Degrees Of Anthropogenic Contamination Research Articles

Evaluate Sediment Contamination with some Heavy Metals. A Case Study of the Al-Gharraf River in Wasit, Iraq

This study aimed to determine the amount of heavy metal pollution in the Al Garraf River sediment in Wasit, Iraq. Seven samples were gathered from the Al-Gharraf River in July 2021. GPS was used to determine the geographic location of these samples. The pollution level in the Al Gharraf River sediments caused by manganese, chromium, cadmium, cobalt, zinc, nickel, copper, and lead pollution indices such as enrichment factor, geo-accumulation, contamination factor, and pollution load were used to analyze the situation. Although geo-accumulation has mostly been used to evaluate contamination in freshwater sediment, one of the most frequently utilized factors is an enrichment to quantify to determine degrees of anthropogenic contamination and ratios of enrichment. On the other hand, the pollution load index is calculated as the number of times the concentration of heavy metals in sediments exceeds the concentration and level and is used for estimating the total amount of toxicity of heavy metals in samples. At the same time, our study discovered that cadmium is heavily polluted (contamination value is 5.70) in Al Gharraf River sediments, while nickel (1.51) and lead (1.75) are moderately polluted, but that the metals manganese, cobalt, chromium, zinc, and copper are not.

Phytoplankton of Water Bodies Differing in the Degree of Anthropogenic Contamination

Phytoplankton of Water Bodies Differing in the Degree of Anthropogenic Contamination

An integrative approach to identify the impacts of multiple metal contamination sources on the Eastern Andean foothills of the Ecuadorian Amazonia

Currently, several concerns have been raised over metal contamination in the upper Amazon basin. Rivers that flow from the high Andes to the lowland Amazon are threatened by anthropogenic activities, which may, in turn, lead to increased metal concentrations in both water and sediments. In the present study, the impacts of multiple metal contamination sources in these ecosystems were identified. The degree of metal contamination was assessed in water and sediment and seed phytotoxicity analyses were carried out in samples taken from 14 sites located in upper Napo River tributaries, combining geochemical and ecotoxicological techniques. These tributaries were chosen based on their degree of anthropogenic contamination and proximity to known sources of relevant pollution, such as small-scale gold mining (MI), urban pollution (UP), fish farming (FF) and non-functional municipal landfill areas (LF). Our results suggest that anthropogenic activities are introducing metals to the aquatic ecosystem, as some metals were up to 500 times above the maximum permissible limits for the preservation of aquatic life established by Ecuadorian and North American guidelines. Sites located close to small-scale gold mining and sanitary landfills presented 100 to 1000 times higher concentrations than sites classified as “few threats”. In water, Cd, Pb, Cu, Zn and Hg were mostly above the maximum permissible limits in the samples, while Cd in sediment reached concentrations 5-fold above the probable effect level (PEL). Phytotoxicity was associated through the diffuse contamination present in urban and landfill areas. Overall, metal concentrations and phytotoxicity assessments suggest anthropogenic effects to environmental contamination, even though natural sources cannot be disregarded. Anthropogenic effects in the eastern Andean Rivers need to be constantly monitored in order to build a complete picture on how pollution sources may affect this strategic Amazon basin area.

Gonado-histopathological changes, intersex and endocrine disruptor responses in relation to contaminant burden in Tilapia species from Ogun River, Nigeria

In the present study, we investigated the occurrence of intersex condition, histopathological changes in the gonad and endocrine disruptor biomarker responses in Tilapia species (Tilaipia guineensis, Sarotherodon galileaus and Oreochromis niloticus) along the Ogun River, Nigeria. The study sites covered a length of 320 km and a total of 1074 tilapias were collected from three sampling sites (Abeokuta, Isheri and Ikorodu) with different degrees of anthropogenic contamination. Samples were also collected from an upstream putative control site (Igboho) along the Ogun River. Hepatic transcript levels for vitellogenin (Vtg), zona radiata (Zrp) and aromatase (cyp19a1) were analyzed using real-time PCR. Gross gonadal morphology revealed a 24% prevalence of intersex showing visible testis and ovary in phenotypic females (25.4%) or males (74.6%). The intersex condition paralleled histopathological changes (ovotestis or testis-ova) in the gonads of female and male fish, respectively. Plasma concentrations of luteinizing hormone (LH), follicle stimulating hormone (FSH), 11-ketotestosterone (11-KT) and estradiol-17β (E2) were measured using enzyme immunoassay, showing that male fish from downstream of the control site had significantly higher plasma E2, LH, and FSH concentrations compared to females. Similarly, Vtg, Zrp and cyp19a1 mRNA was significantly higher in males, compared to females. Analysis of contaminants showed the presence of 15 PCB congeners, lindane and dieldrin, and 4-iso-nonylphenol (4-iso-NP) and 4-tert-octylphenol (4-tert-OP) in fish muscle and sediment samples from Ogun River. Principal component analysis (PCA) revealed site and sex relationships between measured biological responses to groups of environmental contaminants, showing that the endocrine disruptive responses in fish were associated with biota and sediment contaminant burden. In addition, strong positive correlations were observed between male fish and Zrp, cyp19a1, E2, LH, FSH, PCBs, 4-iso-NP and 4-tert-OP, suggesting possible feminization effects of these contaminants on the male. In female fish, PCBs, 4-iso-NP and 4-tert-OP showed positive relationships with 11-KT and gonadosomatic index (GSI), suggesting masculinization effects by these contaminants. Overall, our findings demonstrate a causal relationship between endocrine disruption and contaminants burden in Tilapias species from Ogun River.

Peroxisome proliferator-activated receptors and biotransformation responses in relation to condition factor and contaminant burden in tilapia species from Ogun River, Nigeria

A major development in fishery science has been the Fulton's condition factor (CF) as a reliable physiological index of fish growth and health status (Fulton 1902). As a general rule, CF-value greater than 1 (>1) should be regarded as an indicator for good growth and health. Therefore, exposure of fish to contaminants in the environment will be expected to produce a reduction in scope for growth, since energy for growth will be allocated to overcome stressful conditions. In the present study, we hypothesized that tilapia species from Ogun River (Nigeria) are experiencing severe contaminant-induced obesogen effects leading to high CF (≥2) in fish with pathological alterations. The environmental obesogen hypothesis has related the interaction between environmental pollutants and PPAR isoform activation In this respect, peroxisome proliferator-activated receptors (PPARs) and biotransformation responses in relation to contaminant burden were investigated in a total of 1074 specimens of Tilapias species (Tilapia guineensis, Sarotherodon galileaus and Oreochromis niloticus) collected from three areas with different degrees of anthropogenic contamination and from a putative control site along the Ogun River. Liver mRNA expression of cytochrome cyp1 isoforms (cyp1a, 1b and 1c) and PPAR isoforms (ppar-α, β and γ) were analyzed using validated real-time PCR. Fish were also analyzed for CF and muscle contaminant burden (aliphatic and polycyclic aromatic hydrocarbons, organochlorine pesticides, and polychlorinated biphenyls). A significant increase in mRNA expression of cyp1- and ppar isoforms was observed in fish from polluted areas, and these results paralleled data on PCBs and PAHs tissue concentrations. Further, cyp1 isoforms showed clear sex-related differences, with higher mRNA expression in male fish than in females. Principal component analysis revealed a relationship between cyp1 isoforms, ppar-α, β, PCBs and PAHs and these interactions may suggest a crosstalk between AhR- and PPARs mediated pathways on metabolic and energetic processes. The PCA biplot also highlighted a positive relationship between ppar-γ, body weight, total length and PAHs. The CF for fish from all the sites was ≥2 indicating that this parameter may not be a reliable index for evaluating fish growth and health condition, especially in wild fish population exposed to complex cocktails of environmental pollutants.

Contamination assessments of surface water in coastal lagoon (Maluan Bay, China) incorporating biomarker responses and bioaccumulation in hepatopancreas of exposed shrimp (Litopenaeus vannamei)—an integrative approach

Maluan Bay, characterized by various degrees of anthropogenic contamination, is considered as one of the most industrialized and urbanized coastal lagoon in China, where large amounts of metal contaminants in surface water and biota were detected in previous studies. However, no clear discriminating power among sampling sites could be made only through comparisons between contaminant levels and Environmental Quality Standards and especially biological-based monitoring integrating biomarkers and bioaccumulation of exposure are scarce. For this purpose, antioxidants enzymes (superoxide dismutase, catalase, and glutathione peroxidase) and glutathione-S-transferase were assessed using the hepatopancreas of shrimp Litopenaeus vannamei after 7days laboratory exposure under controlled conditions to characterize the effects of polluted waters to shrimps. The metal concentrations of sampled water and bioaccumulation in hepatopancreatic tissues were also analyzed, and data were linked to biomarkers' responses by multivariate (principal component analysis-factor) analysis. A representation of estimated factor scores was performed to confirm the factor descriptions classifying the pollution status and characterizing the studied sites, which pointed out the impact of multiple sources of contaminants to the water quality and provided further evidences to the existence of clear pollution and toxicological gradients in critical areas. The results of the present investigation underlined that the integrated approach could be a powerful tool for the identification of causal toxic contaminants in complex mixtures and the assessment of human-induced environmental quality of the system in coastal zones.

Multiparametric approach for assessing environmental quality variations in West African aquatic ecosystems using the black-chinned tilapia (Sarotherodon melanotheron) as a sentinel species

The study highlights the potential of the black-chinned tilapia to be used as a sentinel to assess environmental contaminants based on the use of a set of biomarkers. The usefulness of fish species as sentinels for assessing aquatic environment contamination was tested using a set of biomarkers in Senegalese environments characterized by multi-pollution sources. The black-chinned tilapia (Sarotherodon melanotheron) was selected as a sentinel because of its abundance, wide distribution in all coastal aquatic ecosystems and physiological properties. The potential influence of confounding factors such as salinity on biomarker in the tilapia has been examined. Individuals were sampled during two seasons (dry and wet) in eight sites characterized by various degrees of anthropogenic contamination and different salinities (from 0 to 102psu). Biomarkers-including growth rate (GR), condition factor (CF), biotransformation enzymes such as 7-ethoxyresorufin-O-deethylase (EROD) and glutathione-S-transferase (GST), lipid peroxidation (TBARS) and acetylcholinesterase (AChE)-were measured. Chemical contaminant [polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs)] levels showed different sources of contamination with relatively high concentrations of PAHs in the Hann Bay and Foundiougne locations. The most sensitive biomarker present in different sites according to the principal component analysis is EROD. Few variations of the AChE activity and TBARS levels were found. No clear relationship was found between biomarker responses and salinity, but GR and CF were lower in hypersaline conditions. Tilapia is responsive to environmental contaminants such as PAHs, OCPs and PCBs. The S. melanotheron multiparametric approach showed a better discrimination of sites.

A multibiomarker approach in the clam Ruditapes decussatus to assess the impact of pollution in the Ria Formosa lagoon, South Coast of Portugal

The Ria Formosa lagoon is an ecosystem whose water quality reflects the anthropogenic influence upon the surrounding areas. In this lagoon, the clam Ruditapes decussatus has a great economical importance and has been widely used as a biomonitor. A multibiomarker approach (δ-aminolevulinic acid dehydratase, metallothionein, lipid peroxidation, acetylcholinesterase, alkali-labile phosphates, DNA damage) was applied to assess the environmental quality of this ecosystem and the accumulation of contaminants and their potential adverse effects on clams. Clams were sampled in different shellfish beds in the period between July 2007 and December 2008 and abiotic parameters (temperature, salinity, pH and dissolved oxygen of seawater and organic matter in the sediment), condition index, metals (Cd, Cu, Zn, Ni, Pb), TBTs and PAHs concentrations were measured in clam tissues. Data was integrated using Principal Component Analyses and biomarker indices: IBR (Integrated Biomarker Response) and HSI (Health Status Index). This multibiomarker approach enabled discrimination of a time and space trend between sites with different degrees of anthropogenic contamination, identifying one of them (site 2) as the most stressful and summer months as the most critical period for clams due to an increase of environmental stress (anthropogenic pressure along with extreme environmental conditions, e.g. temperature, dissolved oxygen, organic matter in the sediments, etc). The selected biomarkers provided an integrated response to assess the environmental quality of the system, proving to be a useful approach when complex mixtures of contaminants occur.

Temporal clustering of metals in a short sediment core of the Cascais Canyon (Portuguese Margin)

The Cascais Canyon delivers contaminated sediments from the shelf to the deep marine environment. Multi-core PE252-32, located at 2100 m water depth in the canyon, records the latest 300 years of sedimentation. It was dated by 210 Pb and analyzed texturally and geochemically for major elements and selected trace metals (Cu, Cr, Hg, Li, Ni, Pb and Zn). Cluster analysis performed on the down-core geochemical data identified four groups of variables related by grain-size, geochemical source and composition. Mercury, Pb and Zn were grouped in a cluster representing the anthropogenic component. Cluster analysis was applied again particularly to the latter cluster relatively to depth, in order to constrain the onset and temporal evolution of anthropogenic contamination. A second clustering, made on the basis of Hg, Pb and Zn, grouped samples by age and degree of anthropogenic contamination. One cluster contained relatively uncontaminated samples older than 1900 AD, and another cluster samples younger than 1900 AD with distinct metal enrichment. Maximum enrichments occurred during the early 1980s, followed by a slight recovery from the mid-1980s to the present. Mercury was the element with the highest enrichment factor (EFHg=5). Despite relatively low accumulation rates at this core location, our results show the importance of the Cascais Canyon as a transport route for contaminated sediments from the Tagus prodelta into the deep regions of the Portuguese Margin.

Vitellogenin gene expression in the intertidal blenny Lipophrys pholis: A new sentinel species for estrogenic chemical pollution monitoring in the European Atlantic coast?

The presence of estrogenic chemicals (ECs) in the aquatic environment is a growing problem. While most attention was initially given to fresh water and estuarine ecosystems, it is now evident that coastal marine areas are also vulnerable to these pollutants. The use of vitellogenin induction in male fish, a specific biomarker of EC exposure, has been the most widely applied methodology. However, in some occasions, the high mobility and migratory behaviour of common sentinel fish species makes data interpretation difficult. Hence, there is the need to validate new sentinel marine fish species which should display, among other features, a strong homing behaviour. The shanny, Lipophrys pholis, is an intertidal fish that combines many of the required characteristics for a sentinel species: abundance and easy of catch, wide geographical distribution and restricted home range. Thus, in order to evaluate, in the field, the species sensitivity to ECs, L. pholis males were collected at two sites reflecting different degrees of anthropogenic contamination. The vitellogenin II gene (VTGII) was isolated and its liver expression evaluated by RT-PCR in the field samples. A significant induction of gene expression was observed in the specimens collected in the urban area, if compared to the reference site, which suggests exposure to ECs. Moreover, a 21-days laboratory exposure to environmental relevant concentrations of ethinylestradiol (EE2) was also performed. A significant induction of L. pholis VTGII gene in EE2 exposed males was observed suggesting similar sensitivity to that of other marine/estuarine fishes. Even though further validation is currently in progress, the available data indicates that L. pholis is responsive to ECs, thus favouring its future integration in monitoring programmes designed to evaluate the presence of ECs in European marine ecosystems.

The use of the shanny Lipophrys pholis for pollution monitoring: A new sentinel species for the northwestern European marine ecosystems

The contamination of aquatic ecosystems by organic contaminants such as polycyclic aromatic hydrocarbons (PAHs) is a matter of great concern. Mussels have been extensively used as sentinel species in a large number of monitoring programs. However, the use of bivalves as the sole species has some limitations, because they are not as responsive as fish to Aryl Hydrocarbon Receptor agonists. Hence, for many marine areas, there is the need to validate new sentinel fish species that can be used in the assessment of pollution by organic contaminants. The shanny Lipophrys pholis is an intertidal fish that combines many characteristics required in a sentinel species: is abundant and easy to catch, has a wide geographical distribution and restrict home range. After larvae recruitment to the intertidal rocky shores, they remain in the same area for the rest of the life-cycle, thus reflecting local pollutants exposure. In order to evaluate the species sensitivity to organic contaminants under field conditions, L. pholis were collected at six sites reflecting different degrees of anthropogenic contamination. The induction of two biomarkers extensively validated in the assessment of PAHs contamination ethoxyresorufin-O-deethylase activity (EROD) and Fluorescent Aromatic Compounds (FACs) was evaluated. In parallel, mussels were collected at the same locations and levels of 16 PAHs and selected heavy metals determined. Overall, the specimens collected in the urban areas showed a significant induction of EROD and FACs (up to a six-fold induction) if compared with the reference sites. Additionally, a positive correlation was observed between the biomarkers and PAHs levels in mussel tissues. Even though further validation is currently in progress, the available data indicate that L. pholis is responsive to organic contaminants such as PAHs, suggesting its future integration in monitoring programmes designed to evaluate the presence of these contaminants in European marine ecosystems.

Temporal and spatial changes in mercury concentrations in the North Atlantic as indicated by museum specimens of glacier lanternfishBenthosema glaciale (Pisces: Myctophidae)

Museum specimens of glacier lanternfish Benthosema glaciale were used to investigate long-term variations in mercury concentration of mesopelagic organisms from the North Atlantic. B. glaciale is an abundant mesopelagic fish species in the boreal and sub-polar pelagic regions of the North Atlantic, playing an important role in the cycling of energy in the oceanic food webs of these systems. We used 35 museum specimens of lanternfish, collected from the Gulf Stream biogeographic region between 1936 and 1993, to test for long-term variations in mercury concentrations. In addition, we studied the mercury concentrations throughout the geographical range of the species, using 105 specimens collected around 1970s. Mercury concentrations were similar over time; however there was evidence of a noteworthy increase in mercury contamination during the World War II (1941) followed by a general decrease with lowest concentrations being found in 1954 and 1993. Significant differences were found between the different studied areas, probably reflecting different degrees of anthropogenic contamination. The results presented here indicate that museum myctophids may be suitable for the assessment of historical changes in mercury contamination of marine ecosystems.