To clarify the human health risk of inhalation of gaseous elemental mercury (GEM), we measured GEM concentrations in three artisanal small-scale gold mining (ASGM) areas of Palu (Central Sulawesi, 342 000 residents), Muara Aman (Benkulu in Sumatra, about 1000 residents), and Palangka Raya (Central Kalimantan, 236 000 residents). These sites differed with regard to the scale and method of gold mining (ball mill and dredging systems). Although the scale of ASGM activity at these three sites differed for both the ball mill and dredging methods, gold amalgams were always made during the refining process. The air in these cities was therefore polluted by the mercury used in extracting the gold, although the levels of pollution differed. The highest GEM concentrations were measured at gold shops (5 × 10⁵ ng m⁻³). In the ASGM activity area, the measured GEM concentrations were high (100–14 000 ng m⁻³) near grinding drums. GEM concentrations in Palu and Palangka Raya ranged from 2.06 to 375 ng m⁻³ and 2.04 to 25.3 ng m⁻³, respectively. GEM concentrations within an ASGM community area in Muara Aman ranged from 4.10 to 11.5 ng m⁻³. Our results indicated that the health of residents of Palu—not only in the ASGM area but also in the city—may be at risk due to GEM inhalation. In Muara Aman, the health of people who engage in gold refining and of gold shop employees may be at risk, whereas the health of residents of Palangka Raya appears not to be at risk.

A stringent environmental quality standard for zinc (Zn) has been enacted by regulators because of its toxicity to aquatic life. This study’s objective was to evaluate the variability of Zn concentrations and fluxes in the baseflow and stormflow and to estimate the contribution of Zn from point and non-point sources. By using high-resolution temporal sampling, the suspended solids (SS), iron (Fe), and Zn concentrations were measured in a small agricultural river catchment. Fe, as the natural non-point source, and Zn were evaluated using the end member mixing analysis (EMMA) to identify the source apportionment (point and non-point). The results indicate that in the baseflow, Zn mainly originated from point sources and was possibly discharged by manufacturing industries. By contrast, the non-point sources (diffuse sources) were responsible for extremely high SS, Fe, and Zn levels in the stormflow. In addition, Zn discharge during the stormflow was 93 times higher than that during the baseflow. According to the EMMA, approximately 74% of the Zn was from point sources. River management can be improved if Zn point sources are adequately treated. During a storm event, it is also important to control the particulate Zn released into the river.

This study validated the CO₂ distribution predicted by a computational fluid dynamics model considering CO₂ absorption by photosynthesis in a chamber and greenhouse. The effect of photosynthesis with CO₂ emission from a perforated tube remains not fully understood, although previous studies on CO₂ distribution in greenhouses have been conducted. Moreover, comparisons between CO₂ concentration measurement and simulation were obtained in the chamber and greenhouse model. Cases with open and closed side vents of the greenhouse showed that closed side vents have slightly more even of CO₂ concentration than those with open side vents inside the greenhouse. In contrast, the coefficient of variance (CV) of CO₂ inside the plant, open (8.8%) and closed (8.7%) side vents, induced almost no significant improvement. Additionally, cases of a rainy- and sunny-day model showed that photosynthetically active radiation possibly compensated CO₂ absorption through photosynthesis to be low at low light (rainy day) and higher at high light (sunny day). Nonetheless, the variability of CO₂ concentration inside the plant between rainy and sunny days determined almost no significant difference. Thus, this research shows characteristics of CO₂ distribution, assessing photosynthesis and the variability of CO₂ concentration that leads to the efficiency of CO₂ enrichment in the greenhouse.

Smart meters monitor hourly water consumption patterns while reducing the cost and inconvenience of traditional meters. This study comprehensively analyzes 1871 households that previously used traditional meters from the distribution point to the distribution area. All the households were equipped with smart meters and the data collected were used for analysis. On the basis of the total estimated water consumption, 227 households were classified as single households. These households were further classified into single-worker and -nonworker households. This study analyzed smart meter data to evaluate the timings and amounts of water consumption peaks. The results indicate that worker households peaked at 8:00, with 29 L/h of consumption on weekdays, and peaked again on evenings at 20:00–21:00, averaging 32 L/h. For nonworker households, the peak occurred at 9:00, with 20 L/h, with no major changes in the afternoon, and a second peak occurred at 19:00–20:00 in evening, with an average of 19 L/h. Moreover, worker households peaked at 8:00 and 20:00 on weekdays, and at 9:00 and 19:00 on weekends. It was revealed that worker households consume 10% more on weekends than on weekdays, and 262% more from 13:00 to 16:00. These findings may assist in water supply planning by supporting distribution schedules on the basis of peak household consumption, leading to more helpful resource management.

The presence of microplastic pollution in coastal areas has garnered attention due to its detrimental impact on aquatic ecosystems and human health. In this study, our objective was to identify and characterize microplastics in the Banger River area of Pekalongan City, which is known for its...