Physicochemical parameters of Chennai and Pondicherry water samples near antimicrobial manufacturing sites, India, 2023-2024

Samples were collected following a standardized operating procedure mutually agreed upon by the collaborating partners. For water samples, collection was performed at depths ranging from 1 to 5 meters using a sterile container attached to a pulley system. Control samples were collected from upstream sites selected to represent areas unaffected by pollution from manufacturing sources. All samples were collected in triplicates to ensure reproducibility and statistical reliability with composite samples created from three sampling points in each location. Duplicate samples were also randomly collected as part of quality control.

Parameters were measured in situ using a portable multiparameter Aquaprobe AP-200 with a GPS Aquameter (Aquaread AP 2000). Initial data entries were recorded manually on paper and subsequently digitized into Excel spreadsheets. No imputation or gap-filling procedures were applied to the dataset. In cases where certain parameters exhibited readings below the detection threshold, the measurement units automatically shifted to a lower metric scale. For example, dissolved oxygen concentrations were recorded in mg/L by default but were represented in µg/L for particularly low-concentration samples. For the sake of consistency and uniformity across the dataset, all such values were converted back to the default unit of mg/L.

Samples were transported to the laboratory on the same day in a refrigerated isothermal container and stored at −20 °C until analysis to preserve their integrity. Upon arrival, the samples were processed immediately for both culture-based microbiological analyses and metagenomic DNA extraction, thereby maintaining sample freshness and minimizing potential degradation. Bacterial isolates obtained from each sampling site were preserved as glycerol stocks and stored at −80°C to maintain viability for future analyses.

Due to a lack of water at the site because of warm conditions, no water samples were collected from PSL10 in 2023. The levels were similarly low the following year, so this site was excluded from water and physicochemical analysis.

This dataset is under embargo and will be made available by 5 May 2026 at the latest   Find out more »