2.1 The study area and levels of metal contamination

The Santos-Cubatão Estuarine System comprises a narrow strip of land between the Atlantic Ocean (Santos Bay) and the Serra do Mar mountain chair. The mountain is covered by the Atlantic Forest biome, whereas the estuary hosts a mangrove ecosystem (Figure 1). The Morrão River estuary was selected as the area for the present study because it represents the main environment impacted by industrial activities (fertilizer and steel plants and their private harbors) in the area [11, 12]. Sediments in estuaries are generally derived from several sources, which include fluvial, atmospheric, and continental shelf contributions, biological activities, and erosion of the estuarine banks. Sources can vary in the upper and lower reaches of the estuary, with biological inputs generally being more important in higher salinity than in lower salinity region, where terrestrial inputs dominate. In this context, natural sources related to rock weathering, and anthropogenic sources, including industrial and urban activities, may be mixed. The Morrão River estuary is a lower reach from the Santos-Cubatão Estuarine System, where domain sediments come from the weathering and erosion of igneous and metamorphic rocks of the Serra do Mar mountain chain [13]. In addition, the industrial and urban wastes reaching the estuarine system are responsible for the input of trace metals into the environment, which are subsequently incorporated into the sediments [14]. Table 1 shows the background and contamination metal levels in the study area. The average chemical composition of global shale is shown to comparison. In general, the contamination levels for Cd, Cu, Fe, Pb, and Zn (minor Ni) are an order of magnitude relative to the local geochemical background, which is similar to the average global shale composition (except Cu and Ni, lower) [15].

The Santos-Cubatão Estuarine System has been the object of research since the late 1980s [12, 14, 16–22]. However, data regarding metal concentrations in fish captured from this estuarine system and the related human health risk are scarce. This area hosts the largest industrial park and the first busiest commercial harbor in Latin America and some cities that represent together a population of about 1 million inhabitants. Besides the economic importance for Brazil, this area hosts a

preserved mangrove ecosystem and a special part of the Atlantic Forest biome, the latter known as one of the five most important hotspots in the world in terms of endemic species [23]. The chemical study of fish tissues in this highly contaminated area can provide substantial subsidies to improve the understanding about how the health, of physical compartments and dietary habits, affect metal distribution in different species in a subtropical to tropical environment. In addition, the chemical monitoring of a fish community is of great importance since in the area (known as

Study area and sampling points. Source: modified after Gonçalves et al. [11].

Implications of Sediment Geochemistry and Diet Habits in Fish Metal Levels…

DOI: http://dx.doi.org/10.5772/intechopen.89872

Figure 1.

113

Implications of Sediment Geochemistry and Diet Habits in Fish Metal Levels… DOI: http://dx.doi.org/10.5772/intechopen.89872

Figure 1.

An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it and with a free connection to the open sea [8]. Estuaries and mangrove ecosystems provide habitats for a large number of organisms and support very high productivity. They are also very densely populated and together with the coast represent about 60% of the world population [9]. It has been increasingly difficult to ignore the consequences of this occupation by industrial and urban activities on aquatic organisms, especially when it comes to disposal of potentially hazardous metals in sediments and water [10]. These dynamic ecosystems have some of the highest biotic diversities and biological production in the world, providing food and shelter to commercially important fish and shellfish species, including shelf species that spend some of their juvenile stages in

Applied Geochemistry with Case Studies on Geological Formations, Exploration Techniques…

The goal of this study is to characterize the levels of metal in muscle and liver tissues of four estuarine fish species (human-consumable protein) and associate it with different diet habits. Influences of these habits and the physical contaminated compartments on the uptake of metals and their distribution among the tissues are evaluated. The human health risk assessment of metals from fish food intake is

The Santos-Cubatão Estuarine System comprises a narrow strip of land between the Atlantic Ocean (Santos Bay) and the Serra do Mar mountain chair. The mountain is covered by the Atlantic Forest biome, whereas the estuary hosts a mangrove ecosystem (Figure 1). The Morrão River estuary was selected as the area for the present study because it represents the main environment impacted by industrial activities (fertilizer and steel plants and their private harbors) in the area [11, 12]. Sediments in estuaries are generally derived from several sources, which include fluvial, atmospheric, and continental shelf contributions, biological activities, and erosion of the estuarine banks. Sources can vary in the upper and lower reaches of the estuary, with biological inputs generally being more important in higher salinity than in lower salinity region, where terrestrial inputs dominate. In this context, natural sources related to rock weathering, and anthropogenic sources, including industrial and urban activities, may be mixed. The Morrão River estuary is a lower reach from the Santos-Cubatão Estuarine System, where domain sediments come from the weathering and erosion of igneous and metamorphic rocks of the Serra do Mar mountain chain [13]. In addition, the industrial and urban wastes reaching the estuarine system are responsible for the input of trace metals into the environment, which are subsequently incorporated into the sediments [14]. Table 1 shows the background and contamination metal levels in the study area. The average chemical composition of global shale is shown to comparison. In general, the contamination levels for Cd, Cu, Fe, Pb, and Zn (minor Ni) are an order of magnitude relative to the local geochemical background, which is similar to the average global shale

The Santos-Cubatão Estuarine System has been the object of research since the late 1980s [12, 14, 16–22]. However, data regarding metal concentrations in fish captured from this estuarine system and the related human health risk are scarce. This area hosts the largest industrial park and the first busiest commercial harbor in Latin America and some cities that represent together a population of about 1 million inhabitants. Besides the economic importance for Brazil, this area hosts a

estuaries [8].

also estimated.

2. Study area and methods

2.1 The study area and levels of metal contamination

composition (except Cu and Ni, lower) [15].

112

Study area and sampling points. Source: modified after Gonçalves et al. [11].

preserved mangrove ecosystem and a special part of the Atlantic Forest biome, the latter known as one of the five most important hotspots in the world in terms of endemic species [23]. The chemical study of fish tissues in this highly contaminated area can provide substantial subsidies to improve the understanding about how the health, of physical compartments and dietary habits, affect metal distribution in different species in a subtropical to tropical environment. In addition, the chemical monitoring of a fish community is of great importance since in the area (known as


Table 1.

Concentrations (average standard deviation; mg kg<sup>1</sup> , except Fe in % weight; n = 4) at 220–260 (representative of the geogenic geochemical background) and 0–20 cm depth (contamination level) based on a bulk sediment core from the Morrão River, Santos-Cubatão estuarine system [12]. Average chemical composition of global shale (mg kg<sup>1</sup> ) also is shown [15].

"Baixada Santista") thousands of kg of fish and shellfish are caught commercially or sportily for human consumption, besides being a protein source for local aquatic biota including endangered bird species [24, 25].

### 2.2 Sampling and species habits

A total of 44 fish samples was collected with fishing nets and rods (in the case of the carnivorous species), with the aid of local fishermen, in two campaigns in March 2011, at the Morrão River mangrove banks (Figure 1). The fish samples were classified with the aid of Cervigón et al. [26] and Fishbase database [27] in four fish species (Centropomus parallelus, Genidens genidens, Diapterus rhombeus, and Mugil liza). These four species together represent 41% of the most fished species of fish in the area. In general, Genidens genidens does not have high commercial value, although it is consumed by the local population [24]. The commercial value of Diapterus rhombeus is considered medium, and usually specimens longer than 200 mm are marketed [27]. Mugil liza is often caught and sold even before sexual maturity is reached, with about 300 mm in length. Centropomus parallelus commercial size is between 250 and 300 mm [27].

6 mL concentrated HNO3 purified by sub-distillation, and then heated for 3 hours at 80 °C (modified after Agah et al.) [41]. The water used was always ultrapure water (18.2 MΩ.cm), obtained from a Milli-Q system (Millipore, USA). All plastic materials were cleaned using a mixed solution of HNO3 8% and HCl 2% and rinsed with

Family Main food items L (mm)b W (g)c

(190–380)

250 (170–350)

250 (170–400)

(230–470)

198 (91–980)

226 (121–800)

250 (68–507)

382 (154–460)

Centropomidae Fish, insects, crustaceans<sup>d</sup> 280

mollusks, polychaetes, and bony fishe

ostracods, bivalves<sup>f</sup>

Mugilidae Organic debris and algae<sup>g</sup> 310

Ariidae Algae, benthic crustaceans,

Implications of Sediment Geochemistry and Diet Habits in Fish Metal Levels…

Gerreidae Benthic algae, polychaetes,

The metal concentrations in solutions were obtained by ICP-MS XseriesII (Thermo) equipped with collision cell technology (CCT) in the Geochemistry Laboratory at the University of Campinas. Before the analysis, the instrument was optimized according to the manufacturer recommendations. Lead was measured in normal mode, whereas all other isotopes (54Fe, 60Ni, 63Cu, 66Zn, and 114Cd) were measured using CCT mode. The instrument was calibrated using multi-elemental solutions prepared by mixing the necessary amounts from respective elemental

For analytical quality control, we analyzed the certified reference materials DOLT-4 (Dogfish Liver Reference Materials for Trace Metals) and DORM-3 (Dogfish Muscle Certified Reference Material for Trace Metals) produced by the National Research Council of Canada. Calculated recovery was between 83 and 100% (generally better than 90%) considering both certified reference materials, which confirms the good performance of the procedures adopted here (Table 3).

The estimated daily intake (EDI) for Cd, Cu, Fe, Ni, Pb, and Zn (on muscle

When considering the conservative approach, EF is the exposure frequency (365 days/year); ED is the exposure duration (we considered a lifetime of 78 years, average of Brazilians [43]); FIR is the ingestion rate (g/person/day, where we considered 71 g/day, as recorded by the Food and Agricultural Organization [44]); CF is the conversion factor (0.208) to convert fresh weight to dry weight considering

EDI <sup>¼</sup> ½ðEF � ED � FIR � CF � CmÞ=ðWAB � TAÞ� � <sup>10</sup>�<sup>3</sup> (1)

tissue) was calculated following Eq. (1) (after Saha & Zaman, [42]):

ultrapure water.

Scientific name (n)<sup>a</sup>

Centropomus parallelus (24)

Genidens genidens (8)

Diapterus rhombeus (7)

L = total length.

W = total weight.

Tonini et al. [39].

Chaves et al. [31].

Chaves et al. [29].

Fishbase [27].

a

b

c

d

e

f

g

115

Table 2.

Mugil liza (8) Mullet

n = number of specimens analyzed.

Popular name

DOI: http://dx.doi.org/10.5772/intechopen.89872

Fat snook Robalo

> Catfish Bagre

Mojarra Tainha

Carapeva

Characteristics of the analyzed fish species and specimens.

10 mg L�<sup>1</sup> (High Purity Standards, USA).

2.4 Human health risk assessment

Centropomus parallelus, Genidens genidens, and Diapterus rhombeus commonly live in estuaries, and their spatial distribution coincides with the distribution of mangrove ecosystems, which are their main habitat [28–31]. On the other hand, the species Mugil liza spawns in the sea, and the young specimens migrate to the estuaries, where they remain until about 8.5 years (ca. 500 mm in length) [32]. Therefore, here, young Mugil liza specimens only were studied, noting that the body lengths of adult female and male specimens exceed 570 and 500 mm, respectively [33]. The samples of the other three species were mostly adults that had already reached sexual maturity, which occurs when Centropomus parallelus is ca. 290 mm in total length; Genidens genidens female and male specimens are, respectively, ca. 133 and 160 mm long and Diapterus rhombeus between 80 and 90 mm long [34–37].

According to Rajkowska et al. [38], gender does not exert a significant effect on metal concentrations in most organs of fish, and, therefore, the sex of the specimens was not prioritized here. The most important criterion here was to cover specimens that were near the mangrove regions and resident of the estuary at a certain stage of their life cycle. A summary of the characteristics of the selected species and respective biometric data are shown in Table 2.

#### 2.3 Metal analyses

Once collected, the muscle and liver tissues were dissected on a clean surface. The cuts were made with plastic knives to avoid metal contamination [5, 40]. The tissues were freeze-drying, and about 0.25 g (dried in a glass desiccator) of each tissue were digested in 50 mL PFA (Savillex, USA) digestion vessels, by adding



b L = total length.

c W = total weight.

d Tonini et al. [39].

e Chaves et al. [31].

f Chaves et al. [29].

g Fishbase [27].

#### Table 2.

"Baixada Santista") thousands of kg of fish and shellfish are caught commercially or sportily for human consumption, besides being a protein source for local aquatic

(representative of the geogenic geochemical background) and 0–20 cm depth (contamination level) based on a bulk sediment core from the Morrão River, Santos-Cubatão estuarine system [12]. Average chemical

) also is shown [15].

Background 0.2 0.1 18.8 0.23 4.69 0.12 27.1 0.60 29.5 3.66 92.3 4.54 Contamination 1.77 0.48 104 27.5 17.6 4.52 50.3 8.73 146 35.9 541 146 Shale 0.3 45 4.72 68 20 95

Applied Geochemistry with Case Studies on Geological Formations, Exploration Techniques…

Cd Cu Fe Ni Pb Zn

, except Fe in % weight; n = 4) at 220–260

A total of 44 fish samples was collected with fishing nets and rods (in the case of

Centropomus parallelus, Genidens genidens, and Diapterus rhombeus commonly live in estuaries, and their spatial distribution coincides with the distribution of mangrove ecosystems, which are their main habitat [28–31]. On the other hand, the species Mugil liza spawns in the sea, and the young specimens migrate to the estuaries, where they remain until about 8.5 years (ca. 500 mm in length) [32]. Therefore, here, young Mugil liza specimens only were studied, noting that the body lengths of adult female and male specimens exceed 570 and 500 mm, respectively [33]. The samples of the other three species were mostly adults that had already reached sexual maturity, which occurs when Centropomus parallelus is ca. 290 mm in total length; Genidens genidens female and male specimens are, respectively, ca. 133 and 160 mm long and Diapterus rhombeus between 80 and 90 mm long [34–37]. According to Rajkowska et al. [38], gender does not exert a significant effect on metal concentrations in most organs of fish, and, therefore, the sex of the specimens was not prioritized here. The most important criterion here was to cover specimens that were near the mangrove regions and resident of the estuary at a certain stage of their life cycle. A summary of the characteristics of the selected species and respec-

Once collected, the muscle and liver tissues were dissected on a clean surface. The cuts were made with plastic knives to avoid metal contamination [5, 40]. The tissues were freeze-drying, and about 0.25 g (dried in a glass desiccator) of each tissue were digested in 50 mL PFA (Savillex, USA) digestion vessels, by adding

the carnivorous species), with the aid of local fishermen, in two campaigns in March 2011, at the Morrão River mangrove banks (Figure 1). The fish samples were classified with the aid of Cervigón et al. [26] and Fishbase database [27] in four fish species (Centropomus parallelus, Genidens genidens, Diapterus rhombeus, and Mugil liza). These four species together represent 41% of the most fished species of fish in the area. In general, Genidens genidens does not have high commercial value, although it is consumed by the local population [24]. The commercial value of Diapterus rhombeus is considered medium, and usually specimens longer than 200 mm are marketed [27]. Mugil liza is often caught and sold even before sexual maturity is reached, with about 300 mm in length. Centropomus parallelus com-

biota including endangered bird species [24, 25].

Concentrations (average standard deviation; mg kg<sup>1</sup>

mercial size is between 250 and 300 mm [27].

tive biometric data are shown in Table 2.

2.3 Metal analyses

114

2.2 Sampling and species habits

composition of global shale (mg kg<sup>1</sup>

Table 1.

Characteristics of the analyzed fish species and specimens.

6 mL concentrated HNO3 purified by sub-distillation, and then heated for 3 hours at 80 °C (modified after Agah et al.) [41]. The water used was always ultrapure water (18.2 MΩ.cm), obtained from a Milli-Q system (Millipore, USA). All plastic materials were cleaned using a mixed solution of HNO3 8% and HCl 2% and rinsed with ultrapure water.

The metal concentrations in solutions were obtained by ICP-MS XseriesII (Thermo) equipped with collision cell technology (CCT) in the Geochemistry Laboratory at the University of Campinas. Before the analysis, the instrument was optimized according to the manufacturer recommendations. Lead was measured in normal mode, whereas all other isotopes (54Fe, 60Ni, 63Cu, 66Zn, and 114Cd) were measured using CCT mode. The instrument was calibrated using multi-elemental solutions prepared by mixing the necessary amounts from respective elemental 10 mg L�<sup>1</sup> (High Purity Standards, USA).

For analytical quality control, we analyzed the certified reference materials DOLT-4 (Dogfish Liver Reference Materials for Trace Metals) and DORM-3 (Dogfish Muscle Certified Reference Material for Trace Metals) produced by the National Research Council of Canada. Calculated recovery was between 83 and 100% (generally better than 90%) considering both certified reference materials, which confirms the good performance of the procedures adopted here (Table 3).
