Publications by authors named "Ronald A Hites"

Dieldrin, heptachlor epoxide, and oxychlordane are highly chlorinated, persistent, bicyclic epoxides that are widely present in the environment. Given the long-standing restrictions on the production and use of these compounds, it is appropriate to wonder if their environmental levels have decreased over time, and if so, how fast. The Integrated Atmospheric Deposition Network (IADN) provides this information by measuring the concentrations of these compounds in the atmosphere at six sites near the Great Lakes once every 12 days.

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Persistent insecticides have been classic environmental problems for 60-70 years─perhaps starting with Rachel Carson's indictment of DDT. Both national and international regulations have been put in place over the last 20-30 years to eventually eliminate these compounds from the environment. One focus is the atmosphere, which acts as a major long-range transport route of these pollutants from their numerous sources to many ecosystems.

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The nontarget identification of unsuspected organic pollutants in the environment is a topic of current interest, but it is not a new idea. Our laboratory has been engaged in this work for 50 years, and thus, it is timely to ask if our nontarget identifications of pollutants have mattered? The tool used to answer this question is the citation chronologies of several sets of nontarget identification papers we have published. Our papers on polycyclic aromatic hydrocarbons (1800 citations since 1972) and on halogenated flame retardants in the Great Lakes (800 citations since 2005) have clearly led to further work on the environmental sources and fates of these compounds.

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Let's imagine that you have just finished writing a scientific paper. The paper is well-structured and clearly written, and you are proud of it. Now is the time to submit it to a peer-reviewed journal and see what your colleagues think of it.

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Polycyclic aromatic hydrocarbon (PAH) concentrations were measured in atmospheric samples collected at five sites near the shores of the North American Great Lakes once every 12 days from 1997 to 2018 (inclusive). These data were analyzed using multiple linear regression statistics to isolate the environmental variables controlling these PAH concentrations. About 74% of the variability is related to the number of people living and working within 25 km of the sampling site.

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We define here "temporal environmental hysteresis" as the time lag between when a pollutant's input to the environment stops and when its concentration in the environment drops to some desired fraction of its maximum concentration. The goal of this paper is to investigate temporal environmental hysteresis for polybrominated diphenyl ethers (PBDEs), which were widely used as flame retardants in consumer goods. These compounds were taken off the North American market in two steps: At the end of 2004, the so-called Penta-BDE and Octa-BDE products were withdrawn, and at the end of 2013, the Deca-BDE product was also discontinued.

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The present study provides a comprehensive investigation of three suites of commonly used synthetic additives: phenolic and amino antioxidants and ultraviolet filters. The concentrations of 47 such compounds and their transformation products were measured in 20 atmospheric particle samples collected in Chicago, in 21 Canadian e-waste dust samples, in 32 Canadian and United States' residential dust samples, and in 10 sediment samples collected from the Chicago Sanitary and Ship Canal. Despite their large production volumes in the United States, environmental data on antioxidants and UV filters in North America is limited.

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The implementation of the Stockholm Convention (SC) in 2004 should become evident in decreases in environmental concentrations of various pollutants even in countries that not have ratified the SC. However, in some cases, there may be no decreases at all. This paper develops a statistical strategy for investigating time-series measurements such that the rate of change of a pollutant's concentrations at any time can be compared to those at an earlier or later time and thus determine the effectiveness of the SC at any location.

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The concentrations of a pollutant in people or in the environment are often changing as a function of time. In many cases, this rate of change may be relatively constant as a function of time; thus, first-order kinetics can be applied to these data. In other cases, the rate at which the concentrations of a pollutant are changing may be different before and after some event, for example before and after their regulation or usage restriction.

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Using high-resolution mass spectrometry, we identified tri(2,4-di- t-butylphenyl) phosphate (TDTBPP) in e-waste dust. This is a previously unsuspected pollutant that had not been reported before in the environment. To assess its abundance in the environment, we measured its concentration in e-waste dust, house dust, sediment from the Chicago Ship and Sanitary Canal, Indiana Harbor water filters, and filters from high-volume air samplers deployed in Chicago, IL.

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Data on atmospheric levels of toxic pollutants in samples collected near the Great Lakes are now readily available online to scientists, researchers, and the public on a website called IADN Data Viz (https://iadnviz.iu.edu/).

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Regulations designed to lower the concentrations of PCBs and DDTs in the environment have been in place since the 1970s, but the levels of PCBs are still high enough to cause fish consumption advisories for Great Lakes fish. The levels of PCBs and DDTs have been tracked in these fish since about 1975, and the rates at which these age-adjusted concentrations have been decreasing over the period 1999-2014 have been recently been estimated. This paper compares these rates to ones estimated from the entire data set (~1975-2014) and to rates estimated from changes in atmospheric concentrations, which have been tracked since 1992.

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Dechlorane Plus (DP) is a chlorinated flame retardant manufactured only in Niagara Falls, New York and in Huai'an, China. To determine if the environmental levels of this compound were changing significantly, we measured the long-term temporal trends of its concentrations near the Great Lakes between 2005 and 2015 using air (vapor + particle phase) samples (N = 1047) and precipitation samples (N = 449). We used a multiple linear regression model of DP concentrations to isolate the variabilities due to sampling date and population near the sampling site.

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The authors analyzed spatial and seasonal variations of current use pesticides (CUPs) levels in the atmospheric particulate phase in the Great Lakes basin. Twenty-four hour air samples were collected at six sites (two urban, two rural, and two remote) in 2015. The concentrations of 15 CUPs, including nine pyrethroid insecticides, four herbicides, one organophosphate insecticide, and one fungicide, were measured.

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The concentrations of α-, β-, and γ-hexabromocyclododecane (HBCDD) diastereomers in atmospheric particle phase samples were determined at four United States Integrated Atmospheric Deposition Network (IADN) sites located in the North American Great Lakes basin collected between 1 January and 31 December 2014. The concentrations ranged from 0.37 to 8.

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This study revisits and updates the Lake Michigan Mass Balance Project (LMMBP) for polychlorinated biphenyls (PCBs) that was conducted in 1994-1995. This work uses recent concentrations of PCBs in tributary and open lake water, air, and sediment to calculate an updated mass budget. Five of the 11 LMMBP tributaries were revisited in 2015.

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In this study, we measured the concentrations of 65 flame retardants in water samples from five Lake Michigan tributaries. These flame retardants included organophosphate esters (OPEs), brominated flame retardants (BFRs), and Dechlorane-related compounds. A total of 59 samples, including both the particulate and the dissolved phases, were collected from the Grand, Kalamazoo, Saint Joseph, and Lower Fox rivers and from the Indiana Harbor and Ship Canal (IHSC) in 2015.

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