Cd In Seawater Research Articles

Incorporation of Dissolved Heavy Metals Into the Skeleton of Porites Corals Based on Multi‐Element Culturing Experiments

AbstractAnthropogenic activities increase the level of dissolved heavy metals in some tropical near‐shore environments threatening reef ecosystems. The skeleton of stony corals like Porites species potentially provides a high‐resolution geochemical archive for past heavy metal concentrations, with potentially century long records revealing baseline values before large‐scale human disturbance. However, few data exist for heavy metal partitioning into coral skeleton aragonite. To address this, culturing experiments exposing Porites lobata and Porites lichen to a mixture of dissolved Cr, Mn, Ni, Cu, Zn, Ag, Cd, Sn, Hg, and Pb over a wide concentration range have been performed. Water samples were taken frequently to monitor changes in the heavy metal concentration. Laser ablation ICP‐MS measurements of the coral aragonite revealed metal concentrations that were positively correlated with Cr, Mn, Ni, Zn, Ag, Cd, and Pb concentrations in seawater. The DTE values for most metals appear dependent on the seawater metal content, approximating a power law, and therefore stabilize at higher seawater metal/Ca ratios. The partitioning of Pb into the coral skeleton is a notable exception, with DPb being stable around 2 to 1 across a large range of “natural” to highly polluted seawater Pb concentrations. This and the general agreement with partition coefficients estimated by previous work suggests that the reconstruction of the heavy metal concentration in seawater for ecosystem monitoring is possible. However, the high variability within and between coral colonies requires further study and suggests that multiple records from multiple coral colonies should be combined to obtain robust reconstructions.

RGO/MWCNT-COOH-Modified Electrodes for the Detection of Trace Cd(II) and Zn(II) in Coastal Seawater

Cadmium (Cd) and zinc (Zn) in seawater enter the human body through the food chain. Combined toxicity tests indicated that high concentrations of Cd(II) and low concentrations of Zn(II) had a synergistic effect on humans. Thus, there is an urgent need to prepare a sensor for rapid and simultaneous detection of Cd(II) and Zn(II) in seawater. Herein, a reduced graphene oxide/carboxylated multi-walled carbon nanotube (rGO/MWCNT-COOH)-modified glassy carbon electrode was prepared in the experiments using the dropping method. The synthesis of various materials achieved the purpose of expanding the surface area, and scanning electron microscopy was used to observe the structure of the composite membrane. Moreover, the large number of functional groups on the surface of the composite membrane can also increase the adsorption of ions. For the determination of trace cadmium (II) and zinc (II) in seawater, the method used was differential pulse voltammetry (DPV). The results show that the peak current, which was obtained in the range of 5–400 μg/L for Cd(II) and Zn(II), has a linear relationship with concentration, corresponding to the detection limits of 0.8 μg/L for Cd(II) and 0.98 μg/L for Zn(II). The modified electrode was used to determine the Cd(II) and Zn(II) content in the coastal seawater of the Maowei Sea, and the recovery rate was between 95.8 and 98.2% for Cd(II) and 96.7~99.4% for Zn(II), which provided a novel approach of detection to define trace Cd(II) and Zn(II) in seawater.

Development of a Dispersive Liquid-Liquid Aerosol Phase Extraction Method for the Quantification of Ag, Cd, Cu, Ni, and Pb in Seawater by Inductively Coupled Plasma Optical Emission Spectroscopy.

The dispersive liquid-liquid aerosol phase extraction (DLLAPE) method was applied for the determination of Ag, Cd, Cu, Ni, and Pb in seawater samples by inductively coupled plasma optical emission spectroscopy (ICP-OES). Key parameters such as sample pH and extractant concentration were systematically evaluated, with ammonium O,O'-diethyldithiophosphate (DDTP) identified as the optimal chelating agent. Optimal extraction conditions were achieved at pH 2.5 for Ag, Cu, Ni, and Pb, while Cd extraction efficiency was found to be pH independent. The extractant concentration did not greatly improve the extraction efficiency. Furthermore, the influence of nebulizer gas flow rate and extraction time was evaluated, achieving the maximum extraction yield at 0.6 L min-1 and 120 s, respectively. The method was evaluated for accuracy and bias through recovery studies, and the results showed that most elements had recovery rates close to 100% with relative standard deviation values in between 3 and 9%. However, in the case of Ag and Ni, 1.184 and 1.089 correction factors were, respectively, applied to compensate for the bias. Moreover, the procedural limits of quantification (pLOQs) found for Ag, Cd, Cu, Ni, and Pb were 0.4, 0.14, 0.2, 0.2, and 0.2 μg L-1, respectively. The in-house validation of the method provided expanded uncertainty values lower than 6% for all elements except for Ag (16.6%). Finally, the application of the method to real seawater samples from coastal areas in Alicante and San Juan (Spain) confirmed its suitability for trace metal analysis in complex marine matrices, underscoring its potential for environmental monitoring and research.

Assessment of Heavy Metal Cd and Pb Concentrations and the Ecological Risk from Seawater, Sediments, and Perna viridis in Semarang Bay, Indonesia

Semarang Bay is a multiple water source from some rivers located at the forefront of the most populated city in Central Java. These waters are polluted by wastes from various sources. Previous studies conducted were limited to specific areas and were mainly focused on one or two media only. This research aims to analyse the heavy metal Cd and Pb concentrations in seawater, sediments, and green mussels and the ecological risks. Field data were collected from 18 sites from three locations: Semarang, Demak and Kendal during the dry season of 2020. Environmental variables were measured in situ, and the heavy metals concentrations were analysed using Atomic Absorption Spectrometry. The concentrations of Cd and Pb in the waters of Semarang Bay vary spatially and are above the standard threshold values set by the government. The highest concentration of Cd is found in the sediment and of Pb in the seawater. Despite the exceeding concentrations, the environmental conditions in Semarang Bay are still relatively good based on the low values of contamination indices assessed. This condition, however, can be expected to change when the season changes and needs to be considered by green mussel farmers, coastal managers, and local governments.

Assessment of Heavy Metal Cd and Pb Concentrations and the Ecological Risk from Seawater, Sediments, and Perna viridis in Semarang Bay, Indonesia

Semarang Bay is a multiple water source from some rivers located at the forefront of the most populated city in Central Java. These waters are polluted by wastes from various sources. Previous studies conducted were limited to specific areas and were mainly focused on one or two media only. This research aims to analyse the heavy metal Cd and Pb concentrations in seawater, sediments, and green mussels and the ecological risks. Field data were collected from 18 sites from three locations: Semarang, Demak and Kendal during the dry season of 2020. Environmental variables were measured in situ, and the heavy metals concentrations were analysed using Atomic Absorption Spectrometry. The concentrations of Cd and Pb in the waters of Semarang Bay vary spatially and are above the standard threshold values set by the government. The highest concentration of Cd is found in the sediment and of Pb in the seawater. Despite the exceeding concentrations, the environmental conditions in Semarang Bay are still relatively good based on the low values of contamination indices assessed. This condition, however, can be expected to change when the season changes and needs to be considered by green mussel farmers, coastal managers, and local governments.

Plankton diversity and its heavy metal content in Ratai Bay of Pesawaran district, Lampung, Indonesia.

Artisanal and small-scale gold mining (ASGM) activity in Way Ratai River produces heavy metal wastes; therefore, further information regarding heavy metal concentrations in the water was needed, especially in plankton samples. Furthermore, the determination of plankton diversity was also carried out in the waters of Way Ratai to determine the bioconcentration factor (BCF). Eight sampling sites were chosen along the river reaching the coast of Way Ratai. The research was conducted in November 2020 and March 2021. Ten heavy metals, Ag, Cd, Co, Cr, Cu, Fe, Mn, Pb, and Zn that are commonly found in mining areas, were determined in the water and plankton samples by using ICP-OES. The results indicated that the highest concentration found was Fe in plankton samples (0.725 mg/L in the river and 1.294 mg/L on the coast). Meanwhile, contents of Cd, Cu, Fe, Mn, and Zn in the river exceeded the predetermined water quality standards, while Ag and Pb metals were not detected. The Cd, Cr, Cu, Pb, and Zn content in seawater also exceeded quality standards. The highest BCF value (12.96) was found for Fe at station G, whereas the lowest BCF value (0.13) was found for Ag at stations G and H.

Biological, Physical, and Atmospheric Controls on the Distribution of Cadmium and Its Isotopes in the Pacific Ocean

AbstractDespite the Pacific being the location of the earliest seawater Cd studies, the processes which control Cd distributions in this region remain incompletely understood, largely due to the sparsity of data. Here, we present dissolved Cd and δ114Cd data from the US GEOTRACES GP15 meridional transect along 152°W from the Alaskan margin to the equatorial Pacific. Our examination of this region's surface ocean Cd isotope systematics is consistent with previous observations, showing a stark disparity between northern Cd‐rich high‐nutrient low‐chlorophyll waters and Cd‐depleted waters of the subtropical and equatorial Pacific. Away from the margin, an open system model ably describes data in Cd‐depleted surface waters, but atmospheric inputs of isotopically light Cd likely play an important role in setting surface Cd isotope ratios (δ114Cd) at the lowest Cd concentrations. Below the surface, Southern Ocean processes and water mass mixing are the dominant control on Pacific Cd and δ114Cd distributions. Cd‐depleted Antarctic Intermediate Water has a far‐reaching effect on North Pacific intermediate waters as far as 47°N, contrasting with northern‐sourced Cd signatures in North Pacific Intermediate Water. Finally, we show that the previously identified negative Cd* signal at depth in the North Pacific is associated with the PO4 maximum and is thus a consequence of an integrated regeneration signal of Cd and PO4 at a slightly lower Cd:P ratio than the deep ocean ratio (0.35 mmol mol−1), rather than being related to in situ removal processes in low‐oxygen waters.

How environmental factors determine mussel metal concentrations? A comparative study between areas facing different pressures

This study examines mussel accumulation capacity in relation to metal concentrations in the marine environment as well as mussel food availability in the coastal marine environment. Field data obtained from mussel-farms facing different natural and/or human derived pressures (Thermaikos gulf receiving river discharges and Elefsis bay receiving industrial effluents). Cd, Cr, Cu, Fe, Mn, Ni and Zn concentration in mussels and seawater (particulate phase) chlorophyll α, particulate organic carbon and suspended particulate matter (SPM), seawater temperature and salinity were measured. Median mussel metal concentrations measured as μg g−1 dw were 0.62 for Cd, 5.6 for Cu, 2.8 for Cr, 5.0 for Ni, 129 for Zn, 311 for Fe and 12.4 for Mn. The corresponding concentrations in SPM expressed as μg L−1 were 0.004 for Cd, 0.33 for Cu, 1.14 for Cr, 0.31 for Ni, 3.60 for Zn, 46.0 for Fe and 1.63 for Mn. Mussel metal concentrations were higher at the industrial site. Metals in the seawater particulate phase were higher in the estuary front, which was attributed to higher SPM levels from river discharges. Due to the limited nutritional value of the SPM in the industrial area, mussels were exposed to elevated metal load by both the anthropogenic activities and the slower and more effective digestion of their potential food in order to optimize available organic matter exploitation from restricted and low nutrition value food.

Seasonal variations of heavy metals in seawater and integrated poly-cultured scallop Chlamys farreri in Ailian Bay, northern China

Seasonal variations of heavy metals in integrated poly-cultured scallops and seawater from Ailian Bay, northern China were analyzed to reveal the potential factor in bioaccumulation of metals in scallop Chlamys farreri. Results showed that heavy metals (Cu, Zn, As, Cd, Cr, Pb and Hg) in seawater were much below the maximum permissible limits and showed no seasonal changes, but were consistent with the growing period of the poly-cultivated kelp. The content of Zn in scallop tissues was highest with an average value of 88.35 ± 11.50 mg/kg, and Hg content was lowest (0.046 ± 0.025 mg/kg). The accumulation of Cu, As, Cd and Hg in scallops presented a significant seasonal change, and they were closely correlated with the physicochemical quality instead of heavy metals in seawater. Cadmium provided 88.9 % of the total hazard index for adults and 72.2 % for children. Arsenic should also be paid more attention in the risk assessment of human health.

A Chelating Resin of EDTA-Type Modified Cross-Linking Polystyrene to Preconcentrate Trace Metals for Seawater Detection.

The determination of trace metals in seawater is an important project of marine environmental monitoring. However, the presence of many alkali metal ions with high concentration, such as sodium ion, seriously interferes with the detection limit and accuracy of atomic absorption spectrometry (AAS, flame/graphite furnace integrated). The conventional chemical methods for the enrichment of trace metals are complex, and low boiling point organic solvents are used. In this paper, a kind of commercial cross-linked polystyrene resin microspheres was chloromethylated and aminated to introduce EDTA-type amino polycarboxylic groups and then loaded in a column as the absorption filler. A set of seawater pretreatment and enrichment devices was designed and assembled. The enriching process and conditions of trace Cu, Zn, Pb, and Cd in standard seawater were studied. 10 g of the modified resin could enrich the equivalent seawater and remove successfully the light metal ions. pH = 5∼9 and 0.2 mL/min of the flow rate were the suitable conditions for preconcentration. The enriched metal ions in the eluent were analyzed on the AAS. Compared with the conventional solvent method, the novel material and enrichment device have high preconcentration efficiency, strong anti-interference ability, and low cost and could be directly applied for routine seawater detection.

Distribution and ecological health risk assessment of dissolved trace metals in surface and bottom seawater of Yantai offshore, China

The biogeochemical cycle of trace metals plays an important role in the coastal zone. The distribution, interaction, and biogeochemical behavior of dissolved trace metals in surface and bottom seawater are still unclear. This study analyzed the distribution and performed an ecological health risk assessment of dissolved trace metals (Zn, Cd, Co, Pb and Cr) in surface and bottom seawater in the summer (August) of 2019 and 2020 in the seawater of the Yantai offshore area, China. Zinc (Zn), cadmium (Cd), cobalt (Co), lead (Pb) and chromium (Cr) ranged from 23.76–117.47 μg/L (42.67 μg/L ± 15.15), 0.21–0.51 μg/L (0.30 μg/L ± 0.05), 0.90–2.94 μg/L (1.09 μg/L ± 0.31), 0.13–1.06 μg/L (0.39 μg/L ± 0.17), and 2.00–9.9 μg/L (5.38 μg/L ± 2.99) in the summer of the two years. The average metal (Zn and Co) concentrations were slightly higher than the other Chinese coastal areas, while the major contamination pressures were from Zn and Pb. The largest contaminants were in the following order: Zn > Pb > Cd > Cr > Co. Correlation analysis, principal component analysis and hierarchical cluster were used to determine the potential origins and cause the spatial distribution of the multiple dissolved trace metals. The major sources of the trace metal contamination in study area were identified as external inputs from natural human and atmospheric settling and the natural release of the trace metals in sediments under external disturbances. Riverine inputs, the Lubei coastal current and aquaculture significantly influenced the multi-parameter horizontal distributions of the dissolved trace metals and dissolved organic carbon. Although the growth of phytoplankton was strong in summer, the uptake of Zn, Cd, Co and Pb was negligible compared with the exogenous input. The concentrations of Zn, Cd, Co and Pb were higher in the surface than those in the bottom. Monsoons, tides and wind waves also influence the migration, transformation and distribution of dissolved trace metals and dissolved organic carbon. This study provides important information on the biogeochemical cycle process (migration and conversion) and distribution of dissolved trace metals at different depths in coastal and marine pasture areas.

Ecological of human health risk of total petroleum hydrocarbons and four metals in seawater of the southeastern Bohai Sea, China.

To obtain systematic knowledge on the waterborne pollution status and ecological and human health risk of total petroleum hydrocarbons (TPHs) and metals in the southeastern Bohai Sea, seawater samples were collected in three seasons from 2014 to 2018. TPHs and mercury (Hg) levels were determined by ultraviolet spectrophotometry and cold atomic absorption spectrometry, respectively, and concentrations of copper (Cu), lead (Pb), and cadmium (Cd) were detected by anodic stripping voltammetry. Spatial distribution patterns indicated that these waterborne pollutants are mainly sourced from terrestrial inputs. Temporal variation showed that Pb contents decreased in the past five years, and summer exhibited higher concentrations of Hg, Cu, and Cd than spring and autumn. Spearman's rank correlation coefficients demonstrated that temperature correlated positively with Cu content, while dissolved oxygen, pH, and suspended particulate material correlated negatively with pollutant concentrations. While hazard quotient values were lower than 1 for TPHs, Hg, Pb, and Cd, the hazard quotient of Cu (4.88) was greater than 1, suggesting potential ecological risks of this element in seawater of the southeastern Bohai Sea. The total target hazard quotients of Hg, Cu, Pb, and Cd in seawater of the southeastern Bohai Sea were all lower than 1, which indicated that there was no noncarcinogenic risk caused by heavy metals in seawater of the southeastern Bohai Sea. However, the carcinogenic risk of Cd (1.54 × 10-5) was in the range of 10-6-10-4, which may lead to the occurrence of cancer. This study sounds an alarm for stricter control of metal emissions into this sea area.

Determination of Fe, Ni, Cu, Zn, Cd and Pb in seawater by isotope dilution automatic solid-phase extraction—ICP-MS

Determination of Fe, Ni, Cu, Zn, Cd and Pb in seawater by isotope dilution automatic solid-phase extraction—ICP-MS

Contaminant Characteristics and Influencing Factors of Heavy Metals in Seawater and Sediments in a Typical Mariculture Bay in South China

Heavy metal pollution in the mariculture areas is of considerable attention due to its potential ecological effects and public concern for seafood safety. A better understanding of the current contamination status and historical trend of heavy metals in the ecosystems of mariculture areas has an important implication for the sustainable development of marine ecosystems and for public health concerns. To assess the impact of human activities on heavy metal pollution in the mariculture area, seven metals (Cu, Pb, Zn, Cd, Hg, As, and Cr) and the environmental parameters were seasonally investigated in the surface seawater and sediments in Qinzhou Bay, a typical mariculture bay in South China. Seasonal variations in the concentration of heavy metals were found in both seawater and sediment, which are mainly influenced by seasonal hydrological change, biological activity, and human influence. The concentration of heavy metals in the seawater was at a relatively higher level than that of other mariculture areas in China, while a lower level was found in the sediment. The concentration of Cu increased in both seawater and sediment for the past decades (by nearly 2 times), which is mainly influenced by the mariculture and shipping activities. The concentration of Hg decreased significantly in the seawater for the past 40 years (decreased by 13 times) due to the decrease in production and usage of Hg. However, the concentrations of Pb, Zn, and Cd in seawater showed an increasing trend in the mariculture bay, while the concentrations of Pb, Zn, As, and Cr decreased in the sediment over the past decades. The decrease in pH value (decreasing by 4.7% for the past 20 years) was responsible for the different trend of those metals between seawater and sediment because the decrease in pH could re-release metals from sediments into the water column. Hg and As are the main ecological risk factors in the mariculture bay. This study suggests that environmental changes, such as ocean acidification, affect the distribution of metals in seawater and sediments, which we should be more vigilant and concerned about under the global climate change.

Seawater Cadmium in the Florida Straits Over the Holocene and Implications for Upper AMOC Variability

AbstractAtlantic Meridional Overturning Circulation (AMOC) plays a central role in the global redistribution of heat and precipitation during both abrupt and longer‐term climate shifts. Over the next century, AMOC is projected to weaken due to greenhouse gas warming, though projecting its future behavior is dependent on a better understanding of how AMOC changes are forced. Seeking to resolve an apparent contradiction of AMOC trends from paleorecords of the more recent past, we reconstruct seawater cadmium, a nutrient‐like tracer, in the Florida Straits over the last ∼8,000 years, with emphasis on the last millennium. The gradual reduction in seawater Cd over the last 8,000 years could be due to a reduction in AMOC, consistent with cooling Northern Hemisphere temperatures and a southward shift of the Intertropical Convergence Zone. However, it is difficult to reconcile this finding with evidence for an increase in geostrophic flow through the Florida Straits over the same time period. We combine data from intermediate water depth sediment cores to extend this record into the Common Era at sufficient resolution to address the broad scale changes of this time period. There is a small decline in the Cd concentration in the Late Little Ice Age relative to the Medieval Climate Anomaly, but this change was much smaller than the changes observed over the Holocene and on the deglaciation. This suggests that any trend in the strength of AMOC over the last millennium must have been very subtle.

Assessment of Heavy Metal Concentrations in Seawater in the Coastal Areas around Daerah Istimewa Yogyakarta Province, Indonesia

Due to anthropogenic influences that can cause heavy metal pollution in the aquatic environment, it is essential to know the amounts of heavy metals in coastal seawater to assess the potential damage of the ecosystem. The purpose of this study is to assess heavy metal concentrations (Cd, Pb, Cu, and Zn) in seawater in the coastal areas around Daerah Istimewa Yogyakarta Province, Indonesia. This study will be useful for the assessment and monitoring of marine pollution around the study area. A total of 9 water samples were collected in the close of nine types of coastal land use, namely mangrove ecosystem, tourist attraction, airport, harbor, mining area, bare land, shrimp pond, agricultural land, and settlement around Daerah Istimewa Yogyakarta Province in June 2021. The concentrations of Cd, Cu, and Zn were not detected, concentrations were below the limit of detection. The Pb concentrations at all sampling locations did not comply with seawater quality standards for ports, marine tourism, or marine biota based on the Ministry of Environment Decree No. 51, the year 2004 regulation. The source of Pb in the study area was estimated from anthropogenic and natural sources. The anthropogenic sources were corrosion of junk metal items, automobile traffic, resuspension of lead-contaminated soil dust, boat navigation, painting of boats, a coking coal transport service, fishing port, the supply of fuel, fertilizer, fuel for mining equipment, and transportation of mining activities. While the natural sources were the concentration of Pb contained in iron sand (a part of Quarterly Alluvium) eroded due to waves and wind then mixed in seawater.

Application of Cd as a paleo-environment indicator

Cadmium is a micronutrient element and a tracer of biological productivity in the ocean. The contrasting Cd distributions in sediments from modern restricted basins, continental oxygen minimum zones (OMZs), and oxic settings make it possible to establish accurate thresholds to distinguish between various environments. By receiver operating characteristic analysis, we propose that Cd > 14.5 μg/g and Cd/Al > 4.33 × 10 −4 provide strong evidence for deposition within perennial OMZs, while Cd < 0.52 μg/g and Cd/Al < 0.08 × 10 −4 separate oxic sediments from anoxic sediments. With the modern Cd cycle as a guide, we present a case study of sedimentary Cd enrichment through a slope–basin transect in the early Cambrian Nanhua Basin, South China. With increasing water depth, the patterns of Cd concentrations and Cd/Al ratios are similar to those of the modern Peruvian margin, which are characterized by highest Cd enrichments in the OMZ core and muted Cd enrichments at the upper and lower edges of the OMZ. These data, combined with previous studies, indicate that the OMZ-like structure might be common in early Cambrian oceans. Furthermore, we analyzed Cd contents of shales from the Mesoproterozoic and assemble them with published data to explore the secular evolution of seawater Cd inventory. We find that a significant increase in Cd abundance and Cd/Al ratio occurs through the Ediacaran–Cambrian transition, reflecting enlarged Cd reservoir and widespread ocean oxygenation. Overall, Cd geochemistry can provide unique information concerning the redox state and hydrological condition of paleo-environment. • Contrasting Cd enrichments distinguish restricted basins, OMZs, and oxic settings. • Sedimentary Cd pattern reveals active upwelling in the early Cambrian Nanhua Basin. • Cd record reflects an increase in marine Cd reservoir through the E–C transition.

Heavy Metal Pollution and Potential Ecological Risk Assessment in a Typical Mariculture Area in Western Guangdong.

The distribution characteristics, environmental contamination states, and potential ecological risks of chromium (Cr), copper (Cu), arsenic (As), lead (Pb), and cadmium (Cd) in seawater, sediment and breeding feed were studied in a typical mariculture area in western Guangdong of China. Pearson correlation analysis was used to determine metal homology, and the single-factor index, potential ecological risk index, hazard quotient (HQ), and joint probability curve (JPC) were used to evaluate pollution states and ecological risk of metals. Four main statements can be concluded from the results: (1) Pb and Cu showed a similar distribution pattern in the seawater and sediment and their contents in the breeding wastewater exceeded the standard limits in several stations. (2) Cr, Cu, and As have similar sources in the feeds, which may be an important source of metals in water. (3) The risk assessment revealed that the sediment from the studied areas was at a low ecological risk of heavy metal, whereas, water in the pond and outfall was slightly polluted by Pb, and water in the cages and outfall were slightly polluted by Cu. (4) Both the hazard quotient (HQ) and joint probability curve showed the overall risk probabilities (ORPs) in the waters ranked as Cu > Cr > Pb > Cd > As. Although Pb and Cd had HQ values greater than 1, their ORPs were acceptable. This study highlights that multiple evaluation models are more reliable than the single ecological risk assessment for evaluating heavy metal pollution risks in the mariculture area.

Density and intensity of metallothionein of Crassostrea sp. as biomarkers of heavy metal contamination in the Northern coast of East Java, Indonesia

The present study aimed to observe the expression level of metallothionein by analyzing its density and intensity in the gill and stomach of Crassostrea glomerata and Crassostrea iredalei. The mussels were collected from three sampling locations in the Northern coast of East Java, Indonesia: Mayangan, Probolinggo (Station 1), Kenjeran beach, Surabaya (Station 2), and Gresik Ports (Station 3). The density and intensity of metallothionein were analyzed by using immunohistochemistry technique. The results showed that the highest density of metallothionein in Crassostrea iredalei was at Station 3 (Gresik) i.e. 47.8 × 10−3 (MT/µm2) in gill and 42.2 × 10−3 (MT/µm2) in stomach. While, the highest density value in Crassostrea glomerata was observed at Station 3 (Gresik) i.e. 64 × 10−3 (MT/µm2) in gill and 45.6 × 10−3 (MT/µm2) in stomach. Furthermore, the correlation analysis of heavy metals concentration with the density and intensity of metallothionein showed a significant correlation. This result indicates that the concentrations of the investigated heavy metals (i.e. Pb, Cd and Hg) in seawater correlated with the density and intensity of metallothionein in the gill and stomach of mussels (Crassostrea glomerata and Crassostrea iredalei), which can be used as biomarkers of heavy metal contamination.

Seaweed Eucheuma spinosum J. Agardh 1847, is it a bioaccumulator?

Eucheuma spinosum is a species of seaweed widely cultivated in Indonesia. This seaweed contains high carrageenan, ranging between 65-67 percent. Carrageenan plays a very important role as a stabilizer, thickener, gel maker, emulsifier and others. This property is widely used in the food industry, medicine, cosmetics, textiles, paints, toothpaste and other industries. This very important benefit requires that E. spinosum must be safe from harmful metal content. This study aims to analyze whether E. spinosum is a bioaccumulator of harmful metals. This research was conducted in three sea areas around South Sulawesi, namely the Gulf of Bone, the Flores Sea and the Makassar Strait. Seaweed samples were taken from seaweed cultivation locations in these three areas. The metal concentrations analyzed were Copper (Cu), Cadmium (Cd), and Lead (Pb). This study indicated that E. spinosum was a bioaccumulator because at each sampling location the concentrations of Cu, Cd, and Pb at E. spinosum were generally greater than those in ambient seawater. E. spinosum was non permanent or non consistent bioaccumulator because the concentrations of Cu, Cd, and Pb in E. spinosum tissue are not directly proportional to the concentrations of Cu, Cd, and Pb in seawater.