A first study on the bioaccumulation of trace metals in Rhyssoplax olivacea (Mediterranean Polyplacophora)

Investigations into the bioavailability and bioaccumulation of mercury and other trace metals to the sea cucumber, Sclerodactyla briareus, using in vitro solubilization

The aim of the present work was to extend our knowledge on the variability of trace metals in sea urchin tissues, focusing on seasonal fluctuations (2010 February for "winter," May for "spring," August for "summer," November for "autumn") in the three different sampling sites of Algerian west coast (Oran Harbor (S1), Ain Defla (S2), and Hadjaj (belonging to Mostaganem City S3)). For this purpose, the bioavailability (metal indices) and bioaccumulation (metal concentrations in soft tissues) of heavy metals (Zn, Cu, Pb, and Cd), the physiological characteristics (e.g., biological indices such as condition index (CI), repletion index (RI), gonad index (GI)), and the biometric parameters (diameter (D) and the height (H)) of sea urchins Paracentrotus lividus were assessed and related to seasons and sites. To investigate the metal bioavailability to sea urchins more precisely, the metal indices were used as a reliable tool in the present work, instead of the metal concentrations only. The interest to standardize metal concentrations with the weight of the urchin test is to overcome the metal burden variations in the soft tissues of urchin related to the seasonal weight changes of the soft body of animal. We evidence that the most contaminated sites were S1 and S2. Furthermore, it should be noted that the bioavailability of metals, corresponding to the values of metal indices, is also more pronounced in S1 and S2 compared to that measured in S3. Thus, a correlation is observed between seasonal metal content in urchin tissues from the three sites and the corresponding metal indices. The high metal concentrations were obtained during the period when RI and CI were highest. So, it appears that the bioaccumulation of metals in sea urchins of the three sites studied is significantly influenced by the reproductive cycle and diet, feeding activity, and physiological state of these organisms. We noticed that the sea urchins from the sites S1 and S2 were small in size. It is probable that these animals, whose internal tissues contained high concentrations of metals, have been exposed to metal pollution, which might have affected both their growth and altered their physiological capacity. This approach is very original and might be used in the monitoring of the quality of coastal waters, and the present work provided a useful data set for Mediterranean monitoring network.

Spatiotemporal variability of heavy metal bioaccumulation in Trachurus trachurus and seawater: An ecotoxicological biomonitoring approach on the Western Algerian coast.

Trace metal speciation and bioavailability in anaerobic digestion: A review

Bioaccumulation and human health risk assessment of trace metals in the freshwater mussel Cristaria plicata in Dongting Lake, China

As a kind of important pollutants, trace metals and the pollution have been become a concerned worldwide environmental problem. Despite the fact that the bioavailability of trace metals indicated by their speciation has been an indispensible parameter in the assessment and treatment of trace metal pollution, many studies suggest that the bioavailability of trace metals may change according to environmental conditions, and they can also transform between some speciation fractions. These transformations are related with factors such as the compositions, microorganism, time, and other physical-chemical conditions of the system. So, it is necessary to systematically understand and investigate for the factors to affect the transformation aside from analysis at certain time-place. The results of these understanding and investigations can be used for reasonably determining the allocation of financial and technical resources in natural and engineered processes with bringing about inspirations from the evolution of the speciation of the trace metals on environmental impacts.

Mangrove ecosystems are known to act as filters for contaminants between land and sea. In New Caledonia, urbanization has increased along the coastline during the last decades. However, the impact of urbanization on contaminant cycling in mangrove forests has remained unexplored. In this study, we investigated trace metals (TM) dynamics in an urban mangrove soil and their transfer to mangrove tissues for the two dominant mangrove species in New Caledonia: Avicennia marina and Rhizophora stylosa. The results suggest that decades of urban rainwater runoff from an upper neighborhood induced large variations of mangrove soil physico-chemical properties compared to a control mangrove site sharing the same geological watershed. The urban mangrove site had a neutral pH and low salinity in the upper soil, while the control mangrove site presented acidic pH and a salinity ranging from 24 to 62 g L−1. Most TM were significantly less concentrated in the urban mangrove soil varying from 1.3 ± 0.3 μg g−1 at the urban site and 1.9 ± 0.5 μg g−1 at the control site for Cd, to 30 ± 8 mg g−1 and 49 ± 11 mg g−1 for Fe at the urban and control site, respectively. However, higher root bioconcentration factors were measured for As, Cd, Co, Cr, Fe, Mn, Ni, and Pb in the urban mangrove soil (1.7 ± 0.9, 0.14 ± 0.06, 0.23 ± 0.13, 0.042 ± 0.026, 0.088 ± 0.057, 0.47 ± 0.39, 0.21 ± 0.12, and 0.25 ± 0.09, respectively) compared to the control mangrove soil (0.11 ± 0.03, 0.041 ± 0.016, 0.045 ± 0.021, 0.010 ± 0.004, 0.013 ± 0.007, 0.094 ± 0.030, 0.022 ± 0.011, and 0.12 ± 0.03, respectively). The bioavailability of TM in the urban mangrove soil may be favored by suboxic conditions associated to less Cl-TM complexes and pyrite-TM complexes in the soil. Only Cu, Pb, Ti, and Zn, usually associated with urbanization, were more concentrated in the urban mangrove soil with mean concentrations of 27 ± 4, 17 ± 2, 4,571 ± 492, and 62 ± 12 μg g−1 at the urban site, respectively, and 21 ± 4, 10 ± 3, 2,834 ± 541, and 57 ± 12 μg g−1 at the control site, respectively. No significant difference in translocation factors was measured between the two sites, evidencing a regulation of TM translocation to the upper tissues by mangrove trees.

Bioavailability and ecological risks of trace metals in bottom sediments from Doce river continental shelf before and after the biggest environmental disaster in Brazil: The collapse of the Fundão dam

A large number of white hard clam farms are in the estuary shoreline of Saigon-Dongnai Rivers, which flow through Ho Chi Minh City, a megacity, and numerous industrial zones in the basin catchment area. In this study, eleven trace elements (Mn, Fe, Co, Ni, Cu, Zn, As, Se, Cd, Hg, and Pb) in the hard clam Meretrix lyrata and its habitats including surface water, suspended particulate matter, and sediment were evaluated to understand the bioaccumulation of trace metals from the environment into the whole tissues of the hard clam as well as its different organs. The samples were collected monthly in dry, transition, and wet seasons of the southern part of Vietnam from March to September 2016. The results showed that seasonal and spatial variations of the studied metal concentrations in the hard clam M. lyrata might be influenced by the sea current as well as the surface runoff in the rainy season. The relationship between condition index and the element concentrations in M. lyrata might be affected by the living environment conditions and farming methods. In addition, the hazard index values of all trace elements in the hard clam M. lyrata harvested in the sampling time show that the hard clams farmed in the study area were safe for local consumers.

Chapter 8 - Speciation and bioavailability of trace metals (Cd, Cu, Ni, Pb, Zn) in the rhizosphere of contaminated soils

Determination of biometric and somatic parameters of Rhyssoplax olivacea (Polyplacophora: Chitonidae) on the Algerian west coast, Mediterranean Sea: Implication for management and conservation

Reclamation of wastewater for polyculture of freshwater fish: bioaccumulation of trace metals in fish

Seasonal assessment of biological indices, bioaccumulation and bioavailability of heavy metals in mussels Mytilus galloprovincialis from Algerian west coast, applied to environmental monitoring

Despite its prevalence in the Algerian fishery sector, limited research has examined metal contamination in Boops boops (L., 1758), a widely consumed sparid species along the Algerian coast. This study quantified five potentially hazardous metals, zinc (Zn), cadmium (Cd), copper (Cu), lead (Pb), and iron (Fe), in the gonads and gills of B. boops, given their bioaccumulation potential in aquatic ecosystems. Between January and December 2023, monthly samples were collected from four major fishing ports from the Algerian west coast. Atomic absorption spectrophotometry was used to analyze seasonal and sex-based variations in metal concentrations. Findings indicate that males accumulate higher levels of zinc in their gonads, whereas females show greater bioaccumulation of lead, copper, iron, and cadmium. In the gills, males exhibit higher concentrations of heavy metals than females. Seasonal variations reveal increased contamination of gills by Cd, Cu, and Pb in winter, while gonads contain higher levels of Zn, Pb, and Cu during the same period. Nevertheless, metal concentrations in B. boops from the study area are generally lower than those reported in other Mediterranean regions. This study evaluated the estimated daily intake (EDI), weekly intake (EWI), and target hazard quotient (THQ). Copper concentrations were low (EDI: 0.038–0.051mg/ kg), whereas iron levels were comparatively higher (EDI: 1.468–2.932mg/ kg), particularly in children. Lead exposure exceeded recommended intake levels for children (EDI: 0.093–0.113mg/ kg), posing potential health risks. Zinc exhibited the highest EDI values among the analyzed metals, especially for children (EDI: 2.085–2.932mg/ kg). THQ analysis showed that all values remained below 1, indicating no immediate health hazard; however, cadmium and lead presented relatively high THQ values in female children (THQ: 0.17 and 0.123, respectively) All samples showed metal pollution index (MPI) values <1, confirming minimal contamination. These findings highlight Pb as a critical risk for children, despite overall low MPI, underscoring the need for targeted dietary intervention and ongoing health risk assessments.

In the present study, the two lakes, Vengaiah lake (Lake A-Sewage polluted receiving discharge from storm water drain) and Yellamallappa Chetty lake (Lake B-Industrially polluted) situated near Krishnarajpuram-Hoskote taluk, Bangalore, Karnataka were selected for analysis of trace metals viz., arsenic, aluminium, cadmium, lead, mercury, iron, copper and zinc in water samples. Muscle and gill tissues of freshwater fish Labeo rohita reared in these water bodies were analysed for bioaccumulation of trace metals. Hebbal fish farm was considered as a reference site (Control site) for water and fish samples. Trace metals were analysed by atomic absorption spectroscopy and values were compared with those recommended by FAO/WHO in water and fish samples. Trace metals such as Al, As and Hg were detected in the water sampled from lake B which is attributed to the differences in the sources of pollutants. Fish tissues viz., muscle and gills sampled from Lake B exhibited high concentration of Al, Pb and Cd content showing a positive correlation with their concentration in water samples. The remaining metals as Cu, Zn and Fe were detected in water sampled from all water bodies and also in the fish tissues. Gills exhibited higher concentration of metals in fish from lake B. Bioaccumulation of these trace metals in fish tissues may cause potential danger to human health when consumed on regular basis. Thus necessary remedial measures are required to combat water contamination and its management keeping in view the aquatic ecosystem and public health. Values were statistically significant at P < 0.0001.