Determination of Mercury and other Trace ... - ACS Publications

included 95 No. 2 heating oil, 7 high sulfur diesel, 11 ultra-low-sulfur diesel (ULSD), and 8. 149 biodiesel samples. A smaller number of duplicate sa...
1 downloads 6 Views 560KB Size
Subscriber access provided by Caltech Library

Article

Determination of Mercury and other Trace Elements in Home Heating Oil Used in New York State Mahdi Ahmadi, John Graham, Laura Shields, and Paul J. Miller Energy Fuels, Just Accepted Manuscript • DOI: 10.1021/acs.energyfuels.7b02404 • Publication Date (Web): 04 Dec 2017 Downloaded from http://pubs.acs.org on December 4, 2017

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a free service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are accessible to all readers and citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

Energy & Fuels is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 34 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

1

Determination of Mercury and other Trace Elements

2

in Home Heating Oil Used in New York State

3 4

Mahdi Ahmadi*†, John Graham‡, Laura Shields±, Paul J. Miller†

5

† Northeast States for Coordinated Air Use Management, 89 South Street, Suite 602, Boston,

6

Massachusetts 02111-2604, U.S.A.

7

‡ Clean Air Task Force, Columbus, Ohio

8

± San Diego Air Pollution Control District, San Diego, California

9

KEYWORDS: Mercury, fuel oil, elemental analysis, sulfur, No. 2 home heating oil

10

11

ABSTRACT: A 2002 mercury emissions inventory developed by the Northeast States for

12

Coordinated Air Use Management using standard fuel oil mercury (Hg) emission factors from

13

the U.S. Environmental Protection Agency (known as US EPA “AP-42” factors) identified

14

residential fuel oil combustion as an important contributor to Hg air emissions in the northeastern

15

United States. Published literature values, however, suggest much lower mercury content in

16

heating oil than inferred from the US EPA factors. To better characterize mercury (along with

17

other trace element) content in heating oil sold in the Northeast, we conducted a two-phase

ACS Paragon Plus Environment

1

Energy & Fuels 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 2 of 34

18

sampling and analysis study of commercially available fuel oil sold in the northeastern U.S., with

19

a focus on New York State. Changes between the two study periods and relationships between

20

trace element and sulfur levels were evaluated. The study found that concentrations of mercury

21

and other trace elements sampled during both study phases were within typical ranges reported in

22

the literature. Although the average sulfur level in the samples dropped by two orders of

23

magnitude between the two phases because of new government regulations limiting sulfur

24

content in fuel oil after the first sampling phase, we observed no significant relationship between

25

sulfur content and the other trace elements. In addition, derived emission factors for almost all

26

trace elements showed lower values than the tabulated US EPA AP-42 factors. The lower

27

mercury content measured in the samples indicate that heating oil combustion is a much lower

28

source of mercury emitted to the air in the northeastern U.S. than would be inferred from an

29

emission inventory developed using US EPA emission factors.

30 31

INTRODUCTION

32

Approximately 6 million households in the northeastern U.S. rely on home heating oil for

33

heating needs, representing approximately 84% of the total households in the U.S. that are

34

dependent upon home heating oil as their primary heating fuel.1 The top consuming state for

35

home heating oil is New York State (NYS), followed by Pennsylvania, Massachusetts,

36

Connecticut, and Maine. In 2015, NYS consumers bought a little over 890 million gallons of

37

home heating oil, or over 22% of all heating oil sold in the entire U.S.2 In addition, some

38

institutional and commercial buildings use heating oil for space and water heating. According to

39

the EIA, 92% of all residential and 40% of all industrial and residential distillate fuel oil sales in

ACS Paragon Plus Environment

2

Page 3 of 34 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

40

2015 occurred on the East Coast, comprising approximately 3.7 and 1.9 billion gallons of heating

41

oil sold to residential and commercial consumers, respectively.2

42

With the relatively large preponderance of heating oil consumption in the northeastern United

43

State, we conducted a two-phase sampling and analysis study to better characterize the trace

44

element content in heating oil (commonly referred to as No. 2 fuel oil or distillate). This study,

45

which focuses on New York State, improves the understanding of the relative importance of

46

heating oil combustion in regional emissions inventories for the analyzed elements. The elements

47

included are mercury (Hg), vanadium (V), manganese (Mn), cobalt (Co), nickel (Ni), zinc (Zn),

48

arsenic (As), antimony (Sb), selenium (Se), and lead (Pb).

49

Our study placed special emphasis on Hg, a toxic metal found in residential heating oil (and

50

other fuel oils) that is emitted to the air when the oil is burned. Once in the atmosphere, Hg can

51

be deposited locally or transported over long distances before falling back to the surface. When

52

released into the environment and deposited or carried into water bodies, Hg can be converted to

53

methylmercury (MeHg), a particularly toxic form of Hg. Methylated Hg in the aquatic food

54

chain can bioaccumulate in fish tissue to concentrations markedly higher than in the surrounding

55

water.

56

A major route of exposure to Hg is through the consumption of fish. Women of child bearing

57

age are of special concern as MeHg ingested by a mother can transport across the placenta into

58

the brain of a developing fetus. In young children and fetuses, MeHg inhibits the normal

59

development of the nervous system, an effect that may occur even at low exposure levels. Often

60

this damage is not apparent until later in the developmental process, when motor and verbal

61

skills are found to be delayed or abnormal. Developmental effects have been found in children

62

exposed in utero, even though their mothers did not experience any symptoms of adult toxicity.3

ACS Paragon Plus Environment

3

Energy & Fuels 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 4 of 34

63

Women in the Northeast have the highest Hg exposure in the U.S., with 19% having blood

64

organic Hg level exceeding what is considered safe for fetuses.4

65

Most of the Hg present in water bodies − and the fish within them − in NYS and the Northeast

66

is deposited from the atmosphere.5,6 To address Hg in the environment and its threat to human

67

health, NYS and surrounding states have pursued a number of initiatives aimed at the virtual

68

elimination of Hg releases into the environment. In December 2007, the U.S. Environmental

69

Protection Agency (USEPA) approved a request from NYS and the six New England states to

70

establish a regional Total Maximum Daily Load (TMDL) for Hg under the federal Clean Water

71

Act. The regional Hg TMDL was set at a level that would decrease Hg levels in fish tissue low

72

enough for states to lift their fish consumption advisories.7 Subsequently in 2009, New Jersey

73

also received approval from the USEPA for a Hg TMDL for 122 impaired bodies of water within

74

the state. The New Jersey TMDL was set at a comparable level to the regional Hg TMDL

75

previously established by NYS and the six New England states.8

76

There have been a number of relatively recent programs in the U.S. to reduce Hg air emissions,

77

most notably, new state and federal rules aim to reduce or eliminate Hg emissions from

78

municipal waste combustion, medical waste incineration, and coal-fired electric power plants.9,10

79

Studies occurring after these Hg reduction measures took effect have documented measureable

80

decreases in Hg concentrations in leaf litterfall in eastern U.S. forests11 as well as in freshwater

81

fish tissue collected in the northeastern U.S.12,13 and in important commercial marine fish from

82

the Atlantic Ocean off the eastern U.S. coast.14,15 As the large Hg source sectors reduce or

83

eliminate their emissions, other source sectors, such as residential heating oil combustion, can

84

become relatively more important for efforts to reduce the public’s exposure to Hg being

85

deposited from the air onto land and into water bodies.

ACS Paragon Plus Environment

4

Page 5 of 34 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

86

An analysis by the Northeast States for Coordinated Air Use Management16 using fuel oil Hg

87

emission factors taken from the USEPA AP-42 database17,18 identified residential fuel oil

88

combustion as an important source sector in a 2002 regional Hg air emissions inventory of eight

89

northeastern states (Connecticut, Maine, Massachusetts, New Hampshire, New Jersey, New

90

York, Rhode Island, Vermont). When added to estimated Hg emissions from oil used to fire

91

boilers in the commercial, industrial, institutional, and electrical generating sectors, emissions

92

derived from oil combustion comprised nearly one-fourth of the regional Hg inventory total.

93

We note that USEPA AP-42 emission factors are developed mainly for national inventory

94

purposes and may not be suitable for a particular source or location. In addition, comparing the

95

results of elemental fuel analysis and USEPA AP-42 emission factors should be made with the

96

consideration that the AP-42 emission factors are based on the emitted elements after

97

combustion. While the amount of trace elements entering the combustion chamber only depends

98

on the fuel composition, the amount emitted post-combustion depends on combustion

99

temperature, fuel feed mechanism, and particulate matter (PM) treatment technology, in addition

100

to the fuel composition.18 For example, lower flame temperature would result in less metal

101

volatilization from the fuel and less subsequent condensation and enrichment on fine PM, thus

102

lowering the amount of volatized elements in the stack exhaust gas. On the other hand, erosion of

103

metal components or mercury re-entrainment from “cold spots” after combustion may add small

104

amounts of metal emissions to the stack gas. Apart from these latter factors, metal emissions in

105

the stack gas can not be greater than assuming all metal content of the fuel is volatilized through

106

the stack after fuel combustion. This is particularly salient for our study’s focus on Hg, which is

107

more volatile relative to other trace elements analyzed in this study, and is chiefly emitted in the

108

gas phase during combustion.

ACS Paragon Plus Environment

5

Energy & Fuels 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 6 of 34

109

Since the early 1980s, several estimates of Hg in No. 2 distillate oil have been published,

110

describing a wide range of concentrations. The USEPA estimated the concentration of Hg in No.

111

2 distillate oil as 400 µg/kg,19 and with a later adjustment to