# Efficient Inorganic Stabilization Materials for Chromium and Arsenic Pollution in Water and Soil
## 1 Introduction  
Chromium and arsenic are widely present in nature as toxic heavy metals. Chromium is usually found in two forms: Cr(III), an essential trace element in mammalian organisms, and Cr(VI), classified as a Group I human carcinogen [1]. Figure 1 shows the diseases caused by chromium and arsenic on the human body. The presence of chromium and arsenic in drinking water has been proven to pose multiple hazards to human health. The relationship between arsenic exposure and cardiovascular disease has been confirmed by multiple studies. For example, [PERSON] et al. [2] found that arsenic exposure is related to an increased incidence rate of carotid atherosclerosis. In addition, chronic arsenic poisoning may lead to skin lesions, such as pigmentation and keratosis, as well as neurological problems, such as tingling sensations in the hands and feet. Hexavalent chromium (Cr(VI)) has beenclassified as a carcinogen, and its toxic mechanisms include DNA damage, genomic instability, and the generation of reactive oxygen species (ROS). Chromium exposure may lead to diseases of the skin, liver, kidneys, reproductive system, and nervous system. These studies indicate that exposure to chromium and arsenic has significant toxic effects on multiple organ systems, emphasizing the importance of reducing exposure to these heavy metals [3]. Arsenic is distributed in both organic and inorganic forms in nature, mainly as As(III) and As(V) [4]. The sources of chromium and arsenic are primarily identified as industrial emissions, mining, agricultural fertilization, and wood anti-corrosion treatment (Figure 2). Chromium and arsenic could penetrate soil and groundwater through precipitation, soil erosion, and fertilization. Exceeding natural background levels, they trigger soil acidification/salinization, plant growth is inhibited to alter microbial community structures, and the balance of the ecosystem is ultimately disrupted. For example, oxidative imbalance and mutations could be caused by Cr(VI), significantly suppressing plant biomass production and reproductive development [5]. Furthermore, aquatic chromium and arsenic undergo biomagnification through food chains, demonstrating dose-dependent correlations with human hepatoreal dysfunction and carcinogenesis [6]. At present, chromium and arsenic contamination is still recognized as a serious problem worldwide; over 200 million people are exposed to arsenic-contaminated groundwater globally [7; 8; 9; 10]. Specifically, the World Health Organization (WHO) estimates that at least 150 million people worldwide drink water with arsenic levels exceeding the WHO safe limit of 10 \(\upmu\)g/L in over 70 countries [11]. In terms of chromium pollution, these polluted sites are primarily concentrated in South Asia, where about 75% are associated with the leather industry; a survey by [PERSON] et al. [12] found that 66% of the groundwater samples collected from 23 sampling points near the Para River in India had chromium levels that severely exceeded the safe range set by the World Health Organization, highlighting the urgency for remediation innovation. Conventional remediation technologies such as electrochemical treatment, chemical precipitation, coagulation-flocculation, membrane filtration, ion exchange, bioremediation, and adsorption have been extensively applied [13]. Electrochemical remediation is used to drive heavy metal ions to precipitate in weakly acidic or neutralized electrolytes as hydroxides, thus allowing pollutants to be removed [14]. In contrast, adsorption via biochar or zeolites capitalizes on high specific surface areas and active sites [13]. Microbial remediation employs enzymes for reduction of Cr(VI) to less toxic species [15]. Despite the fact that these traditional methods have their own advantages in practical applications, their long-term effectiveness remains a significant issue to be addressed in chromium and arsenic pollution treatment.