Environmental Health Engineering and Management Journal
Volume:11 Issue: 2, Spring 2024

Water quality deterioration is becoming a serious challenge for water utility corporations supplying treated water through the use of a centralized distribution system. After water leaves the treatment plant and enters the distribution system, it is subjected to numerous complex physical, chemical, and biological changes. This study aimed to investigate the major physical factors deteriorating water quality in an aged distribution system.

Deterioration modeling was undertaken using an EPANET computer program. For model calibration processes, data collected from field measurements were used. Descriptive statistics were employed to analyze the data. Water age and residual chlorine were selected parameters to investigate the deterioration level. The identification of major factors posing water quality changes was undertaken by examining distinct physical and operational settings.

The maximum water-age variation obtained between two extreme water-use periods was 21.97%. In the same way, the maximum residual chlorine concentration variation obtained was 11.68%. On the contrary, with tested extreme pipe sizes in the study, the maximum water-age variation obtained was only 0.93%. Whereas, the obtained maximum residual chlorine concentration variation between the two extreme pipe sizes was 21.03%.

Water use variation poses more water quality degradation than pipe geometry. Water age in aged distribution is rarely influenced by conditions of pipe geometry.

Cities negatively affect the environment. Urban pollution levels have risen considerably, affecting sensitive groups such as pregnant women.

This study aimed to investigate the relationship between particulate matter and kidney biomarkers of pregnant women in Yazd from September to November 2023. Urea, uric acid, and creatinine levels were measured in 30 pregnant women (third trimester). The concentration of PM2.5 was estimated using the land use regression (LUR) model and 5 independent variables of road networks, distance from the city center, building density, elevation, and slope. For each mother, the mean concentration of the modeled PM2.5 was measured in multiple buffer rings drawn around her residential location. Generalized additive model (GAM) was employed to establish a relationship between PM2.5 concentrations with physiological indicators.

Average urea, uric acid, and creatinine were 18.06 ± 5.74, 3.65 ± 1.11, and 0.79 ± 0.12 mg/dL, respectively. The LUR model identified road networks and distance from the city center as critical factors contributing to increased particulate matter concentration. The GAM R2 was 0.79, 0.31, and 0.28 for urea, uric acid, and creatinine, respectively. The mean PM2.5 within a radius of 2000 m was identified as the most significant independent variable and showed an increasing impact on the renal parameters.

According to the results, reducing pollutant levels and preventing the creation of pollution hotspots via lowering road density are vital urban planning strategies to protect vulnerable groups, especially pregnant women.

Wastewater from poultry slaughterhouses is a serious environmental threat if they are incompletely treated. Recently, the utilization of microalgal species has gained significant attention for treating such wastewater. Chlorella vulgaris is one of the most efficient microalgae for treating poultry slaughterhouse wastewater due to its exceptional capacity for N, P, and chemical oxygen demand (COD) removal. This study aimed to investigate the impact of initial total nitrogen concentration, total phosphorus, photoperiod, and cultivation time on reducing the organic load and enhancing the production of biomass in slaughterhouse wastewater.

Samples were collected from the effluent of a poultry slaughterhouse and underwent qualitative analysis. C. vulgaris was cultivated in the BBM culture medium. Experiments were designed using the response surface method. The designed experiments were then carried out and the obtained data were subjected to analysis of variance (ANOVA), resulting in fitted models for the data on organic load removal and biomass production. Numerical optimization was performed to optimize COD removal and increase algal biomass. Finally, the models were validated.

The results demonstrated that the quadratic model has a good fit for COD removal and biomass increase data. In the optimal conditions, including TN = 600 mg/L, TP = 34 mg/L, culture duration = 15 d, and photoperiod = 12.6 hr, the COD removal efficiency and algal biomass production were 93.88% and 92.37%, respectively.

Chlorella vulgaris exhibits significant potential for the removal of the organic load from poultry slaughterhouse effluent. Also, substantial algal biomass is generated, which can be used in various areas such as livestock feed and sanitary uses.

Wastewater treatment plants are important sources of emissions of greenhouse gases (GHSs) such as carbon dioxide and methane in the atmosphere. Also, energy consumption in the wastewater treatment process causes indirect carbon dioxide emissions.

One hundred thirty-three operating wastewater treatment plants in Iran treat municipal wastewater. The carbon dioxide and methane emissions from the wastewater treatment plants for the year 2022 were estimated by establishing a calculation model according to the methods recommended by the Intergovernmental Panel on Climate Change for National Greenhouse Gas Inventories (2006) and United States Environmental Protection Agency (USEPA) guidelines.

Based on the Intergovernmental Panel on Climate Change guideline, the total methane emission was 158.63 tons. Based on the USEPA guideline, the total emissions of methane and carbon dioxide were 47.61 and 351.47 tons, respectively. This amount is 3.2% of all the methane and carbon dioxide emissions of Iran. Isfahan and Tehran provinces have the highest emissions rates of methane at 31.85 and 22.91 tons, respectively. While South Khorasan and Kerman provinces have the lowest methane emissions rates of 0.46 and 0.67 tons, respectively.

The results will provide a scientific basis and effective strategies for policymakers to reduce the methane and carbon dioxide emissions from the wastewater treatment plants of Iran.

Nitrate (NO3) is a necessary element for plant growth, but its excessive use in agricultural products causes different health problems. This study aimed to investigate the relationship between NO3 concentrations in vegetables and the prevalence of gastrointestinal cancers in Minab city, Iran.

This case-control study was conducted on 60 people with cancer as the case group and 120 healthy people as the control group in Minab city. Data were collected through a questionnaire and measuring NO3 concentration levels in vegetables. All samples were examined for NO3 by reverse-phase HPLC (RP-HPLC) method.

The concentration levels of NO3 in all vegetables ranged from 15.08 (onion) to 1143.55 mg/kg (spinach). There was no significant difference between the concentrations of NO3 in all vegetables among the different regions. The most common cancer in the case group was stomach cancer (61.7%). There was a significant difference between the amount of daily intake of NO3, through different vegetables, and the prevalence of gastrointestinal cancer between the case and control groups (P < 0.05). The results showed that increasing the consumption of vegetables increases the chance of getting gastrointestinal cancer (OR: 5.72; P < 0.001).

According to the results, there is a significant relationship between the NO3 concentration in vegetables and the prevalence of gastrointestinal cancers in the studied areas. It is highly recommended to closely monitor the cultivation, fertilization, and spray process of agricultural products, and frequent monitoring of NO3 levels in fruits and vegetables.

Modifying and enhancing treatment methods is essential to meet effluent standards for treating landfill leachate. This study investigated the treatment of municipal solid waste leachate (MSWL) using coagulation, flocculation, advanced oxidation, and extended aeration processes.

The effects of different coagulant doses and pH values on coagulation processes were compared. The treatment procedure was analyzed to determine the impact of varying concentrations of potassium persulfate (K2S2O8) and hydrogen peroxide (H2O2) on the results after coagulation with FeCl3. The extended aeration process’s biological stages were studied using a sludge retention time (SRT) of 23 days and the effects of hydraulic retention time (HRT) of 18 and 36 hours.

The experimental results show that in the pH range of 5–8, the lower the pH value, the higher the treatment efficiency. The addition of 0.8 g L1− FeCl3 can achieve a 57% removal of chemical oxygen demand (COD). The addition of 2.5 g L1− K2S2O8 and 1.5 g L1− H2O2 with UV-C (15 W) for 70 minutes at pH 7 can effectively remove 86% of COD. Activated sludge extended aeration can attain an 88% removal of COD under optimal operating conditions (HRT = 36 hours, SRT = 23 days, and aeration = 36 hours). The studied hybrid process with the efficiency of 99%, 98%, 95%, 87%, and 83% removal of COD, biochemical oxygen demand (BOD), total suspended solids (TSS), turbidity, and total Kjeldahl nitrogen (TKN), respectively, is suitable for leachate treatment.

This study showed that flocculation-coagulation followed by the advanced oxidation process (AOP) and extended aeration can be an efficient and promising treatment method for MSWL.

Fish are consumed worldwide due to their nutritional and health benefits; however, heavy metal pollution is compromising their safety. This study aimed to determine heavy metal safety in water and fish, specifically tilapia (Oreochromis niloticus) and catfish (Clarias gariepinus), collected from Bunza River in Kebbi State, Nigeria.

Water and fish samples underwent analysis for zinc (Zn), cadmium (Cd), copper (Cu), and lead (Pb) using atomic absorption spectroscopy. The obtained values were then utilized to assess the associated health risks.

The atomic absorption spectroscopy of fish revealed significant differences (P < 0.05) between heavy metal concentrations in the fish organs and FAO/WHO standards. It indicated non-tolerable concentrations of copper (1.77-5.24 mg kg-1) and lead (1.85-4.53 mg kg-1). The estimated daily intake (EDI) of Pb and Cd through fish consumption was above the recommended daily intake (RDI). However, the hazard quotient (HQ) and health risk index (HI) of all the heavy metals were within tolerable limits ( < 1). On water samples, non-tolerable levels of the heavy metals and significant differences (P < 0.05) were observed when compared with the standards. The water samples had average concentrations of Cu (4.64 ± 0.62 mg kg-1), Pb (1.78 ± 0.70 mg kg-1), Cd (0.50 ± 0.02 mg kg-1), and Zn (18.90 ± 3.08 mg kg-1). The average daily ingestion (ADI) and HQ of the heavy metals through the consumption of the water were above the recommended limits.

Based on the results, the fish and water samples could cause heavy metal-related toxicity. There is a need for policies aimed at decontaminating the river.

Uninhabited shophouses become breeding places for mosquitoes which cause high levels of dengue hemorrhagic fever (DHF), whereas the existence of squatters causes a reduction in green open space, one of which becomes a breeding place for Aedes sp.

This study aimed to develop a DHF risk model in shophouses and squatters in Batam city. This research applied an ecological study design using a spatial approach with the geographically weighted regression (GWR) method. The variables studied were the incidence of dengue fever, vector density, and rainfall.

The results of the analysis show that for the vector density in the shophouses, the odds ratio (OR) was 4.71 while for the vector density in squatters, the OR was 6.76. For the rainfall in the shophouses, the OR was 0.83 while for the rainfall in the Squatters, the OR was 1.68. Model analysis shows that the higher shophouses and squatters can cause an increase in dengue cases.

Risk analysis shows that factors that can increase DHF vulnerability include high vector density with a risk of 4.71 times (shophouses) and 6.76 times (squatters), and high rainfall in squatters with a risk of 1680 times. The distribution of dengue cases shows that Sambau dan Batu Selicin are subdistricts that have a high distribution of vulnerabilities in both shophouses and squatters. The mathematical model of dengue risk shows that every construction of one shophouse or one squatter can cause an increase in dengue cases by one case.

Welding is an extensively utilized industrial technique, which involves the fusion of fumes containing various heavy metals. To protect exposed workers, it is crucial to investigate the subsequent adverse effects. This study aimed to carry out the welding process within a regulated welding chamber and examine the effects of glutathione peroxidase (GPX) and superoxide dismutase (SOD) as antioxidant enzymes and pathological damage on rat testicular tissue.

Male adult Wistar rats (n = 7/experiment group) were exposed to an average concentration of (44.48 mg/m3) welding fumes (WFs) for 30 min/d × 8 days through shielded metal arc welding (SMAW). The control group (n = 7) was in similar conditions without direct exposure to WFs.

The metal composition of WFs was found to contain iron (Fe), manganese (Mn), copper (Cu), aluminum (Al), lead (Pb), and chromium (Cr). Among these metals, Fe had the highest average concentration (12.06 mg/m3), while Cu displayed the lowest one (0.019 mg/m3). The majority of the produced particles were found within the micron size range (0.25 to 0.5 μm). The mean activity of GPX and SOD was determined 15.16777 (mU/mg protein) and 81.955 (U/mg protein) in the exposed group, respectively. In the microscopic examination of testis tissue, some complications were observed.

Oxidative damage occurred in the testicular tissue of experimental rats by decreasing the mean activity of antioxidant enzymes. Besides, the exposed group showed reduced sperm quality and quantity indexes.

Wetlands are among the most important ecosystems and areas of life that are ecologically and economically important in the world and susceptible for heavy metal contamination. The elements in water and sediment may be easily and in large quantities available to animals in aquatic ecosystems. This study aimed to investigate the level of heavy metal contamination in Anodonta cygnea.

Anodonta cygnea sampling was carried out in the summer 2023. A total of 35 specimens were collected randomly by fishing net. Following the laboratory analyses, the concentration of aluminum (Al), arsenic (As), copper (Cu), cobalt (Co), cadmium (Cd), iron (Fe), manganese (Mn), magnesium (mg), lead (Pb), nickel (Ni), tin, vanadium (V) and zinc (Zn) were determined by ICP-OES.

Target hazard quotient (THQ) values of Mn were above 1. The pi index showed that A. cygnea is slightly contaminated by Pb. Analyses of the metal accumulation showed that A. cygnea bivalve was moderately contaminated by Zn and severely contaminated by As. The results showed no significant relationship between the total weight of the organism and concentration of Al, Fe, and Ni.

Aquatic organisms, including bivalves, do not possess an advanced excretory system, therefore the excretion of metabolites and pollutants is a is a slow process. once the concentration of heavy metals in the aquatic environment increases, they become easily available to aquatic organisms and enter the biological system. In this study, the absorption rate of metals was higher than its excretion or removal by the excretory system which results in their accumulation in various tissues and organs of the organism.

Optimal feeding of children with adequate nutrients is regarded as the most effective method for proper growth and development, which occurs rapidly during the first few years of life. In this regard, Ayurvedic nutritional supplements and herbal medicines are given in infancy and early childhood. This age group is of utmost importance in dentistry. Plants and herbal derivatives are rich sources of fluoride. Hence, monitoring of ingested fluoride levels during this stage is of utmost importance to optimize its intake and avoid toxicity. The study assessed and compared the fluoride concentration in preparations of indigenous Ayurvedic prescribed for infants, toddlers, and preschool children in Kerala, India.

In this laboratory study, three samples each of nine indigenous Ayurvedic preparations of solid, semi-solid, and liquid forms were used. Fluoride level was measured by high range fluoride colorimeter—Checker HC—Hanna Instruments, based on sodium 2-(parasulphophenylazo)-1,8- dihydroxy-3,6-naphthalene disulphonate (SPADNS) method, and recorded in parts per million (ppm).

Among powder forms, the highest fluoride concentration was observed for Gopichandanadi (2.40 ± 2.02 ppm). Among semi-solid and liquid forms, the highest concentration was found in Chyavanaprasha (1.30 ± 1.73 ppm) and Indukantham syrup (9.8 ± 0.10 ppm), respectively. The highest mean fluoride concentration was obtained from liquid forms, followed by solid forms, and the lowest one was present in semi-solid forms.

Although the concentration of fluoride varied across the various forms of preparation, none of them exceeded the safely tolerated dose (STD) of 8-16 mg/kg.

Welding fumes (WFs) contain heavy metals that can induce oxidative stress and health issues in welders. This review investigated the relationship between oxidative stress biomarkers and trace metals in welders’ bodily fluids.

Online databases such as Scopus, PubMed, Web of Science, Science Direct, EMBASE, and Google Scholar were reviewed, with a specific emphasis on the effects of metal fume exposure during welding. Specific keywords such as “welding fumes”, “metal fumes”, “antioxidant enzymes”, “biomarkers”, and similar terms were employed to search for articles published between 2004 and 2023. After the evaluation of article titles and abstracts, this study reviewed a total of 19 articles.

Studies suggest that welders experience oxidative stress due to changes in trace metals in their body fluids, affecting antioxidant enzymes and oxidative stress biomarkers. Elevated heavy metals in welders’ biological samples lead to oxidative stress and inflammation, even at low levels. Certain metals in blood and urine, such as lead (Pb), manganese (Mn), iron (Fe), chromium (Cr), and cadmium (Cd), positively correlate with serum superoxide dismutase (SOD) and glutathione peroxidase (GPx) levels. There is also a significant positive correlation between serum/EBC MDA and blood/urine Pb, Mn, Cd, Cr, and Fe, indicating cellular damage, lipid peroxidation, and reduced antioxidant capacity. Additionally, welders may experience more DNA damage compared to non-welders.

Exposure to WFs significantly altered oxidative stress biomarkers in bodily fluids, underscoring the importance of the relationship between oxidative stress and trace metal imbalances in WF-related injuries. These factors could serve as valuable biomarkers for monitoring workers exposed to WFs.