The A.D. 2011 Tohoku-Oki M w 9 earthquake ruptured the megathrust up to the Japan Trench with a large displacement and caused a catastrophic tsunami. This study is the first to use short-lived radioisotopes, including those emitted by the damaged nuclear reactors at the Fukushima Daiichi nuclear power plant (Japan), to document the remobilization of the upper few centimeters of sediment as a highly significant process triggered by the earthquake and its aftershocks. Targeting the post-earthquake environment allowed characterization of the sedimentary signature of this event for a better understanding of paleoearthquakes in Japan and other tectonically active boundary areas. The results stem from 23 piston cores recovered by the 2013 expedition NT13-19 of the Japan Agency for Marine-Earth Science and Technology. We document submarine homogeneous muddy flow deposits that were triggered by ground motion in 2011. They are highly enriched with excess (xs) xs 210 Pb, requiring only centimeters-deep sediment remobilization over large areas of the seafloor. Some contain 134 Cs and 137 Cs radioisotopes derived from the Fukushima nuclear reactors, indicating that sedimentation persisted for at least 30 days after the main shock. We found these deposits at all sampling sites in an ∼5000 km 2 area of the seafloor in 4000–6000 m of water depth. The study area extends for ∼260 km parallel to the strike of the trench. The thickness of this "Tohoku layer" (3–200 cm) increases toward the zone of maximum megathrust slip, where deposits are thickest. These results demonstrate that the shaking of the seafloor above large megathrust ruptures near the trench remobilized surficial unconsolidated sediment for hundreds of kilometers. The characteristics of these deposits may typify deposits resulting from large fault slips like that of the Tohoku-Oki earthquake, but also other earthquake deposits, contributing to their identification in the sedimentary record globally.

The chronology of a 184-cm-long sediment core from Onondaga Lake, New York (USA), is known with annual certainty from 2006 to the 1880s. Sediment age is known with similar precision, but less confidence, from the 1880s to the 1820s. Paired dark and light laminations are visible throughout most of the core, and are confirmed as annual varves by individual particle analysis and well-defined 137Cs age horizons. The varves can be correlated with historical impacts on the lake to within 1–2 years, stratigraphic resolution that is comparable to the best obtained from other varved lakes in which minimally disruptive sampling techniques such as freeze coring were used. Seven stratigraphic units and four sub-units were defined using visual description and the Sr/Ca profile. Onset of laminations correlates to an 1822 change in lake level. The core contains evidence of past water-quality changes, including: (1) shortened extent of seasonal calcite supersaturation in the lake during the 1800s, (2) salt industry activity during the mid-1800s, (3) calcite-precipitation (whiting) events during the 1900s, and (4) greater impact of local hydrology on lake sedimentation prior to 1900. During the late 1800s, varves were interrupted by an approximately 12-year interval of non-laminated sediment that corresponds to a time of major alteration and industrial development in the watershed. There are no apparent turbidite layers in the sediment column. Onondaga Lake owes its remarkably preserved, 200-year sediment record largely to its high rate of sediment accumulation. The rate rises from 0.1 to 0.3 cm/year just after artificial lowering of the lake water level in 1822, to about 1 cm/year during the 1900s. This study shows that anthropogenically altered lakes can contain stratigraphic records in their bottom sediments with temporal resolution comparable to the annual time steps of mechanistic water-quality models. It also demonstrates the utility of the Sr/Ca ratio profile as a sediment descriptor in carbonate-rich lake systems and provides a detailed stratigraphic basis for continued historical water-quality assessment in what used to be one of the world’s most polluted lakes.

La Organización Mundial de la Salud (OMS) refiere que las etapas básicas de evaluación de la carga de morbilidad ambiental por metilmercurio son las siguientes: determinar la distribución de las concentraciones de mercurio en el cabello de las mujeres en edad fértil que consumen pescado contaminado con metilmercurio; calcular los descensos del coeficiente intelectual en los lactantes basándose en la distribución de las concentraciones de mercurio en el cabello de mujeres en edad fértil, y estimar la tasa de incidencia de retraso mental leve inducido por el metilmercurio y la consiguiente carga de morbilidad expresada en años de vida ajustados por discapacidad (AVAD). Esto debe realizarse para cada población. El objetivo del estudio fue desarrollar una etapa de evaluación gestacional básica del metilmercurio a través del cabello del recién nacido que permita identificar a infantes en zonas de riesgo ambiental, y posterior evaluación neuroconductual.

Relative contributions of polycyclic aromatic hydrocarbons (PAHs) from combustion sources of wood, petroleum, and coal were computed in sediments from Central Park Lake in New York City (NY, USA) by chemical mass balance based on several reliable source indicators. These indicators are the ratio of retene to the sum of retene and chrysene, the ratio of 1,7‐dimethylphenanthrene (DMP) to 1,7‐DMP and 2,6‐DMP, and the ratio of fluroanthene to fluroanthene and pyrene. The authors found that petroleum combustion–derived PAH fluxes generally followed the historical consumption data of New York State. Coal combustion‐derived PAH flux peaked approximately in the late 1910s, remained at a relatively high level over the next 3 decades, then rapidly declined from the 1950s to the 1960s; according to historical New York State coal consumption data, however, there was a 2‐peak trend, with peaks around the early 1920s and the mid‐1940s. The 1940s peak was not observed in Central Park Lake, most likely because of the well‐documented shift from coal to oil as the major residential heating fuel in New York City during the late 1930s. It was widely believed that the decreased PAH concentrations and fluxes in global sediments during the last century resulted from a major energy shift from coal to petroleum. The data, however, show that this shift occurred from 1945 through the 1960s and did not result in an obvious decline. The sharpest decrease, which occurred in the 1970s was not predominantly related to coal usage but rather was the result of multiple factors, including a decline in petroleum usage largely, the introduction of low sulfur–content fuel in New York City, and the introduction of emission‐control technologies. Environ Toxicol Chem 2014;33:985–992. © 2014 SETAC

The distribution of alkyltrimethylammonium compounds (ATMAC), cationic surfactants used in a wide variety of applications, has been determined in sediments from Jamaica Bay (NY). Total concentrations in surficial sediments collected between 1998 and 2008 ranged from 361 to 6750 ng/g. The highest values were found in samples from a deeper basin directly affected by treated wastewater discharges. Behentrimonium, a mixture dominated by a homologue having 22 carbon atoms in its alkyl chain (ATMAC 22), was identified for the first time using time-of-flight mass spectrometry and accounted for approximately 80% of the total ATMAC in recent sediment samples. Analyses of a dated sediment core and subsequent surface grab samples revealed an exponential increase in concentration over the last three decades with a doubling time of 3.9 years. Similar temporal trends were seen in surface samples from other sites in Jamaica Bay and Newton Creek (NY), another site greatly influenced by wastewater discharges. This dramatic increase in ATMAC 22 reflects greater use of behentrimonium and likely replacement of other products containing other ATMAC homologues in personal care products. Further monitoring is recommended to assess the environmental risk and fate of this persistent emerging contaminant.

BACKGROUND:Elevated concentrations of mercury have been documented in fish in Lake Chapala in central Mexico, an area that is home to a large subsistence fishing community. However, neither the extent of human mercury exposure nor its sources and routes have been elucidated.METHODS:Total mercury concentrations were measured in samples of fish from Lake Chapala; in sections of sediment cores from the delta of Rio Lerma, the major tributary to the lake; and in a series of suspended-particle samples collected at sites from the mouth of the Lerma to mid-Lake. A cross-sectional survey of 92 women ranging in age from 18-45 years was conducted in three communities along the Lake to investigate the relationship between fish consumption and hair mercury concentrations among women of child-bearing age.RESULTS:Highest concentrations of mercury in fish samples were found in carp (mean 0.87 ppm). Sediment data suggest a pattern of moderate ongoing contamination. Analyses of particles filtered from the water column showed highest concentrations of mercury near the mouth of the Lerma. In the human study, 27.2% of women had >1 ppm hair mercury. On multivariable analysis, carp consumption and consumption of fish purchased or captured from Lake Chapala were both associated with significantly higher mean hair mercury concentrations.CONCLUSIONS:Our preliminary data indicate that, despite a moderate level of contamination in recent sediments and suspended particulate matter, carp in Lake Chapala contain mercury concentrations of concern for local fish consumers. Consumption of carp appears to contribute significantly to body burden in this population. Further studies of the consequences of prenatal exposure for child neurodevelopment are being initiated.

BACKGROUND:Tetraethyl lead was phased out of gasoline in Uganda in 2005. Recent mitigation of an important source of lead exposure suggests examination and re-evaluation of the prevalence of childhood lead poisoning in this country. Ongoing concerns persist about exposure from the Kiteezi landfill in Kampala, the country's capital. OBJECTIVES:We determined blood lead distributions among Kampala schoolchildren and identified risk factors for elevated blood lead levels (EBLLs; >or= 10 microg/dL). Analytical approach: Using a stratified, cross-sectional design, we obtained blood samples, questionnaire data, and soil and dust samples from the homes and schools of 163 4- to 8-year-old children representing communities with different risks of exposure. RESULTS:The mean blood lead level (BLL) was 7.15 microg/dL; 20.5% of the children were found to have EBLL. Multivariable analysis found participants whose families owned fewer household items, ate canned food, or used the community water supply as their primary water source to have higher BLLs and likelihood of EBLLs. Distance < 0.5 mi from the landfill was the factor most strongly associated with increments in BLL (5.51 microg/dL, p < 0.0001) and likelihood of EBLL (OR = 4.71, p = 0.0093). Dust/soil lead was not significantly predictive of BLL/EBLL. CONCLUSIONS:Lead poisoning remains highly prevalent among school-age children in Kampala. Confirmatory studies are needed, but further efforts are indicated to limit lead exposure from the landfill, whether through water contamination or through another mechanism. Although African nations are to be lauded for the removal of lead from gasoline, this study serves as a reminder that other sources of exposure to this potent neurotoxicant merit ongoing attention.

The biocides triclosan and triclocarban are wastewater contaminants whose occurrence and fate in estuarine sediments remain unexplored. We examined contaminant profiles in 137Cs/7Be-dated sediment cores taken near wastewater treatment plants in the Chesapeake Bay watershed (CB), Maryland and Jamaica Bay(JB), New York. In JB, biocide occurrences tracked the time course of biocide usage and wastewater treatment strategies employed, first appearing in the 1950s (triclocarban) and 1960s (triclosan), and peaking in the late 1960s and 1970s (24 +/- 0.54 and 0.8 +/- 0.4 mg/kg dry weight, respectively). In CB, where the time of sediment accumulation was not as well constrained by 137Cs depth profiles, triclocarban was only measurable in 137Cs-bearing sediments, peaking at 3.6 +/- 0.6 mg/ kg midway through the core and exceeding 1 mg/kg in recent deposits. In contrast, triclosan concentrations were low or not detectable in the CB core. Analysis of CB sediment by tandem mass spectrometry produced the first evidence for complete sequential dechlorination of triclocarban to the transformation products dichloro-, monochloro-, and unsubstituted carbanilide, which were detected at maxima of 15.5 +/- 1.8, 4.1 +/- 2.4, and 0.5 +/- 0.1 mg/kg, respectively. Concentrations of all carbanilide congeners combined were correlated with heavy metals (R2 > 0.64, P < 0.01), thereby identifying wastewater as the principal pathway of contamination. Environmental persistence over the past 40 years was observed for triclosan and triclocarban in JB, and for triclocarban's diphenylurea backbone in CB sediments.

BACKGROUND:Polychlorinated biphenyls and other organochlorines have contaminated the Hudson River and New York/New Jersey Harbor for many decades. Although body burdens and health effects resulting from exposure to these pollutants have been measured in other populations, little is known about anglers from the lower Hudson area.METHODS:Anglers were recruited from fishing clubs and along piers on the lower Hudson River. One hundred twenty-five participants provided blood samples and questionnaire information. Serum was analyzed at Mount Sinai School of Medicine for organochlorines.RESULTS:Mean concentration of total PCB congeners was 4.78 microg/L. A non-significant adjusted mean difference of -0.59 microg/L was observed between local fish eaters and non-eaters with higher levels among the non-eaters. Similar negative, but non-significant associations were observed for p,p'-DDT, HCB, and beta-BHC. For pp'-DDE, and several chlordane residues, levels were higher among anglers reporting local fish consumption, but the difference was statistically significant only for TN.CONCLUSIONS:These findings suggest eating fish from the lower Hudson River and NY/NJ harbor is not associated with an increased body burden of PCBs or most other organochlorines.

Soot black carbon (here expressed as GBC) is present in sediments of Central Park and Prospect Park Lakes, New York City (NYC), and peaks in the middle of the 20th Century at the highest values (1-3% dry weight) ever reported in urban lakes. During that period (approximately 1940-1970), the GBC represents up to 28% of the total organic carbon (OC). Radionuclide-normalized whole core inventories of accumulated GBC are similar in the two lakes which are separated by approximately 15 km, suggesting that emissions of fine soot particles may have accumulated homogeneously over at least the urban center of NYC. The distribution of polycyclic aromatic hydrocarbons (PAHs) in the sediments is decoupled from that of GBC. The highest levels of total PAHs correspond to peak coal use for space heating in NYC in the early 1900s. In contrast, GBC concentrations were highest in the mid 1900s, a period when oil combustion dominated local fossil fuel use and incineration of municipal solid waste (MSW) was common practice in NYC. Decreases in GBC levels observed in more recently deposited sediments are consistent with improvements in particle emissions control systems. Non-soot BC (char) was identified by a high carbon to nitrogen (C/N) ratio that persisted after correction for GBC. This likely tracer of MSW incineration was estimated to contribute an additional '35% of total organic carbon found in the sediments deposited during the peak period of combustion. The temporal trends of soot-BC observed in our lake cores do not agree with published historical reconstructions based on fuel consumption and estimated emission factors.