## 5 Potential Side Effects  
While _C. vulgaris_ is recognized for its nutritional benefits, it also presents potential side effects and toxicological concerns, particularly regarding heavy metal accumulation. Metals such as lead (Pb), cadmium (Cd), mercury (Hg), arsenic (As), copper (Cu), and zinc (Zn) are particularly concerning due to their toxicity and ability to bioaccumulate in organisms, including microalgae. Research indicates that _C. vulgaris_ absorbs heavy metals from its environment, which raises apprehensions about its safety as a dietary supplement. For instance, exposure to copper and zinc can negatively impact metabolic processes, leading to decreased photosynthetic pigment content and overall cellular health [138]. Studies have shown that _C. vulgaris_ can accumulate significant levels of cadmium and lead, potentially exceeding safe consumption limits when sourced from contaminated waters [139]. Additionally, it \begin{table}
\begin{tabular}{c l c} \hline \hline
**Compound** & **Benefit** & **Reference(s)** \\ \hline \multirow{3}{*}{Chlorophyll} & Antioxidant, reduces oxidative stress & [4] \\  & Neuroprotective effects & \\ \hline Carotenoids & Induces apoptosis in cancer cells & [18] \\ (lutein, beta-carotene) & Neuroprotective effects & [18] \\ \hline \multirow{2}{*}{Sulphated Polysaccharides} & Antiviral activity against enveloped viruses & [41,42] \\ \hline \multirow{6}{*}{Polysaccharides} & Enhances immune function, boosts & \\  & NK cell activity & \\  & Anti-inflammatory properties & \\  & Inhibits viral adsorption and & \\  & replication & \\  & Potential adjunct in cancer & [3,4,18,43,120,123] \\  & treatment & \\  & Improves glycemic control in & \\  & diabetes & \\  & Blocks tumor proliferation & \\  & Neuroprotective effects & \\ \hline \multirow{2}{*}{Lipids} & Reduces total cholesterol, LDL, and & \\  & triglycerides & \\ \hline \multirow{2}{*}{Bioactive compounds} & Prevonts infections and supports & \\  & immune function & [21] \\ \hline \multirow{2}{*}{Dietary Fiber} & Lower lipid absorption & \\  & Modulates cholesterol levels & [3,7,40] \\ \end{tabular}
\end{table} 
Table 3: Medicinal applications of compounds in _Chlorella vulgaris_ and associated health effects. has been demonstrated that cadmium accumulation occurs in a dose-dependent manner; concentrations as low as 10 \(\upmu\)M adversely affect growth, while levels of 100 \(\upmu\)M can cause significant toxicity and cell death [140]. Lead accumulation has also been documented, with concentrations of 10 \(\upmu\)M resulting in observable physiological stress in algal cells [138]. To protect consumer health, the World Health Organization (WHO) and the Food and Agriculture Organization (FAO) have set guidelines for acceptable levels of these metals in food products. The maximum allowable limits for cadmium and lead are 0.1 mg/kg and 0.2 mg/kg, respectively, while mercury is regulated at a maximum level of 0.5 mg/kg in fish and seafood [141]. To mitigate these risks, producers of _C. vulgaris_ supplements need to implement rigorous quality controls, including regular monitoring of water quality, heavy metal testing, and adherence to cultivation protocols such as good agricultural practices (GAP) and ISO certifications. These measures help ensure that _C. vulgaris_ products are safe for consumer use and free from harmful contaminants. Studies have shown that pollutants, including pesticides like cypermethrin, can inhibit the growth of _C. vulgaris_ at relatively low concentrations, suggesting that environmental contaminants may compromise its safety as a food supplement [142]. Producers employ controlled environments, such as closed bioreactors, to reduce exposure to pollutants, while third-party certifications like organic or non-GMO labels offer additional consumer assurance. Furthermore, the presence of ROS and oxidative stress induced by various nanoparticles has been documented to negatively impact the growth and metabolic functions of _C.