کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4421019 1308502 2011 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Mercury bioaccumulation and biomagnification in Ozark stream ecosystems
موضوعات مرتبط
علوم زیستی و بیوفناوری علوم محیط زیست شیمی زیست محیطی
پیش نمایش صفحه اول مقاله
Mercury bioaccumulation and biomagnification in Ozark stream ecosystems
چکیده انگلیسی

Crayfish (Orconectes spp.), Asian clam (Corbicula fluminea), northern hog sucker (hog sucker; Hypentelium nigricans), and smallmouth bass (smallmouth; Micropterus dolomieu) from streams in southeastern Missouri (USA) were analyzed for total mercury (HgT) and for stable isotopes of carbon (δ13C), nitrogen (δ15N), and sulfur (δ34S) to discern Hg transfer pathways. HgT concentrations were generally lowest in crayfish (0.005–0.112 μg/g dw) and highest in smallmouth (0.093–4.041 μg/g dw), as was δ15N. HgT was also lower and δ15N was higher in all biota from a stream draining a more heavily populated historical lead–zinc mining area than from similar sites with mostly undeveloped forested watersheds. δ13C in biota was lowest at spring-influenced sites, reflecting CO2 inputs and temperature influences, and δ34S increased from south to north in all taxa. However, HgT was not strongly correlated with either δ13C or δ34S in biota. Trophic position (TP) computed from crayfish δ15N was lower in hog suckers (mean=2.8) than in smallmouth (mean=3.2), but not at all sites. HgT, δ13C, δ34S, and TP in hog suckers increased with total length (length) at some sites, indicating site-specific ontogenetic diet shifts. Changes with length were less evident in smallmouth. Length-adjusted HgT site means in both species were strongly correlated with HgT in crayfish (r2=0.97, P<0.01), but not with HgT in Corbicula (r2=0.02, P>0.05). ANCOVA and regression models incorporating only TP and, for hog suckers, length, accurately and precisely predicted HgT concentrations in both fish species from all locations. Although low compared to many areas of the USA, HgT (and therefore methylmercury) concentrations in smallmouth and hog suckers are sufficiently high to represent a threat to human health and wildlife. Our data indicate that in Ozark streams, Hg concentrations in crayfish are at least partly determined by their diet, with concentrations in hog suckers, smallmouth, and possibly other higher-level consumers largely determined by concentrations in crayfish and other primary and secondary consumers, fish growth rates, and TP.


► Fish and invertebrates were analyzed for total Hg and for stable isotopes of C, N, and S.
► Length-adjusted total Hg in both fish species was strongly correlated with Hg in crayfish.
► Stable isotope and Hg changes in hog suckers indicated site-specific ontogenetic diet shifts.
► Ontogentic diet shifts were less evident in smallmouth bass.
► Hg in both fishes was sufficiently high to represent a threat to human and wildlife health.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Ecotoxicology and Environmental Safety - Volume 74, Issue 8, November 2011, Pages 2215–2224
نویسندگان
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