*Monitoring Strategies for Heavy Metals in Foods and Beverages: Limitations for Human… DOI: http://dx.doi.org/10.5772/intechopen.110542*

beverages are toxic and longtime exposure can be life threatening. Contamination of food by both essential (Co, Cu, Cr, Fe, Mg, Mn, Mo, Ni, Se, Zn Na, K, Mn, etc.) and non-essential (Pb, As, Hg, Sb, etc.) heavy metals can causes various health problems. Cardiovascular disease, diabetes, lung-cancer, hearing disorders, visual impairment are some serious issues associated with heavy metal contamination. **Table 1** shows the potential toxicity associated with heavy contaminations based on earlier reports.



### **Table 1.**

*Heavy metals with potential toxicity to human exposure, food sources and maximum permissible limit of intake.*

Therefore, heavy metal contamination in foods as a serious matter of concern now-adays for global scientific forum.

Heavy metal contamination in foods and beverages originated from different routes. Environmental pollution, industrial waste, soil where plant-based foods are cooked, processing of foods etc. are some well-known sources of heavy metal contamination. For instance, Anderson et al. [56] reported that contamination of food chain with heavy metal is due to environmental pollution, Cabrera et al. [57] reported that some food processing techniques are responsible for heavy metal contamination also [56–58]. Furthermore, exposure of humans to contaminated soil, air and water may be another reason for contamination with heavy metals. Raw material used, water, food-processing are some leading reason associated with metal contents in foods [3]. The schematic representation of various sources of heavy metal contaminations in foods is shown in **Figure 1**.

Heavy metals may be originated in both alcoholic and non-alcoholic beverages from added plant-based material during brewing procedure (cereal, hop etc.), manufacturing protocol, storage etc. [3, 5]. Pesticides and various man-made chemical fertilizers generally used during cultivation can be the cause of metal contaminations

*Monitoring Strategies for Heavy Metals in Foods and Beverages: Limitations for Human… DOI: http://dx.doi.org/10.5772/intechopen.110542*

in plants, which are transmitted to corresponding foods and beverages during processing and packaging [3, 59]. The classification of beverages and various sources responsible for heavy metal contaminations are shown in **Figure 2**. During beverage formulations although addition of any chemical and biological contaminants are strictly prohibited but sometimes unintentionally their formation occur in beverages. Prolonged exposure to low level contaminations also lead human health to potential health risks like carcinogenic, mutagenic and teratogenic effects [60, 61].

### **2.2 Various limitation parameters for heavy metal exposure to humans**

### *2.2.1 Recommended daily allowances (RDA)*

It is the daily exposure limits for heavy metal exposure as prescribed by WHO, FAO/ WHO, EVM, USEPA [5]. For instance, RDA of Co is 100 μg/day [3, 5], RDA of Cu ranges from 15 to 500 μg/kg bw/day [11]. Heavy metals Fe and Mn can be ingested upto 10–18 mg/day/person and 2–5 mg/day/person respectively [62]. For Ni, tolerable daily intake (TDI) is 5 μg/kg bw/day. Pb has TDI 7.14 μg/kg bw/day for 60 kg adult [3, 5, 63].

### *2.2.2 Estimated daily intake (EDI)*

Human exposure to heavy metals can be calculated by EDI as described by United States of Environmental Protection Agency (USEPA) [64].

The mathematical formula for determination of EDI is given below [65]:

$$EDI = \frac{C\_{metal} \times Q\_{\rm g}}{b.w} \tag{1}$$

Where *C* is the concentration of metal in foods, vegetables and other sources (in μg, mg etc.); *QIg* = quality of ingestion (kg/day); bw = body weight (generally considered 60 kg adult); EDI is generally expressed as μg/kg bw/day or mg/kg bw/day.

### *2.2.3 Target Hazard Quotient (THQ)*

THQ as prescribed by USEPA [65] explains the carcinogenic and non-carcinogenic effects of foods, beverages etc. The mathematical equation for calculation of THQ is given below:

$$\text{THQ} = \frac{E\_{fr} \times E\_{Dur} \times C\_{metal} \times S\_{lg}}{O\_{Rf} \times bw \times ATn} \times 10^{-3} \tag{2}$$

Where *Efr* = exposure frequency (365 days/year); *EDur* = duration of exposure (year); *SIg* = ingestion rate (g/day); *Cmetal* = concentration of metal (μg or mg); *ORf* = oral reference dose (mg/kg bw/day, **Figure 3**, shows oral reference doses of some heavy metals as per limits suggested by USEPA, WHO etc.); *bw* = average body weight (60 kg); *ATn* = average time for non-carcinogens; 10�<sup>3</sup> = unit conversion factor.

If, THQ < 1, the food or beverage is less carcinogenic or no-health carcinogenic health risk is associated with this.

If, THQ > 1, food staff is highly carcinogenic or associated with adverse health risk.

### *2.2.4 Hazard index (HI)*

Multiple heavy metal contamination can occur in same food & beverage at same time. HI is the summation of THQ of each metal present in food staff or other. It is an estimation of more than one metal induced toxicity and calculated as [3–5, 65]:

$$HI = \sum THQ\_{\text{metals}}\tag{3}$$

$$\mathbf{H} = \mathbf{T} \mathbf{H} \mathbf{Q}\_{\mathbf{M}1} + \mathbf{T} \mathbf{H} \mathbf{Q}\_{\mathbf{M}2} + \mathbf{T} \mathbf{H} \mathbf{Q}\_{\mathbf{M}3} + \mathbf{T} \mathbf{H} \mathbf{Q}\_{\mathbf{M}4} + \cdots \tag{4}$$

Where *M*1, *M*2, *M*3 are metal 1, 2, 3, respectively.

**Figure 3.** *Oral reference doses for some heavy metals prescribed by USEPA [5, 62, 66].*

*Monitoring Strategies for Heavy Metals in Foods and Beverages: Limitations for Human… DOI: http://dx.doi.org/10.5772/intechopen.110542*

### *2.2.5 Total cancer risk (TCR)*

This is the estimation of cancer risk associated with food staff. USEPA, 2011 prescribed the calculation for target cancer risk (TCR) as given by following mathematical equation [67]:

$$\text{TCR} = \text{C}\_{\text{SF}} \times \text{EDI} \tag{5}$$

where, CSF is the cancer slope factor of heavy metals. USEPA [67] prescribed CSF of various heavy metals for instance Cn for Pb is 36 mg/kg/day and for Cd it is 15 mg/kg/day.

As per estimation of New York State Department of Health (NYSDOH). If TCR ≤ 10�<sup>6</sup> , heavy metal associated health risk is low. Moderate cancer risk is associated with heavy metal exposure if is 10�<sup>3</sup> to ≥10�<sup>1</sup> . Above this range cancer risk is too high [68].
