Assessment of the Levels of Bisphenol a and Di-butyl Phthalates in Water, Soil, Sediment and Weeds Along the Coastal Beaches of Kenya

Abstract

Plastic materials have a wide range of uses in the society today. However, large scale application of plastic materials has resulted into accumulation of wastes with potential toxic effect to human health and the environment. Plastic materials may contain a variety of toxic chemicals such as phthalates, heavy metals, BPA, brominated flame retardants, nonylphenol, polychlorinated biphenyl ethers among others. These compounds are known to induce ill health effects such as immune system suppression, tetratogenic disorders, fetal developmental defects and cancer. The goal of this research was to determine the levels of Bisphenol A and Di-butyl phthalate in water, soil, sediments and sea weeds along the Kenyan coastal Beaches of Pirate, Mombasa, Kilifi, Malindi and Sabaki estuary. Sampling was done quarterly between the months of October 2018 and January 2019, covering the short rain and the dry season respectively. DBP and BPA analytes extraction from water samples was achieved by liquid-liquid extraction while from soil, sediment and sea weeds was by soxhlet extraction method using DCM solvent. Sample clean-up was conducted using chromatographic columns filled with silica gel while analysis of BPA and DBP was done using Agilent 6890 coupled to 5973 Mass Selective Detector. Electrical conductivity was lowest in Sabaki River water samples, followed by Sabaki Beach compared to other coastal Beaches while Ph was relatively similar for all the sites. DBP concentrations in water were < 1.29±0.13 ng/mL, soil (<39.75±0.91 ng/g), sediments (<3.04±0.38 ng/g) and sea weeds (<1.49±0.25 ng/g). BPA levels were <2.74±0.57 ng/mL (water), <3.39±0.14 ng/g (soil), 0.10±0.03-3.76±0.17 ng/g (sediments) and <11.66±0.94 ng/g (sea weeds). Pirate and Mombasa Beaches registered the highest levels of BPA and DBP in water samples, while the wet season had higher levels of pollution than the dry season. BPA levels in soil were higher than in water, sediments and sea weed samples during dry season as compared to the wet season. Concentrations of DBP and BPA residue levels in soil from Mombasa sites were higher in the dry season as compared to the wet season. According to the results, plastic pollution along Kenya's Beaches may be a factor in the occurrence of DBP and BPA in water, soil, sediments and sea weeds. Therefore, there is need for prudent management of plastic wastes and regular monitoring of pollution load along the coastal Beaches to protect human health and wildlife from toxic effects of ingredients from plastic wastes.