Observed Concentrations in the Environment

The Handbook of Environmental Chemistry Vol. 3, Part Q (2003): 125– 177 DOI 10.1007/b11465

Observed Concentrations in the Environment Kathryn Clark 1 · Ian T. Cousins 2 · Donald Mackay 2 · Kentaro Yamada 3 1 2 3

BEC Technologies Inc., 61 Catherine Avenue, Aurora, Ontario, L4G 1K6, Canada E-mail: [email protected] Canadian Environmental Modelling Centre, Environmental and Resource Studies, Trent University, Peterborough, Ontario, K9J 7B8, Canada CG Ester Corporation, Landic Bldg. 8F, 2-16-13, Nihonbashi, Chuo-ku, Tokyo 103-0027, Japan

Measured concentrations of six phthalate esters in seven environmental media are compiled and analyzed. The data are predominantly from Europe, the United States, and Japan. The six phthalate esters are dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), butylbenzyl phthalate (BBP), bis(2-ethylhexyl) phthalate (DEHP), and di-n-octyl phthalate (DnOP). The media addressed are water, sediment, soil, air, dust, food, wastewater, sewage sludges, and rainwater. The reported concentrations vary widely as a result of several factors including analytical error, sample contamination, and proximity to a variety of past and present sources. To gain an impression of the absolute levels and distributions, histograms are prepared with binning on a semi-decade logarithmic scale. Cumulative histograms are also prepared to convey an impression of cumulative distribution. To gain an appreciation of the relative concentrations in various media, fugacities are estimated and plotted, thus revealing the relative equilibrium status between media and any biomagnification. These plots suggest that phthalate esters are not persistent in the environment and do not biomagnify, as they are rapidly metabolized in organisms. Keywords. Phthalate ester, Concentrations, Fugacity, Persistence

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1

Introduction

2

Methodology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128

2.1 2.2 2.3

Database Generation . . . . . . . . . . . . . . . . . . . . . . . . . 128 Histograms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129 Transforming Concentrations into Fugacities . . . . . . . . . . . . 130

3

Dimethyl Phthalate (DMP) . . . . . . . . . . . . . . . . . . . . . . 132

3.1 3.1.1 3.1.2 3.1.3 3.2 3.3 3.4 3.5

Water . . . . . Surface Water . Groundwater . Drinking Water Sediment . . . Soil . . . . . . Air . . . . . . . Dust . . . . . .

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132 132 132 136 136 136 136 136

© Springer-Verlag Berlin Heidelberg 2003

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K. Clark et al.

3.6 3.7 3.7.1 3.7.2

Food . . . . Other Media Wastewater Sludge . . .

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4

Diethyl Phthalate (DEP) . . . . . . . . . . . . . . . . . . . . . . . 137

4.1 4.1.1 4.1.2 4.1.3 4.2 4.3 4.4 4.5 4.6 4.7 4.7.1 4.7.2

Water . . . . . Surface Water . Groundwater . Drinking Water Sediment . . . Soil . . . . . . Air . . . . . . . Dust . . . . . . Food . . . . . . Other Media . . Wastewater . . Sludge . . . . .

5

Dibutyl Phthalate (DBP) . . . . . . . . . . . . . . . . . . . . . . . 142

5.1 5.1.1 5.1.2 5.1.3 5.2 5.3 5.4 5.5 5.6 5.7 5.7.1 5.7.2


6

Butylbenzyl Phthalate (BBP) . . . . . . . . . . . . . . . . . . . . . 149

6.1 6.1.1 6.1.2 6.1.3 6.2 6.3 6.4 6.5 6.6 6.7 6.7.1 6.7.2


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136 137 137 137

137 137 137 141 141 141 141 141 142 142 142 142

142 142 147 147 147 147 148 148 148 148 148 148

149 149 149 149 153 153 153 153 153 154 154 154

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Observed Concentrations in the Environment

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154 154 154 159 159 159 159 160 160 160 160 160 161 161

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161 161 161 161 164 164 164 164 164 164 164 165

9 9.1 9.2 9.3

Discussion and Recommendations Histograms . . . . . . . . . . . . . Fugacities in Various Media . . . . Conclusions . . . . . . . . . . . . .

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165 165 172 175

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References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176

7 7.1 7.1.1 7.1.2 7.1.3 7.2 7.3 7.4 7.5 7.6 7.7 7.7.1 7.7.2 7.7.3

Bis(2-Ethylhexyl) Phthalate (DEHP) Water . . . . . . . . . . . . . . . . Surface Water . . . . . . . . . . . . Groundwater . . . . . . . . . . . . Drinking Water . . . . . . . . . . . Sediment . . . . . . . . . . . . . . Soil . . . . . . . . . . . . . . . . . Air . . . . . . . . . . . . . . . . . . Dust . . . . . . . . . . . . . . . . . Food . . . . . . . . . . . . . . . . . Other Media . . . . . . . . . . . . . Wastewater . . . . . . . . . . . . . Sludge . . . . . . . . . . . . . . . . Rainwater . . . . . . . . . . . . . .

8 8.1 8.1.1 8.1.2 8.2 8.3 8.4 8.5 8.6 8.7 8.7.1 8.7.2

Di-n-Octyl Phthalate (DnOP) Water . . . . . . . . . . . . Surface Water . . . . . . . . Drinking Water . . . . . . . Sediment . . . . . . . . . . Soil . . . . . . . . . . . . . Air . . . . . . . . . . . . . . Dust . . . . . . . . . . . . . Food . . . . . . . . . . . . . Other Media . . . . . . . . . Sludge . . . . . . . . . . . . Wastewater . . . . . . . . .

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Abbreviations BBP C DBP DEHP DEP DMP DnOP f fOM fD

Butylbenzyl phthalate Concentration (mol m–3) Dibutyl phthalate Bis(2-ethylhexyl) phthalate Diethyl phthalate Dimethyl phthalate Di-n-octyl phthalate Fugacity (Pa) Organic matter content of the aerosol Fraction of chemical in the dissolved phase of water

128 fOC H K KOW KOA KOC KP M R T TSP vSP Z r j

K. Clark et al.

Fraction of organic carbon in the suspended sediment Henry’s law constant (Pa m3 mol–1) Kelvin Octanol-water partition coefficient Octanol-air partition coefficient Organic carbon-water partition coefficient Gas-particle partition coefficient (m3 µg–1) Molar mass (g mol–1) Gas constant (Pa m3 mol–1 K–1) Absolute temperature (K) Total suspended particle concentration (µg m–3) Volume fraction of suspended particles in water Fugacity capacity of the phase (mol m–3 Pa–1) Density of the phase (kg m–3) Fraction of chemical associated with particles in air

1 Introduction Measured concentrations of six phthalate esters in seven environmental media are compiled and analyzed. The six phthalate esters are dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), butylbenzyl phthalate (BBP), bis(2-ethylhexyl) phthalate (DEHP), and di-n-octyl phthalate (DnOP). The media addressed are water, sediment, soil, air, dust, food, and “other media” including wastewater, sewage sludges, and rainwater. The data are predominantly from Europe, the United States, and Japan. The monitoring data have been collected for a variety of reasons and by different groups (e.g., by regulators to support development of regulations, by industry for compliance purposes, by researchers to support modeling efforts, etc.). Due to the varying interests of the organizations that have collected the data, there is variation in the proximity of the measurements to sources of the phthalate esters. Where possible, data locations are classified as rural or urban to assist in evaluation of the data.

2 Methodology 2.1 Database Generation

Numerous data sources have been reviewed to determine the ranges and distributions of phthalate esters in the environment. A compilation of data was produced by Exxon Mobil Biomedical Sciences Inc. (EMBSI) [1] for five phthalate esters: DEP, DMP, DBP, BBP, and DEHP. The data were categorized by EMBSI into regions including Canada, United States, Europe, and Japan/Asia. The data were also categorized by EMBSI in terms of data quality. The following ranking scheme was employed:

129

Observed Concentrations in the Environment

1. 2. 3. 4.

Reliable without restrictions Reliable with restrictions Not reliable Unassignable

The EMBSI database is used as the starting point for the database presented herein. Additional data, available as of August 31, 2000, have been added to this database. These data include recent measurements of phthalates in air, dust, fish, milk, and vegetation in the Netherlands [2, 3], phthalates in surface water and wastewater in Germany [4], DEHP and DBP in milk, breast milk, baby food, and dust [5], DBP in surface water and wastewater in Europe [6], DEHP in surface water, sediments, and sludge in Europe [7], phthalates in Canadian drinking water and surface water [8, 9] and sludge [10, 11], and data from Environment Canada and Health Canada (EC &HC) [12–15]. In addition to the five phthalate esters in the original EMBSI database, some information on DnOP concentrations in the environment is available in the Canadian Environmental Protection Act (CEPA) Priority Substances List assessment report [16, 17] as well as from Alberta Environment [8, 9]. Measured concentrations, particularly for phthalates other than DEHP, are often reported as “not detected”. As a result, treatment of the detection limit significantly influences the characteristics (i.e., mean and standard deviation) of the data. For the results presented herein, the non-detectable data have been set to one-half the detection limit. Tables and histograms that summarize the data are presented herein. The complete database, with references, is presented in a report to the American Chemistry Council [18]. 2.2 Histograms

It is difficult to visualize the distribution of the monitoring data by examining the raw data contained in the monitoring database or by examining the summary tables and statistics. Therefore, it was decided to display the monitoring data graphically using both frequency histograms and cumulative distribution plots derived from these histograms. These are termed “cumulative histograms”. Environmental concentrations in each medium are divided logarithmically into classes or bins, with a factor of approximately three between adjacent bins. For example, for surface water concentrations, the following bins are allocated: Bin

Range (µg L–1)

Midpoint of range (µg L–1)

1 2 3 4 5 6 7 8

0.01–0.03 0.03–0.1 0.1–0.3 0.3–1.0 1.0–3.0 3.0–10 10– 30 30– 100

0.017 0.055 0.17 0.55 1.7 5.5 17 55

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The bins allocated can be adjusted to fit the range of environmental concentrations in the database. The frequency histograms are devised by recording the number of study averages in the monitoring database that fall within each bin.A weighted frequency histogram is devised by adding up the number of samples that contribute to each study average within a particular bin. For example, if there are three study averages, within a bin ranging from 0.1 to 0.3 µg L–1, of 0.12 µg L–1 (n=10), 0.20 µg L–1 (n=1), and 0.25 µg L–1 (n=5), then this bin will have a frequency of 3 in the unweighted histogram and a frequency of 16 in the weighted histogram. The cumulative histograms are devised by calculating the cumulative percentage contribution of each successive bin to the total number of study averages in the case of the unweighted cumulative histogram, or to the total number of samples in the case of the weighted cumulative histogram. Weighted and unweighted frequency and cumulative histograms are plotted for DEHP, surface water, sediment, and air concentrations in Europe and are discussed in Section 9.0. Insufficient data are available to produce a histogram for concentrations in soil. 2.3 Transforming Concentrations into Fugacities

The study of both aquatic and terrestrial ecosystems has shown that one useful approach for studying food chain bioaccumulation is through transforming environmental concentrations into fugacities [19]. Fugacities offer the advantage of being able to use a single currency to compare levels of contamination in different environmental media and organisms. The fugacity f (Pa) of a compound in a particular phase can be calculated from the concentration C (mol m–3) by using the following equation: f = C/Z

(1)

where Z is the fugacity capacity of the phase for the compound (mol m–3 Pa–1). Hence, if the fugacity capacities are known, then the fugacities can be calculated from measured concentrations on a volume basis. It is possible to derive concentrations in units of mol m–3 by using the molecular mass M (g mol–1) and density of the phase r (kg m–3). The fugacity capacities or Z values for the phases can be estimated by using methods outlined by Mackay [20]. In this report, concentrations of phthalates in Europe are transformed into their corresponding fugacities for the media of air, surface water, sewage sludge, vegetation, soil, sediments, fish, cow’s milk, and human milk.We use only concentration data from the recent RIVM/ECPI monitoring campaign [2, 3] for calculating fugacities, except for surface water concentrations [4] and human milk concentrations [5, 21]. This high quality subset of multimedia concentrations is selected to minimize data variability. Unfortunately, it is only possible to calculate the fugacities of DEHP and DBP with this limited data set. The equations used to estimate the Z values for these phases are briefly described below. Physical-chemical data used in the calculations such as KOW , H, and KOA are taken from Cousins and Mackay [22]. Environmental parameters used in the calculations are listed in Table 1.

131

Observed Concentrations in the Environment Table 1. Environmental parameters assumed for calculating media-specific fugacities

Parameter

Value

Total suspended particle concentration in air (µg m–3) Fraction of organic matter in air particles Volume fraction of suspended particles in water Fraction of soil organic carbon Fraction of sediment organic carbon Gas constant (Pa m3 mol–1 K–1) Environmental temperature (K) Temperature of cow’s milk (K) Temperature of human milk (K) Fraction of plant lipid Fraction of lipid in fish Fraction of lipid in cow’s milk Fraction of lipid in human milk

80 0.20 0.000015 0.02 0.05 8.314 273 310 310 0.01 0.05 0.033 0.04

The fugacity capacity of pure air ZA is given by ZA = 1/(RT)

(2)

where R is the gas constant (Pa m3 mol–1 K–1) and T is the absolute temperature (K).Air concentrations given in the database are total air concentrations (the sum of the amount in gaseous and particle phases). To calculate the fraction on the particles (j) and from this the gaseous phase concentration ((1– j) multiplied by the total air concentration), the following equation is used:

j = KP (TSP)/[1+KP (TSP)]

(3) (m3

µg–1)

where KP is the gas-particle partition coefficient and TSP is the total suspended particle concentration (µg m–3). KP is estimated from KP = 1.23 ¥ 10–12 fOM KOA

(4)

where fOM is the organic matter content of the aerosol and KOA is the octanol-air partition coefficient. The fugacity capacity of pure water ZW is given by ZW = 1/H

(5)

where H is the Henry’s law constant (Pa m3 mol–1). Surface water concentrations given in the database are total water concentrations (the sum of the amount in dissolved and suspended particle phases). To calculate the dissolved water concentration the following equation is used: fD = 1/(1 + fOC nSP KOC)

(6)

where fD is the fraction in the dissolved phase, fOC is the fraction of organic carbon in the suspended sediment, vSP is the volume fraction of suspended particles, and KOC is the organic carbon/water partition coefficient; it is assumed that KOC is equal to KOW .

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Concentrations in soil, sediments, cow’s milk, human milk, fish, and sewage sludge are all reported on a mass per lipid or mass per organic carbon basis. These concentrations are converted to units of mol m–3 (assuming a density of 1000 kg m–3 for all phases). Concentrations in plants are not given on a lipid basis, thus they are first converted to units on a mass per lipid basis by assuming the volume fraction of lipid in the plant is 0.01. The fugacity capacity of the lipid/organic carbon phase (ZO) in each medium is calculated as ZO = KOW ZW

(7)

This assumes that KOW is equivalent to the lipid-water and organic carbon-water partition coefficients. The fugacities of the phthalates in each medium are then calculated by using Eq. (1).

3 Dimethyl Phthalate (DMP) A summary of the reported concentrations of DMP is presented in Table 2. 3.1 Water 3.1.1 Surface Water

The overall mean concentration of DMP in surface water in Canada (1.40 µg L–1) is significantly higher than that calculated for the United States (0.0017 µg L–1) and Europe (0.034 µg L–1). As indicated in Table 2, the concentrations measured in rural and urban regions in Canada do not differ significantly. The maximum measured concentration in the United States surface water (0.003 µg L–1) is much less than the maximum measured concentration in Canada (33 µg L–1). The maximum concentration for water with substantial industrial sources in Canada (9 µg L–1) is slightly lower than the overall maximum concentration; however, the mean concentration for water with substantial industrial sources is 2.76 µg L–1, which significantly affects the overall mean concentration. No data are reported for Japan/Asia. 3.1.2 Groundwater

A maximum concentration of 355 µg L–1 is reported for the United States as a mean value; however, the median (27 µg L–1) is much lower than the mean. Only one reference is available for Europe, which indicates concentrations less than 0.1 µg L–1. Canadian data are available in a drinking water database reported below. Although some of these data represent Canadian groundwater, the data does not differentiate between surface water supplies and groundwater supplies.

Medium

Mean

Canada USA Europe Japan/Asia

Canada rural urban USA Europe Japan/Asia

USA Europe Japan/Asia

Canada

Sediments (mg kg NA 3.6 0.011 NA

–1)

Drinking water (µg L 0.5 0.5 0.5 NA NA NA

27 NA NA

NA 0.004 0.0001 NA

0.5 0.5 0.5 NA