Carbaryl: a literature review

Toxic Effects of Carbaryl Exposure on Juvenile Asian Seabass (Lates calcarifer)

This study examines the physiological and immunological effects of 0.5 ppm carbaryl exposure on juvenile Asian seabass (Lates calcarifer) over 12 h to 72 h. Notable results include decreased activities of liver enzymes catalase (CAT), lactate dehydrogenase (LDH), and glutathione peroxidase (GSH-PX), while superoxide dismutase (SOD) levels remained stable, with the lowest activities of CAT and GSH-PX observed at 72 h. Serum biochemistry revealed increased alkaline phosphatase (AKP) and acid phosphatase (ACP) at 24 h, with declining aspartate aminotransferase (AST) and a peak in creatinine at 48 h. Histopathological analysis showed carbaryl-induced necrosis in liver and spleen cells, and increased melanomacrophage centers in both organs. Additionally, immune gene expression analysis indicated an upregulation of heat shock proteins and consistent elevation of complement component C3 and interleukin-8 (IL-8). These findings suggest that carbaryl exposure significantly impairs organ function and modulates immune responses in L. calcarifer, underlining the need for further research on protective strategies against pesticide impacts in aquaculture.

Micellar electrokinetic chromatography with amperometric detection and off-line solid-phase extraction for analysis of carbamate insecticides

Six selected primary carbamate insecticides, methomyl, carbaryl, carbofuran, propoxur, isoprocarb, and promecarb, were hydrolyzed in alkaline solution, resulting in electroactive derivatives detectable at a platinum (Pt) electrode poised at +0.8 V vs Ag/AgCl (3 M NaCl). The Pt electrode was inserted into a small electrochemical cell and positioned close to the capillary outlet as an end-column detector to detect the carbamate derivatives after electrophoretic separation. Based on their predicted pK(a) values and aqueous solubilities, micellar electrokinetic chromatography (MEKC) was optimized for baseline separation of the derivatives using 20 mM borate, pH 10.2 containing 20 mM sodium dodecyl sulfate as a running buffer. When combined with solid-phase extraction (SPE) on octadecyl silica, a preconcentration factor of 100-fold achieved detection to 0.5 microM methomyl and to 0.01 microM for the remaining five pesticides, significantly below the level regulated by government agencies of most countries. The SPE-MEKC method when applied to the separation and analysis of spiked river water and soil samples, yielded results with excellent reproducibility, recovery and selectivity.

Response of an estuarine benthic community to application of the pesticide carbaryl and cultivation of Pacific oysters (Crassostrea gigas) in Willapa Bay, Washington

Oyster culture operations on the West coast of North America have developed into complete farming operations for the introduced Japanese oyster, Crassostrea gigas, which now covers vast areas of the intertidal landscape, particularly in Washington State where the pesticide carbaryl has also been used to control burrowing thalassinid shrimp for more than 30 years. Field experiments were conducted to examine the effects of these habitat modifications on the benthic community in Willapa, Bay Washington (124 degrees 06'W,46 degrees 24'N) where 50% of the state's oyster production occurs. Results indicated that the primary long-term effect of carbaryl application was removal of the two species of thalassinid shrimp (Neotrypaea californiensis and Upogebia pugettensis), which dominated the community at the start of the experiment and clearly influenced community composition themselves. Small peracarid crustaceans like the amphipods Corophium acherusicum and Eohaustorius estuarius experienced the most significant short-term mortalities, but generally recruited back to treated sites within 3 months, and were often more abundant on treated than untreated sites 1 year after carbaryl application. Results for molluscs were mixed, with no significant effect on Macoma spp, but a significant effect on the commensal clam Crytomya californica and mixed results for the cockle Clinocardium nutalli. Polychaetes were the least susceptible to carbaryl and with the exception of a short-term effect on oligochaetes, no significant negative effects were observed. The addition of oysters did not affect the infaunal community in this study, however greater abundance of epifaunal organisms like mussels, scaleworms, and the amphipod Amphithoe valida, which builds tubes in algae attached to shells, was observed. Carbaryl, which is currently applied to roughly 242 ha (< 6% of the intertidal) in Willapa Bay on an annual basis, has a variable but relatively short-term effect on the benthic community, which should be viewed in the context of other oyster culture operations like the addition of oysters themselves to a community often dominated by burrowing thalassinid shrimp which clearly control its dynamics.

Toxicology of carbaryl and aldicarb on brain and limb cultures of chick embryos

A variety of carbamates have been developed since the 1960s for use as broad-spectrum insecticides. An easy and inexpensive in vitro assay using chick-embryo derived cells was examined for its capability to screen and test the toxicity of these compounds. Chick embryo brain and limb bud cultures were treated with different concentrations of either carbaryl or aldicarb with or without activation (+/- S-9) for 5 days. Viability and cytotoxicity using the neutral red assay, and carbamate effects on cell migration and colony spread were measured. S-9 decreased the effects of carbaryl and aldicarb on brain cell cytotoxicity at exposures of 15-60 ppm and 40-200 ppm, respectively, as indicated by increased concentrations of neutral red. Viability of brain cell cultures was not altered by aldicarb, but was decreased by carbaryl plus S-9 in concentrations of greater than 40 ppm. In limb cultures, carbaryl without S-9 was significantly toxic at 8-25 ppm, but only concentrations of greater than 25 ppm of carbaryl plus S-9 significantly affected cytotoxicity. In contrast, aldicarb without S-9 caused no effect on limb cell cytotoxicity at concentrations of 40-200 ppm, but aldicarb plus S-9 significantly reduced cellular cytotoxicity at concentrations of greater than 160 ppm. Carbaryl +/- S-9 decreased the spread of both brain and limb colonies; aldicarb +/- S-9 caused a significant increase in the spread of the brain but not limb colonies.(ABSTRACT TRUNCATED AT 250 WORDS)

A comparison of a single occasion treatment of head louse infestation with phenothrin liquid shampoo or a carbaryl lotion

Fifty subjects with head louse infestation were recruited into a controlled trial to compare a phenothrin liquid shampoo with a carbaryl lotion. Twenty-seven subjects were treated with phenothrin and 23 with carbaryl, each formulation being applied only on a single occasion. Subjects were inspected for evidence of live lice and eggs at 24 hours and 3 to 4 weeks after application of treatment. The results showed that both the phenothrin liquid shampoo and the carbaryl lotion were effective in killing adult lice and viable eggs. No statistically significant difference in treatment efficacy was observed between the two groups. Fewer side-effects, however, were observed with the phenothrin liquid shampoo than with the carbaryl lotion. These results indicate that, when applied as a single treatment, a phenothrin liquid shampoo was as effective as a carbaryl lotion in eradicating head lice and eggs.

Effects of in ovo injection of carbamates on chick embryo hatchability, esterase enzyme activity and locomotion of chicks

Carbaryl and aldicarb, two carbamate pesticides used extensively throughout the United States, are known to act as acetylcholinesterase inhibitors. We have demonstrated previously that exposure to carbaryl and aldicarb in young chicks caused persistent locomotion alterations with no correlation to esterase inhibition. In this study, we investigated the effects of these carbamates when injected in ovo to chick embryos, at two time periods (days 5 and 15) during incubation. Carbaryl dosed at 45 mg kg-1 egg weight was extremely toxic to the embryos on day 5 of incubation. Hatchability was reduced to 0% as compared to 80% when carbaryl was injected on day 15 of incubation. Aldicarb at 1.5 mg kg-1 egg weight had no major effect on hatchability when injected either on day 5 or day 15 of incubation (hatchability = 90 and 100%, respectively). Plasma, liver and brain esterases were measured in the chick at different time points during incubation and after hatching. Brain acetylcholinesterase (AChE) and liver cholinesterase (ChE) were inhibited significantly during incubation in embryos dosed on day 15 with both carbaryl and aldicarb. Liver carboxylesterase was inhibited significantly during incubation with only the carbaryl treatment. All esterase enzyme activities returned to normal after hatching. Plasma ChE and carboxylesterase levels were not affected with either carbaryl or aldicarb treatment from 8 until 47 days after hatching. Neither carbamate had any effect on brain neuropathy target esterase (NTE) activity either during incubation or after hatching. The locomotion of chicks was affected in both treatment groups until 47 days after hatching. This study indicates that carbaryl and aldicarb may cause long-term delayed alterations in the chicks.