Health risk assessment by trace elements in an aquatic system in midwestern Brazil

Water is an important asset for the maintenance of life and socioeconomic development. Aquatic environments have been anthropized, receiving a large polluting load, mainly from trace elements.This study investigates the occurrence of health risks caused by 15 trace elements in the surface water of João Leite stream. Health risk indices were evaluated as average daily dose (ADD), hazard quotient (HQ), hazard index and carcinogenic risk. The risk analysis to human health of the stream João Leite water, indicated that the ADDingestion for the adults had the highest for Fe 1.86E00 μg/kg/day and lower value for Be 8.0E-05 μg/kg/day. On the other hand, of ADDdermal the highest value was for Fe 5.02E-02 μg/kg/day and, the smallest for Sb 1.54E-05 μg/kg/day. For children to ADDingestion obtained was obtained the highest Fe value 2.60E-00 μg/kg/day and smaller for Be 1.12E-04 μg/kg/day. For ADDdermal the highest value was for Fe 8.58E-02 μg/kg/day and smaller for Sb 2.64E-05 μg/kg/day. HQ for adults ranged from 1.61E-05 to 2.97E-01 for HQingestion and 7.71E-06 to 1.01E-01 for HQdermal. For children 2.25E-05 to 3.74E-01 for HQingestion and 1.32E-05 to 1.73E-01 for HQdermal. The health risk assessment showed that for children, the trace elements present in water have a potentially adverse effect on non-carcinogenic health. The carcinogenic risks were unacceptable for both children and adults. Thus, it is recommended that the use of these waters be limited and that measures be taken to minimize pollution by trace elements.


Introduction
Among the pollutants in the river and stream, products with genotoxic and mutagenic potential, even in very low concentrations and in the form of complex mixtures of potentially dangerous compounds, have drawn attention concerning water quality (Roubicek et al., 2020). One of these pollutants is toxic trace elements, which can persist for long periods in water and soils, and toxic and accumulate in organisms (Kumar et al., 2020). Trace elements have carcinogenic and genotoxic mechanisms, can interact with proteins, stimulate the production of reactive oxygen species (ROS), inhibit the DNA repair system and disrupt cell proliferation (Beyersmann & Hartwig 2008).
Due to the health effects adverse that trace elements can cause, the Environmental Protection Agency of United States (USEPA) indicates that human health risk assessment is "the process of estimating the nature and likelihood of adverse health effects in humans that may be exposed to chemicals in the contaminated environment, now or in the future". This risk assessment stipulates the identification of hazards of contaminants present in the environment, which have non-cancerous effects, which include mutagenicity, developmental toxicity, neurotoxicity and reproductive toxicity, for example, and also carcinogenic effects (Wongsasuluk et al., 2014). The risk to human health in a contaminated environment can be assessed by considering the concentration of pollutants in that location, the exposure time and the exposure degree (Zhou et al., 2020).
In this context, the objectives of this study were to estimate the risks to human health, and the non-carcinogenic and carcinogenic, with based on the ingestion and dermal contact of trace elements present in the superficial water of the stream João Leite. Reflecting in this way the great impact that can occur due to the great importance of the stream for the population that uses this aquatic system. Also, because there are no reports in the literature or previous data that demonstrate the potential risk to human health due to heavy trace elements in the selected study area, therefore being an innovation.

Methodology
This study deals with an experimental research (Köche, 2016;Pereira et al., 2018) for its methodological basement.

Study area and Sampling location
The metropolitan region of Goiânia (capital of the Goiás State) is composed of 25 cities located in the Midwest region of Brazil, and has an estimated population of 7.018.354 inhabitants. The water sources of this place is are mainly supplied by the Meia Ponte river and the stream João Leite. The hydrographic basin of the stream João Leite represents an area of approximately 764 km2, with a total length of watercourses equal to 679.88 km and a length of 86 km. Its climate, according to the Koeppen classification AW, is divided as rain station in summer and dry station in winter (Ferreira et al., 2011).
Two surface water samples were taken, one in the dry period (collect 1, in November 2017 this year the drought period was extended) and another in the rainy period (collect 2, in April 2017). In the João Leite stream, eight water samples, two samples from each location ( Table 1). The water samples were collect and stored until further analysis according to Guide for the collection and conservation of water samples, sediments, aquatic communities and liquid effluents of the Environmental Company of São Paulo State (Cetesb, 2011).

Trace element analysis
One liters of water were collect in each site to analyse the concentration metal, Dissolved Aluminum (Ald), Antimony (Sb), Arsenic (As), Barium (Ba), Beryllium (Be), Boron (B), Cadmium (Cd), Lead (Pb), Total Cobalt (Co), Dissolved Copper (Cu), Chrome (Cr), Dissolved Iron (Fe), Manganese (Mn), Nickel (Ni) and Zinc (Zn). The water samples were sent to Companhia Saneamento de Goiás (SANEAGO) and, were analyzed using the methods established by the Standard Methods for Examining Water and Wastewater (Clescerl et al., 1999). The samples were processed within 24 hours of collection. In which a filtration, acidification with nitric acid and digestion of the samples was carried out, later analyzed in the 710-ES inductively coupled plasma optical emission spectrometers (ICP-OESs).

Human health risk assessment
Based on the results obtained from the metal concentrations in the water, the risk assessment for human health will be calculated, by ingestion and dermal absorption, of the superficial waters of the João Leite stream, using the methodology and equations proposed by Means (1989) and Ilechukwu et al. (2021), with some modification. The analyzes were performed for two groups of subpopulations, adults and children separately. Considering the two routes of entry, by ingestion and dermal absorption, the average daily dose (ADD) was calculated from equation 1 and 2.
Where ADD represents the average daily dose per ingestion (ADDingestion) and dermal absorption (ADDdermal) (µg/kg/day); Cm is the average of the metal concentrations in the water (µg/L); IR is the rate of water intake (L/day); GA is the Research, Society andDevelopment, v. 10, n. 10, e398101019037, 2021 (CC BY 4.0) | ISSN 2525-3409 | DOI: http://dx.doi.org/10.33448/rsd-v10i10.19037 4 gastrointestinal absorption of said metal (%); EF is exposure frequency (day/year); ED is the frequency of duration of exposure (year); AS is the surface area of the skin exposed (m2); Kp is the dermal permeability constant (cm/h); ET is the exposure time (h/day); CF is the unit conversion factor (L/cm³); Bw is body weight (Kg); TA is the average time (days).

Non-carcinogenic analysis
Non-carcinogenic risks to human health when exposed to heavy trace elements are described by the hazard quotient (HQ) (µg/kg/day), which is calculated by equation 3 and 4.
To assess the non-carcinogenic risk of more than one exposure route for various heavy trace elements in the water, the hazard index (HI) was applied, which is the sum of the HQs of all applicable routes (equation 5).

HI= (5)
Where i is the route of exposure (ingestion and dermal absorption). HI > 1 indicates the potential for an adverse effect on human health or the need for further studies.

Carcinogenic analysis
Carcinogenic risks to human health when exposed to heavy trace elements in water are calculated by equation 6, of the carcinogenic risk (CR): Where CSF is the cancer addiction factor and is defined as the risk generated by an average lifetime amount of a chemical (µg/kg/day) carcinogenic and is specific for contaminants. USEPA indicates a range of acceptable or tolerable carcinogenic risks which are those that are 1 × 10−6 to 1 × 10−4 and unacceptable risks are those that go beyond 1 × 10−4.
The input values and assumptions for the calculations of risk assessment for human health, non-cancer risk and cancer risk (equations 1, 2, 3, 4, 5 and 6) are summarized in Table 2.

Ingestion
Dermal absorption

Adult Child Adult Child
Média da concentração dos metais pesados (Cw) (µg/L) value found in the study regarding the quantification of the average of each metal in the water value found in the study regarding the quantification of the average of each metal in the water value found in the study regarding the quantification of the average of each metal in the water value found in the study regarding the quantification of the average of each metal in the water Water intake rate (IR) (L/day) 2 0,6 --

Results and Discussion
According to Oca et al. (2020) "the nature and spatial arrangement of the materials with which water interacts are the factors that condition the composition and relative abundance of constituents in groundwater". This concept can also be extrapolated to surface waters since its composition is also represented by the interactions that surface waters undergo.
However, these interactions occur in higher numbers than when compared to groundwater interactions, mainly due to being in an open environment subject to specific and non-specific variations. To assess these interactions, table 3 show the trace elements characterization, respectively, found in the samples of raw water from the stream João Leite, Goiás.    -v10i10.19037 7 4 in the rainy season with 783.3 µg/L (Table 3). In the study of (Sarkar and Shekhar 2018) showed that the increase of iron in water could be linked to processes of oxy-reduction in nature (weathering), a microbiological activity that reducing Fe3+ to Fe2+, is the main source that is anthropogenic contamination, which causes anomalous growth. It is suggested that the high concentrations of Fe found agree with the authors cited; however additional studies should be carried out for this confirmation.
Fe in high concentrations in water brings bad taste, stains, increases the growth of bacteria and increases deposition and crusting in river networks (Mehta and Srivastava 2012).
The metal Al in the dry season had its highest value for site 1 (163.6 µg/L), in the rainy season at this same point it was not detected, having its highest value for site 4 (761.0 µg/L) (Table 3) The highest value for Mn was in the rainy season at site 4 with 851.2 µg/L ( Table 3). The toxic metal Mn, when in the form of oxides serve as absorption or binding sites for other metals such as Cd, Co, Ni and Zn, and can act as natural (bio)remediation of metals (Schäffner et al., 2015). In the study of Munger et al. (2017) (Table 3). Ni is a source of fertilizer and can be carried by runoff into water Igbinedion & Oguzie (2016), domestic wastewater effluents can be the main source of Ni pollution (Abdel-satar et al., 2017) and progress in industrialization increases Ni emissions in ecosystems (Cempel & Nikel, 2006). These may be some of the explanations for the increased Ni concentration at site 4.
Metal V only had a high concentration at site 4 (288.5 µg/L). Most of the pollution by V is in the air, by burning fossil fuels and as a result of the combustion processes used in its purification, which is emitted as oxides (VO2, V2O3, and V2O5), this can settle in the soil and sediments bodies of water. V in freshwater may vary depending on the difference in rainwater runoff from natural sources or industrial sources (Gummow & Sciences, 2011).
To calculate this health risk, first the ADDingestion and ADDdermal (Table 4). From the ADD, HQ and HI, were calculated for non-carcinogenic risks for adults and children by ingestion and dermal absorption described in table 4. Among the investigated metals, children and adults are more exposed and absorb more Fe, Al and Mn, when compared to some of the metals with the highest detection concentration in the waters of the João Leite stream. Comparing the total group of trace elements analyzed from ADDingestion and ADDdermal, adult and child, it was found that there is a statistically significant difference (p = 0.0221, p = 0.0305, respectively) among the two groups of populations, demonstrating that adults and children absorb differently, whether through gastrointestinal or dermal. HQ for adults ranged from 1.61E-05 to 2.97E-01 for HQingestion and 7.71E-06 to 1.01E-01 for HQdermal. For children 2.25E-05 to 3.74E-01 for HQingestion and 1.32E-05 to 1.73E-01 for HQdermal (Table 4). The HI referring to Co (2.43E-01 adult; 3.41E-01 child) and Cr (3.68E-01 adult; 5.47E-01 child) (Table 4) is not >1 to indicates a potential for an adverse effect on human health, however the values are close to 1, it is a warning sign. The HI sum of all metals was 7.08E-01 for adult and 1.04E+00 for child, indicating that for children the metals present in the water of the stream João Leite have a potential adverse effect on non-carcinogenic health, since total HI is > 1. HI for adults followed the trend of Cr > Co > As > Mn > Pb > Ni > Zn > Cd > Fe > Ba > B > Al > Cu and for child Cr > Co > Mn > As > Pb > Ni > Zn > Cd > Fe > Ba > B > Al > Cu. Research, Society and Development, v. 10, n. 10, e398101019037, 2021 (CC BY 4. In the study of Ferré-Huguet et al. (2009) found HI higher in children than in adults, which was also found by Sánchez-Mateos et al. (2020), which indicated that children have a higher non-carcinogenic risk, developing some disease as a result of being more vulnerable and having less tolerance to trace elements.
In the Ambato River, in Ecuador, Cr was the metal with the highest non-carcinogenic risk studied for ingestion (Sánchez-Mateos et al., 2020). This corroborates with this study since Cr was the second metal with the highest HI in this study. Co was the metal with the highest HI, despite being biologically crucial as a component of vitamin B12, with excessive consumption, it can induce neurological, cardiovascular and endocrine deficits (Leyssens et al., 2017). In the study of Ma et al. (2016) did not find HI of trace elements > 1 and indicated that trace elements, even if they do not pose non-cancerous risks to human health, the presence of these can be toxic to health, and highlights that the conventional toxicity thresholds must be updated for the risk index thresholds. The last authors confirm what our study is suggesting.
The carcinogenic risk values throughout life were calculated (Table 5). CRdermal for As was 2.26E-01 and 3.86E-01, for adults and children, respectively, one being considered an unacceptable risk. The CRingestion followed the decreasing trend of Cr > Pb > As > Ni > Cd > Be, for both populations studied, demonstrating an unacceptable cancer risk, for all studied trace elements. The metallic compounds (As, Cd, Cr, Co, Pb, Hg and Ni) are carcinogenic, their mechanisms of tumor formation are not well understood. The main hypothesis due to oxidative stress that causes homeostasis imbalance and the production of free radicals, as well as interfering with the detoxification system. All of these events cause DNA damage, lipid peroxidation, protein modification (Koedrith & Seo 2011).
As obtained an unacceptable cancer risk for both ingestion and dermal contact. Toxic metal As is a carcinogenic, it can cause various health effects, among them, skin manifestations (black foot disease, hypopigmentation, keratosis), reproductive disorder, immune deficiency, diseases (cardiovascular, hematological, renal, neurological and respiratory) and cancer (bladder, kidney, liver, lungs, skin and prostate). The harmful effects of As affect all age groups, making it difficult to remove them from the environment, but whenever possible, it should be eradicated in drinking water and food crops (Joardar et al., 2020).
Cr was the potentially toxic metal with the highest CRingestion. The Cr performs the common cellular process of toxic elements due to oxidative stress, DNA damage, apoptosis and cell death, also its cations have a strong affinity for sulfur, which is present in proteins, thus being able to deactivate, interrupt or alter the metabolic processes (Yaman, 2020).
The river Mahananda in West Bengal and Bangladesh, indicated that the CR of the river was unacceptable, and its highest CR rate is 8.2E-04 (Shil & Singh 2019). In the Atuwara River in Nigeria, the CR of the trace elements found in the water ranged from 4.62E-3 to 1.01E-1 for adults and from 2.11E-4 to 4.96E-2 for children, indicating that 1 in 10 adults and 1 in every 20 children may suffer from cancer throughout their lives exposed to river waters (Emenike et al., 2020). Comparing with the result of table 4, the CR values for trace elements were much higher, which may suggest that the João Leite waters may induce the risk of cancer throughout the life of the exposed population. In the study of Rehman et al. (2018) found results for surface water in the vicinity of the Sewakht mines in Pakistan, in which he indicated the likelihood of cancer and non-cancer and indicated that this water should not be used for drinking purposes. Similarly, it is suggested that the water of Leite ribeirrão is not used for drinking purposes. It also suggests that the primary contact recreation such as swimming, diving and water skiing, is avoided due to the RC for The have been considered unacceptable.

Conclusion
The decreasing trend in the concentration of trace elements in water samples from João Leite stream was Fe > Mn > Al > Ba > Cr > Zn > Ni > B > Pb > Co > Cu > Be > Cd > As > Sb, not following the same trend for carcinogenic risk that had its highest value for Cr and Pb, and non-cancerous with the highest values for Co and Cr. The non-cancer risk associated with trace elements was evaluated and verified for children who use water from João Leite stream. Carcinogenic risk has been demonstrated, both in children and adults. It has been reported as an unacceptable risk, demonstrating the high risk associated with ingestion and dermal contact with water from the João Leite stream and its potential to cause cancer throughout life due to pollution by trace elements. Finally, the results shown in this study demonstrate with a scientific basis the verification of pollution and its effects on the consumer population of the João Leite stream. The importance of public policies for monitoring, management and use, in addition to actions for the recovery, preservation and maintenance of the João Leite stream, is highlighted here. Given the importance that this water system has for approximately 1 million people, directly and indirectly, who use it for consumption, supply for human consumption, primary contact recreation, irrigation of vegetables and fruit plants, park and gardens and others with which the public may have direct contact, aquaculture and fishing activity. Mainly the riverside population that is vulnerable to health risk due to contamination by trace elements in which this surface water is used for survival. New work and research must be carried out to minimize pollution by trace elements, as well as its possible effects on the health of the population in aquatic environments.