Bioaccumulation Of Pentachlorophenol Research Articles

Effects of carboxylated multi-walled carbon nanotubes on bioconcentration of pentachlorophenol and hepatic damages in goldfish.

Carboxylated multi-walled carbon nanotubes (MWCNT-COOH) exerts strong adsorption capacity for pentachlorophenol (PCP) and they inevitably co-occur in the environment, but few studies have characterized the effects of MWCNT-COOH on the bioavailability of PCP and its oxidative and tissue damages to fish. In this work, we assessed the PCP accumulation in different organs and the induced oxidative and tissue damages of goldfish following 50-d in vivo exposure to PCP alone or co-exposure with MWCNT-COOH. Our results indicated that PCP bioaccumulation in goldfish liver, gill, muscle, intestine and gut contents was inhibited after co-exposure with MWCNT-COOH in uptake phase. PCP exposure alone and co-exposure with MWCNT-COOH evoked severe oxidative and tissue damages in goldfish bodies, as indicated by significant inhibition of activities of antioxidant enzymes, remarkable decrease in glutathione level, simultaneous elevation of malondialdehyde content, and obvious histological damages to liver and gill. The decreased accumulation of PCP in the presence of MWCNT-COOH led to the reduction of PCP-induced toxicity to liver tissues, as confirmed by the alleviation of hepatic oxidative damages. However, co-exposure groups had higher concentrations of PCP in the tissues than PCP treatment alone (p < 0.05 each) in the depuration phase, revealing that MWCNT-COOH-bound pollutants might pose higher risk once desorbed from the nanoparticles. These results provided substantial information regarding the combined effects of PCP and MWCNT-COOH on aquatic species, which helps to deeply understand the potential ecological risks of the emerging pollutants.

Pentachlorophenol and ciprofloxacin present dissimilar joint toxicities with carbon nanotubes to Bacillus subtilis.

Discharged carbon nanotubes (CNTs) likely interact with co-existing organic contaminants (OCs) and pose joint toxicity to environmental microbes. Herein, hydrophobic pentachlorophenol (PCP) and hydrophilic ciprofloxacin (CIP) were used as representative OCs and their joint toxicities with CNTs to Bacillus subtilis were systematically investigated at cellular, biochemical, and omics levels. The 3-h bacterial growth half inhibitory concentrations of CNTs, PCP, and CIP were 12.5±2.6, 3.5±0.5, and 0.46±0.03mg/L, respectively, and they all could damage cell membrane, increase intracellular oxidative stress, and alter bacterial metabolomics and transcriptomics; while CNTs-PCP and CNTs-CIP binary exposures exhibited distinct additive and synergistic toxicities, respectively. CNTs increased bacterial bioaccumulation of PCP and CIP via destabilizing and damaging cell membrane. PCP reduced the bioaccumulation of CNTs, while CIP had no significant effect; this difference could be owing to the different effects of the two OCs on cell-surface hydrophobicity and CNTs electronegativity. The additive toxicity outcome upon CNTs-PCP co-exposure could be a result of the balance between the increased toxicity from increased PCP bioaccumulation and the decreased toxicity from decreased CNTs bioaccumulation. The increased bioaccumulation of CIP contributed to the synergistic toxicity upon CNTs-CIP co-exposure, as confirmed by the increased inhibition of topoisomerase Ⅳ activity and interference in gene expressions regulating ABC transporters and lysine biosynthesis. The findings provide novel insights into environmental risks of CNTs.

Uptake and Bioaccumulation of Pentachlorophenol by Emergent Wetland Plant Phragmites australis (Common Reed) in Cadmium Co-contaminated Soil

Despite many studies on phytoremediation of soils contaminated with either heavy metals or organics, little information is available on the effectiveness of phytoremediation of co-occurring metal and organic pollutants especially by using wetland species. Phragmites australis is a common wetland plant and its potential for phytoremediation of cadmium pentachlorophenol (Cd-PCP) co-contaminated soil was investigated. A greenhouse study was executed to elucidate the effects of Cd (0, 10, and 20 mg kg−1) without or with PCP (0, 50, and 250 mg kg−1) on the growth of the wetland plant P. australis and its uptake, accumulation and removal of pollutant from soils. After 75 days, plant biomass was significantly influenced by interaction of Cd and PCP and the effect of Cd on plant growth being stronger than that of PCP. Coexistence of PCP at low level lessened Cd toxicity to plants, resulting in improved plant growth and increased Cd accumulation in plant tissues. The dissipation of PCP in soils was significantly influenced by interactions of Cd, PCP and plant presence or absence. As an evaluation of soil biological activities after remediation soil enzyme was measured.

Soil monitoring of pentachlorophenol by bioavailability and ecotoxicity measurements

Several approaches to monitor the bioavailability and ecotoxicity of pentachlorophenol (PCP) in sterile and non sterile soils as a function of aging are reported. Porapak resins and water were used to assess the bioaccessibility and the bioavailability of PCP in soil. Aging effects were observed mainly after 240 d of aging. Actual bioavailability, measured as PCP bioaccumulation in earthworms, decreased more markedly with time. The ecotoxicological biomarker neutral red retention time (NRRT) displayed a dose dependent effect but no aging effects after exposing the earthworms to polluted soils. Nevertheless, mortality of earthworms increased after 240 d at 150 mg kg(-1) contamination. In contrast, the luminescent biosensor Pseudomonas fluorescens pUCD607 evidenced in non sterilized samples a slight reduction of ecotoxicity in time related to the degradation of the molecule. Once again, results highlight the necessity to study the fate of soil pollutants with different chemical and biological approaches. Different PCP degradation pathways and/or the different sensitivity of earthworms and bacteria could explain the different behaviours observed.

Bioavailability of Pentachlorophenol to Earthworms (Eisenia fetida) in Artificially Contaminated Soils

The bioaccumulation of pentachlorophenol in earthworms (Eisenia fetida) was studied for two artificially contaminated soils (S1 and S2). The uptake kinetics of pentachlorophenol (PCP) in earthworms increased quickly within the initial 10 days. This was followed by a nearly steady state for the next 20 days that fit with the equilibrium partitioning model. The correlation coefficients were 0.812 and 0.715 for S1 and S2, respectively. The average biota-to-soil accumulation factor of PCP in S1 was 0.51 ± 0.09, whereas that of S2 was 0.79 ± 0.12. There was a significant correlation between log C soil and log C worm, demonstrating the validity of the equilibrium partitioning model. The bioavailability of PCP was assessed by chemical extraction methods. The results demonstrated a close correlation between extractable amounts of PCP freshly added in soils and those in earthworms. With increasing residence time of PCP in soil, there was a progressively smaller amount of PCP assimilated by the earthworms. In contrast, the amount extracted by Soxhlet extraction did not show a similar decline. However, the extractable amount of PCP by methanol and methanol–water (1:1) significantly decreased over 440 days. Compared with the methanol–water (1:1) extraction method, the methanol extraction method was preferred to the prediction of the bioavailability of PCP in aged soils.

Effects of pentachlorophenol-contaminated food organisms on toxicity and bioaccumulation in the frogXenopus laevis

Sub-adult African clawed frogs (Xenopus laevis) were fed pentachlorophenol (PCP)-injected mealworms containing 64.8 to 2604 ug of PCP per gram of worm for 27 days. There was no mortality and no significant bioaccumulation of PCP in the frogs. After three weeks, frogs fed 2,604 micrograms/g of PCP ceased eating. The no observed adverse effects level (NOAEL) based on significantly reduced food consumption (PCP-injected mealworms) was 638 micrograms/g. This corresponded to a NOAEL based on PCP intake of about 8 micrograms PCP/g frog/day. A toxicity threshold model estimated that about 800 micrograms/L of waterborne PCP may be a threshold for adverse effects in Xenopus or similar amphibians. Further study is needed to verify threshold estimates.

Pentachlorophenol toxicity to amphipods and fathead minnows at different test pH values

AbstractJuvenile amphipods (Gammarus pseudolimnaeus and Crangonyx pseudogracilis) and fathead minnows (Pimephales promelas) were exposed to pentachlorophenol (PCP) at pH values of 6.5, 7.5, 8.0 and 8.5 for 96 h, and early life stages of fathead minnows were exposed for 32 d at the same pH values to determine the relationship between test pH and the acute and chronic toxicity of PCP. Residue analyses were performed on fathead minnows after 32 d to determine the relationship between test pH and PCP bioaccumulation. Technical‐grade PCP (88% active ingredient; Dowicide EC7) was used as the toxicant source.Acute exposures with all three species showed that PCP toxicity was decreased with increased test pH. The slopes of this relationship were similar for the amphipods, but were different from that observed for fathead minnows. Early life stage exposures of fathead minnows showed that chronic PCP toxicity and bioaccumulation were similarly decreased when pH values were increased. The decrease in chronic PCP toxicity appeared to be due to the reduction in PCP accumulation as a direct result of the increased ionization of PCP at higher pH values, indicating that the ionized form was less toxic per unit concentration than was the un‐ionized form. However, these studies suggest that chronic as well as acute toxicity may be caused by both forms of PCP when significant concentrations are present in solution.

Toxicity and Bioaccumulation of Pentachlorophenol in Broiler Chickens

Hubbard-Hubbard broiler chickens were fed graded levels (0, 1, 10, 100, and 1000 ppm) of pentachlorophenol (PCP) containing less than .0023% octachlorodibenzo-p-dioxin (OCDD) for 8 weeks. Tissue samples for PCP, OCDD, and pentachloroanisole (PCA) were cleaned up via gel permeation chromatography and analyzed by gas chromatography employing electron capture detection.Kidney weights were significantly increased by the 100 ppm and 1000 ppm PCP diet. Weights of all other organs including the body weights were significantly lowered by the 1000 ppm PCP diet. Except for the control group, histopathologic examination of the liver revealed bile duct proliferation and some fatty changes in all of the 6-week-old birds. Examination of the brain, liver, gizzard, pancreas, intestine, proventriculus, spleen, kidney, lung, and heart revealed no histopathological lesions in the treated or control birds.Significant linear relationships were found between PCP accumulation in tissues and the concentration of dietary PCP. Accumulation of PCP was greatest in the kidney followed by liver, heart, leg, breast, gizzard, and fat. The high residue levels in the kidney and liver may reflect principal routes of elimination and metabolism.Following a 5 week withdrawal of PCP from the diet, PCP residues were still present in the adipose tissue of all treated birds. Residue levels in the kidney and liver were reduced at the first and third week of withdrawal, but a continuous decline was interrupted by a slight elevation in residue level at the fifth week of withdrawal from the chemical.