Metals and metalloids in blood and feathers of common moorhens (Gallinula chloropus) from wetlands that receive treated wastewater

Comet assay to evaluate chromosomal changes in chickens (Gallus gallus domesticus) contaminated by lead in a city in Bahia

Chicken (Gallus gallus domesticus) is one of the primary sources of animal protein for the Brazilian population. Thus, the safety of this food is highly relevant. This study was based on the evidence of severe contamination of these animals by metals such as lead in Santo Amaro, Bahia. This exploratory study aimed to evaluate associations between lead levels in blood of chicken exposed to a contaminated area with the occurrence of chromosomal alterations, evidencing genotoxic effects. Serum lead analysis was performed by GF-AAS after dilution with a matrix modifier solution (Triton X-100 0.2% v/v and HNO3 0.1% v/v), while chromosomal damage was evaluated using the comet assay. The results showed genotoxic effects (positive comet assay) only for the specimen sample with higher serum lead concentrations (33.9 µg dL-1), suggesting the occurrence of toxic effects at this level of exposure. This work evaluated a relationship between the reduction of serum lead levels in chicken and increased distance from the primary polluting source - a lead processing plant (COBRAC). It also showed that lead is bioavailable in this territory, contaminating chicken and causing genotoxic effects in these animals, further expanding the concern with the local biota and the health of the residents of Santo Amaro.

Exploring the recovery of a large wetland using black-necked swan blood parameters and body condition 16 years after a pollution-induced disturbance

Resilience theory has taken center stage in tackling the challenge of wetland recovery on a fast-changing planet. Because of waterbirds' enormous dependence on wetlands, their numbers have long been used as surrogates for wetland recovery over time. However, immigration of individuals can mask actual recoveries at a given wetland. One alternative to expanding the knowledge of wetland recovery is the use of physiological parameters from aquatic organism populations. We explored the variations in the physiological parameters of black-necked swan (BNS) before, during, and after a 16-year period of a pollution-induced disturbance that originated in a pulp-mill wastewater discharge. This disturbance triggered the precipitation of iron (Fe) in the water column of the Río Cruces Wetland in southern Chile, one of the main sites for the global population of BNS Cygnus melancoryphus. We compared our recent (2019) original data (body mass index [BMI], hematocrit, hemoglobin, mean corpuscular volume, blood enzymes, and metabolites) with available datasets from the site obtained before the pollution-induced disturbance (2003) and immediately after the disturbance (2004). Results indicate that, 16 years after the pollution-induced disturbance, some important parameters of animal physiology did not return to their pre-disturbance state. For instance, BMI, triglycerides, and glucose were significantly higher in 2019 than in 2004, right after the disturbance. By contrast, the hemoglobin concentration was significantly lower in 2019 than in 2003 and 2004, and uric acid was 42% higher in 2019 than in 2004. Our results demonstrate that, despite higher BNS numbers with larger body weights present in 2019, the Río Cruces wetland has only partially recovered. We suggest that the impact of megadrought and wetland disappearance far from the site results in high rate of swan immigration, casting uncertainty about using the number of swans alone as honest indicators of wetland recovery after a pollution disturbance. Integr Environ Assess Manag 2023;19:663-675. © 2023 SETAC.

Use of Feathers from Birds that Collided with Vehicles to Monitor Heavy Metal Contamination in Western Khorasan Razavi, Iran

In the present study, lead, zinc and copper concentrations in the feathers of Common kestrel (Falco tinnunculus), Eurasian magpie (Pica pica), Common buzzard (Buteo buteo), Crested lark (Galerida cristata), Eurasian hoopoe (Upupa epops), Little owl (Athene noctua), Long-eared owl (Asio otus), Eurasian eagle-owl (Bubo bubo) and Long-legged buzzard (Buteo rufinus) from Sabzevar and Neghab, Khorasan Razavi of Iran were measured. Almost all of the specimens were obtained from birds that had collided with vehicles or were unable to fly. There were no significant differences in metal concentrations between adult and juvenile, diurnal and nocturnal raptors and species with different diets. Elemental concentrations were lower than toxicity threshold values, so exposure to these elements does not appear to pose a health risk to the studied species. It should be noted that this study was the first study of metals in Galerida cristata, Asio otus and Buteo rufinus.

Potential use of distinct biomarkers (trace metals, micronuclei, and nuclear abnormalities) in a heterogeneous sample of birds in southern Brazil

The analysis of metal concentrations in bird feathers and genotoxicity tests are tools used to evaluate anthropogenic impacts on ecosystems. We investigated the response of birds, used as bioindicators, to disturbances observed in three areas with distinctive environmental characteristics (natural, agricultural, and urban) in southern Brazil. For this purpose, we quantified metals (Mn, Cu, Cr, and Zn) in feathers and determined the number of micronuclei (MN) and other nuclear abnormalities (NA) in 108 birds from 25 species and 17 families captured in the study area. No significant differences was found in the metal concentrations and the number of MN and NA between the sampling areas. Zn and Cu concentrations were significantly higher in insectivorous than those in omnivorous birds. The Zn concentration was significantly different between some species, and the Cu concentration was significantly higher in juveniles than that in adults. The best generalized linear models showed that omnivorous birds had more MN and NA and that juveniles and birds with better body condition index had increased NA numbers. This study demonstrates that the analyzed variables contribute in different ways to the result of each biomarker, mainly due to particular ecological and physiological characteristics of each species. We conclude that wild birds have the potential to be used as environmental bioindicators in the study area, but future studies should focus on one or a few species whose ecological and physiological habits are well known.

Measurement of metal concentrations in feathers of bird-vehicle collisions, Sabzevar, Iran

The purpose of the present study is to compare the concentrations of lead, copper, and zinc in feathers of birds struck in collisions with vehicles. Two main assumptions were investigated: that there is a significant difference between species with different diets and that large and old species have higher concentrations of lead than small and young species because of their longer life span and longer exposure time to pollutants. Mean concentrations were obtained for lead 0.122, 0.006, 0.007, 0.010, and 0.014, for copper 0.718, 0.783, 0.530, 0.853, and 0.793, and for zinc 0.891, 0.940, 0.787, 0.932, and 1.003 in house sparrow (Passer domesticus), tree sparrow (Passer montanus), European roller (Coracias garrulus), Little bittern (Ixobrychus minutus), and Levant sparrowhawk (Accipiter brevipes), respectively. The results showed that there were no significant differences in the concentrations of the studied elements between species with different diets and as well as between large and small size or juveniles and adults; thus, the two hypotheses were rejected. The concentrations of the studied elements were lower than the "negative effects" threshold values suggested by previous studies; thus, they are not likely to pose a serious threat to the selected species. However, it is important to include not only other non-essential elements in future studies but also larger sample sizes. It is also noteworthy that this is the first study to determine the concentration of metals in two of the species, Coracias garrulous and Accipiter brevipes.

A spatial prioritization method for identifying potential eco-risk distributions of heavy metals in soil and birds

Geochemical approaches are popular for evaluations based on heavy metal concentrations in sediments or soils for eco-risk assessment. This study proposes a systematic geochemical approach (SymGeo) to explore six heavy metals in topsoils and bird tissues and organs of the target birds. We assume that the proposed approach based on field-collected heavy metals in topsoils and feathers can predict the areas with the potential risk of the heavy metals in birds. Finite mixture distribution modeling (FMDM) was used to identify background values of the heavy metal concentrations in topsoil. A spatial enrichment factor (EF), potential contamination index (PCI), contamination degree (Cod), and potential ecological risk index (PRI) based on FMDM results for topsoil, and a potential risk index (PRI_bird) of heavy metals in the birds, were utilized for systematic prioritization of high eco-risk areas. Using multiple EF, PRI, and Cod results and multiple PRI-based maps of the heavy metals in feathers, we systematically prioritized risk areas where there is a high potential for heavy metal contamination in the birds. Our results indicate that heavy metal concentrations in the feather, liver, and kidney are not spatially cross-autocorrelated but are statistically significantly correlated with some heavy metals in topsoil due to external and internal depositions. Further, multiple EF, Cod, and RI distributions for topsoil, along with the PRI of the feather, showed that adequate coverages for potential risk for birds were greater than 71.05% in the top 30% and 84.69% in the top 20% potential eco-risk priority area of heavy metals in bird liver and kidney. Hence, our proposed approach suggests that assessments of heavy metals in bird feathers and topsoils without bird organs can be utilized to identify spatially high-risk areas. The proposed approach could be improved by incorporating water and sediment samples to enhance the crowdsourcing and the species-specific data.

Nutrient enrichment and trace element accumulation in sediments caused by waterbird colonies at a Mediterranean semiarid floodplain

Waterfowl are vectors of nutrients, metals, and other pollutants (i.e. PCBs and microorganisms) on wetlands and other water bodies, especially when bird population density is high, e.g., in nesting, roosting or breeding periods. This work reports the effects caused by the increase in breeding pairs of herons and cormorants between 2010 and 2014 on sediments in an eutrophic Mediterranean wetland belonging to La Mancha Húmeda Biosphere Reserve. Nutrients, metals, metalloids, and isotopic composition (δ¹⁵N and δ¹³C) were analysed in sediments and faeces at several points in the Tablas de Daimiel National Park (TDNP), as well as in the nearby Navaseca wetland, which receives inputs from a wastewater treatment plant (WWTP). Sediments from Navaseca and from one site that is affected by heron colonies (Garcera) in the TDNP showed higher concentrations of organic matter, total organic carbon, total nitrogen, total phosphorus, Al, Co, Cu, Cr, Fe, Ni and Zn than the rest of the sampling sites. Significant correlations between these variables were found, probably suggesting that they have a common organic source. The highest δ¹⁵N values in sediments of the TDNP were registered in Guadiana, a site where there is no impact from colonies; these values might therefore be due to anthropogenic activities. Metal and metalloid content in sediments was lower than the regional reference values in soils, except for Se in the TDNP, and Zn and Cu in Navaseca. High Se level in TDNP sediment may be caused by seleniferous soils located upstream. Results showed a low impact of bird droppings compared to other sources of nutrients in the annual input in the TDNP.

Metals and metalloids in freshwater fish from the floodplain of Tablas de Daimiel National Park, Spain

The Tablas de Daimiel National Park (TDNP) is a floodplain ecosystem in central Spain with a potential risk of heavy metal and metalloid pollution. The objective of this study was to know the accumulation of arsenic (As), cadmium (Cd), mercury (Hg), lead (Pb), and selenium (Se) in muscle of six species of freshwater fish from the floodplain of TDNP. We obtained muscle samples of Cyprinus carpio (n = 89); Squalius pyrenaicus (n = 16); Ameiurus melas (n = 9); Lepomis gibbosus (n = 8); Micropterus salmoides (n = 6) and Carassius auratus (n = 5). A. melas, which is a predatory species, had significantly higher Hg concentrations than omnivorous or herbivorous species (i.e. C. carpio). On the contrary, A. melas showed lower concentrations of As, Pb and Se than omnivorous species (i.e. S. pyrenaicus and L. gibbosus ). The concentration of Hg was positively associated with fish size in C. carpio and A. melas. Some individuals of C. carpio (5.7%) and S. pyrenaicus (12.5%) showed Pb muscle concentrations above the maximum residue levels established by the European legislation for human consumers. The observed muscle Se concentrations can be associated with adverse effects on fish such as blood changes, reduced growth, mortality of juveniles and reproductive failure. The accumulation of Se in this floodplain located in a seleniferous area and the contamination produced by spent Pb shot pellets used for hunting in the past are discussed as potential sources of the elevated levels of these two elements in fish from this floodplain wetland.

Assessing the association and predictability of heavy metals in avian organs, feathers, and bones using crowdsourced samples

Birds are bioindicators for research on the relationship between environmental heavy metal concentration levels and accumulation levels in bird tissues. We use roadkill samples, collected by citizen science participants, to investigate the accumulation levels and associations of seven heavy metals in internal organs (heart, liver, and kidney), feathers (primary and breast), and bones (sternum and femur) of two focal species, Amaurornis phoenicurus and Gallinula chloropus. We found that heavy metal accumulation varied by target tissue, and that variables are associated with bird species and heavy metal type. Although Zn and Cu were highest by concentration among both species, Cu was mostly accumulated in internal organs, As in feathers, and Pb in bones. Concentrations of As, Ni, and Pb in feathers of both focal species were lower than those reported in literature, whereas Cd and Cr were above toxic levels. The results also showed that spatial correlation for heavy metal concentration among bird tissues were weaker than non-spatial correlation, suggesting low spatial autocorrelations and variability. In addition, multiple regression analysis revealed significant correlation for Cr, As, and Pb estimations in A. phoenicurus heart, sternum, and kidney, respectively; and potentially Cr in G. chloropus femur by using feathers. These results support the feasibility of using feathers as indicators of As, Cr, and Pb heavy metal contamination to enhance our understanding of heavy metal accumulation in birds, although caution is required for feather-based estimations of Cd, Cu, and Ni concentration.

Wax esters of uropygial gland secretion as biomarkers of endocrine disruption in birds exposed to treated sewage water

The chemical composition of the uropygial gland secretion of birds shows seasonal, sex and age-related variations following sex hormones fluctuations. We explore the use of the composition of the uropygial gland secretion as a non-invasive biomarker of endocrine disruption in 137 common moorhens (Gallinula chloropus) from Navaseca Pond, which receives the effluent of a wastewater treatment plant, and from the more pristine Tablas de Daimiel National Park in Spain. Wax ester and fatty acid compositions were measured by means gas chromatography - mass spectrometry (GC-MS) in the uropygial gland secretion of moorhens from both wetlands. Organochlorine compounds (p,p'-DDE and PCBs) were measured in blood and uropygial gland secretion of moorhens as indicators of anthropogenic pollutants, and this information was interpreted together with previous results of the accumulation of metals and metalloids in blood and feathers of these moorhens and a wide range of endocrine disrupting chemicals (EDCs) measured in water from both study sites. PCBs and p,p'-DDE were found in 32% of the blood and 51% of uropygial gland secretion samples, being at highest levels in Navaseca. Wax composition was dominated by monoesters of 35-38 carbons and displayed a clear seasonal variation, in which long-chain wax esters were more abundant in spring-summer than in autumn-winter. This seasonal change was less evident in birds from Navaseca, where the presence of shorter wax esters was associated with the higher concentration of PCBs in uropygial gland secretion. The observed effect may not be associated with this specific type of pollutants because moorhens in Navaseca are also exposed to a wide diversity endocrine disruptors as shown in a previous study. Uropygial gland secretion can be a useful non-invasive sample for integrating chemical monitoring of pollutants and their effects as endocrine disruptors in birds.