The Occurrence of Unfavorable Phenomena in Swimming Pool Water ^†

Abstract

The study assessed unfavorable phenomena occurring in swimming pool water, including the occurrence of organic micropollutants in swimming pools and the transformation of these compounds during the swimming pool water treatment processes. The presence of three selected compounds was examined from the personal care products group (PCP) in pool water samples, collected in 2018 and 2019, from fifteen pools characterized using three different solutions of swimming pool water treatment systems. In addition, experimental studies on the effects of UV radiation and ozone on selected organic micropollutants, previously identified in swimming pools and the relationship between swimming pool water turbidity and the concentration of the selected PCP micropollutants, were carried out

1. Introduction

The aim of the study is to assess unfavorable phenomena that may concern swimming pool water, including the presence of organic micropollutants in swimming pools and the transformation of these compounds in the processes used to treat swimming pool water.

From the point of view of water requirements in swimming pools, most effectively treat the water in their systems; however, extensive qualitative research needs to be conducted in a broader scope than is required by formal and legal requirements. This need results from the dynamic development of analytical techniques that currently allow the identification of micro-pollutants present in aquatic environments at trace concentrations. The biological activity of these pollutants significantly affects the health and life of living organisms. There is a risk of hormonal imbalance leading to, for example, the feminization of animals [1]. Likewise, human consumption of micropollutants having a biological effect may cause similar issues [2]. Other health effects in humans resulting from exposure to these compounds may be related, for example, to the occurrence of reproductive, endocrine, and neoplastic diseases [3].

The work includes research on the occurrence of three selected organic micropollutants from the personal care products group (PCP) in pool water samples collected in 2018 and 2019, from fifteen pools characterized using three different methods of pool water treatment solutions, as well as experimental studies on the effects of UV radiation and ozone on selected organic micropollutants that have been previously identified in swimming pools, including by-products generated by these processes.

Moreover, as part of this study, the dependence of swimming pool water turbidity on the concentration of selected micropollutants from the PCP group was investigated.

2. Methodology

2.1. Research Plan

The research carried out as part of this work included three stages:

• Assessment of the presence of three selected organic micropollutants from the PCP group in pool water samples with a comparison of changes in their concentrations that occurred in 2018 and 2019,
• Assessment of the impacts of UV radiation and ozonation on the three selected organic micropollutants, identified in pools in stage 1,
• Assessment of the dependence of turbidity of swimming pool water samples on the concentration of the three selected organic micropollutants.

2.2. Tested Compounds

The presented work includes research on the occurrence of three selected organic micropollutants from the personal care products group (PCP), which are characterized in

Table 1. The list of tested compounds.

Name	Structural Formula	Formula	CAS	Molar Mass (g/mol)
Oksybenzone (BP-3)		C14H12O3	131-57-7	228.25
Dioksybenzene (BP-8)		C14H12O4	131-53-3	244.25
Dibutylhydroxytoluene (BHT)		C15H24O	128-37-0	220.36

.

2.3. Anatilical Procedure

Due to the lack of reference methods for the determination of micropollutants in a swimming pool water environment, the authors developed their own procedure [4]. This method enables quantitative determination of trace contaminants with satisfactory reproducibility and accuracy, which guarantees full quantitative control of selected compounds in samples from swimming pools. The sample preparation methodology included solid phase extraction. For sample analysis, gas chromatography (GC-MS) was used.

3. Selected Results

The selected results of the research are presented in Figure 1 and Figure 2.

4. Conclusions

The paper shows the presence of three micropollutants from the PCP group in pool water samples taken from facilities with different solutions for pool water treatment systems. The concentrations of the tested compounds in swimming pool water increased during one year of operation of the facilities, which proves the accumulation of organic micropollutants in swimming pool water.

The dependence of the concentration of compounds on the disinfection method used by the facility was observed. In facilities using both UV radiation and ozone disinfection of swimming pool water, the concentrations of the tested micropollutants were lower than in facilities that did not use any disinfection support methods. UV radiation was more effective in removing the antioxidant BHT from water than ozone treatment, but the ozone method was more effective for sunscreens BP3 and BP8. The observation of these dependencies in real samples of pool water was confirmed by experimental laboratory tests, which also showed that, with an increase in exposure time of the compound to UV radiation, the effectiveness of BHT antioxidant removal from the pool water increased significantly. There was also a correlation for sunscreens BP3 and BP8, but the increase in effectiveness over time was smaller. In the case of the ozonation process, the degree of removal of all tested compounds from swimming pool water increased with an increase in the ozone dose.

The dependence of swimming pool water turbidity on the concentration of tested micropollutants in swimming pool water was also demonstrated. Turbidity, as a parameter that can be quickly measured through the use of inexpensive and uncomplicated equipment, can potentially be a valuable indicator of water pollution with organic compounds.