Chan Thnal reservoir, built during the Pol Pot period, is the major water source for the people in Krang Chek commune, Kampong Speu Province, Cambodia. Metal pollution caused by agricultural activities, improper wastewater treatment, and municipal waste disposal poses serious environmental health problems. In this study, the concentrations of four potential toxic metals (i.e., Cd, Cu, Pb, and Zn) from six locations across the reservoir were investigated both in the water and sediment. The results reflected progressive deterioration and indicated moderate to heavy pollution from the metals. The metal levels in the water were in the order of Zn > Cu > Pb > Cd. The statistical analysis revealed primary sources of heavy metals contamination in the water. Cd, Cu, Zn, and Pb in the water likely originate from anthropogenic activities including agricultural runoff (i.e., the use of fertilizers and pesticides) and urban runoff (i.e., improper wastewater discharge and waste disposal). Among the four metals, the Pb levels in the water significantly exceeded the guideline for drinking water in all locations. The health risk assessment revealed serious non-carcinogenic risks of Pb intake in the children at the age below 10 and infants. Appropriate control and protection strategies are urgently needed to cut off the main Pb exposure pathway in pregnant women, children, and infants.

Metal contamination from farming, inadequate wastewater treatment, and poor disposal of municipal garbage are major threats to public health. This research aimed to (1) assess the extent of heavy metal contamination in sediment samples, (2) describe the distribution of heavy metals by locating likely pollution sources using a positive matrix factorization (PMF) model, and (3) quantify the potential ecological consequences associated with these metals at six different places around the Chan Thnal Reservoir. The findings indicated steady degradation and suggested moderate to high metal contamination. Fe > Zn > Cr > Cu > Pb > Co > As > Mn > Cd was the trend of metal concentrations in the sediment. Various soil pollution indices showed that most of the studied sediment samples were clean, moderately clean, or slightly contaminated. However, Co and Cd reached high-risk conditions posing a severe problem to the local population living in and around the Chan Thnal Reservoir. Principal component analysis (PCA) was used to estimate primary factors in PMF analysis. It was found that the contamination of As, Cu, Zn, Cd, and Pb originated from agricultural and traffic vehicle sources; however, Zn, Fe, Mn, Cr, and Cu were derived from natural sources (e.g., atmospheric deposition and compost amendment). Furthermore, Fe, Cd, Mn, Co, Pb, and Cr were generated from urban and industrial sources (metal coatings, plastic burning, wastewater irrigation, and sewage sludge). Accordingly, this research improves our knowledge of the prevalence of heavy metal pollution in agroecosystems, which may be used to foresee and mitigate the risks of heavy metal exposure to humans and other organisms.

Coffee silverskin (CS), the main by-product of coffee roasting production, contains various valuable bioactive compounds in its chemical compositions. Hydrothermal water extraction (HDTE) is one of the promising techniques for valorizing the organic fraction of CS into functional bioactive ingredients, which can be further exploited in various applications. This study aimed to evaluate the hyaluronidase and α-glucosidase inhibition activities of the CS extracts obtained under optimized water extraction conditions. Process optimization was performed using central composite design response surface methodology (CCD-RSM) with a broader range of extraction temperatures (25, 137.5, and 250 °C), reaction times (5, 38.5, and 72 min), and solid-to-liquid ratios (1:10, 1:80, and 1:150). The highest yield of 39.62% was obtained at 137.5 °C, with a reaction time of 72 min and an S/L ratio of 1:80. The total caffeoylquinic acid contents (T-CQA) were quantified based on the sum of three major isomers, including 3-CQA, 4-CQA, and 5-CQA. The results revealed that the highest T-CQA (2.76 ± 0.20 mg/g CS) was significantly obtained (p < 0.05) by subcritical water extraction (SWE) at 143.2 °C with an S/L ratio of 1:10 and an extraction time of 10.41 min. At such conditions, the total phenolic content (TPC), antioxidant properties (AP), and caffeine were 96.13 mg gallic acid equivalence per gram (GAE/g) CS, 20.85 ± 0.17 mg Trolox equivalence per gram (TE/g) CS, and 10.84 ± 1.25 mg/g CS, respectively. The 50% inhibition capacity (IC50) of hyaluronidase and α-glucosidase inhibition of the CS extracted were 5.00 mg/mL and 9.00 mg/mL, respectively. Our results supported the potential direct or indirect applications of CS, such as hydrothermal CS extract (HDT-CSE), in functional food or drinks. Repurposing CS residue to manufacture new products can efficiently reduce the amount of organic waste in landfills, thus conserving resources and energy and contributing to a lower overall carbon footprint in coffee production.

The cultivation of straw mushroom Volvariella volvacea has a long history and has undergone continuous development. Nevertheless, ongoing research aims to utilize various agricultural wastes to improve biological efficiency. In this study, we investigate a sustainable strategy that promotes the conversion to a circular economy by recycling spent mushroom substrate in new mushroom crops. Our research provides insight into reducing spent mushroom sawdust waste (SMSW) of Pleurotus ostreatus for application in Volvariella volvacea cultivation. We found that the optimal conditions for cultivating V. volvacea were at a temperature of 35.0℃ a humidity of 80-85%, resulting in an average growth rate of 10.60 cm and a total weight of fruit bodies of 0.77 kg, with a biological efficiency of approximately 15.47% within 15 days of cultivation. We discovered that the SMSW could be an alternative substrate for V. volvacea cultivation. Our findings can be applied to improve V. volvacea cultivation and practical applications in agriculture. By involving innovative waste management practices, this article can foster economic growth while preserving the environment for future generations. Therefore, this study contributes to significant socio-economic development and supports green economic policies by discussing the improvements from using SMSW.

Drinking water contamination by toxic elements poses significant public health risks, particularly in rural communities. This study quantified Pb, Cd, Zn, Cu, and K in 100 household drinking-water samples from Kratie Province, Cambodia, using atomic absorption spectrophotometry following acid digestion. Health risks for children and adults were assessed using exposure parameters obtained from a survey of 147 local participants. Zn and Cu concentrations remained within World Health Organization (WHO) guideline values, whereas Pb and Cd exceeded the applicable limits. Cd exceeded the WHO guideline value by up to 7.5-fold in 69% of samples. K showed the highest concentration among the investigated elements and was considered an indicator of dissolved-ion content. All hazard quotients were below 1 except for Cd. The cumulative hazard index exceeded 1 for children (2.46) and adults (2.07) under a conservative screening scenario, with exceedance persisting across all tested approaches for handling non-detects. The estimated lifetime cancer risk for Cd exceeded 1 × 10–4 across the published range of oral slope factors considered, although these factors were not validated for oral exposure to Cd. These preliminary risk estimates are based on a single sampling round and modelled intake assumptions. Further monitoring and investigation of potential contamination sources are recommended to better understand the extent of the problem.