History of contaminant inputs into Lake Mead derived from sediment cores

Assessing the changes in contaminant inputs (both organic and inorganic) over time is important in determining sources and sinks of these inputs. Variations in contaminant input were assessed in four sediment cores taken in 1998 from three different parts of Lake Mead (two from Las Vegas Bay and one from Overton Arm and Virgin Basin). Sediments were analyzed for major and trace elements, radionuclides, and organic compounds. Anthropogenic contaminant concentrations are greatest in Las Vegas Bay reflecting inputs from the Las Vegas urban area, although concentrations are low compared to sediment quality guidelines and to other USA lakes. One exception to this pattern was higher mercury concentrations in the Virgin Basin core. The Virgin Basin core is in the main body of the reservoir and is influenced by the hydrology of the Colorado River, which changed after completion of Glen Canyon Dam. Major- and trace-elements in the core show pronounced shifts in the early 1960s and, in many cases, gradually return to concentrations more typical of pre-1960s by the 1980s and 1990s, after the filling of Lake Powell upstream. The Overton Arm is the sub-basin least effected by anthropogenic contaminant inputs. Cores from Las Vegas Bay taken in 2007 were analyzed for emerging contaminants and although data are still preliminary, detections of musk fragrances have been found only in the upper 10 – 15 cm of the core, indicating that these compounds either degrade with time or have only been accumulating for the past 10 – 20 years

Organochlorine Chemical Residues in Northern Cardinal (Cardinalis cardinalis) Eggs from Greater Washington, DC USA

Northern Cardinal eggs from six neighborhoods near Washington DC were analyzed for organochlorine pesticides and PCBs. All compounds were detected more frequently and at higher concentrations in more heavily urbanized neighborhoods. DDT (mostly as p,pʹ-DDE) was detected in all neighborhoods. p,pʹ-DDT was typically 0.5‒16 ng/g (ww) in most suburban neighborhoods but was not detected (\u3c 0.1 ng/g) in more rural areas; however, p,pʹ-DDT was 127‒1130 ng/g in eggs from two suburban Maryland nests and comprised 65.7% of total p,pʹ-DDT isomers in the most contaminated sample, indicating recent exposure to un-weathered DDT. Total chlordane (sum of 5 compounds) was 2‒70 ng/g; concentrations were greatest in older suburban neighborhoods. Total PCB (sum of detected congeners) was \u3c 5‒21 ng/g. Congener patterns were similar in all neighborhoods and resembled those typical of weathered mixtures. Results indicate that wildlife remains exposed to low concentrations of legacy contaminants in suburban neighborhoods and that cardinal eggs can be used to monitor local- ized contamination

ENVIRONMENTAL CONTAMINANTS ASSOCIATED WITH A SWINE CONCENTRATED ANIMAL FEEDING OPERATION AND IMPLICATIONS FOR MCMURTREY NATIONAL WILDLIFE REFUGE

Waste generated by concentrated animal feeding operations (CAFOs) may contain a variety of contaminants including nutrients, pathogens, trace elements, antibiotics, and hormones. In 2000, the U.S. Fish and Wildlife Service began to characterize CAFO contaminants in lagoons, canals, and created wetlands operated by Hastings Pork, a large swine CAFO adjacent to McMurtrey National Wildlife Refuge (McMurtrey) in Clay County, Nebraska. The created wetlands were designed to attract waterfowl; therefore, the primary purpose of this research was to evaluate whether migratory waterfowl were likely exposed to CAFO contaminants. A secondary research objective was to determine if created wetland water was suitable as a supplementary water source for McMurtrey. Wetlands created from swine wastewater effluent had 5-50 fold greater concentrations of phosphorus, ammonia, and total nitrogen and 2-3 fold greater salinity compared to control sites. Cyanobacteria (Microcystis spp.) were abundant in the created wetlands and microcystin toxins were detected in concentrated water samples. Tetracycline, macrolide, and diterpene antibiotics were detected in lagoon and canal sediment and water samples; however, in the created wetlands only oxytetracycline was detected (once in sediment at 41 nanograms per gram). Concentrations of 17-β estradiol and testosterone in CAFO wastewater (n=4) exceeded toxicity thresholds for aquatic life. Fecal coliform and streptococci counts in water (n=38) generally exhibited a decreasing gradient with lagoons \u3e canals \u3e created wetlands \u3e McMurtrey. Bacteria (Salmonella spp. and Yersinia enterocolitica) were recovered in the created wetlands but not McMurtrey. Created wetland invertebrate communities were dominated by chironomid species and had lower taxa diversity when compared to McMurtrey. Eutrophication of created wetlands may represent the greatest health threat to waterfowl by creating an environment conducive to cyanobacteria blooms and outbreaks of avian botulism and avian cholera. Trace elements from swine waste will likely continue to accumulate in the created wetlands over time, leading to an increased risk of exposure to wetland biota. Research is ongoing and includes use of sentinel mallards (Anas platyrhynchos) to further evaluate the need to decrease concentrations of CAFO contaminants in swine wastewater before it is used to create waterfowl habitat

Organochlorine Chemical Residues in Northern Cardinal (Cardinalis cardinalis) Eggs from Greater Washington, DC USA

Northern Cardinal eggs from six neighborhoods near Washington DC were analyzed for organochlorine pesticides and PCBs. All compounds were detected more frequently and at higher concentrations in more heavily urbanized neighborhoods. DDT (mostly as p,pʹ-DDE) was detected in all neighborhoods. p,pʹ-DDT was typically 0.5‒16 ng/g (ww) in most suburban neighborhoods but was not detected (\u3c 0.1 ng/g) in more rural areas; however, p,pʹ-DDT was 127‒1130 ng/g in eggs from two suburban Maryland nests and comprised 65.7% of total p,pʹ-DDT isomers in the most contaminated sample, indicating recent exposure to un-weathered DDT. Total chlordane (sum of 5 compounds) was 2‒70 ng/g; concentrations were greatest in older suburban neighborhoods. Total PCB (sum of detected congeners) was \u3c 5‒21 ng/g. Congener patterns were similar in all neighborhoods and resembled those typical of weathered mixtures. Results indicate that wildlife remains exposed to low concentrations of legacy contaminants in suburban neighborhoods and that cardinal eggs can be used to monitor local- ized contamination

Loading capacity and chromatographic behavior of a porous graphitic carbon column for polychlorinated biphenyls

A porous graphitic carbon column (Hypercarb) was used for the fractionation of polychlorinated biphenyls (PCBs) into classes of 2-4 ortho chlorines, 1 ortho chlorine and 0 ortho chlorine congeners. A method was developed that combined the fractionation of PCBs, polychlorinated dibenzo-p-dioxins and dibenzofurans in a variety of biotic environmental samples. Many of these samples have high concentrations of PCBs which cause fractionation problems as adsorption sites on the graphitic surface are occupied. The loading capacity of the column for PCBs was determined by injecting up to 1 mg of total PCBs and monitoring changes in chromatographic behavior of tetra- / di-ortho, mono-ortho and non-ortho substituted PCBs. Effective loading capacities were 1 mg for tetra- / di-ortho PCBs, but only 3–5 µg for non-ortho PCBs and about 2 µg for mono-ortho PCBs. Loading capacity of the PGC column for environmental fish and avian egg samples was determined to depend on the mono-ortho and non-ortho PCB levels found in these samples

Environmental Contaminants in Fish and Their Associated Risk to Piscivorous Wildlife in the Yukon River Basin, Alaska

Organochlorine chemical residues and elemental contaminants were measured in northern pike (Esox lucius), longnose sucker (Catostomus catostomus), and burbot (Lota lota) from 10 sites in the Yukon River Basin (YRB) during 2002. Contaminant concentrations were compared to historical YRB data and to toxicity thresholds for fish and piscivorous wildlife from the scientific literature. A risk analysis was conducted to screen for potential hazards to piscivorous wildlife for contaminants that exceeded literature-based toxicity thresholds. Concentrations of total DDT (sum of p,p¢-homologs; 1.09–13.6 ng/g), total chlordane (0.67–7.5 ng/g), dieldrin (\u3c0.16–0.6 ng/g), toxaphene (\u3c11–34 ng/g), total PCBs (\u3c20– 87 ng/g), TCDD-EQ (\u3c1.7 pg/g), arsenic (0.03–1.95 lg/g), cadmium (\u3c0.02–0.12 lg/g), copper (0.41–1.49 lg/g), and lead (\u3c0.21–0.27 lg/g) did not exceed toxicity thresholds for growth and reproduction in YRB fish. Concentrations of mercury (0.08–0.65 lg/g), selenium (0.23–0.85 lg/g), and zinc (11–56 lg/g) exceeded toxicity thresholds in one or more samples and were included in the risk analysis for piscivorous wildlife. No effect hazard concentrations (NEHCs) and low effect hazard concentrations (LEHCs), derived from literaturebased toxicity reference values and avian and mammalian life history parameters, were calculated for mercury, selenium, and zinc. Mercury concentrations in YRB fish exceeded the NEHCs for all bird and small mammal models, which indicated that mercury concentrations in fish may represent a risk to piscivorous wildlife throughout the YRB. Low risk to piscivorous wildlife was associated with selenium and zinc concentrations in YRB fish. Selenium and zinc concentrations exceeded the NEHCs and LEHCs for only the small bird model. These results indicate that mercury should continue to be monitored and assessed in Alaskan fish and wildlife

Correction to: Organochlorine Chemical Residues in Northern Cardinal (Cardinalis cardinalis) Eggs from Greater Washington, DC USA

The original version of this article contained a mistake. Author name in the text citation and reference in section should be Maldonado et al (2016), it was incorrectly spelled as Maldinado et al (2015)