Thomas J. Butler

Biological Mercury Hotspots in the Northeastern United States and Southeastern Canada

ABSTRACT Biological mercury (Hg) hotspots were identified in the northeastern United States and southeastern Canada using a data set of biotic Hg concentrations. Eight layers representing three major taxa and more than 7300 observations were used to locate five biological Hg hotspots and nine areas of concern. The yellow perch and common loon were chosen as indicator species for the human and ecological effects of Hg, respectively. Biological Hg hotspots receive elevated atmospheric Hg deposition, have high landscape sensitivity, and/or experience large reservoir fluctuations. In the Merrimack River watershed, local Hg emissions are linked to elevated local deposition and high Hg concentrations in biota. Time series data for this region suggest that reductions in Hg emissions from local sources can lead to rapid reductions of Hg in biota. An enhanced Hg monitoring network is needed to further document areas of high deposition, biological hotspots, and the response to emissions reductions and other mitigation strategies.

Climatic control on eutrophication of the Hudson River estuary.

ABSTRACT Eutrophication is arguably the biggest pollution problem facing estuaries globally, with extensive consequences including anoxic and hypoxic waters, reduced fishery harvests, toxic algal blooms, and loss of biotic diversity. However, estuaries vary greatly in their susceptibility to eutrophication. The Hudson River estuary receives very high levels of nutrient inputs yet in the past has shown relatively low rates of phytoplankton productivity and is generally considered to be only moderately susceptible to eutrophication. Here, we show that eutrophication and primary production in the Hudson estuary can increase dramatically in response to climatic variation and lowered freshwater discharge from the watershed. During dry summer periods in 1995 and 1997, rates of primary production were substantially higher than those measured during the 1970s, when freshwater discharge tended to be high. In the Hudson, low freshwater discharge increases waterresidence times and stratification and deepens the photic zone, all of which (alone or in combination) could lead to the observed increase in primary production. Our data, along with the prediction of most climate change models that freshwater discharge will be lower in the future during the summer in the northeastern US, suggest that the Hudson will become more susceptible to eutrophication. Eutrophication in an estuary is a complex process, and climate change is likely to affect each estuary differently due to interactions with nutrient loadings and physical circulation. Hence, it is essential to consider the effects of climate change in the context of individual estuarine functioning to successfully manage eutrophication in the future.

Recent acidification of precipitation in North America

Abstract Temporal trends in precipitation acidity indicate a large spread and probable intensification of acid precipitation (pH Limited data for eastern North America indicate that precipitation prior to 1930 had pH greater than 5.6. By 1955–1956 calculated pH values from a monthly, wet-only network showed acid precipitation throughout the northeastern U.S. Subsequently, measured data from two networks (a monthly, wet-only and a monthly, bulk-sample collection) operated during 1965–1966 showed a pattern similar to that in 1955–1956 with some westward extension of acid precipitation. Values from both bulk and wet-only precipitation samples during 1975–1976 showed a substantial southward and westward extension of the area subjected to acid precipitation and an intensification of acidity in the northeastern and southeastern regions of the U.S. A few long-term data on precipitation at individual sites showed either increasing acidity or no statistically significant trend during 1955–1980.

Long- and short-term changes in sulfate deposition: Effects of the 1990 Clean Air Act Amendments

Annual, volume-weighted concentrations ofSO42− in bulk precipitation have declinedsteadily (−0.44 μmol/liter-yr) since 1965 atthe Hubbard Brook Experimental Forest (HBEF), NH inresponse to decreases in regional SO2 emissions(r2 = 0.74). Similar declines in concentrationshave occurred in wet-only precipitation at HBEF and atnearby sites since 1978. However, decreases inSO42− concentrations following passage ofthe U.S. Clean Air Act Amendments in 1990, were notunusual from the perspective of long-term data fromthe HBEF. Statistically significant declines (−5.6mol/ha-yr) in bulk deposition of SO42− also have occurred since 1965 in relation to decreases inSO2 emissions (r2 = 0.58), but annualvariations in deposition also are strongly related toamount of precipitation and other factors.

Weekly and daily precipitation chemistry network comparisons in the eastern U.S.: NADP/NTN vs MAP3S/AIRMoN

Abstract This study is a comparison of the weekly aggregated MAP3S (1981–1989) and AIRMoN (1992–1995) daily precipitation chemistry record, to the NADP/NTN weekly data at four collocated sites in the eastern U.S.A. Data for conductivity, H+, NO-3, and SO2-4 all strongly support the hypothesis that the weekly and daily network concentrations of these ions are comparable for both time periods. Data for ammonium show a statistically significant bias for both time periods with the daily record having concentrations approximately 14% higher than the weekly values. This bias also has been observed in other studies of weekly and daily networks, and may be a function of residence time samples remain in the field and/or in storage before analysis. Significantly higher Cl- and K+ concentrations in the MAP3S data set from 1986 to 1989 suggest a contamination problem and use of these data is not recommended for this time period. Potassium concentrations during the other years of record compare poorly between the daily and weekly networks on a weekly basis. Annual data compare well. The other base cation weekly concentrations (Ca2+, Mg2+, Na+) also do not compare well, with average weekly differences ranging from 23 to 51%. However, both the daily and weekly networks show a very similar temporal decline in the sum of base cation concentrations of about 30% from the periods 1981–1985 to 1992–1995. Network Ca2+ and Mg2+ concentration trends also compare well for the entire period of record. Intranetwork variability, assessed in a separate study at several collocated NADP sites in the eastern U.S.A., could account for 1/5 to 1/2 of the internetwork bias for most ions. Intranetwork relative error may account for 1/4 to 2/3 of the internetwork relative error. This study supports the concept that the MAP3S and AIRMoN networks represent a continuous event/daily network data base of high quality for conductivity, H+, NO-3, and SO2-4 concentrations. Comparisons in trends of NH+4, Ca2+ and Mg2+ also suggest that these ions represent a quality long-term database. Daily network NH+4 (and possibly Na+) concentrations may be better estimates of actual precipitation concentrations than the weekly network data.

The relation between NOx emissions and precipitation NO3- in the eastern USA

Abstract Changes in total NOx emissions in the eastern USA have been relatively small through the 1990s, even with implementation of the Clean Air Act Amendments of 1990. The decreases in NOx emissions from the non-vehicle sectors have been significantly offset by increases from the vehicle sector. To quantify the impact of NOx emissions on precipitation NO3−, we used a random coefficient model. Regional NOx emission densities were regressed on NO3− concentrations in precipitation from 24 NADP/NTN and NADP/AIRMoN sites for precipitation chemistry in the northeastern and mid-Atlantic regions of the USA. These were areas where changes in NOx emissions have been the greatest. Total NOx, and non-vehicle NOx emissions have declined from 7% to 12% and 19% to 25%, respectively, from 1991 to 2000 in these regions. Different NOx source regions impacting particular sites were evaluated based on 12-, 24- and 36-h air mass back trajectories. A simple random coefficient model based on precipitation NO3− (dependent variable) and total NOx emissions (independent variable) showed a highly significant (P-value

Monthly and annual bias in weekly (NADP/NTN) versus daily (AIRMoN) precipitation chemistry data in the Eastern USA

Abstract Previous comparisons of the data from the National Atmospheric Deposition Program, National Trends Network (NTN) against collocated event sampled data and daily sampled data suggest a substantial bias in the concentration of ammonium [NH 4 + ] and concentrations of several base cations, while the comparability of other ion concentrations ranges among the studies. Eight years of collocated data from five NTN and Atmospheric Integrated Research and Monitoring Network (AIRMoN) sites are compared here. Unlike previous analyses, the data from these two data sets were analyzed in the same laboratory using the same analytical methods; therefore, factors that influence concentration differences can be isolated to sampling frequency and sample preservation techniques. For comparison, the relative biases for these data have been calculated using both median value and volume-weighted mean concentrations, following two different approaches in the literature. The results suggest a relative bias of about 10% in [NH 4 + ] (NTN less than AIRMoN), which is smaller than previous estimates that included the influence of inter-laboratory comparisons. The annual relative bias of [H + ] increases over the analysis period, which results in a larger total relative bias for [H + ] than found in a previous analysis of AIRMoN and NTN data. When comparing NTN and AIRMoN data on monthly time scales, strong seasonal variations are evident in the relative bias for [H + ], [NH 4 + ], and [SO 4 2− ]. Large biases in [SO 4 2− ] (NTN greater than AIRMoN) on monthly times scales have not been detected in previous analyses where data for all seasons were considered together.

Long-term relationships between SO2 and NOx emissions and SO42− and NO3− concentration in bulk deposition at the Hubbard Brook Experimental Forest, NH

A highly significant second-order polynomial relation between SO(2) emissions and SO(4)(2-) concentrations during 1970-2000 (r(2)= 0.80, p= <0.001), and a linear relation between NO(x) and NO(3)(-) concentrations during 1991-2000 (r(2)= 0.67, p= 0.004) in bulk precipitation were found for the Hubbard Brook Experimental Forest, NH based on emissions from a 24 h, back-trajectory determined source area. Earlier periods (1965-1980) for SO(2)ratio SO(4)(2-) and longer periods (1965-2000) for NO(x)ratio NO(3)(-) had poorer linear relations, r(2)= 0.03, p= 0.51 and r(2)= 0.22, p= 0.004, respectively. Methodology by the US Environmental Protection Agency for calculating emissions data during this period has changed significantly and frequently, making trend analysis difficult. Given the large potential for errors in estimating emissions and to a lesser extent, deposition, the robust relations between SO(2) emissions and SO(4)(2-) concentrations in bulk precipitation at the Hubbard Brook Experimental Forest show that careful, long-term measurements from a single monitoring site can provide sound and reasonable data on trends in air pollution.

Use of energy analysis for assessing environmental impacts due to transportation

Abstract This paper reports on a study to develop an energy analysis applications manual for environmental benefit/cost analysis of transportation actions. The manual is intended for state and local transportation agency analysts. The analysis procedure evaluates environmental impacts in energy terms. With energy as a common denominator of impact costs or benefits, the severities of different kinds of impacts are compared and the aggregate severity of a group of impacts is evaluated. A technique for evaluating the economic effects of environmental impacts is also suggested. The energy analysis procedure is briefly illustrated by means of a case study. The research findings indicate that the energy analysis procedure may supplement traditional methods of environmental impact assessment by providing: (i) comprehensive quantifications of individual kinds of impacts or the aggregate environmental impact of a transportation action: (ii) quantitative comparisons of the significance of different kinds of environmental impacts, even enabling comparison of government-regulated impacts with non-regulated ones and of any one category of impact with the aggregate environmental impact; and (iii) a basis for determining dollar values of environmental impacts.

Response from driscoll and colleagues

Author(s): CHARLES T. DRISCOLL, GREGORY B. LAWRENCE, ARTHUR J. BULGER, THOMAS J. BUTLER, CHRISTOPHER S. CRONAN, CHRISTOPHER EAGAR, KATHLEEN F. LAMBERT, GENE E. LIKENS, JOHN L. STODDARD, and KATHLEEN C. WEATHERS Source: BioScience, Vol. 52, No. 1 (January 2002), p. 6 Published by: University of California Press on behalf of the American Institute of Biological Sciences Stable URL: http://www.jstor.org/stable/10.1641/00063568%282002%29052%5B0006%3ARFDAC%5D2.0.CO%3B2 . Accessed: 10/12/2013 12:32