**1. Introduction**

Lead (Pb) is an environmental toxicant that causes serious harm to child health [1,2]. Children are highly susceptible to Pb toxicity due to hand-to-mouth behavior, high metal absorption rates, and the nervous system that is still in developing stage [3]. Pb enters the body through ingestion and breathing. It accumulates and causes toxicity in various tissues and organs that include the liver, kidneys, blood system, central nervous system (CNS), bone, and teeth [1]. Pb toxicity in the CNS cannot be restored to normal, and the World Health Organization considers mental retardation caused by excessive Pb exposure as one of the most serious environmental diseases [4]. There are no reports of blood Pb levels that are safe for children's health. Moreover, chronic Pb exposure in childhood may predispose individuals to various diseases later in life.

Chronic exposure to Pb among children has been observed in various nations, including China, Brazil, Ukraine, South Africa, United States of America, and Australia [5–12]. Previous studies have suggested that the main reason for Pb exposure in children is environmentally related [5–8]. Elevation of blood Pb levels have been seen in children living in areas with high Pb contaminations, and residential areas have often been found to be a determinant of high blood Pb in children [6–9]. Children living near an electronic waste disposal area in China were found to have blood Pb levels between 4.14 to 37.78 μg/dL [10], while children lived near zinc and lead mining areas in Zambia had blood Pb levels ranging from 5.4 to 427.8 μg/dL [11]. In other studies, children living in fishing villages near the coast of South Africa and Tasajera (Colombian Caribbean coast) were found to have blood Pb levels ranging from 2.2 to 22.4 μg/dL and 0.4 to 50.1 μg/dL, respectively [8,12].

Nakhon Si Thammarat Province situates in the southern part of the Gulf of Thailand, where fishing communities with mini-scale repair boatyards exist, especially in Pakpoon suburb. In the traditional boat repair method, plumboplumbic oxide (Pb3O4) has been used; the strands of cotton ropes coated with Pb3O4 are caulked between wooden planks as waterproofing and to prevent barnacles. In one study, boat-repair workers were found to have blood Pb levels ranging from 9 to 89 μg/dL, and 67% of the workers had blood Pb levels exceeding 40 μg/dL, the level of concern for Pb exposure [13]. Other studies detected substantial amounts of Pb in soil and house dust from areas in close proximity to repair boatyards [14–16]. Of concern, mothers who made fishing nets with lead weights at home can introduce an additional Pb source to family members, especially young children who are the most vulnerable. Data of blood Pb levels in children in these communities are lacking. Hence, the present study was undertaken to assess the levels of environmental exposure to Pb among young children, 3–7 years of age, as reflected by blood Pb levels. We used blood Pb levels ≥ 5 μg/dL as a warning level, established by the U.S. Center for Disease Control [17]. In addition, we aimed to explore a range of environmental and behavioral factors, known as determinants of children's blood Pb levels from the literature reports [5–12].

#### **2. Materials and Methods**
