Yi-Fan Li

Global technical hexachlorocyclohexane usage and its contamination consequences in the environment: from 1948 to 1997

Global technical 1,2,3,4,5,6-hexachlorocyclohexane (HCH) usage data are surveyed from 1948 to 1997. In order to fill both temporal and spatial gaps of the usage data, registration status and the residue concentration of this insecticide in various environmental compartments are considered. A linkage between the accumulated use-density over arable land and the contamination in the environment in each country has been studied. Six levels are classified for both use-density and contamination. By assuming the use-density should be at the same level as the contamination for each country, a spatial interpolation for usage data is made for those countries with residue concentration data but no usage data. Similarly, a spatial interpolation for contamination level is made for those countries with usage data but no residue concentration data. This hypothesis is also applied to judge the accuracy of usage data for those countries where these two sets of data are not in the same level. The total global technical HCH usage between 1948 and 1997 has been estimated to be approximately 10 million t. Historical maximum contamination levels as well as 1990 contamination levels are also presented for each country based on the published sources and an estimation from the use-density. The results show that, China, Japan, and India were most polluted countries by this pesticide during different period of time, and India was still the highest contaminated country in 1990, and most likely, the most polluted area by technical HCH today.

Polychlorinated Biphenyls in Global Air and Surface Soil: Distributions, Air−Soil Exchange, and Fractionation Effect†

Polychlorinated biphenyl (PCB) concentrations in air and soil, measured by various research groups from around the world, were compiled and analyzed. Data for air were available from most regions, particularly in Europe and Asia. The average air concentrations (pg/m(3)) for SigmaPCB at background sites were 70 (5.1-170) for Europe, 79 (49-120) for North America, 66 (18-110) for South America, 270 (9-670) for Central America, 59 (17-150) for Asia, and 15 (13-17) for Australia. Data for soils exhibited better global coverage compared to air and were available from most regions. The average soil concentrations (pg/g dry weight) for SigmaPCB at background sites were 7500 (47-97 000) for Europe, 4300 (110-25 000) for North America, 1400 (61-9 500) for South America, 580 (120-2 900) for Asia, 390 (94-620) for Africa, and 280 (140-540) for Australia. Based on available studies where coupled measurements of PCBs in air and soil were made, the equilibrium status of PCBs in the air-soil system was investigated for China, West Midlands of the UK, central and southern Europe, and along a latitudinal transect from the south of the UK to the north of Norway. Differences were observed in plots of the soil-air equilibrium status (expressed as the soil-air fugacity fraction, ff) for different PCB homologues. This was explained by varying contributions from primary and secondary emissions-spatially and temporally. The net effect after several decades of PCB emissions to air, preferential transport of lower molecular weight PCBs through primary and secondary emission, and reductions in emissions to air in recent decades is that the lower molecular weight PCBs have achieved (and in some cases exceeded) soil-air equilibrium in many parts of the world. The exception is remote and background sites that are still dominated by primary sources.

Seasonal variations of sources of polycyclic aromatic hydrocarbons (PAHs) to a northeastern urban city, China

Understanding the seasonal variations of sources of polycyclic aromatic hydrocarbons (PAHs) in air in urban region is important to the effective control of air pollution in the region. Based on a year round dataset (from August 2008 to July 2009), the sources of atmospheric PAHs in Harbin, a typical Chinese northeastern urban city, were analyzed by principal component analysis (PCA) and positive matrix factorization (PMF). The average total (gas plus particulate) PAH concentration varied from 6.3 ng m(-3) to 340 ng m(-3) with a mean of 100+/-94 ng m(-3), with higher concentrations in heating season than those in non-heating season. PCA and PMF identified similar source factors to atmospheric PAHs with obvious seasonal variation. The results obtained by PMF method indicated that the main sources were coal-fired boiler (39%), diesel engine (34%) and coal average (22%) in heating season and traffic emissions (59%), ground evaporation (18%) and coal average (17%) in non-heating season. Excellent correlation coefficients between predicted and measured concentrations of PAHs indicated that PMF was a useful model for source apportionment of PAHs in atmosphere.

An Asia-Specific Source of Dechlorane Plus: Concentration, Isomer Profiles, and Other Related Compounds

The distribution of dechloranes, a group of chlorinated flame retardants, were investigated in air, soil, and sediment around a newly discovered Dechlorane Plus (DP) production facility in China (Anpon). To date, the only known DP manufacturing plant is located in Niagara Falls, NY (OxyChem). Dechloranes including DP, Dechlorane (Mirex), and the recently discovered Dechlorane 602 (Dec 602) were detected in air, soil, and sediment, while Dechlorane 603 and Dechlorane 604 were below detection limit in all matrices. DP air concentrations near the facility ranged from 7737 to 26 734 pg m(-3), the greatest reported thus far. Soil concentrations in the same area for DP, Dechlorane, and Dec 602 were 1490+/-3580 ng g(-1), 81.6+/-96.5 ng g(-1), and 7.24+/-13.2 ng g(-1) dry weight, respectively. Interestingly, lower concentrations of DP (4.93+/-4.34 ng g(-1)), Dechlorane (30.2+/-19.9 ng g(-1)), and Dec 602 (2.14+/-2.23 ng g(-1)) were found in sediment from a nearby canal. Spatial trends of Dechlorane and Dec 602 in soil were similar to DP, implying that the DP manufacturing plant may also be a source of these other flame retardants. DP soil concentrations surrounding the facility decreased by an order of magnitude within 7.5 km. The syn-DP fractional abundance (fsyn) value (0.40) for the commercial DP product manufactured at Anpon was slightly higher than that (0.20-0.36) produced by OxyChem. The fsyn value in most air samples was largely similar to the Chinese commercial DP mixture, while most soil and sediment abundances were lower, suggesting a stereoselective depletion of syn-DP.

Occurrence and Profiles of Phthalates in Foodstuffs from China and Their Implications for Human Exposure

Phthalate esters are used in a wide variety of consumer products, and human exposure to this class of compounds is widespread. Nevertheless, studies on dietary exposure of humans to phthalates are limited. In this study, nine phthalate esters were analyzed in eight categories of foodstuffs (n = 78) collected from Harbin and Shanghai, China, in 2011. Dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), diisobutyl phthalate (DIBP), benzyl butyl phthalate (BzBP), and diethylhexyl phthalate (DEHP) were frequently detected in food samples. DEHP was the major compound found in most of the food samples, with concentrations that ranged from below the limit of quantification (LOQ) to 762 ng/g wet weight (wt). The concentrations of phthalates in food samples from China were comparable to concentrations reported for several other countries, but the profiles were different; DMP was found more frequently in Chinese foods than in foods from other countries. The estimated daily dietary intake of phthalates (EDIdiet) was calculated based on the concentrations measured and the daily ingestion rates of food items. The EDIdiet values for DMP, DEP, DIBP, DBP, BzBP, and DEHP (based on mean concentrations) were 0.092, 0.051, 0.505, 0.703, 0.022, and 1.60 μg/kg-bw/d, respectively, for Chinese adults. The EDIdiet values calculated for phthalates were below the reference doses suggested by the United States Environmental Protection Agency (EPA). Comparison of total daily intakes, reported previously based on a biomonitoring study, with the current dietary intake estimates suggests that diet is the main source of DEHP exposure in China. Nevertheless, diet accounted for only <10% of the total exposure to DMP, DEP, DBP, and DIBP, which suggested the existence of other sources of exposure to these phthalates.

Global usage of toxaphene

Abstract In order to interpret present and predict future environmental concentrations of persistent organochlorine pesticides in remote regions information on historical and future trends in emissions and use of these compounds on a global scale is required. Through contact with international agencies, literature surveys and other means information on registration status, trends in regional use/emissions, mode and time of application as well as representative soil concentrations of ten pesticides are been compiled. Data of global toxaphene usage were collected for more than 50 countries around world. The accounted for cumulative global toxaphene usage were estimated to be 450,000 tonnes, the interpolated usage from 1950 to 1993 were 1,330,000 tonnes and from 1970 to 1993 were 670,000 tonnes. Toxaphene is still being in applied eg. in former Soviet Union and in Mexico. International cooperation and improved record keeping by governments are required to improve the estimates.

Concentration and bioaccumulation of dechlorane compounds in coastal environment of northern China.

Dechloranes, including Dechlorane Plus (DP), Mirex (Dechlorane), Dechlorane 602 (Dec 602), Dechlorane 603 (Dec 603), and Dechlorane 604 (Dec 604), were determined using GC-MSD for water, sediment and oyster samples collected at 15 sampling sites near the Bohai and Huanghai Sea shore area of northern China in 2008. DP and Mirex were detected in most water, sediment, and oyster samples, which indicated widespread distribution of these two compounds. The mean concentrations in water, sediment and oyster samples, respectively, were 1.8 ng/L, 2.9 ng/g dry weight (dw) and 4.1 ng/g wet weight (ww) for total DP, and 0.29 ng/L, 0.90 ng/g dw, and 2.0 ng/g ww for Mirex. Dec 602 and Dec 603 were not detected in water but in small portions of the sediment and oyster samples, showing a low level of contamination by these two chemicals in the region. Strong and significant correlations were found between total DP and Mirex concentrations in water, sediment and oyster samples, probably suggesting similar local sources of these two chemicals. Dec 604 was not found in any samples. The biota-sediment accumulation factor (BSAF) of DP, Mirex, and Dec 602 declined along with the increase of their logarithm of octanol-water partition coefficients (log Kow), possibly indicating that compounds with lower log Kow (like Mirex and Dec 602) accumulated more readily in biota. The mean fractional abundance of syn-DP (fsyn) was 0.34 in water samples, a value lower than that in Chinese commercial mixture (0.41), while the mean fsyn for surface sediment (0.44) and oyster (0.45) samples were higher than technical values. Enrichment of syn-DP in oyster was in agreement with previously reported findings in Great Lakes fish. Enrichment of syn-DP in marine surface sediments, however, is contrary to data reported for fresh water sediments. To our knowledge this is the first report of Dec 602, Dec 603, and Dec 604 in a marine environment and also the first report of Dechloranes in marine biota.

Application of positive matrix factorization to identify potential sources of PAHs in soil of Dalian, China

Soil derived sources of polycyclic aromatic hydrocarbons (PAHs) in the region of Dalian, China were investigated using positive matrix factorization (PMF). Three factors were separated based on PMF for the statistical investigation of the datasets both in summer and winter. These factors were dominated by the pattern of single sources or groups of similar sources, showing seasonal and regional variations. The main sources of PAHs in Dalian soil in summer were the emissions from coal combustion average (46%), diesel engine (30%), and gasoline engine (24%). In winter, the main sources were the emissions from coal-fired boiler (72%), traffic average (20%), and gasoline engine (8%). These factors with strong seasonality indicated that coal combustion in winter and traffic exhaust in summer dominated the sources of PAHs in soil. These results suggested that PMF model was a proper approach to identify the sources of PAHs in soil.

Dechlorane Plus in Surficial Water and Sediment in a Northeastern Chinese River

Surface water and sediment samples concurrently collected in Songhua River in northeastern China from May to October 2006 were analyzed for Dechlorane Plus (DP), a chlorinated flame retardant. Samples were obtained from three main areas: SHR-Rul (rural area of Songhua River), SHR-Hrb (the section of the river within the city of Harbin), and Hrb (urban waters of Harbin). The majority of SHR-Rul water samples (85%) and SHR-Hrb water samples (73%) and 33% of urban water samples (Hrb) were below the detection limit. The mean water DP concentration in Hrb (0.55 +/- 0.81 ng L(-1)) was approximately 3 times greater than the levels measured in SHR-Hrb (0.17 +/- 0.38 ng L(-1)) and more than 15 times greater than the levels measured in SHR-Rul (0.03 +/- 0.07 ng L(-1)). DP detection rates in sediment samples were 50% (Hrb), 100% (SHR-Hrb), and 78% (SHR-Rul). The mean sediment DP concentration in SHR-Hrb (0.11 +/- 0.05 ng g(-1)) was approximately three times greater than that in SHR-Rul (0.04 +/- 0.05 ng g(-1)). These DP concentrations are likely attributable to local sources in urban areas rather than distant sources via long-range transport. The mean fractional abundance of the syn isomer of DP (f(syn)) was 0.34 +/- 0.10 in all water samples, a value indistinguishable from that of a commercial mixture (f(syn) = 0.35), indicating the source was local. The mean f(syn) value of 0.23 +/- 0.06 in all sediment samples suggested a stereoselective depletion of syn-DP relative to the anti-DP isomer in sediments. To our knowledge, this paper represents the first report of DP concentrations in Chinese water and sediments.

Polybrominated Diphenyl Ethers in Air across China: Levels, Compositions, and Gas-Particle Partitioning

Air samples were concurrently collected using high volume air samplers for 24 h every week from September 2008 to August 2009 at 15 sites (11 urban, 1 suburban, and 3 background/rural) across China. Twelve polybrominated diphenyl ether (PBDE) congeners (BDE-17, -28, -47, -66, -85, -99, -100, -138, -153, -154, -183, and -209) were measured. Total PBDE concentrations (∑12PBDEs) in air (gas + particle phases) were in the range of 11.0-838 pg m(-3) with a mean of 232 ± 72 (mean ± SE) pg m(-3). The site with the highest concentration was Guangzhou (838 ± 126 pg m(-3)), followed by Beijing (781 ± 107 pg m(-3)). Significant positive correlations were found between PBDEs levels and urban population (R = 0.69, P < 0.05) and gross industrial output values (R = 0.87, P < 0.001) as well. BDE-209 was the dominating congener with the contribution of 64 ± 23% to ∑12PBDEs, followed by BDE-47(8 ± 8%) and -99(6 ± 5%) at all urban and suburban sites. At background/rural sites, however, BDE-47 was the dominating congener, followed by BDE-99, together accounting for 52 ± 21% of ∑12PBDEs, while BDE-209 was only 11 ± 2%. It was found that PBDEs at the 15 sites showed a primary distribution and fractionation pattern. This study produced more than 700 pairs of air samples in gaseous and particulate phases with a wide temperature range of ∼60 °C, providing a good opportunity to investigate gas-particle partitioning for individual PBDE congeners. The results of gas-particle partitioning analysis for PBDEs using both subcooled-liquid-vapor pressure (PL)-based and octanol-air partition coefficient (KOA)-based models indicated that PBDEs in air at all sampling sites had not reached equilibrium because the slope values (mO) in the KOA-based equation and the opposite slope values (mP) in the PL-based equation at all 15 sampling sites were less than 1. It also found that both mO and -mP were significantly and positively correlated with the annual average temperatures of sampling sites and also significantly and negatively correlated with the mole masses of PBDE congeners, indicating a general trend that the higher the temperature at the sampling site and the lower the mole mass of the PBDE congeners are, the closer to the equilibrium the congeners approach and vice versa. To our knowledge, this is the first study to report the correlations of the slope values for both the KOA-based and PL-based equations with temperatures at sampling sites and mole masses for individual PBDE congeners.