Project 2: exploring pollution monitoring proxies for characterizing urban lake environments: under the program ten years after Millennium Ecosystem Assessment of Laguna de Bay [Philippines]: towards a sustainable future (OVPAA-EIDR 06-006)

Laguna de Bay [Philippines], being the largest lake in the Philippines, is known to be a multiple-use resource that provides supporting, provisioning, regulating and cultural ecosystems services; such services may lead to its degradation. Conditions of the lake is affected both by environmental, biological and socioecological factors which is needed for holistic approach in lake restoration. Pollution is a major concerns in many urban lake environments, particularly at the Laguna de Bay. Thus, timely and relevant monitoring is a necessary to minimize environmental pollutants and their hazardous effects on the lake and its surrounding communities. This project aimed to assess pollutants signatures within the Laguna de Bay lacustrine environment by looking at water quality and heavy metal concentrations in lakebed sediment. This project reviewed the results of the sub-global assessment and compares them with more recent data for three of the lake's rivers: San Cristobal, San Juan, and the Molawin-Dampalit Rivers. Variations in basic parameters such as dissolved oxygen (DO), pH and temperature was published from the years after the assessment report until present. In addition, the Stream Visual Assessment Protocol (SVAP) developed by the United States Department of Agriculture was applied to four rivers at the southern portion of Laguna de Bay. Aside from the water quality of the lake, biological indicators have been eminent in the assessment of water bodies. Plakton are key components of the dynamics of pelagic ecosystem and can tolerate wide-range of environmental conditions making them excellent indicators of environmental stress. Corbicula fluminea across sampling stations have similar linear morphometric measurements. Compositional mapping of the sediments revealed the predominance of silica-and aluminum-rich materials in the lake sediments. To determine lake sediment quality, 75 cm to 100 cm cores were extracted from the South Bay of the lake and analyzed for their geochemical compositions. Various industrial process result in harmful emissions that contain different pollutants, which in many cases contain heavy metals. This study aimed to develop an alternative method using environmental magnetism techniques as most heavy metals are magnetic in character, and some that are non-magnetic can be associated with materials that are naturally magnetic.