Limits...
Biomonitoring Heavy Metal Pollution Using an Aquatic Apex Predator, the American Alligator, and Its Parasites.

Tellez M, Merchant M - PLoS ONE (2015)

Bottom Line: Interestingly, Fe levels were significantly greater in intestinal trematodes than their alligator hosts when analyzed independently from other parasitic taxa.Interestingly, parasitic abundance decreased as levels of As increased.Conclusively, we suggest that parasites, particularly intestinal trematodes, are superior biomagnifiers of As, Cu, Se, and Zn, whereas alligators are likely good biological indicators of Fe, Cd, and Pb levels within the environment.

View Article: PubMed Central - PubMed

Affiliation: Marine Science Institute, University of California Santa Barbara, Santa Barbara, California, United States of America.

ABSTRACT
Monitoring the bioaccumulation of chemical elements within various organismal tissues has become a useful tool to survey current or chronic levels of heavy metal exposure within an environment. In this study, we compared the bioaccumulations of As, Cd, Cu, Fe, Pb, Se, and Zn between the American alligator, Alligator mississippiensis, and its parasites in order to establish their use as bioindicators of heavy metal pollution. Concomitant with these results, we were interested to determine if parasites were more sensitive bioindicators of heavy metals relative to alligators. We found parasites collectively accumulated higher levels of As, Cu, Se, and Zn in comparison to their alligator hosts, whereas Fe, Cd, and Pb concentrations were higher in alligators. Interestingly, Fe levels were significantly greater in intestinal trematodes than their alligator hosts when analyzed independently from other parasitic taxa. Further analyses showed alligator intestinal trematodes concentrated As, Cu, Fe, Se, and Zn at significantly higher levels than intestinal nematodes and parasites from other organs. However, pentastomids also employed the role as a good biomagnifier of As. Interestingly, parasitic abundance decreased as levels of As increased. Stomach and intestinal nematodes were the poorest bioaccumulators of metals, yet stomach nematodes showed their ability to concentrate Pb at orders of magnitude higher in comparison to other parasites. Conclusively, we suggest that parasites, particularly intestinal trematodes, are superior biomagnifiers of As, Cu, Se, and Zn, whereas alligators are likely good biological indicators of Fe, Cd, and Pb levels within the environment.

No MeSH data available.


Related in: MedlinePlus

Comparative data of As concentrations among pentastomids from SWLA, SELA, and FL.Quantity of pentastomids analyzed from each region is shown (n =).
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4640838&req=5

pone.0142522.g002: Comparative data of As concentrations among pentastomids from SWLA, SELA, and FL.Quantity of pentastomids analyzed from each region is shown (n =).

Mentions: Given the diverse array of microhabitats throughout southern Louisiana and north-central Florida in which alligator and parasite samples were collected, it was anticipated that heavy metal levels among host and parasites would differ as a reflection of the different environments and prey species throughout the range. However, bioaccumulation levels of heavy metals did not differ significantly among locality sites. However, en masse, parasites showed higher accumulation of As, Fe, Cu, and Zn in SWLA. Interestingly, Fe, Cu, and Zn coincide with the high levels detected from their alligator hosts in SWLA or Florida. The high bioaccumulation of As among parasites, however, did not correlate. Collectively as a group, parasites from SWLA concentrated As at a higher magnitude (5350 mg/kg vs. 7 mg/kg detected among SWLA alligators), however levels of As were slightly higher among alligators from SELA (11 mg/kg). Yet, despite these contrasting results, the bioaccumulation of As was highest among lung pentastomids from SELA (Fig 2). The above results generate two plausible explanations. First, it is hypothesized that a large disparity between parasite and host bioaccumulation levels (i.e., a high ratio [Cparasite/Chost]) are indicative of acute pollutant exposure, whereas long or chronic exposure of the pollutant correlates with high concentrations in both the host and parasites [17,19,22]. Thus, the significant difference of As bioaccumulation between alligators and their collective parasites illustrates the possible acute exposure to this trace metal within SWLA (Table 7). Secondly, given that lungs are the site of infection for pentastomids, the biomagnification of As among SELA pentastomids is perhaps caused by indirect (excess circulation of As among alligator hosts via consumed prey), and direct (airborne, inhaled through alligator respiratory tract) exposure. Compared to other collection sites, SELA is highly industrialized and urbanized, which can contribute to higher soil, water, and aerial As pollution [56–58]. Based on these data, pentastomids, in addition to trematodes, may be ideal bioindicators of environmental and alligator accumulation of As.


Biomonitoring Heavy Metal Pollution Using an Aquatic Apex Predator, the American Alligator, and Its Parasites.

Tellez M, Merchant M - PLoS ONE (2015)

Comparative data of As concentrations among pentastomids from SWLA, SELA, and FL.Quantity of pentastomids analyzed from each region is shown (n =).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4640838&req=5

pone.0142522.g002: Comparative data of As concentrations among pentastomids from SWLA, SELA, and FL.Quantity of pentastomids analyzed from each region is shown (n =).
Mentions: Given the diverse array of microhabitats throughout southern Louisiana and north-central Florida in which alligator and parasite samples were collected, it was anticipated that heavy metal levels among host and parasites would differ as a reflection of the different environments and prey species throughout the range. However, bioaccumulation levels of heavy metals did not differ significantly among locality sites. However, en masse, parasites showed higher accumulation of As, Fe, Cu, and Zn in SWLA. Interestingly, Fe, Cu, and Zn coincide with the high levels detected from their alligator hosts in SWLA or Florida. The high bioaccumulation of As among parasites, however, did not correlate. Collectively as a group, parasites from SWLA concentrated As at a higher magnitude (5350 mg/kg vs. 7 mg/kg detected among SWLA alligators), however levels of As were slightly higher among alligators from SELA (11 mg/kg). Yet, despite these contrasting results, the bioaccumulation of As was highest among lung pentastomids from SELA (Fig 2). The above results generate two plausible explanations. First, it is hypothesized that a large disparity between parasite and host bioaccumulation levels (i.e., a high ratio [Cparasite/Chost]) are indicative of acute pollutant exposure, whereas long or chronic exposure of the pollutant correlates with high concentrations in both the host and parasites [17,19,22]. Thus, the significant difference of As bioaccumulation between alligators and their collective parasites illustrates the possible acute exposure to this trace metal within SWLA (Table 7). Secondly, given that lungs are the site of infection for pentastomids, the biomagnification of As among SELA pentastomids is perhaps caused by indirect (excess circulation of As among alligator hosts via consumed prey), and direct (airborne, inhaled through alligator respiratory tract) exposure. Compared to other collection sites, SELA is highly industrialized and urbanized, which can contribute to higher soil, water, and aerial As pollution [56–58]. Based on these data, pentastomids, in addition to trematodes, may be ideal bioindicators of environmental and alligator accumulation of As.

Bottom Line: Interestingly, Fe levels were significantly greater in intestinal trematodes than their alligator hosts when analyzed independently from other parasitic taxa.Interestingly, parasitic abundance decreased as levels of As increased.Conclusively, we suggest that parasites, particularly intestinal trematodes, are superior biomagnifiers of As, Cu, Se, and Zn, whereas alligators are likely good biological indicators of Fe, Cd, and Pb levels within the environment.

View Article: PubMed Central - PubMed

Affiliation: Marine Science Institute, University of California Santa Barbara, Santa Barbara, California, United States of America.

ABSTRACT
Monitoring the bioaccumulation of chemical elements within various organismal tissues has become a useful tool to survey current or chronic levels of heavy metal exposure within an environment. In this study, we compared the bioaccumulations of As, Cd, Cu, Fe, Pb, Se, and Zn between the American alligator, Alligator mississippiensis, and its parasites in order to establish their use as bioindicators of heavy metal pollution. Concomitant with these results, we were interested to determine if parasites were more sensitive bioindicators of heavy metals relative to alligators. We found parasites collectively accumulated higher levels of As, Cu, Se, and Zn in comparison to their alligator hosts, whereas Fe, Cd, and Pb concentrations were higher in alligators. Interestingly, Fe levels were significantly greater in intestinal trematodes than their alligator hosts when analyzed independently from other parasitic taxa. Further analyses showed alligator intestinal trematodes concentrated As, Cu, Fe, Se, and Zn at significantly higher levels than intestinal nematodes and parasites from other organs. However, pentastomids also employed the role as a good biomagnifier of As. Interestingly, parasitic abundance decreased as levels of As increased. Stomach and intestinal nematodes were the poorest bioaccumulators of metals, yet stomach nematodes showed their ability to concentrate Pb at orders of magnitude higher in comparison to other parasites. Conclusively, we suggest that parasites, particularly intestinal trematodes, are superior biomagnifiers of As, Cu, Se, and Zn, whereas alligators are likely good biological indicators of Fe, Cd, and Pb levels within the environment.

No MeSH data available.


Related in: MedlinePlus