Metals bioaccumulation in two edible bivalves and health risk assessment

Assessment of persistent and emerging pollutants levels in marine bivalves in the Gulf of Suez, Egypt

Bivalves possess important ecological and economic values. They have been extensively used as bioindicators for both emerging and classical pollutants in the aquatic environment. This study investigates the levels of trace metals, polycyclic aromatic hydrocarbons (PAHs), and organochlorine pesticides (OCPs), alongside microplastic (MPs), in Tridacna maxima, Paphia textile, and Paratapes undulatus, collected from the Gulf of Suez. This work represents the first investigation of MPs in marine bivalves from the Gulf of Suez. MPs were detected in 72% of the specimens examined and four types of MPs were identified. The metal pollution index indicated that bivalves may have long-term toxic effects on human consumers. The results showed minimal hydrocarbon pollution. Diagnostic ratios indicated a combination of pyrolytic and petrogenic sources, with a notable influence from pyrolytic origins. The risk assessment reflected that the levels of certain trace metals, PAHs, and OCP contaminants could present a low risk to human health.

Implications for the seafood industry, consumers and the environment arising from contamination of shellfish with pharmaceuticals, plastics and potentially toxic elements: A case study from Irish waters with a global orientation

Shellfish are a rich source of minerals, B-vitamins and omega-3 to the human diet. The global population is expected to reach 9.6 billion people by 2050 where there will be increased demand for shellfish and for sustained improvements in harvesting. The production of most consumed species of shellfish is sea-based and are thus susceptible to in situ environmental conditions and water quality. Population growth has contributed to expansion of urbanization and the generation of effluent and waste that reaches aquatic environments, potentially contaminating seafood by exposure to non-treated effluents or inappropriately discarded waste. Environmental contaminants as microplastics (MP), pharmaceuticals (PHAR) and potentially toxic contaminants (PTE) are being identified in all trophic levels and are a current threat to both shellfish and consumer safety. Immunotoxicity, genotoxicity, fertility reduction, mortality and bioaccumulation of PTE are representative examples of the variety of effects already established in contaminated shellfish. In humans, the consumption of contaminated shellfish can lead to neurological and developmental effects, reproductive and gastrointestinal disorders and in extreme cases, death. This timely review provides insights into the presence of MP, PHAR and PTE in shellfish, and estimate the daily intake and hazard quotient for consumption behaviours. Alternatives approaches for seafood depuration that encompass risk reduction are addressed, to reflect state of the art knowledge from a Republic of Ireland perspective. Review of best-published literature revealed that MP, PHAR and PTE contaminants were detected in commercialised species of shellfish, such as Crassostrea and Mytilus. The ability to accumulate these contaminants by shellfish due to feeding characteristics is attested by extensive in vitro studies. However, there is lack of knowledge surrounding the distribution of these contaminants in the aquatic environment their interactions with humans. Preventive approaches including risk assessment are necessary to safeguard the shellfish industry and the consumer.

Comparing the concentrations of heavy metals on two bivalve species in Santos Bay, Brazil: Subsidies to understanding the assimilation dynamic of bivalve contaminants

Contaminant substances consist of chemical elements that present the potential to adversely impact the ecology of the environment, thus representing a threat to local fauna and flora. In this context, heavy metals are critical agents that, depending on the nature and level, are potentially toxic to living organisms. In order to evaluate the bioaccumulation of heavy metals in the Santos estuary and to determine the potential influence of salinity gradient on the heavy metal bioconcentration, the present study measured the concentrations of As, Cd, Pb, Cu, Cr, Fe, Ni, and Zn in two bivalve species (Crassostrea rhizophorae and Perna Perna) sampled at different sites of Santos Bay, in the southeastern region of Brazil. Throughout the study, the "sentinel species" used were effective in bioaccumulating contaminants. In oysters, based on the Brazilian legislation, critical limits were exceeded for As, Zn, Cu, and Cr. In the case of mussels, on the other hand, only for As, Zn, and Cr, the critical limits were overcome. In the present study, obtained data suggested salinity as a determinant parameter in As incorporation processes of bivalve mollusks. PRACTITIONER POINTS: The present study presents important results for the development of environmental management policies in estuarine environments. The present study points out differences between different organisms as biomonitors, providing subsidies for the decision of an effective biomonitoring program. The present study discusses values of contaminants as a danger to public health in Santos Bay, which can be extrapolated to other similar environments around the world.

Concentrations and health risks of heavy metals in five major marketed marine bivalves from three coastal cities in Guangxi, China

Seafood consumption provides essential elements to humans while also posing risks to human health. A total of 2610 individuals of five edible marine bivalve species (Ruditapes philippinarum, Paphia undulata, Meretrix meretrix, Sinonovacula constricta and Meretrix lyrata) were randomly sampled from six farmer markets in three cities (Beihai, Qinzhou and Fangchenggang) in the southernmost coastal region of China. The concentrations of heavy metals (Cu, Pb, Zn, Cd, Cr, Hg and As) were determined by inductively coupled plasma mass spectrometry (ICP-MS). The estimated daily intake (EDI), target hazard quotient (THQ), total hazard index (HI), and target cancer risk (TR) were calculated to evaluate potential human health risks from bivalve consumption. The mean concentrations of metals in the tissues of bivalves descended in the order Zn > Cu > As > Cd > Cr >Pb > Hg in descending order, and the concentrations varied substantially among the five bivalves. Heavy metal concentrations in edible tissues of most bivalve samples were below the safety limits set by national and international regulations, and there were significant correlations between certain metal concentrations. The EDI values for each metal in each bivalve were significantly lower than the corresponding PTDI (provisional tolerable daily intake) values. Health risk assessment showed that although there is no noncarcinogenic health risk for local residents exposed to individual or combined metals from these bivalves, there is a carcinogenic risk from Cd and Cr exposure. Thus, in the long term, monitoring and controlling bivalve consumption will be important. Although current accumulation levels of bivalves are safe, continued and excessive lifetime consumption over 70 years may pose a target cancer risk.

Turmeric and vitamin C mitigate testicular atrophy induced by lead diacetate via regulation of GRP-78/17β-HSD pathways in rat's model

Occupational and ecological contacts to lead persist as a universal concern. Lead alters most of the physiological processes via enhancing oxidative stress. Thus, this study was purposed to assess the influence of turmeric (TMRC) and/or vitamin C (VIT-C) on Lead diacetate (Lead diAC)-induced testicular atrophy with an emphasis on oxidative stress, inflammation, BAX/STAR and GRP-78/17β-HSD signalling. Rats were injected with Lead diAC and then treated with TMRC and/or VIT-C orally for 1 week. Lead diAC decreased serum testosterone and testicular glutathione levels. It also decreased superoxide dismutase activity. On the contrary, levels of malondialdehyde, tumour necrosis factor-α, IL-1β and caspase-3 were increased. mRNA levels and protein expressions of GRP-78 and BAX were upregulated, while the expression of both steroidogenic acute regulatory protein and 17β-HSD were downregulated. DNA fragmentation was increased as well. These changes were further confirmed by histopathological findings. Supplementation with TMRC and/or VIT-C ameliorated all of the above parameters. In Conclusion: TMRC or VIT-C specially in combination group prevents Lead diAC testicular damage via reduction of oxidative injury as well as inflammation, downregulation of GRP-78/BAX and upregulation of 17β-HSD and STAR expression as well as improvement in the histological architecture of the testis.

Comprehensive assessments of ecological states of Songhua River using chemical analysis and bivalves as bioindicators

The aim of this study was to compare environmental pollution and ecological states of two different areas of the Songhua River areas: near Harbin City and Tongjiang City, located at a distance of about 500 km downstream. The anthropogenic pollution concentrations of heavy metals (HM) were determined. The results showed that concentrations of eight metals (Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) in the water were in the range of 0.001-0.588 mg/L for Tongjiang and 0.001-0.508 mg/L for Harbin, while that in sediments were in the range of 0.67-1575.37 mg/kg for Tongjiang and 0.07-5617.13 mg/kg for Harbin, respectively. Bivalves from tested sites exposed to environmental pollution exhibited significantly different physiological states. The latter was assessed using the method of physiological loading, based on measuring the recovery time (T_rec) of heart rate (HR) after removal of the load. T_rec in mussels from Harbin was recorded in the range of 151 to 234 min, while that from Tongjiang was only 115 min. Cd, Cu, Pb, and Zn in mollusk soft tissues were also determined for Harbin and Tongjiang, respectively. The metal pollution index (MPI) and bioconcentration factor (BCF) in the mollusks were calculated for each metal. BCF in the mussels from the Tongjiang area was lower than that from the Harbin area. Physiological testing, as well as the concentration of HM in water, and sediment, and also the bioaccumulation of HM in tissue showed that the ecological state of the Tongjiang area was better than that of Harbin. Apparently, after more extensive studies, a methodological approach of assessing the ecological state of water areas, based on physiological state testing of aboriginal mollusks, could be used in the monitoring of pollution effects in water bodies and streams.

Health Risk Assessment of Heavy Metals from Smoked Corbicula fluminea Collected on Roadside Vendors at Kelantan, Malaysia

Corbicula fluminea serves as traditional food to the local people in Kelantan, Malaysia. Concerns regarding river contamination, smoking method, and associated adverse effects on public health had been increasing. Hence, this study aims to measure the level of heavy metals (Cd, Cu, Mn, Pb, and Zn) and assess human health risk in C. fluminea consumption at Kelantan. Heavy-metal analysis was done using flame atomic absorption spectrophotometry, while human health risk was assessed using provisional tolerable weekly intake (PTWI), target hazard quotient (THQ), and hazard index (HI). The estimated weekly intake (EWI) for all metals was found within PTWI, while THQ for Cd, Cu, Mn, Pb, and Zn was 0.12, 0.06, 0.04, 0.41, and 0.03, respectively. The HI was calculated at 0.61 which is less than 1, considered as the safe consumption level. Therefore, C. fluminea consumption in this study was found safe from the health risk of noncarcinogenic effect over a lifetime.