Ali Ishaque | University of Maryland Eastern Shore (original) (raw)

Papers by Ali Ishaque

Reviews on environmental health, 1999

Drinking water contamination by arsenic remains a major public health problem. Acute and chronic ... more Drinking water contamination by arsenic remains a major public health problem. Acute and chronic arsenic exposure via drinking water has been reported in many countries of the world; especially in Argentina, Bangladesh, India, Mexico, Thailand, and Taiwan, where a large proportion of drinking water (ground water) is contaminated with a high concentration of arsenic. Research has also pointed out significantly higher standardized mortality ratios and cumulative mortality rates for cancers of the bladder, kidney, skin, liver, and colon in many areas of arsenic pollution. General health effects that are associated with arsenic exposure include cardiovascular and peripheral vascular disease, developmental anomalies, neurologic and neurobehavioral disorders, diabetes, hearing loss, portal fibrosis of the liver, lung fibrosis, hematologic disorders (anemia, leukopenia, and eosinophilia), and carcinoma. Although, the clinical manifestations of arsenic poisoning appear similar, the toxicity of arsenic compounds depends largely u[on the chemical species and the form of arsenic involved. On the basis of its high degree of toxicity to humans, and the non-threshold dose-T

GSA Annual Meeting in Seattle, Washington, USA - 2017, 2017

International Journal of Molecular Sciences, Sep 30, 2002

Pentachlorophenol (PCP) is a biocidal chemical with several industrial, agricultural, and domesti... more Pentachlorophenol (PCP) is a biocidal chemical with several industrial, agricultural, and domestic applications. There is accumulating evidence indicating that PCP is highly toxic to humans, with major target organs including the lung, liver, kidneys, heart, and brain. Little is known regarding the molecular basis by which PCP induces toxicity, mutagenesis, and carcinogenesis. Therefore, this research was designed to assess the cellular and molecular responses of HepG 2 cells following exposure to PCP. The cytotoxicity experiment yielded a LD 50 value of 23.4 + 9.7 µg PCP/mL upon 48 hrs of exposure, indicating that PCP is acutely toxic. A dose-response relationship was recorded with respect to gene induction. For example, fold inductions of CYP1A1 were 1.

Reviews on environmental health, 2003

Methyl parathion-MP (C 8 H 10 NO 5 PS) is a restricted-use pesticide that has been widely used as... more Methyl parathion-MP (C 8 H 10 NO 5 PS) is a restricted-use pesticide that has been widely used as an agricultural insecticide. It belongs to the class of organophosphate chemicals characterized by their ability to inhibit acetylcholinesterase activity. The main route of human exposure is inhalation, but dermal contact and inadvertent ingestion can also be substantial. Populations that are susceptible to MP exposure primarily are applicators, manufacturers and individuals living near application and/or disposal sites. Exposure has also been reported as a result of illegal indoor application. MP related health effects include headaches, nausea, night-waking, diarrhea, difficulty breathing, excessive sweating and salivation, incoordination, and mental confusion. Other symptoms including behavior problems, motor skill problems and impairment of memory recall have also been reported. The primary targets of toxicity are the hematopoietic system (serum cholinesterase inhibition), the cardiovascular system (cardiovascular lesions, abnormalities in heart rate and increase in heart-to-body ratio), the reproductive system (placental morphology, fibrosis and hemorrhage, and inhibition of DNA synthesis in seminiferous tubules), and the nervous system (headache, muscle weakness, insomnia, dizziness, and impaired memory). MP is believed to not have any carcinogenic effects. In an attempt to update its toxicologic profile, we hereby provide a critical review of MP-related environmental and toxicologic effects, with a special emphasis on their potential implications for public health.

Journal of Coastal Research, Jul 1, 2022

Evaluation of joint toxic action of metal ion mixtures is one of the priority research areas due ... more Evaluation of joint toxic action of metal ion mixtures is one of the priority research areas due to the simultaneous occurrence of metals in the environment and the health risk they posed to humans and the environment as a mixture. Individual and composite mixture acute toxicities of arsenic (As), cadmium (Cd), mercury (Hg), and lead (Pb), which are among the top eight toxic chemicals, were characterized at varying concentrations. MCF 7 cell lines were exposed to individual and composite mixtures containing the four metal ions in the proportion of their EPA’s MCL for 24 hours, and the concentration-response data were generated spectrofluorometrically. Acute toxicities were estimated based on the uptake of fluorescence diacetate dye. Toxicological interactions among the four metals were profiled, based on computed interactive index. Results demonstrated that the toxicity of each of the metal ions was enhanced in the composite mixture, and the metals demonstrated differential interact...

Abstract: Although most researches with non-essential metals (NEMs) have been done with single or... more Abstract: Although most researches with non-essential metals (NEMs) have been done with single or individual metals, in reality, organisms are often exposed to multiple contaminants at the same time through the air, food and water. In this study, we tested the toxicity of four NEMs, As, Cd, Pb, and Hg, individually and as a composite mixture using the microtox bioassay. This assay uses the reduction of bioluminescence of the bacterium Vibrio fischeri as a measure of toxicity. The concentrations of each chemical in the mixture were based on multiples of their maximum contaminant levels (MCLs) set by the U.S. EPA. The highest concentration of exposure was 20 times the MCL, which translated into 200, 100, 40 and 300 ppb for As, Cd, Hg and Pb, respectively. The ratio for the mixture from these concentrations was 10:5:2:15 for As, Cd, Hg and Pb, respectively. Among the individual metals tested, the ranking of toxicity was Hg>Pb>Cd>As based on the EC50 values of 109, 455, 508 and...

Cancer Research, 2007

1404 Evidence is accumulating that atrazine (ATZ), cadmium ( Cd), Arsenic (As) and nitrate (NO3) ... more 1404 Evidence is accumulating that atrazine (ATZ), cadmium ( Cd), Arsenic (As) and nitrate (NO3) have estrogenic activity. These environmental hormonally active agents (HHAs) may be carcinogenic. Evidence indicates that the herbicide atrazine may be a direct carcinogen based on its clastogenic effects and may also act as a promotor based on its ability to induce the aromatase enzyme. Arsenic and Cd have both been classified as human carcinogens by IARC. Arsenic has been implicated in the etiology of skin, lung, bladder and liver cancers and Cd has been associated with lung and prostate cancers. Nitrate exposure through drinking water has been associated with an increased risk for bladder cancer. This study involves exposing MCF-7 cell lines to a mixture of ATZ, Cd, As and NO 3 at environmentally relevant concentrations to study their clastogenic potential by flow karyotyping. The mixture of the chemicals was prepared using their maximum contaminant level (MCL) as a unit for concentr...

African-American women have a higher breast cancer mortality rate than Caucasian women. Harmful r... more African-American women have a higher breast cancer mortality rate than Caucasian women. Harmful reactive oxygen species (ROS) exert oxidative stress in cells of the human body and lead to several types of DNA damage. Recent studies have shown that flavonoids may protect against cancer through inhibition of oxidative damage. Naringenin, a universal flavonoid, can also inhibit the proliferation of cancer cells. This project studied the oxidative stress (cell death) pathways of naringenin in ER-positive (MCF-7), ER-negative (MDA-MB-468), and non-tumorigenic human breast cell (MCF-10A) lines. Cellular levels of ROS, superoxide (O2 -), glutathione (GSH), and mitochondrial membrane potential (MMP) were assayed using the FACS Calibur flow cytometer and cell quest software for data collection. The results showed that naringenin induced oxidative stress that resulted in cell death in all cell lines. The highest production of ROS and O2 was observed in ER-negative cells. Naringenin did not ha...

American Journal of Biomedical Science & Research, 2019

This work is licensed under Creative Commons Attribution 4.0 License AJBSR.MS.ID.000846.

Estuarine, Coastal and Shelf Science, 2015

Abstract Dissolved organic matter (DOM) provides nutrients and energy subsidies for harmful algal... more Abstract Dissolved organic matter (DOM) provides nutrients and energy subsidies for harmful algal blooms in Maryland's Coastal Bays (MCBs, USA). The composition, sources and dynamics of DOM in MCBs are not well known. In this study, dissolved organic carbon (DOC) and total dissolved nitrogen (TDN) were monitored monthly over a period of one year (July 2011 to June 2012) at 13 stations in the MCBs. Absorption and fluorescence spectroscopy were used to characterize DOM composition and track terrestrial inputs versus aquatic sources of DOM. Results show that DOC and TDN concentrations in the MCBs (187–501 μM and 19.4–40.6 μM) were comparable to eutrophic coastal waters in the United States but much higher than the mid-Atlantic Bight. This suggests that the MCBs are a DOM source for the coastal ocean. Spatially, nearshore sites had relatively higher DOC and TDN concentrations and terrestrially-derived aromatic DOM (indicated by high humification index) than the bays that were directly connected to the Atlantic Ocean. Seasonally, DOC from the main body of the MCBs (Chincoteague and Assawoman Bays) displayed a pronounced seasonal pattern with the highest values occurring in summer. Protein-like DOM from algal/bacterial inputs (indicated by high biological freshness index or fluorescence index) was also highest in summer but then decreased gradually until April. DOC concentrations at the nearshore site were highest in later spring, probably due to terrestrial inputs. Conversely, TDN concentrations in smaller bays with faster flushing rates (Newport, Sinepuxent and Isle of Wight Bays) were highest in April, probably due to watershed nitrogen inputs. This spring TDN peak was not apparent in the main body of the MCBs, which have longer flushing times (indicating stronger biological nitrogen uptake). This study suggests that DOM in eutrophic, shallow coastal bays such as the MCBs consists of a large fraction of protein-like components from local algal/microbial sources during summer. This enhanced primary productivity is likely fueled by watershed nitrogen inputs from agricultural and urban land use during spring. Further insights regarding spatiotemporal variations and controls of DOM abundance, composition and sources in the MCBs can be helpful in guiding and prioritizing coastal restoration efforts for reducing eutrophication and water quality degradation.

Journal of Coastal Research, 2013

Changes in land use and cover influence surface water quality and thus are a potential threat to ... more Changes in land use and cover influence surface water quality and thus are a potential threat to water systems and coastal ecosystem health. The objectives of this study were to evaluate the influence of historical land use-land cover (LULC) changes and point-source sewage discharge on surface water quality of some lower Eastern Shore watersheds of Maryland. LANDSAT data for 1986-2006 was acquired and classified using Anderson level-1 classification system in ENVI 4.5, whereas LULC changes were detected in Arc-GIS 9.2 environment. Historical water monitoring and climatic data were obtained from Maryland Department of Environment-Chesapeake Bay Program, and National Oceanic and Atmospheric Administration, respectively. Nutrient loading data from wastewater treatment plants were obtained from Maryland Department of Environment and data analyzed using regression analysis and principal component analysis (PCA). The result shows that total phosphorous levels in the surface waters decreased significantly (p , 0.05) during the 20-year study period. However, using PCA, we determined that the declining P trend was attributable to the decreasing agricultural land use rather than the sewage discharge from wastewater treatment plants. The increase in urban land use and the resultant runoff to the water bodies may explain the declining trends in dissolved oxygen levels observed during the period, with serious implications for eutrophication. An empirical model developed for P in surface waters (r 2 5 0.90) showed that the combination of point and nonpoint sources and land use/cover change factors are good predictors. The incorporation of quantitative LULC data component as well as point-source nutrient loading into existing models is highly recommended for a more holistic assessment of land-use influence on water systems in general.

The provisions of this publication are not to be regarded as an irrevocable contract between the ... more The provisions of this publication are not to be regarded as an irrevocable contract between the student and the University of Maryland Eastern Shore. At the time of publication, every reasonable effort was made to attain factual accuracy in the material presented. This Catalog is not intended to be a complete statement of all procedures, processes and regulations governing graduate or professional degree programs which may be covered in separate program and office manuals and handbooks. The University of Maryland Eastern Shore reserves the right to make changes in fees, course offerings and general regulations and academic requirements without prior notice. All effort has been made to ensure that the information in this Catalog is current and accurate. However, policies, procedures, fees, forms and other information are subject to change after publication. For the most up-to-date information on course offerings, program requirements, fees and deadlines, please write, call, email or visit the website of the program or department to which you are applying.

There is strong evidence that hormonally active agents (HAAs) such as Atrazine (ATZ), Cadmium (Cd... more There is strong evidence that hormonally active agents (HAAs) such as Atrazine (ATZ), Cadmium (Cd), Arsenic (As) and Nitrate (NO 3 ) have both estrogenic activity and carcinogenic potential. Atrazine has clastogenic effects and may also act as tumor promoter as it induces the aromatase enzyme. Arsenic and Cadmium have been implicated in the etiology of skin, lung, prostate and liver cancers. Nitrate in drinking water has been found to increase the risk of bladder cancer. This study examined the genotoxicity of the aforementioned HAAs alone and in mixtures using mammalian breast cell lines, MCF-7 and MCF-10A, which are estrogen receptorpositive (ER+) and estrogen receptor-negative (ER-), respectively. To study the clastogenic potential by whole cell and flow karyotype damage, cells were exposed to environmentally relevant concentrations of ATZ, Cd, As and NO 3 for 4 and 7 days. Results indicated that all treatments induced whole cell clastogenicity in MCF-7 cells; except Cd and NO3 a...

Glycobiology

Bladder cancer is the ninth most frequently diagnosed cancer worldwide, and there is a need to de... more Bladder cancer is the ninth most frequently diagnosed cancer worldwide, and there is a need to develop new biomarkers for staging and prognosis of this disease. Here we report that cell lines derived from low-grade and high-grade bladder cancers exhibit major differences in expression of glycans in surface glycoproteins. We analyzed protein glycosylation in three low-grade bladder cancer cell lines RT4 (grade-1-2), 5637 (grade-2), and SW780 (grade-1), and three high-grade bladder cancer cell lines J82COT (grade-3), T24 (grade-3) and TCCSUP (grade-4), with primary bladder epithelial cells, A/T/N, serving as a normal bladder cell control. Using a variety of approaches including flow cytometry, immunofluorescence, glycomics and gene expression analysis, we observed that the low-grade bladder cancer cell lines RT4, 5637 and SW780 express high levels of the fucosylated Lewis-X antigen (Lex, CD15) (Galβ1–4(Fucα1–3)GlcNAcβ1-R), while normal bladder epithelial A/T/N cells lack Lex expressio...

International Journal of Environmental Research and Public Health

Contaminants of Emerging Concern (CECs) with estrogenic or estrogenic-like activity have been inc... more Contaminants of Emerging Concern (CECs) with estrogenic or estrogenic-like activity have been increasingly detected in aquatic environments and have been an issue of global concern due to their potential negative effects on wildlife and human health. This study used the MCF-7 cell proliferation assay (E-Screen) to assess the estrogenic activity profiles in Maryland Coastal Bays (MCBs), a eutrophic system of estuaries impacted by human activities. Estrogenic activity was observed in all study sites tested. Water samples from MCBs increased MCF-7 cell proliferation above the negative control from 2.1-fold at site 8, located in Sinepuxent Bay close to the Ocean City Inlet, to 6.3-fold at site 6, located in Newport Bay. The proliferative effects of the sediment samples over the negative control ranged from 1.9-fold at the Assateague Island National Seashore site to 7.7-fold at the Public Landing site. Moreover, elevated cell proliferation (p < 0.05) was observed when cells were co-ex...

Water

The suspended particulate organic matter (SPOM) in transitional waters such as the Maryland Coast... more The suspended particulate organic matter (SPOM) in transitional waters such as the Maryland Coastal Bays (MCBs) is derived from allochthonous and autochthonous sources. Little is known, however, about the contribution of terrestrially derived organic matter to SPOM in the MCBs. The sources of SPOM in the MCBs were evaluated using stable isotope ratios of nitrogen (δ15N) and carbon (δ13C), and C/N molar ratios. The values of SPOM δ15N, δ13C and C/N ratios from samples collected seasonally (July 2014 to October 2017) at 13 sites ranged from −0.58 to 10.51‰, −26.85 to −20.33‰, and 1.67 to 11.36, respectively, indicating a mixture of terrestrial SPOM transported by tributaries, marine organic matter from phytoplankton, and sewage. SPOM δ13C levels less than −24‰, suggesting the dominance of terrestrially derived carbon, occurred mainly at sites close to the mouths of tributaries, and were less depleted at sites near the ocean. The mean value of SPOM δ13C was higher in October 2014 (−22....

Water, 2020

The suspended particulate organic matter (SPOM) in transitional waters such as the Maryland Coast... more The suspended particulate organic matter (SPOM) in transitional waters such as the Maryland Coastal Bays (MCBs) is derived from allochthonous and autochthonous sources. Little is known, however, about the contribution of terrestrially derived organic matter to SPOM in the MCBs. The sources of SPOM in the MCBs were evaluated using stable isotope ratios of nitrogen (δ 15 N) and carbon (δ 13 C), and C/N molar ratios. The values of SPOM δ 15 N, δ 13 C and C/N ratios from samples collected seasonally (July 2014 to October 2017) at 13 sites ranged from −0.58 to 10.51% , −26.85 to −20.33% , and 1.67 to 11.36, respectively, indicating a mixture of terrestrial SPOM transported by tributaries, marine organic matter from phytoplankton, and sewage. SPOM δ 13 C levels less than −24% , suggesting the dominance of terrestrially derived carbon, occurred mainly at sites close to the mouths of tributaries, and were less depleted at sites near the ocean. The mean value of SPOM δ 13 C was higher in Oct...

Reviews on environmental health, 1999

Drinking water contamination by arsenic remains a major public health problem. Acute and chronic ... more Drinking water contamination by arsenic remains a major public health problem. Acute and chronic arsenic exposure via drinking water has been reported in many countries of the world; especially in Argentina, Bangladesh, India, Mexico, Thailand, and Taiwan, where a large proportion of drinking water (ground water) is contaminated with a high concentration of arsenic. Research has also pointed out significantly higher standardized mortality ratios and cumulative mortality rates for cancers of the bladder, kidney, skin, liver, and colon in many areas of arsenic pollution. General health effects that are associated with arsenic exposure include cardiovascular and peripheral vascular disease, developmental anomalies, neurologic and neurobehavioral disorders, diabetes, hearing loss, portal fibrosis of the liver, lung fibrosis, hematologic disorders (anemia, leukopenia, and eosinophilia), and carcinoma. Although, the clinical manifestations of arsenic poisoning appear similar, the toxicity of arsenic compounds depends largely u[on the chemical species and the form of arsenic involved. On the basis of its high degree of toxicity to humans, and the non-threshold dose-T

GSA Annual Meeting in Seattle, Washington, USA - 2017, 2017

International Journal of Molecular Sciences, Sep 30, 2002

Pentachlorophenol (PCP) is a biocidal chemical with several industrial, agricultural, and domesti... more Pentachlorophenol (PCP) is a biocidal chemical with several industrial, agricultural, and domestic applications. There is accumulating evidence indicating that PCP is highly toxic to humans, with major target organs including the lung, liver, kidneys, heart, and brain. Little is known regarding the molecular basis by which PCP induces toxicity, mutagenesis, and carcinogenesis. Therefore, this research was designed to assess the cellular and molecular responses of HepG 2 cells following exposure to PCP. The cytotoxicity experiment yielded a LD 50 value of 23.4 + 9.7 µg PCP/mL upon 48 hrs of exposure, indicating that PCP is acutely toxic. A dose-response relationship was recorded with respect to gene induction. For example, fold inductions of CYP1A1 were 1.

Reviews on environmental health, 2003

Methyl parathion-MP (C 8 H 10 NO 5 PS) is a restricted-use pesticide that has been widely used as... more Methyl parathion-MP (C 8 H 10 NO 5 PS) is a restricted-use pesticide that has been widely used as an agricultural insecticide. It belongs to the class of organophosphate chemicals characterized by their ability to inhibit acetylcholinesterase activity. The main route of human exposure is inhalation, but dermal contact and inadvertent ingestion can also be substantial. Populations that are susceptible to MP exposure primarily are applicators, manufacturers and individuals living near application and/or disposal sites. Exposure has also been reported as a result of illegal indoor application. MP related health effects include headaches, nausea, night-waking, diarrhea, difficulty breathing, excessive sweating and salivation, incoordination, and mental confusion. Other symptoms including behavior problems, motor skill problems and impairment of memory recall have also been reported. The primary targets of toxicity are the hematopoietic system (serum cholinesterase inhibition), the cardiovascular system (cardiovascular lesions, abnormalities in heart rate and increase in heart-to-body ratio), the reproductive system (placental morphology, fibrosis and hemorrhage, and inhibition of DNA synthesis in seminiferous tubules), and the nervous system (headache, muscle weakness, insomnia, dizziness, and impaired memory). MP is believed to not have any carcinogenic effects. In an attempt to update its toxicologic profile, we hereby provide a critical review of MP-related environmental and toxicologic effects, with a special emphasis on their potential implications for public health.

Journal of Coastal Research, Jul 1, 2022

Evaluation of joint toxic action of metal ion mixtures is one of the priority research areas due ... more Evaluation of joint toxic action of metal ion mixtures is one of the priority research areas due to the simultaneous occurrence of metals in the environment and the health risk they posed to humans and the environment as a mixture. Individual and composite mixture acute toxicities of arsenic (As), cadmium (Cd), mercury (Hg), and lead (Pb), which are among the top eight toxic chemicals, were characterized at varying concentrations. MCF 7 cell lines were exposed to individual and composite mixtures containing the four metal ions in the proportion of their EPA’s MCL for 24 hours, and the concentration-response data were generated spectrofluorometrically. Acute toxicities were estimated based on the uptake of fluorescence diacetate dye. Toxicological interactions among the four metals were profiled, based on computed interactive index. Results demonstrated that the toxicity of each of the metal ions was enhanced in the composite mixture, and the metals demonstrated differential interact...

Abstract: Although most researches with non-essential metals (NEMs) have been done with single or... more Abstract: Although most researches with non-essential metals (NEMs) have been done with single or individual metals, in reality, organisms are often exposed to multiple contaminants at the same time through the air, food and water. In this study, we tested the toxicity of four NEMs, As, Cd, Pb, and Hg, individually and as a composite mixture using the microtox bioassay. This assay uses the reduction of bioluminescence of the bacterium Vibrio fischeri as a measure of toxicity. The concentrations of each chemical in the mixture were based on multiples of their maximum contaminant levels (MCLs) set by the U.S. EPA. The highest concentration of exposure was 20 times the MCL, which translated into 200, 100, 40 and 300 ppb for As, Cd, Hg and Pb, respectively. The ratio for the mixture from these concentrations was 10:5:2:15 for As, Cd, Hg and Pb, respectively. Among the individual metals tested, the ranking of toxicity was Hg>Pb>Cd>As based on the EC50 values of 109, 455, 508 and...

Cancer Research, 2007

1404 Evidence is accumulating that atrazine (ATZ), cadmium ( Cd), Arsenic (As) and nitrate (NO3) ... more 1404 Evidence is accumulating that atrazine (ATZ), cadmium ( Cd), Arsenic (As) and nitrate (NO3) have estrogenic activity. These environmental hormonally active agents (HHAs) may be carcinogenic. Evidence indicates that the herbicide atrazine may be a direct carcinogen based on its clastogenic effects and may also act as a promotor based on its ability to induce the aromatase enzyme. Arsenic and Cd have both been classified as human carcinogens by IARC. Arsenic has been implicated in the etiology of skin, lung, bladder and liver cancers and Cd has been associated with lung and prostate cancers. Nitrate exposure through drinking water has been associated with an increased risk for bladder cancer. This study involves exposing MCF-7 cell lines to a mixture of ATZ, Cd, As and NO 3 at environmentally relevant concentrations to study their clastogenic potential by flow karyotyping. The mixture of the chemicals was prepared using their maximum contaminant level (MCL) as a unit for concentr...

African-American women have a higher breast cancer mortality rate than Caucasian women. Harmful r... more African-American women have a higher breast cancer mortality rate than Caucasian women. Harmful reactive oxygen species (ROS) exert oxidative stress in cells of the human body and lead to several types of DNA damage. Recent studies have shown that flavonoids may protect against cancer through inhibition of oxidative damage. Naringenin, a universal flavonoid, can also inhibit the proliferation of cancer cells. This project studied the oxidative stress (cell death) pathways of naringenin in ER-positive (MCF-7), ER-negative (MDA-MB-468), and non-tumorigenic human breast cell (MCF-10A) lines. Cellular levels of ROS, superoxide (O2 -), glutathione (GSH), and mitochondrial membrane potential (MMP) were assayed using the FACS Calibur flow cytometer and cell quest software for data collection. The results showed that naringenin induced oxidative stress that resulted in cell death in all cell lines. The highest production of ROS and O2 was observed in ER-negative cells. Naringenin did not ha...

American Journal of Biomedical Science & Research, 2019

This work is licensed under Creative Commons Attribution 4.0 License AJBSR.MS.ID.000846.

Estuarine, Coastal and Shelf Science, 2015

Abstract Dissolved organic matter (DOM) provides nutrients and energy subsidies for harmful algal... more Abstract Dissolved organic matter (DOM) provides nutrients and energy subsidies for harmful algal blooms in Maryland's Coastal Bays (MCBs, USA). The composition, sources and dynamics of DOM in MCBs are not well known. In this study, dissolved organic carbon (DOC) and total dissolved nitrogen (TDN) were monitored monthly over a period of one year (July 2011 to June 2012) at 13 stations in the MCBs. Absorption and fluorescence spectroscopy were used to characterize DOM composition and track terrestrial inputs versus aquatic sources of DOM. Results show that DOC and TDN concentrations in the MCBs (187–501 μM and 19.4–40.6 μM) were comparable to eutrophic coastal waters in the United States but much higher than the mid-Atlantic Bight. This suggests that the MCBs are a DOM source for the coastal ocean. Spatially, nearshore sites had relatively higher DOC and TDN concentrations and terrestrially-derived aromatic DOM (indicated by high humification index) than the bays that were directly connected to the Atlantic Ocean. Seasonally, DOC from the main body of the MCBs (Chincoteague and Assawoman Bays) displayed a pronounced seasonal pattern with the highest values occurring in summer. Protein-like DOM from algal/bacterial inputs (indicated by high biological freshness index or fluorescence index) was also highest in summer but then decreased gradually until April. DOC concentrations at the nearshore site were highest in later spring, probably due to terrestrial inputs. Conversely, TDN concentrations in smaller bays with faster flushing rates (Newport, Sinepuxent and Isle of Wight Bays) were highest in April, probably due to watershed nitrogen inputs. This spring TDN peak was not apparent in the main body of the MCBs, which have longer flushing times (indicating stronger biological nitrogen uptake). This study suggests that DOM in eutrophic, shallow coastal bays such as the MCBs consists of a large fraction of protein-like components from local algal/microbial sources during summer. This enhanced primary productivity is likely fueled by watershed nitrogen inputs from agricultural and urban land use during spring. Further insights regarding spatiotemporal variations and controls of DOM abundance, composition and sources in the MCBs can be helpful in guiding and prioritizing coastal restoration efforts for reducing eutrophication and water quality degradation.

Journal of Coastal Research, 2013

Changes in land use and cover influence surface water quality and thus are a potential threat to ... more Changes in land use and cover influence surface water quality and thus are a potential threat to water systems and coastal ecosystem health. The objectives of this study were to evaluate the influence of historical land use-land cover (LULC) changes and point-source sewage discharge on surface water quality of some lower Eastern Shore watersheds of Maryland. LANDSAT data for 1986-2006 was acquired and classified using Anderson level-1 classification system in ENVI 4.5, whereas LULC changes were detected in Arc-GIS 9.2 environment. Historical water monitoring and climatic data were obtained from Maryland Department of Environment-Chesapeake Bay Program, and National Oceanic and Atmospheric Administration, respectively. Nutrient loading data from wastewater treatment plants were obtained from Maryland Department of Environment and data analyzed using regression analysis and principal component analysis (PCA). The result shows that total phosphorous levels in the surface waters decreased significantly (p , 0.05) during the 20-year study period. However, using PCA, we determined that the declining P trend was attributable to the decreasing agricultural land use rather than the sewage discharge from wastewater treatment plants. The increase in urban land use and the resultant runoff to the water bodies may explain the declining trends in dissolved oxygen levels observed during the period, with serious implications for eutrophication. An empirical model developed for P in surface waters (r 2 5 0.90) showed that the combination of point and nonpoint sources and land use/cover change factors are good predictors. The incorporation of quantitative LULC data component as well as point-source nutrient loading into existing models is highly recommended for a more holistic assessment of land-use influence on water systems in general.

The provisions of this publication are not to be regarded as an irrevocable contract between the ... more The provisions of this publication are not to be regarded as an irrevocable contract between the student and the University of Maryland Eastern Shore. At the time of publication, every reasonable effort was made to attain factual accuracy in the material presented. This Catalog is not intended to be a complete statement of all procedures, processes and regulations governing graduate or professional degree programs which may be covered in separate program and office manuals and handbooks. The University of Maryland Eastern Shore reserves the right to make changes in fees, course offerings and general regulations and academic requirements without prior notice. All effort has been made to ensure that the information in this Catalog is current and accurate. However, policies, procedures, fees, forms and other information are subject to change after publication. For the most up-to-date information on course offerings, program requirements, fees and deadlines, please write, call, email or visit the website of the program or department to which you are applying.

There is strong evidence that hormonally active agents (HAAs) such as Atrazine (ATZ), Cadmium (Cd... more There is strong evidence that hormonally active agents (HAAs) such as Atrazine (ATZ), Cadmium (Cd), Arsenic (As) and Nitrate (NO 3 ) have both estrogenic activity and carcinogenic potential. Atrazine has clastogenic effects and may also act as tumor promoter as it induces the aromatase enzyme. Arsenic and Cadmium have been implicated in the etiology of skin, lung, prostate and liver cancers. Nitrate in drinking water has been found to increase the risk of bladder cancer. This study examined the genotoxicity of the aforementioned HAAs alone and in mixtures using mammalian breast cell lines, MCF-7 and MCF-10A, which are estrogen receptorpositive (ER+) and estrogen receptor-negative (ER-), respectively. To study the clastogenic potential by whole cell and flow karyotype damage, cells were exposed to environmentally relevant concentrations of ATZ, Cd, As and NO 3 for 4 and 7 days. Results indicated that all treatments induced whole cell clastogenicity in MCF-7 cells; except Cd and NO3 a...

Glycobiology

Bladder cancer is the ninth most frequently diagnosed cancer worldwide, and there is a need to de... more Bladder cancer is the ninth most frequently diagnosed cancer worldwide, and there is a need to develop new biomarkers for staging and prognosis of this disease. Here we report that cell lines derived from low-grade and high-grade bladder cancers exhibit major differences in expression of glycans in surface glycoproteins. We analyzed protein glycosylation in three low-grade bladder cancer cell lines RT4 (grade-1-2), 5637 (grade-2), and SW780 (grade-1), and three high-grade bladder cancer cell lines J82COT (grade-3), T24 (grade-3) and TCCSUP (grade-4), with primary bladder epithelial cells, A/T/N, serving as a normal bladder cell control. Using a variety of approaches including flow cytometry, immunofluorescence, glycomics and gene expression analysis, we observed that the low-grade bladder cancer cell lines RT4, 5637 and SW780 express high levels of the fucosylated Lewis-X antigen (Lex, CD15) (Galβ1–4(Fucα1–3)GlcNAcβ1-R), while normal bladder epithelial A/T/N cells lack Lex expressio...

International Journal of Environmental Research and Public Health

Contaminants of Emerging Concern (CECs) with estrogenic or estrogenic-like activity have been inc... more Contaminants of Emerging Concern (CECs) with estrogenic or estrogenic-like activity have been increasingly detected in aquatic environments and have been an issue of global concern due to their potential negative effects on wildlife and human health. This study used the MCF-7 cell proliferation assay (E-Screen) to assess the estrogenic activity profiles in Maryland Coastal Bays (MCBs), a eutrophic system of estuaries impacted by human activities. Estrogenic activity was observed in all study sites tested. Water samples from MCBs increased MCF-7 cell proliferation above the negative control from 2.1-fold at site 8, located in Sinepuxent Bay close to the Ocean City Inlet, to 6.3-fold at site 6, located in Newport Bay. The proliferative effects of the sediment samples over the negative control ranged from 1.9-fold at the Assateague Island National Seashore site to 7.7-fold at the Public Landing site. Moreover, elevated cell proliferation (p < 0.05) was observed when cells were co-ex...

Water

The suspended particulate organic matter (SPOM) in transitional waters such as the Maryland Coast... more The suspended particulate organic matter (SPOM) in transitional waters such as the Maryland Coastal Bays (MCBs) is derived from allochthonous and autochthonous sources. Little is known, however, about the contribution of terrestrially derived organic matter to SPOM in the MCBs. The sources of SPOM in the MCBs were evaluated using stable isotope ratios of nitrogen (δ15N) and carbon (δ13C), and C/N molar ratios. The values of SPOM δ15N, δ13C and C/N ratios from samples collected seasonally (July 2014 to October 2017) at 13 sites ranged from −0.58 to 10.51‰, −26.85 to −20.33‰, and 1.67 to 11.36, respectively, indicating a mixture of terrestrial SPOM transported by tributaries, marine organic matter from phytoplankton, and sewage. SPOM δ13C levels less than −24‰, suggesting the dominance of terrestrially derived carbon, occurred mainly at sites close to the mouths of tributaries, and were less depleted at sites near the ocean. The mean value of SPOM δ13C was higher in October 2014 (−22....

Water, 2020

The suspended particulate organic matter (SPOM) in transitional waters such as the Maryland Coast... more The suspended particulate organic matter (SPOM) in transitional waters such as the Maryland Coastal Bays (MCBs) is derived from allochthonous and autochthonous sources. Little is known, however, about the contribution of terrestrially derived organic matter to SPOM in the MCBs. The sources of SPOM in the MCBs were evaluated using stable isotope ratios of nitrogen (δ 15 N) and carbon (δ 13 C), and C/N molar ratios. The values of SPOM δ 15 N, δ 13 C and C/N ratios from samples collected seasonally (July 2014 to October 2017) at 13 sites ranged from −0.58 to 10.51% , −26.85 to −20.33% , and 1.67 to 11.36, respectively, indicating a mixture of terrestrial SPOM transported by tributaries, marine organic matter from phytoplankton, and sewage. SPOM δ 13 C levels less than −24% , suggesting the dominance of terrestrially derived carbon, occurred mainly at sites close to the mouths of tributaries, and were less depleted at sites near the ocean. The mean value of SPOM δ 13 C was higher in Oct...