The 18th World Lake Conference, entitled “Governance, Resilience, and Sustainability of Lakes for a Better Society” was held virtually from November 9th to 11th, 2022 at the University of Guanajuato, Mexico. This forum was designed with the primary objective of providing a space where scientists, professionals, students, managers, and practitioners could propose, share, and learn about studies, strategies, and actions which enhance the management of lakes around the world. Different activities were contemplated and scheduled in the organization of this forum, such as conferences, special sessions, technical sessions, and workshops where 194 distinguished investigators and participants shared the results of their research and the knowledge they have gained over the years.

The study aimed to determine the heating values (HV) and proximate composition of the four varieties of Napier Grass (Pennisetum purpureum Schumach) and native wild sugarcane (Sacharrum spontaneum L.)  to generate a mathematical model for predicting HV of Napier Grass varieties and wild sugarcane biomass. The four varieties of Napier Grass namely King, Florida, Dwarf, and Princess Caroline as well as the wild sugarcane were used in this study. The proximate composition such as moisture, ash, organic matter (OM), carbon (C), nitrogen (N), C/N ratio, and heating value (HV) were determined to generate mathematical models. Only ash, nitrogen, organic matter (OM) and carbon (C) have statistically significant r values toward the heating value. Positive correlation was obtained in OM and C whereas negative correlations were obtained in ash and N. Linear regression using Waikato Environment for Knowledge Analysis (WEKA) machine learning generated mathematical models for group variables for predicting the heating value (HV). The organic matter (OM) content showed the most accurate model among the group variables used with adjusted R2 value of 0.900, Pearson’s r value of 0.915 and root mean square error (RMSE) value of 481.64 MJ/kg. Among the proximate composition parameters tested, OM is the most accurate predictor of the HV of the Napier Grass varieties and wild sugarcane biomass.

This study measured the total mercury (THg) concentration in Palawan Quicksilver Mines, Inc., Sta. Lourdes, Philippines. A relatively variable but higher mercury concentration was found in this mine site (23.40 and 250.00 mg-kg–1) than the background global mercury concentration for pristine soil (0.045–0.16 mg-kg–1). The O and A horizons contained the highest mercury concentration, where humic substances abound. The B horizon, composed mainly of clay material, had a mercury level ranging from 23.40–188.00 mg-kg–1. The soil profiles have a substantial amount of clay minerals that could hold a labile fraction of mercury, and infiltration into the groundwater was improbable. Revegetation could help improve soil structure stabilization and may help stabilize soil particles containing mercury from erosion or runoff.

The study aimed to determine the soil physicochemical conditions, soil quality index (SQI), its relationship to soil total mercury (THg), and their spatial autocorrelation of the two mercury- contaminated agricultural areas in Monkayo, Davao de Oro, Philippines. Soil physicochemical parameters and THg were assessed, and the data underwent principal component analysis (PCA). The minimum data set (MDS) revealed that percent sand, pH, THg, phosphorus (P), and organic carbon (OC) significantly contributed to the SQI expression. The two agricultural areas (Diwata and Naboc) had comparable (P > 0.05) soil quality indices (0.46 ± 0.073 and 0.46 ± 0.11), which were categorized as Grade 3 (moderate SQI). THg was negatively associated with the SQI, with the regression coefficient (R) equal to –0.419 (p = 0.021); however, this association did not mean a causal effect. Hence, mercury (Hg) contamination could not be singled out as the sole factor in soil quality deterioration but rather the synergistic effects of the agricultural practices and the Hg contamination. Spatial autocorrelation analysis revealed that THg spatial distribution in both areas and the SQI of Diwata were clustered; however, the spatial distribution of SQI in Naboc was random. An in-depth study of soil microbiological function and the ecotoxicological effect of mercury on soil quality is deemed important to be studied.