aimed at evaluating the efficiency of conventional water treatment processes using the natural coagulant Moringa oleifera Lam, with and without shell, for the treatment of raw water captured in the Poxim River, Aracaju, state of Sergipe, Brazil. After this evaluation, the chemical composition of the sludge and its toxicity was analyzed. The stages of coagulation/flocculation and decanting (30 and 60 min) were performed in jar test with the coagulant, followed by rapid descending filtration. The effectiveness of the coagulants was analyzed by the characterization of the water in dosages of 100, 200, 300, and 400 mg.L-1, according to physicochemical analyses, including the parameters pH, apparent color, and turbidity. The treatment sludge, in both situations under study, was characterized in relation to the composition of protein, starch and lipid, in addition to verifying the toxicity of the residue by the growth and germination of Lactuca sativa. As a result, moringa showed potential in the treatment of water for human consumption, mainly the extract of moringa in shell, with an optimal dosage of 300 mg.L-1 for both color and turbidity parameters. Regarding pH, the treatments did not promote significant variation in the raw water values. In terms of sludge characterization, the presence of lipids and proteins was verified, but not that of starch. In addition, the sludge residue was considered nontoxic to the environment.

Multivariate analysis of the distribution and formation of trihalomethanes in treated water for human consumption.

The disinfection of water for human consumption with chlorine or other compounds produces secondary reactions with the organic matter, generating undesirable disinfection by-products (DBPs). Among these are trihalomethanes (THMs), identified as carcinogenic compounds. This work determined the trihalomethanes concentration, both speciated and total, in treated water distributed and stored in tanks of residential condominiums of different social classes. THMs were quantified using static manual Headspace as preconcentration technique, injecting the vapor phase collected in a GC/FID. The results show that the water distributed to the homes already contains THMs, trichloromethane being the major compound. The Principal Components Analysis (PCA) and Hierarchical Cluster Analysis (HCA) with 60 water samples showed that there is no significant distinction among samples of treated water distributed water and water stored in tanks. This study warns to the importance of controlling the formation of trihalomethanes in water throughout treatment and distribution for users.