Good News: Some Insecticides Have Been Virtually Eliminated in Air near the Great Lakes.

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. This paper will ask, "Have we have made any progress in eliminating insecticides from the atmosphere?" We will focus only on the atmosphere around the North American Great Lakes and only on concentration measurements made once every 12 days since about 1990 for six classic insecticides. The answer is that some of these compounds (lindane, α-HCH, and endosulfans) are well on their way to being virtually eliminated, while the concentrations of others (DDT, chlordane, and hexachlorobenzene) have not changed much. We speculate that this difference in elimination is a result of soil compaction in cities (DDT, etc.) versus soil mixing in rural areas (lindane, etc.).

Mass Spectrometric Identification of Pollutants in the Environment: A Personal and Bibliometric Perspective.

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. On the other hand, our papers on trifluoromethyl chlorobenzene derivatives in the Niagara River (170 citations since 1982) and on several alkyl phenols in the Detroit River (90 citations since 1991) have not led to further work. The attention that our identifications of polycyclic aromatic hydrocarbons and unusual flame retardants received was probably due to the known toxicity and environmental persistence of some of these compounds. On the other hand, our identifications of some compounds in the Niagara and Detroit Rivers may have been too site specific to attract much attention. We suggest that simply publishing lists of newly identified compounds in the environment, even if they have been well-characterized, is not necessarily enough. Readers need a reason to focus on a particular result; probably, the most significant reasons for such attention are a compound's toxicity and environmental persistence.

How to convince an editor to accept your paper quickly.

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. You are now entering the peer-review publishing system, which is overseen by journal editors. Dealing with these editors is a skill that can be acquired like any other. Here is some advice on dealing with the peer-review system and with editors. This advice is based on my years of experience as an associate editor of an American Chemical Society journal. I have also submitted and revised hundreds of papers in my career and have reviewed hundreds more. (Google my name for details.) Thus, I have learned how to deal with editors from both sides.

Polycyclic Aromatic Hydrocarbons in the Atmosphere near the Great Lakes: Why Do Their Concentrations Vary?

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. Clearly, urban areas are major sources of PAH to the atmosphere. PAH concentrations at all sites lumped together are decreasing with halving times of about 25 years, and this factor represents about 1.5% of the variability. This is slower than the halving times for most banned compounds because PAH continue to be emitted directly into the atmosphere from many combustion sources. In the atmosphere, the concentrations of relatively volatile PAH maximize in July, but those of relatively nonvolatile PAH maximize in January. This seasonality factor represents about 2.5% of the variability. PAH concentrations at these Great Lakes sites tend to be elevated when the wind is coming out of the south-southeast, and this factor represents about 1.2% of the variability. PAH concentrations are lower when the wind speed is higher; this is a significant but small effect, representing only about 0.17% of the variability. The sum of these partial variabilities is about 80%, which suggests that the measurement and sampling errors are about 20%, which is a reasonable value. On the basis of two approaches, the range of atmospheric PAH transport from these sites is estimated to be on the order of 100-200 km. For these data, meteorology matters, but not by much.

Temporal environmental hysteresis: A definition and implications for polybrominated diphenyl ethers.

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. We focus here on PBDE concentrations in about 700 atmospheric samples collected every 12 days from 2005 to 2018 (inclusive) at two urban sites: Chicago, Illinois, and Cleveland, Ohio. In Chicago, the concentrations of BDE-47 and 99 decreased by a factor of two every 5.9 ±â€¯0.9 and 8.0 ±â€¯1.4 years, respectively, but the concentrations of BDE-209 doubled every 7.6 ±â€¯1.8 years. In Cleveland, the concentrations of BDE-47 and 99 decreased by a factor of two every 5.1 ±â€¯0.4 and 5.7 ±â€¯0.5 years, respectively, and the concentrations of BDE-209 decreased by a factor of two every 9.2 ±â€¯1.6 years. The delay in all these environmental responses relative to when these compounds were removed from the market is a result of decadal scale environmental hysteresis.

Broad Exposure of the North American Environment to Phenolic and Amino Antioxidants and to Ultraviolet Filters.

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. These compounds were detected in all the samples, indicating their ubiquitous distribution in the North American environment. The most prevalent compounds were 2,6-di-t-butyl-p-benzoquinone, diphenylamine, 4,4'-di-t-octyl diphenylamine, 2,4-dihydroxybenzophenone, and 2-hydroxy-4-methoxybenzophenone. The e-waste dust contained significantly greater total concentrations of these compounds than the Canadian residential dust, while intermediate levels were detected in the United States residential dust. The sediment samples showed relatively high levels of N,N'-diphenylbenzidine, the source of which is unclear, and some benzotriazole UV filters. Daily intake rates by dust ingestion for these compounds ranged from 1-10 ng/(kg·day) for adults to 10-100 ng/(kg·day) for toddlers. Due to the wide distribution of these compounds in both the ambient and built environments, future research on their potential toxic effects on people and ecosystems is important.

Statistical Approach for Assessing the Stockholm Convention's Effectiveness: Great Lakes Atmospheric Data.

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. The general approach is to modify a first-order regression to include a second order time term: ln(Ct)= a0 + a1 t + a2 t2, where Ct is the concentration at time t. Thus, the rate constant at any time is k(t) = a1 + 2 a2 t. Given that the errors associated with a1 and a2 can be calculated, one can compare the rate constants at different times with statistical rigor to determine if the rates at which the concentrations are changing are significantly different. As examples of this approach, this paper uses vapor and particle phase atmospheric concentrations of several organic pollutants measured at six sites around the North American Great Lakes every 12 days since about 1992. After correcting for the population near the sampling sites, for seasonality, and for the different numbers of samples collected on the same date, up to 830 data were used in this second-order regression. In general, the loss rates of vapor phase chlorinated pesticides have slowed by about a factor of 2 between 1995 and 2015, which is not SC-like behavior. The exceptions are the endosulfans, the vapor and particle phase concentrations of which were both doubling in 1995 but were both decreasing in 2015, probably because of the greatly diminished use of this insecticide in the United States over the last 20-25 years. The loss rates of vapor phase polychlorinated biphenyls became more rapid between 1995 and 2015, which is SC-like behavior.

Break point analyses of human or environmental temporal trends of POPs.

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. This time is called a break point, and one needs to be able to determine this break point objectively before one can determine the rates of change on either side of it. This paper presents a method for doing this using the Solver feature of Excel followed by multiple linear regression to determine if the rates of change before and after the break point are statistically different from one another.

Temporal trends of PCBs and DDTs in Great Lakes fish compared to those in air.

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. In general the halving times (9-17 years for PCBs and 7-10 years for DDTs) estimated from the full fish dataset are similar to those estimated from the atmospheric data, suggesting that the atmospheric and the fish levels are coupled. The more recent, age-adjusted rates are sometimes significantly faster than those from the full fish and atmospheric datasets, suggesting that the air-water dynamic may now be changing.

Tri(2,4-di- t-butylphenyl) Phosphate: A Previously Unrecognized, Abundant, Ubiquitous Pollutant in the Built and Natural Environment.

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. To provide a context for interpreting these quantitative results, we also measured the concentrations of triphenyl phosphate (TPhP), a structurally similar compound, in these samples. Median concentrations of TDTBPP and TPhP were 14 400 and 41 500 ng/g, respectively, in e-waste dust and 4900 and 2100 ng/g, respectively, in house dust. TDTBPP was detected in sediment, water, and air with median concentrations of 527 ng/g, 3700 pg/L, and 149 pg/m3, respectively. TDTBPP concentrations were generally higher or comparable to those of TPhP in all media analyzed, except for the e-waste dust. Exposure from dust ingestion and dermal absorption in the e-waste recycling facility and in homes was calculated. TDTBPP exposure was 571 ng/kg bw/day in the e-waste recycling facility (pro-rated for an 8-h shift), and 536 ng/kg bw and 7550 ng/kg bw/day for adults and toddlers, respectively, in residential environments.

The IADN data visualization tool.

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/). These data come from the Integrated Atmospheric Deposition Network (IADN), a long term monitoring program run by the U.S. Environmental Protection Agency (US EPA).

Temporal trends of Dechlorane Plus in air and precipitation around the North American Great Lakes.

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. The results show that the total DP concentrations in precipitation varied seasonally, maximizing on January 18, but the concentrations in the vapor + particle phase did not show seasonal variations. Vapor + particle phase DP levels were relatively high in Cleveland, and precipitation DP levels were relatively high at Point Petre. DP's concentrations in neither phase were changing as a function of sampling date, indicating that the input of this compound into the environment is continuing, presumably because its use and production are not regulated. Based on the ratio of the anti conformer relative to the total of the two conformer concentrations, we suggest that the syn conformer is somewhat more environmentally stable than the anti conformer.

Spatial and Seasonal Distributions of Current Use Pesticides (CUPs) in the Atmospheric Particulate Phase in the Great Lakes Region.

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. The total CUPs concentrations were higher at the urban sites (0.38-1760 pg/m3) than at the rural and remote sites (0.07-530 pg/m3). The most abundant CUPs were pyrethroid insecticides at the urban sites. The levels of the other CUPs did not vary much among the six sites, except at the most remote site at Eagle Harbor, where the levels were significantly lower. Chlorothalonil was the most frequently detected CUP, which was detected in more than 76% of the samples. The atmospheric concentrations of total pyrethroid insecticides and total herbicides were correlated with local human population and developed land use. Significantly higher concentrations of most CUPs were observed in the warmer months than in the colder months at all sites. In addition to agricultural applications, which occur during the warmer months, the CUPs atmospheric concentrations may also be influenced by nonagricultural activities and the urban development.

Atmospheric concentrations of hexabromocyclododecane (HBCDD) diastereomers in the Great Lakes region.

The concentrations of α-, ß-, 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 8.9 pg/m3, 0.12-4.0 pg/m3, and 0.26-22 pg/m3 for α-, ß-, and γ-HBCDD, respectively among the four sampling sites. The median ΣHBCDD concentrations for the four sites were 2.0 pg/m3, 2.1 pg/m3, 1.7 pg/m3 and 5.2 pg/m3 for Chicago, Cleveland, Sturgeon Point and Sleeping Bear Dunes, respectively. Higher levels of ∑HBCDD were observed at the remote site of Sleeping Bear Dunes with comparable levels at the remaining three sites. α-HBCDD and γ-HBCDD were the dominant isomers with an average contribution of about 40% and 50% to ΣHBCDD concentrations, respectively. These HBCDD concentrations were compared with the levels of other brominated flame retardants measured in these samples, including polybrominated diphenyl ethers (PBDEs), 2,3,4,5-tetrabromoethylhexyl benzoate (EHTBB), bis(2-ethylhexyl) tetrabromophthalate (BEHTBP), and decabromodiphenylethane (DBDPE). ∑HBCDD concentrations were significantly lower than or indistinguishable from those of PBDEs, EHTBB, BEHTBP, and DBDPE at all sites except Sleeping Bear Dunes. No significant correlations were found between ΣHBCDD and ΣPBDE, EHTBB, BEHTBP, and DBDPE concentrations, suggesting a different source of HBCDD contamination. This is the first study reporting concentrations of HBCDD isomers in the Great Lakes ambient air, and our results indicate that HBCDD is ubiquitous in the Great Lakes basin, including at remote sites.