**1. Introduction**

Heavy metals are metallic elements with a higher density than water [1]. Heavy metals also include metalloids, such as arsenic, that can cause toxicity at low levels of exposure, based on the notion that heaviness and toxicity are linked. Because of its physical and chemical features, this group comprises arsenic (As), cobalt (Co), Iron (Fe), and manganese (Mn) are less common heavy metals (Mn) [1]. Essential and non-essential heavy metals were divided into two groups based on their toxicity [1]. At low concentrations, heavy metals essential are either nontoxic or considerably less harmful (Zn, Cu, Co, and Fe). Even at low concentrations, non-essential metals are very hazardous (such as Cd, Hg, Cr, and As) [2]. Apart from a few emissions into the atmosphere in the form of dust particles or vapors, these heavy metals are mostly found in the planet's aquatic and soil phases [3]. Because of their toxicity, persistence, and non-degradability, arsenic (As), cadmium (Cd), and lead (Pb) are considered

primary hazardous elements [4]. Researchers devised this study to detect the presence or absence of these fatal heavy metals in samples obtained of infant formula milk using Atomic Absorption Spectrophotometry (AAS) since lead, mercury, and arsenic were named as the top three most harmful chemicals on the priority list. The quantity of these heavy metals is measured in parts per million (ppm) [5]. Because, lead, mercury and arsenic were listed as the top three most dangerous compounds on the priority list, researchers devised this study to detect the presence or absence of these deadly heavy metals in chosen samples of infant formula milk using Atomic Absorption Spectrophotometry (AAS). These heavy metals' presence is measured in parts per million (ppm) [5]. Heavy metals are non-biodegradable, poisonous, and easy to accumulate in living creatures in general, and the human body in particular, in low quantities [6]. Heavy metal bioaccumulation in humans, such as cadmium and copper, can lead to cancer, nerve damage, failure of the liver and kidneys, as well as death [7]. Some heavy metals, such as Cd, Pb, and Cr, have no known biological purpose, whereas others, such as Cu, Zn, and Mn, are required in small amounts for normal plant growth and development but are severely poisonous to plants and animals when concentrations are somewhat higher than those required [8]. Heavy metal toxicity is still a hot topic in science, and more research is required to better to recognize the effects of the damaging mechanism and how to control them to lessen medical problems [9]. Due to rapid development, heavy metals wastewaters are increasingly discharged into the environment, mainly in developing nations, due to the rapid development of businesses such as metal plating facilities, mining operations, fertilizer industries, tanneries, batteries, paper industries, and pesticides, among others. Heavy metals, unlike organic pollutants, are non-biodegradable and tend to accumulate in living things. Many heavy metal ions are hazardous or carcinogenic [10]. The majority of heavy metals, such as cadmium, copper, and zinc, are linked to pollution and hazardous concerns, particularly when they are dissolved. Because of their toxicity and mobility, the presence of any of these heavy metals at high levels is dangerous to individuals and can interfere with a variety of environmental benefits [11]. Heavy metals' capacity to penetrate membranes until cells is a key role in many of their harmful effects. Furthermore, metals' transmembrane transfer may be implicated in their absorption, distribution in the body, and excretion, hence transmembrane transfer aids in the determination of metal toxic kinetics. Because cell membranes are so important in metal toxicity [12]. Toxic metals are commonly found in industrial, municipal, and urban runoff, and they can affect humans and other living things. Rising levels of trace metals, particularly heavy metals, in our rivers are due to increased urbanization and industry. Many hazardous chemical components accumulate in the soil and sediments of water bodies after being released into the environment. There are more than 50 elements categorized as heavy metals, with 17 of them being extremely hazardous and easily accessible. Anions play a significant role in drinking water, and the outcomes have been shown to have an impact on people's health [13]. China was close to the city streets. The residents are exposed to street dust regularly. Metal pollutants are often non-degradable and have no recognized homeostasis mechanism. As a result, any large concentration of heavy metals poses a threat to biological life [14]. An increase in anthropogenic activity has resulted in the release of numerous dangerous compounds into water resources, endangering aquatic ecosystems and the environment. Because heavy metal ions are very poisonous, non-degradable, and tend to bioaccumulate and biomagnify as a result of the food chain, they are the most serious contributors to water pollution. Their mere presence in aquatic habitats is enough to have a direct or indirect impact on living systems.
