Contamination and Toxicology

Effect of Individual and Combined Treatments of Pesticide, Fertilizer, and Salt on Growth and Corticosterone Levels of Larval Southern Leopard Frogs ( Lithobates sphenocephala ) Abstract Human activities have introduced a variety of chemicals, including pesticides, fertilizers, and salt, into the environment, which may have deleterious effects on the organisms inhabiting these areas. Amphibians are especially susceptible to absorption of chemical pollutants. To determine the possible combined effects of these chemicals on amphibian development and stress levels, Southern leopard frog (Lithobates sphenocephala) larvae were exposed to one of eight individual or combined treatments of atrazine, ammonium nitrate fertilizer, and sodium chloride salt. Stress levels, indicated by release of the stress hormone corticosterone, were measured premetamorphosis at week 8 of development. Water hormone samples were processed to analyze corticosterone levels. Changes in tadpole growth were determined by surface area measurements taken from biweekly photographs. The combined chemical treatment of atrazine, salt, and fertilizer had a significant interactive effect by increasing stress levels before metamorphosis (p = 0.003). After a month of larval development, tadpoles exposed to ammonium nitrate had larger surface area (p = 0.035). Tadpoles exposed to atrazine had a lower growth rate throughout larval development (p = 0.025) and the lowest number of individuals reaching metamorphosis at 33%. However, the frogs in the atrazine treatment that did successfully metamorphose did so in fewer days (p = 0.002). Because amphibians are exposed to multiple chemicals simultaneously in the environment, assessing the effects of a combination of contaminants is necessary to improve application strategies and ecosystem health.

Concentration, Distribution, and Potential Aquatic Risk Assessment of Metals in Water from Chott Merouane (Ramsar Site), Algeria Abstract In this study, 28 surface water samples were collected from eight different sites throughout the Chott Merouane. Samples were detected by atomic absorption spectrometry for Cd, Co, Cr, Cu, Fe, Ni, Mn, Pb, and Zn. The dissolved metal concentrations (mg/L) ranged from 0.05 to 0.90 mg/L for Cd, 0.13–6.45 mg/L for Co, bDL—2.05 mg/L for Cr, 0.03–0.27 mg/L for Cu, 0.34–7.41 mg/L for Fe, 01.6–4.54 mg/L for Ni, 0.15–1.19 mg/L for Mn, 0.23–5.88 mg/L for Pb, and 0.01–0.28 mg/L for Zn. Compared with U.S. EPA standards and other freshwaters worldwide, the most mean concentration of metals in surface water of this salt lake are higher than the guideline levels of aquatic life. This was further corroborated by results from the water quality indices that Chott Merouane is seriously polluted by metals. The values of the metal pollution index indicated that metal pollution level was Cd > Pb > Ni > Fe > Cr > Cu > Mn > Zn, and those metals belong to moderate or high pollution level. The Nemerow pollution index further indicated that Chott Merouane was suffering from serious metal contamination. Based on geostatistics analyses, generally distributions of these metal contents decreased in the order of the North Chott Merouane ≈ the Northwest Chott Merouane > the Eastern part of Chott Merouane > the South Chott Merouane. The quality of water has drastically deteriorated due to the mixed source of anthropogenic inputs. Therefore, necessary conservation and management measures should be taken to improve the water quality of this Ramsar wetland.

Severe Nitrate Pollution and Health Risks of Coastal Aquifer Simultaneously Influenced by Saltwater Intrusion and Intensive Anthropogenic Activities Abstract Groundwater quality is critical for regional sustainability and human well-beings in coastal regions, because groundwater is an important water resource for these areas facing water scarcity. Anthropogenic activities might induce nitrate pollution, whereas saltwater intrusion could decrease coastal groundwater discharge into sea to subsequently cause the persistent accumulation of pollutants in coastal aquifer. Rare information is available on the nitrate pollution of coastal aquifer under simultaneous influences of saltwater intrusion and intensive anthropogenic activities. This study investigated the distribution, pollution, possible sources, and potential health risks of groundwater nitrate of typical coastal aquifer simultaneously influenced by saltwater intrusion and intensive anthropogenic activities. The average/maximal concentration of groundwater nitrate was 173.70/824.80 mg/L, indicating the severe accumulation of nitrate in the coastal aquifer. Concentrations of nitrate in coastal groundwater were much higher than those in adjacent seawater. Groundwater salinization did not have significant effects on nitrate distribution. Groundwater in 87.6% of sampling sites was not suitable for drinking based on nitrate evaluation criterion. Anthropogenic activities might induce nitrate pollution in approximately 94.7% of sampling sites. Sources, including sewage and manure, soil nitrogen, and ammonium fertilizers, contributed to groundwater nitrate with concentration > 100 mg/L in the study area, whereas sewage and manure were the predominant source affecting groundwater nitrate in 97.5% of sampling sites. Groundwater nitrate exerted unacceptable noncancer health risks for infants, children, teenagers, and adults in more than 87.6% of the study area. Infants and children were the most susceptibly influenced by groundwater nitrate. It is urgent to take effective measures for controlling groundwater nitrate pollution in the study area.

A Comparative Assessment of the Aquatic Toxicity of Corexit 9500 to Marine Organisms Abstract The use of chemical dispersants during oil spill responses has long been controversial. During the Deepwater Horizon (DWH) oil spill, 1.8 million gallons of dispersant, mainly Corexit 9500, were applied in offshore waters to mitigate the human health and coastal environmental impact of surface oil contamination. To evaluate the potential impact of the dispersant on marine life, 18 species, representing important ecological and commercial taxa, were tested using low-energy, dispersant-only water accommodated fractions (WAFs) of Corexit 9500 and standard acute toxicity test methods. All prepared WAFs were analytically characterized. Analyses included the two dispersant markers found in the dispersant and evaluated in samples collected during the DWH Response, dioctylsulfosuccinate sodium salt, and dipropylene glycol n-butyl ether (DPnB). The median lethal and effective concentrations (LC/EC50s) were calculated using a nominal exposure concentration (mg/L, based on the experimental loading rate of 50 mg/L) and measured DPnB (µg/L). Results ranged from 5.50 to > 50 mg/L dispersant and 492 to > 304,000 µg/L DPnB. Species sensitivity distributions of the data demonstrated that taxa were evenly distributed; however, algae and oysters were among the more sensitive organisms. The calculated 5% hazard concentration (HC5) for DPnB (1172 µg/L) was slightly higher than the USEPA chronic criteria of 1000 µg/L and substantially higher than all measured concentrations of DPnB measured in the Gulf of Mexico during the DWH oil spill response.

Persistent Halogenated Organic Pollutants in Surface Water in a Megacity: Distribution Characteristics and Ecological Risks in Wuhan, China Abstract Surface water pollution in megacities is strongly linked to human and environmental health, and surface water quality has deteriorated sharply recently because of increasing persistent halogenated organic pollutant (HOP) concentrations. In the present study, we collected 112 water samples from 14 lakes and 11 drinking water sources in Wuhan, China, and analyzed them for two typical groups of HOPs: polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs). The mean values of the ΣPCB concentrations were 4.34 and 10.05 ng L−1 in winter and summer, respectively. For ΣPBDE concentrations, the mean values were 0.88 and 1.53 ng L−1 in winter and summer, respectively. The PCB and PBDE concentrations at most sites in summer were significantly higher than those in winter, probably because of heavy stormwater runoff in summer. The degree of urbanization predicted from the population density was positively correlated with ΣPCB concentrations in the drinking water sources in summer. PBDE and PCB composition analysis suggested the major sources were penta-BDE and Aroclor mixtures. Risk assessments showed the PBDEs in water from the Zhuankou site exceeded the threshold set by the European Union, which could result in adverse effects on aquatic organisms. Negligible noncarcinogenic risks were found for PCBs and PBDEs in the surface water with regard to drinking and bathing. However, the carcinogenic risks of PCBs for bathing in surface water were higher than the safe level of 1.00 × 10−6, implying that the surface water in Wuhan is not safe for bathing.

Perfluoroalkyl Contaminant Exposure and Effects in Tree Swallows Nesting at Clarks Marsh, Oscoda, Michigan, USA Abstract A site in northeastern Michigan, Oscoda Township, has some of the highest recorded exposure in birds to perfluorinated substances (PFASs) in the United States. Some egg and plasma concentrations at that location exceeded the lowest reproductive effect threshold established for two avian laboratory species. The objectives of this study were to determine whether there were reproductive effects or physiological responses in a model bird species, the tree swallow (Tachycineta bicolor), associated with this extremely high exposure to PFASs. The lack of exposure above background to other contaminants at this site allowed for an assessment of PFAS effects without the complication that responses may be caused by other contaminants. A secondary objective was to determine the distribution of PFASs in multiple tissue types to better understand and interpret residues in different tissues. This can best be done at highly exposed locations where tissue concentrations would be expected to be above detectable levels if they are present in that tissue. There were no demonstrable effects of PFAS exposure on reproduction nor on most physiological responses.

The Relationship Between Human Adenovirus and Metals and Semimetals in the Waters of the Rio Doce, Brazil Abstract The 2015 rupture of the Fundão dam near the district of Bento Rodrigues in Mariana, Minas Gerais, Brazil, released around 50 million m3 of iron ore tailings. The first tributary of the Rio Doceto receive this waste was the Gualaxo do Norte River. Many groups in Brazil and from around the world have studied the environmental and social impacts of this disaster. However, relationships between the introduction of mining waste, the geological complexity of the area, and the presence of pathogenic organisms have not yet been investigated. The present study aimed to measure the concentrations of enteric pathogens along the Gualaxo do Norte River after the environmental disaster and to correlate their abundance with the presence of metals and semimetals coming from both mining tailings and geological sources. For this purpose, we collected water samples from 27 stations along the entire basin during a hydrological year. The concentrations of metals and semimetals measured in this study were generally within limits established by national and international legislation, except for those of iron and manganese. Positive correlations between the human adenovirus (HAdV) and arsenic, barium, iron, lead, manganese, and nickel were confirmed, allowing us to observe that there is an abundance of the potentially infectious virus present in the studied sites containing metal/semimetal concentrations. These studies indicate the importance of investigations that consider viral enteric pathogens complexed with metals and may favor the stability and prolongation of the infectivity of such pathogens in water destined for human and animal usage.

The Effects of Selenomethionine on the Escape Behaviours of Fathead Minnows Abstract Selenium (Se) is an essential micronutrient for animals and yet becomes toxic with only a small increase in concentration. Toxicological studies have reported various effects of Se on fishes, including developmental impacts and deformities of the musculature and sensory systems. This paper investigates the impact of sublethal concentrations of Se on the ability of the Fathead Minnow (Pimephales promelas) to perform escape responses, a routine behaviour important to predator–prey dynamics. Predation is among the strongest evolutionary driving forces in nature. Changes to this dynamic can have effects that cascade through the ecosystem. We used responses to mechanical and visual stimuli to determine the impact of environmentally relevant concentrations of dietary selenomethionine on the behaviour of minnows. Latency to respond to the stimulus and kinematic performance were assessed. Our results indicated that there was no significant effect of selenomethionine on either the visual response to a threat or burst swimming behaviours of the fast-start response in minnows. Levels of Se in tissues approached that of tissue-specific guidelines set by regulatory bodies across North America. This suggests that current regulations are adequately protecting this key component of predator avoidance in Fathead Minnows.

Genotoxic Evaluation in Tadpoles Associated with Agriculture in the Central Cerrado, Brazil Abstract Many agricultural practices cause environmental degradation that affects the cellular integrity of anurans. In the present study, we provided in situ data of Dendropsophus minutus, Physalaemus cuvieri, and Scinax fuscovarius collected in soybean/corn and conservation units in the Brazilian Cerrado. The in situ data showed no significant variation in the micronucleus frequency between the sites, only the reniform cells had a higher rate for the agricultural environment. A combined analysis of all nuclear erythrocyte abnormalities (ENAs = nuclear buds, reniform nuclei, apoptotic cell, binucleated, and anucleated cells) was recorded higher frequencies in farmland. Overall, Scinax fuscovarius was considered the best potential bioindicator for soybean/corn plantations. Finally, we recommend expanding the micronucleus test for in situ studies to expand our understanding of the sensitivity of native anuran species and provide a more systematic assessment of the adverse effects of environmental pollutants on wildlife.

Distribution of Organohalogen and Synthetic Musk Compounds in Breast Adipose Tissue of Breast Cancer Patients in Ulster County, New York, USA Abstract We determined the concentrations of 98 halogenated organic compounds and synthetic musks in breast fat tissues of 50 breast cancer patients (age range: 34–77 years) collected during 1996–1998 in Ulster County, New York, USA. Polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), polybrominated biphenyl 153 (PBB-153), polybrominated diphenyl ethers (PBDEs), and synthetic musk compounds (SMCs) were analyzed in breast fat tissues, and 46 analytes were found at a detection frequency of ≥ 65% and at concentrations in the decreasing order of OCPs > PCBs > SMCs > PBDEs > PBB-153. PCBs (median: 323 ng/g wet wt) and dichlorodiphenyltrichloroethanes (DDTs, median: 293 ng/g wet wt) were the major compounds found in breast fat tissues. Among PCB congeners, hexa- and hepta-chlorobiphenyls (60% of total PCBs) were the abundant ones. p,p′-DDE accounted for more than 99% of the total DDT concentrations. The concentrations of SMCs and PBDEs were 1–2 orders of magnitude lower than those of PCBs and DDTs. 1,3,4,6,7,8-Hexahydro-4,6,6,7,8,8-hexamethylcyclopenta-r-2-benzopyran (median: 33 ng/g wet wt) was the most abundant SMC, whereas BDE-47 (median: 4.5 ng/g wet wt) was the most dominant PBDE congener present in breast tissues. A significant correlation (p < 0.05) between women's age and concentrations of DDTs, chlordanes, hexachlorobenzene and PCBs in breast tissues was found. Concentrations of PCBs, PBDEs, OCPs, and SMCs were not significantly different between malignant and benign tumor cases. This study adds baseline information on target tissue burdens of persistent organic contaminants in breast cancer patients. Graphical Abstract

Alexandros Sfakianakis
Anapafseos 5 . Agios Nikolaos
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6948891480

alsfakia@gmail.com