Background: Today, the effects of environmental pollution on human life and human needs, which reduces the level of community health caused by traffic noise in large cities, are clearly visible by creating irritation and pathogenic conditions. The aim of this study was to assess the risk of noise pollution
resulted from central traffic in Shiraz by analyzing its indicators and related components.
Methods: By specifying the high traffic jam in Shiraz, the sound and its frequency in 156 points of the city were analyzed using a sound analyzer (Tes-1358C model). The sound pressure levels (LA and LP) and the one and one-third octave band were continuously measured in A and C networks. Then, data were extracted and analyzed using Excel 2016 and Minitab 18.1. Eventually, phon and sone indexes were calculated for the heavy traffic jam in some of the central streets of Shiraz and the results were statistically calculated and their charts were prepared with comfort disturbance ranges.
Results: The highest harmful frequency of traffic in Shiraz was 50 Hz and 83.3 dB. The sound pressure level ranged from 70 to 92.7 dB in network A and 87.8 dB in network C. The maximum sound level was 87 phon and the maximum sone was 26 at 14 stations.
Conclusion: According to the results, the sound pressure levels exceeded the environmental standards of Iran and the values of phon and sone were higher than the standard of comfort at night and day.

Background: Heavy metals (HMs) are toxic pollutants whose concentrations in confined spaces might cause severe health impacts. This study aimed to determine the concentration and health risk of As, Cd, Co, Pb, Mn, Ni, and V in indoor household dust in Isfahan during 2022-2023.
Methods: Ninety dust samples were collected from 30 sampling homes. After preparation and acid digestion of the samples in the laboratory, the concentrations of the elements were determined using the ICP-OES method and analyzed statistically.
Results: Except for Pb, the HMs’ mean concentrations were significantly lower than the permissible limit (P < 0.050). The maximum daily exposure through ingestion, inhalation, and dermal contact for children and adults were 66.1 and 79.1 mg/kg/d, respectively, with Pb as the relevant element in both groups. Furthermore, the maximum lifetime daily exposure doses of 8-10 × 26.1 mg/kg/d belonged to Pb. The maximum non-carcinogenic and carcinogenic risk values through direct ingestion, inhalation, and dermal contact were 4.83 × 1-10 and 1.40 × 8-10 for children and 5.23 × 2-10 and 7.91 × 9-10 for adults, which were associated with Pb in both groups.
Conclusion: The results showed that the HMs content in indoor household dust in Isfahan followed a decreasing trend of Pb > Mn > Ni > V > As > Co > Cd. Moreover, direct ingestion followed by dermal contact and inhalation were the most important exposure pathways to the HMs-contaminated dust for both children and adults.

Background: Dukku and Kalgo rivers in Kebbi, Nigeria, provide essential ecosystem services such as drinking and domestic water, fishing, and farming. However, the safety of these rivers in terms of microplastic pollution has not been investigated. This study aimed to characterize and determine the concentration and associated risks of microplastics in both rivers.
Methods: Microplastics were extracted from water samples through filtration and analyzed using spectroscopy and microscopy.
Results: Significant concentrations of microplastics were detected in both rivers. Dukku River samples showed concentrations ranging from 125.00 to 160.30 particles/liter, while Kalgo River ranged from 119.30 to 134.70 particles/liter. Both rivers predominantly contained microplastic fibers and fragments, with fibers comprising the highest percentages (61% in the Dukku River and 56% in the Kalgo River). Microplastics in Kalgo River were predominantly sized between 0 and 100 μm, whereas in Dukku River, sizes ranged from 500 to 1000 μm. Polyamide was the dominant polymer, constituting 50% in the Dukku River and 42.50% in the Kalgo River, followed by polyethylene (34% in the Kalgo River and 25.60% in Dukku River), and polyvinyl alcohol (24.40% in Dukku River and 23.50% in Kalgo River). The predominant risk level posed by these polymers was level III (moderate risk), although polyamide posed a level IV risk (high risk). The pollution load index (PLI) for both rivers exceeded one, indicating a high risk.
Conclusion: Microplastic pollution in these rivers poses ecological and health risks. Identifying and mitigating sources of microplastic entry into the rivers is crucial to reducing exposure levels.