Residues of Organochlorinated Pesticides in Eggs of Water Birds from Tai Lake in China

Abstract

The levels of organochlorine compounds in eggs of water birds from the colony on Tai Lake in China were studied. The eggs were collected in 2000 and belonged to the following species: 65 samples of black-crowned night heron (Nycticorax nycticorax), 36 samples of little egret (Egretta garzetta), 26 samples of cattle egret (Bubulcus ibis) from 13 clutches and 43 samples of Chinese pond heron (Ardeola bacchus) from 17 clutches. Dichlorodiphenyltrichloroethane (DDT) and its derivates (DDE and DDD), hexachlorocyclohexane (HCH) and its isomers (alpha-HCH, beta-HCH, gamma-HCH, delta-HCH), heptachlor, heptachlor epoxide, aldrin, dieldrin, endrin, endrin aldehyde, alpha-endosulfan, beta-endosulfan, and endosulfan sulfate were determined in the laboratory by gas chromatography. The data showed that DDE had the highest levels in all the samples, followed by beta-HCH. The mean levels of DDE among the water bird species were in the order as follows: black-crowned night heron (5464.26 ng/g, dry weight) > Chinese pond heron (2791.12 ng/g, dry weight) > little egret (1979.97 ng/g, dry weight) > cattle egret (660.11 ng/g, dry weight). DDT and its metabolites accounted for 90% of the total organochlorines, except that it was only 73% for cattle egret. The differences of the residue among the bird species were statistically significant and could be attributed to their variations in prey and habitat. Although the DDE burdens in Tai Lake were much lower than 8 microg/g (wet weight) which are thought to have significant adverse effects on black-crowned night herons, they would be expected to increase the risk of adverse effects on survival of chicks of herons and egrets, particularly black-crowned night heron, based on the critical value of 1 microg/g (wet weight) DDE. The burdens of HCHs in this study were higher and the cyclodienes were lower than those found elsewhere.

Little Egrets (Egretta Garzetta) and Trace-Metal Contamination in Wetlands of China

“…A similar situation, of relatively low contamination, was found in one of our study areas, Tai Lake, for organochlorine pesticides and PCBs (Dong et al, 2004). The only alarming concentrations for trace metals were for As in sediments, especially from Poyang and Pearl.…”

“…However, comparatively very few studies on environmental contamination exist for East Asia, contrary to America and Europe. Some studies have been conducted on birds in China (Burger and Gochfeld, 1993;Jeng and Yang, 1995;Dong et al, 2004) and in Korea (Honda et al, 1986;Lee et al, 1989;Nam et al, 2004a, b); on other components of the environment of China (Chui et al, 1991;Connell et al, 1998), Korea (Jung and Thornton, 1997) and Japan (Doi et al, 1984); on humans in China (among others, Cai et al, 1995;Nordberg et al, 1997;Yang et al, 1994), and in Japan (Fujiwara, 1975;Ikeda, 1992). Recently, the Pearl River Delta has repeatedly been monitored for pollutants (Cardoso da Silva, 1988;Connell et al, 2002).…”

Organochlorine residual concentrations in cattle egret from the Punjab Province, Pakistan

“…Prey samples collected from heronries from River Ravi (40.8 ng/g) and Chenab (37.3 ng/g) were more contaminated compared to those measured in prey collected from Rawal Lake Reservoir (32.0 ng/g). The concentrations measured in prey were greater than those found in the prey of little egrets (10.80 ng/g) from China (Dong et al 2004) and lower than those found in prey of little egrets (78.4 ng/g) from Pakistan (Sanpera et al 2003).…”

“…Concentration of DDD in eggs from three heronries varied between 126 and 166 ng/g which were relatively lower than those measured in eggs of Egretta garzetta (5-357 ng/g) and Nycticorex nycticorex (6-1,203 ng/g) from China (Dong et al 2004)a and in the eggs of yellow-legged gulls (564.86 ppb ww) from the Northeastern Mediterranean (Albanis et al 2003). However, measured concentrations were higher than those found in eggs of cattle egrets (0.017 ppm ww) from northwest Mexico (Mora and Anderson 1991) and E. garzetta (22-146 ng/g) from Northern Italy (Fasola et al 1998).…”

“…The literature suggested that egg sample size varied considerably among different studies, e.g., egg sample sizes of little egret varied between three and five per heronry (Keithmaleesatti et al 2007), 12 eggs from brown boobies at eight colonies from the northern Gulf of California to southern Mexico (Mellink et al 2009), five to 15 eggs per heronry in the study of Henny et al (2003), three to five eggs per colony of great blue herons (Ardea herodias) from Indiana (Baker and Sepu'lveda 2009), three to 14 eggs of little egrets from three breeding heronries of three selected wetlands of Pakistan (Sanpera et al 2003), five to 11 eggs from two cattle egret heronries from south Africa (Bouwman et al 2008), and 20 eggs of cattle egrets from Tai Lake in China (Dong et al 2004). Therefore, in this study, from each heronry, a total of 10 nests were sampled, and one egg from each nest was collected.…”