Agricultural activities are one of the main income sources in Bangka Regency, but this activity also provides a dilemma for environmental conservation. Oil palm plantation activities always use fertilizers and pesticides, leaving organic contamination in the waters. Cases of poisoning against pesticides, especially organophosphate groups, have been widely reported. To avoid that preventive measures are required, so we must know the water quality and pollution load that contained in the water around the area of oil palm plantations. This study aims to monitor water quality based on chemical parameters (DO, BOD, COD, nitrate and phosphate levels), and the presence of pesticide residues in the waters around oil palm plantations in Bangka Regency. The results showed waters around oil palm plantations in Zed meet mild to moderate pollution (3.21-4.95 mg/L) based on DO parameters, meet class II water quality standards for BOD (2.37-2.68 mg/L), COD criteria (8.7-11.4 mg/L), nitrate (0.985 mg/L) and phosphate (<0.0313 mg/L). Waters around oil palm plantations in Sempan meet moderate pollution based on DO parameters (3.59-3.78 mg/L), and meeting the class II water quality standards for the criteria of BOD(2.37-2.47 mg/L), COD (8.68-9.56 mg/L), nitrate and phosphate. The results did not found any pesticide organophosphate residue.

Green inhibitors are inhibitors that utilize secondary metabolites of plant to reduce the rate of corrosion. Secondary metabolites with heteroatom content phosphate, nitrogen, oxygen and sulfur function as ligands and adsorption centers to bind metals. These metabolites compounds include alkaloids, flavonoids, and tannins. Tristaniopsis merguensis Griff. is a local plant of Bangka Belitung which contains alkaloid, flavonoids and tannins. The focus of this research is to analyze the effect of T. merguensis leaf extract on corrosion rate of stainless steel. T. merguensis extract was obtained by maceration for 3 x 24 hours using ethanol solvent. Determination of corrosion rate using the mass reduction method. Then, functional group analysis contained in extract uses the Fourier Transform Infrared (FT-IR) at wavenumber region 4000–400 cm−1. The results obtained that at the highest concentration of 1000 mg/L the extract of T. merguensis was able to inhibit the corrosion rate of stainless steel until the corrosion rate was 0.3826 mmpy equal to inhibition efficiency 85.27%. This inhibiting ability is more likely because T. merguensis leaf extract containing phenolic compounds. Therefor T. merguensis extract can be used as a green inhibitor.