There are two files in this dataset, both of which are part of the AquaSat dataset (paper DOI HERE) and code here: https://github.com/GlobalHydrologyLab/watersat
The first (wqp_lagos_unity.csv) is a dataset containing all merged observations in the LAGOS-NE databse (https://doi.org/10.1093/gigascience/gix101) and data from the Water Quality Portal. This includes concentration data for chlorophyll a (in ug/L), total suspended solids (in mg/L), dissolved organic carbon (in mg/L), and secchi disk depth (in m). There is also SiteID names for each observation.
The second dataset (wqp_long_with_methods) contains a long-form dataset of water quality portal data that includes potentially import additional information like depth of sample, original analytical method, and more.