Mihoko Kojima

4-Nonylphenols and 4-tert-octylphenol in water and fish from rivers flowing into Lake Biwa.

Surveys of 4-nonylphenols (NOs) and 4-tert-octylphenol (OC) were performed for water and fish samples obtained from eight rivers flowing into Lake Biwa once every two months from April 1998 to March 1999. For water samples, NOs were detected all the year round (0.11-3.08 ng ml(-1)) at high frequency (48/48) in the eight rivers. OC was detected at lower concentrations (ND approximately 0.09 ng ml(-1)) and at lower frequency (23/48). The concentrations of NOs in the river water always showed minimum values at 5-8 degrees C in winter. It was presumed that the formation of NOs by the biotransformation of nonylphenol polyethoxylates decreased much in the sludge treatment of nonionic surfactants at the low temperature (5-8 degrees C) in winter. Average BCF values of NOs and OC in the six kinds of fish were calculated from the field data. The field BCF values of NOs 15-31 in the six kinds of fish were lower than the laboratory BCF values of 167 in Killifish and 282 in Salmon. For OC, the field BCF values 129-297 for the three kinds of fish were nearly equal to the laboratory BCF value, 261, in Killifish.

Acute toxicity, accumulation and excretion of organophosphorous insecticides and their oxidation products in killifish

Acute toxicity, accumulation and excretion of four organophosphorous insecticides (diazinon, malathion, fenitrothion and EPN) and their oxidation products (diazinon oxon, malaoxon, fenitrothion oxon and EPN oxon) were studied for killifish (Oryzias latipes). The 48-hr LC50 was 4.4 mg l-1 for diazinon, 1.8 mg l-1 for malathion, 3.5 mg l-1 for fenitrothion, 0.58 mg l-1 for EPN, 0.22 mg l-1 for diazinon oxon, 0.28 mg l-1 for malaoxon, 6.8 mg l-1 for fenitrothion oxon, and 0.16 mg l-1 for EPN oxon. The bioconcentration factors (BCF) of diazinon oxon 0.5, malaoxon 1.1, fenitrothion oxon 2.3 and EPN oxon 11 in the whole body of the fish were much lower than those of diazinon 49, malathion 11, fenitrothion 122 and EPN 1124. As reference data, partition coefficients between n-octanol and water (Pow) were measured for these chemicals. The BCF values of each pesticide and its oxidation product were consistent with the Pow values. The excretion rate constants (k) from the whole body of the fish were 0.12 hr-1 for diazinon, 0.27 hr-1 for malathion, 0.11 hr-1 for fenitrothion, 0.02 hr-1 for EPN, 0.30 hr-1 for fenitrothion oxon and 0.59 hr-1 for EPN oxon. The rates of diazinon oxon and malaoxon could not be measured, but were presumed to be as rapid as or more rapid than those of fenitrothion oxon and EPN oxon. The results suggest that the contamination of fish and other aquatic organisms by the oxidation products in the environment is very low.

Evaluation of 4-nonylphenols and 4-tert-octylphenol contamination of fish in rivers by laboratory accumulation and excretion experiments

Laboratory accumulation and excretion experiments of 4-nonylphenols (NP) and 4-tert-octylphenol (OP) were performed for killifish (Oryzias latipes). The bioconcentration factors (BCF, wet weight) in the whole fish were mean +/- SD of 167 +/- 23 (n = 4) for NP and 261 +/- 62 (n = 4) for OP. The biological half-lives in the whole fish were 9.9 h for NP and 7.7 h for OP. Parallel to the laboratory experiments, field survey on the chemicals contamination for water and ayu fish (Plecoglossus altivelis) from rivers flowing into Lake Biwa was performed. The contamination was not so high in agreement with the laboratory experimental data and the field BCF values (wet weight) in the ayu fish were 21 +/- 15 (n = 8) for NP and 297 +/- 194 (n = 3) for OP.

Gas chromatographic–mass spectrometric determination of 4-nonylphenols and 4-tert-octylphenol in biological samples

A simple and rapid method is described for the GC-MS determination of 4-nonylphenols (NOs) and 4-tert-octylphenol (OC) in biological samples. The NOs and OC in the sample are extracted with acetonitrile and the lipid in the sample extract is eliminated by partitioning between hexane and acetonitrile. After Florisil PR column clean-up, the sample extract is analyzed by GC-MS in the selected ion monitoring (SIM) mode. Average recoveries in pale chub (fish) and corbicula (shellfish) are 86.0 and 93.4% for NOs, and 95.8 and 96.4% for OC, respectively, spiked at the levels of 1.0 microg of NOs and 0.1 microg of OC per 5 g of fish and shellfish samples. The detection limits are 20 ng/g for NOs and 2 ng/g for OC.

Evaluation of estrogenic activities of pesticides using an in vitro reporter gene assay

The estrogenic activities of 32 pesticides in agricultural products were evaluated using the E-CALUX assay system developed by Xenobiotic Detection Systems Inc (North Carolina, USA). This system utilizes human ovarian carcinoma cells (BG1) stably transfected with an estrogen-responsive luciferase reporter gene plasmid. It was found that tolclofos-methyl, prothiofos, diazinon, Thiabenclazole (TBZ) and pyriproxyfen had estrogenic activity. Several pesticides are often present in agricultural products. Therefore the estrogenicity of the mixtures of two kinds of pesticides was evaluated. The activity of diazinon/tolclofos-methyl, pyriproxyfen/prothiofos and TBZ/o-phenylphenol (OPP) was increased up to 1.2 – 5.3 fold. On the other hand, chlorfluazuron, imazalil and chlorfenapyr had anti-estrogenic activity. Further, to evaluate the change in the estrogenic activity of pesticide metabolites, an experimental system was established using a rat S9 mixture. Metabolites of permethrin and OPP had no estrogenic activity, but they had weak activity after the metabolism. On the other hand, the metabolites of TBZ exhibited less estrogenic activity than the original compounds.

The influence of pH on the accumulation of tri-n-butyltin chloride and triphenyltin chloride in carp

1. 1. The order of the bioconcentration factors (BCF) in carp at three pH values was pH 7.8 > pH 6.8 > pH 6.0 for both Bu3SnCl and Ph3SnCl over the 14 days exposure period. 2. 2. There were significant differences (P < 0.05 − P < 0.001) in the BCF values of both Bu3SnCl and Ph3SnCl between the pH values at 1, 3, 7, 10 and 14 days. 3. 3. Partition coefficients between n-octanol and water (Pow) of both Bu3SnCl and Ph3SnCl increased with increasing pH (pH 5.8–8.0). 4. 4. The increase in the BCF values of Bu3SnCl and Ph3SnCl with increasing pH is probably due to the change of the chemical forms (Bu3Sn+ to Bu3SnOH and Ph3Sn+ to Ph3SnOH).

Bioconcentration and excretion of diazinon, IBP, malathion and fenitrothion by willow shiner

Bioconcentration and excretion of diazinon (diethyl 2‐isopropyl‐4‐methyl‐6‐pyrimidinyl phosphorothionate), IBP (S‐benzyl diisopropyl phosphorothiolate), malathion (S‐1,2‐bis(ethoxycarbonyl)ethyl dimethyl phosphorothiolothionate) and fenitrothion (dimethyl 4‐nitro‐m‐tolyl phosphorothionate) was studied for the fresh‐water fish, willow shiner (Gnathopogon caerulescens). The concentrations of these pesticides in whole body of fish reached plateaus in 6–48 h exposure (IBP 6h, fenitrothion and malathion 24 h, diazinon 48 h). The average values of bioconcentration factors (BCF) in whole body of fish were 33.2 for IBP, 398.5 for fenitrothion, 34.4 for malathion and 247.9 for diazinon through the 168 h exposure period. The excretion rate constants from whole body offish were 0.07b‐1 for diazinon, 0.07b‐1 for fenitrothion and 0.49h‐1 for malathion assuming their processes to be first‐order kinetics. For IBP, the rate constant was 0.0017gng‐lh‐1 assuming the process to be second‐order kinetics.

Accumulation and excretion of diazinon, fenthion and fenitrothion by killifish: Comparison of individual and mixed pesticides

Abstract A study was made of differences in the accumulation and excretion of diazinon, fenthion and fenitrothion by killifish (Oryzias latipes) between experiments with individual and mixed pesticides. The bioconcentration factor (BCF) of the pesticides in the former reached plateau levels less rapidly than that in the latter. There was little difference in the BCF and excretion rate constants of the pesticides between the experiments. It was concluded that the accumulation and excretion of pesticides present in mixtures can be evaluated by data for the individual pesticides.

Bioconcentration and excretion of diazinon, IBP, malathion and fenitrothion by carp

Abstract 1. Bioconcentration and excretion of diazinon, IBP, malathion and fenitrothion were studied for carp ( Cyprinus carpio L.). 2. The concentrations of these pesticides in muscle and viscera of the carp reached plateaus in 12–48 hr exposure. 3. The average values of bioconcentration factors (BCF) for diazinon were 20.9 in muscle, 60.0 in liver, 111.1 in kidney and 32.2 in gallbladder over the 168 hr exposure period. Similarly, those values were 4.3–26.7 for IBP, 2.7–17.3 for malathion, and 36.0–157.1 for fenitrothion. 4. The excretion rate constants of malathion (hr −1 ) were 0.13 for muscle, 0.12 for liver, 0.08 for kidney and 0.06 for gallbladder. Those of diazinon, IBP and fenitrothion (g · ng −1 · hr −1 ) were 0.002–0.024 for muscle, 0.001–0.020 for liver, 0.0004–0.004 for kidney and 0.002–0.023 for gallbladder, respectively.

Bioconcentration and excretion of benthiocarb and simetryne by carp

Abstract Bioconcentration and excretion of benthiocarb(S- p -chlorobenzyl N , N -diethylthiocarbamate) and simetryne [2,4-bis(ethylamino)-6-methylthio-1,3,5-triazine)] were studied for carp ( Cyprinus carpio L.). The concentrations of both chemicals in muscle and viscera of carp reached plateaus after 12 h exposure. Bioconcentration factors (BCF) of benthiocarb were 25.5 in muscle, 62.7 in liver, 72.7 in kidney and 63.3 (mean, n = 4) in gallbladder over the 168 h exposure period. Similarly, BCF of simetryne were 2.4 in muscle, 13.5 in liver, 8.1 in kidney and 10.9 in gallbladder over the 72 h exposure period. The excretion rate constants of benthiocarb were 0.10 h −1 for muscle, 0.09 h −1 for liver, 0.13 h −1 for kidney and 0.09 h −1 for gallbladder assuming their processes to be first-order kinetics. Similarly, those of simetryne were 0.44 h −1 for muscle, 0.37 h −1 for liver, 0.29 h −1 for kidney and 0.23 h −1 for gallbladder.