Exposure to phthalate esters (PAEs) poses health risks to humans. Much research has been performed evaluating PAE levels in foodstuffs, river sediment and drinking water, but little attention has been paid to their presence in urban outdoor environments where human activities are highly intense. Here we evaluated PAE presence and distribution in street dust in Kaohsiung, the most industrialized city in Taiwan. Our results showed that PAEs were ubiquitous in fifty-two street-dust samples (levels of total PAEs 5.4–۹۸۹٫۲ mg kg−۱ ). Di-(2-ethylhexyl) phthalate was the most abundant congener observed and made up 85.0%, 79.7%, and 97.2% of the total PAEs found in industrial, residential and commercial areas, respectively. PAE levels in street dust in commercial areas (night markets) were significantly higher, suggesting a higher risk of contamination on people present in these areas (H value N χU 2). In residential and commercial areas, the higher the intensity of human activity, the higher the PAE content observed. PAE content decreased progressively from the center to the outskirts of the Houjing night market, suggesting that the increased human and consumer activities inside this commercial hotspot were the main PAE source in street dust. Children had higher estimated daily intakes (DIs) than adults and dermal absorption contributed more to these levels than oral ingestion. Although all calculated DIs were below referenced danger thresholds, street dust PAEs in the area should remain an environmental concern especially since night markets play an important role in Taiwanese/Asian culture and economy. Contrary to other studies, PAEs in this study were found less related to industrial manufacturing activities but highly linked to commercial activities. These findings are relevant for future pollution prevention efforts dedicated to mitigating public exposure to PAEs.

Introduction

Phthalate esters (PAEs), flexible and elastic chemicals, are used widely as plasticizers, particularly in products made of polyvinyl chloride (PVC) (Niu et al., 2014). They are found in a wide variety of daily products including children’s toys, pesticides, food packaging, household furnishings, personal care products, medicines and even foodstuffs (Niu et al., 2014; Skrbic et al., 2016). One hundred fifty million tons of plastic is manufactured globally every year and PAEs are consumed at a rate of 6.0 to 8.0 million tons annually (Niu et al., 2014). As a result, PAEs are widespread in soil, water, sediments and air (Zeng et al., 2008b). PAEs are classified as endocrine disruptors that pose health risks to both terrestrial and aquatic species (Zeng et al., 2008a; Niu et al., 2014). Exposure to these substances leads to various adverse health complications (Kozumbo et al., 1982; Kluwe, 1986). Six specific PAEs (dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate (DnBP), benzyl butyl phthalate (BBP), di(2-ethylhexyl) phthalate (DEHP), di-n-octyl phthalate (DnOP) are highly toxic and are categorized as priority contaminants by the US Environmental Protection Agency (USEPA, 2013) and the European Union (EU) (Zeng et al., 2008b; Wu et al., 2012). Therefore, PAE contamination and propagation are often the subject of worldwide monitoring studies (Niu et al., 2014; Skrbic et al., 2016). Kaohsiung City is the most industrialized area in Taiwan. It has a population of around three million and is an important economic and industrial center in Asia. In Kaohsiung, PAEs have been found in river sediment (Lin et al., 2009), drinking water (Yang et al., 2014), soil (Kaewlaoyoong et al., 2018) and foodstuff (Wu et al., 2013). PAEs were also detected in human urine in studies performed following a scandal involving industries that used PAEs as a substitute of emulsifier to food products they manufactured (Chen et al., 2016). Since that time, PAE contamination and associated health risk have been a major concern of Kaohsiung City government and its citizens (Yang et al., 2014). A large number of studies have investigated PAEs in indoor dust (Bornehag et al., 2005; Hwang et al., 2008; Orecchio et al., 2013; Zhang et al., 2013; Ait Bamai et al., 2014; Jeon et al., 2016; Albar et al., 2017; Larsson et al., 2017; Subedi et al., 2017), and human incidences of PAEs from indoor contamination have been reported (Pei et al., 2013; Tran et al., 2016; Albar et al., 2017).