Sediment desorption of PCB congeners and their bio-uptake by dipteran larvae

Sediment desorption of PCB congeners and their bio-uptake by Chironomus tentans Fabricus were investigated in a continuous flow system. The desorption of 71 congeners (in Aroclors 1221, 1016, 1254 and 1260) determined by glass capillary gas chromatography could be described by a first order function. The release rate of the individual congeners was inversely related to their octanol/water partition coefficients (K_ow). The depth of mobilization generally decreased with the number of chlorine substitutions and was inversely related to K_ow.Bio-uptake of the congeners by Chironomus tentans Fabricus was selective with the bio-uptake factor being highest for those with 2–4 chlorines. There was no correlation between the factor and either K_ow or desorption rate from the sediments.     

Uptake and release of zinc by aquatic bryophytes (Fontinalis antipyretica L. ex. Hedw.)

The zinc uptake and posterior release by an aquatic bryophyte—Fontinalis antipyretica L. Ex Hedw.—was experimentally studied in laboratory exposing the plants to different zinc concentrations in the range, 1.0–5.0 mg l⁻¹, for a 144 h contamination period, and then exposed to metal-free water for a 120 h decontamination period. The experiments were carried out in perfectly mixed contactors at controlled illumination, using mosses picked out in February 1997, with a background initial zinc concentration of 263 mg g⁻¹ (dry wt.). A first-order mass transfer kinetic model was fitted to the experimental data to determine the uptake and release constants, k₁ and k₂, the zinc concentration in mosses at the end of the uptake period, C_mu, and at the equilibrium, for the contamination and decontamination stages, C_me and C_mr, respectively. A bioconcentration factor, BCF=k₁/k₂ (zinc concentration in the plant, dry wt./zinc concentration in the water) was determined. A biological elimination factor defined as BEF=1−C_mr/C_mu was also calculated. BCF decreases from about 4500 to 2950 as Zn concentration in water increases from 1.05 to 3.80 mg l⁻¹. BEF is approximately constant and equal to 0.80. Comparing Zn and Cu accumulation by Fontinalis antipyretica, it was concluded that the uptake rate for Zn (145 h⁻¹) is much lower than for Cu (628 h⁻¹) and the amount retained by the plant decreased by a factor of about seven.     

Plant crown traits and carbon sequestration capability by Platanus hybrida Brot. in Rome

Measurements of carbon dioxide (CO₂) concentration carried out in the city of Rome in the period January–December 2005 showed a mean yearly CO₂ concentration of 414 ± 45 ppm; polluted sites (P sites) had 21% higher CO₂ concentration than control sites (C sites). The significant (p < 0.01) correlation analysis between CO₂ concentration and traffic density measured during the study period at P sites showed that traffic density explained 51% of the CO₂ variation. The CO₂ trend during the traffic limitation days (provision imposed by ordinance of the City Council) did not show significant differences as regards regular traffic days, suggesting the ineffectiveness of this provision. Leaf area index (LAI) of Platanus hybrida Brot. was on an average 11% lower at P sites than at C ones associated with a lower total photosynthetic leaf surface area (SPT, 34% lower at P sites than at C ones). P. hybrida had a total carbon sequestration of 117 ± 13 kg year⁻¹ (mean value of P and C sites) playing an important role in sequestering CO₂. Thus, the choice of plant species for urban areas may be set out taking into account their own air amelioration capability. Plant traits of each species may be used for urban tree planting programs to ameliorate urban air pollution.     

The fate of chlorine in recirculating cooling towers Field results

Chlorine and chloramines are volatile compounds which are stripped (“flashed off”) from recirculating cooling water systems by the large volumes of air which flow through the water in the cooling tower. The fraction of a volatile gas, such as hypochlorous acid (HOCl), which is removed by stripping is determined by Henry's constant H for that gas: H = X_G/X_L, where X_G is the mole fraction of the gas in the air and X_L is the mole fraction of the gas in the water. We have measured H for HOCl, OCl⁻, NH₃, NH₂Cl, NHCl₂ and NCl₃ at 20 and 40°C. We found H = 0.076 for HOCl, compared to 0.71 for NH₃, at 20°C. At 40°C, H was about 2.5-fold larger for HOCl. This means that 10–15% of the HOCl is stripped from cooling water on each passage through a typical cooling tower. The measured flashoff of free available chlorine (HOCl + OCl⁻) was markedly pH-sensitive with a pK of 7.5, exactly as expected if HOCl is volatile but OCl⁻ is not. The data permit a quantitative understanding of the fate of chlorine in cooling systems. The values of H at 40°C for NH₂Cl, NHCl₂ and NCl₃ were 1.28, 3.76 and 1067. This means that all of the chloramines are quickly stripped in a cooling tower.     

The feasibility of using disused water treatment filter beds for rearing carp (Cyprinus Carpio L.) in the U.K.

The feasibility of rearing carp (Cyprinus carpio) at a disused water treatment works in East London (U.K.) was investigated. The 10 ha of filter beds represented an atypical site for carp culture; in order to assess whether in-house aquaculture would enable a Water Authority to gain advantage in cost, availability and disease-free status of stock, a series of trials was undertaken. These enabled comparison of the weight of carp produced in relation to: extensive cultivation, artificial feeding, a range of stock densities and a range of ages and sizes. The filter beds were unsuitable for natural spawning, early fry production and the rearing of first year fish (0⁺ age group). However, growing-on of subsequent stages (i.e. 0⁺ − 1⁺ or 1⁺ − 2⁺) gave good survival (60–80%) and growth rates. Fish stocked at 20 g in April/May reached 200–400 g by September and 1 kg plus, 1 yr later. Production levels of 300–350 kg ha⁻¹ yr⁻¹ without artificial foods (i.e. extensive cultivation) and up to 2.2 tonnes ha⁻¹ yr⁻¹ with supplementary feeding were comparable with mainland European fish farms. These high values reflect the eutrophic nature of this site and successful exploitation of the available secondary production. It was possible to harvest 15,000–20,000 carp yr⁻¹ for restocking. Carp rearing integrated with existing operations and activities on site (e.g. pipe and equipment stores) and represents a novel, alternative use of a semi-redundant site. Cost benefit assessment showed that fish production was economically viable returning nominal profit margins of between £1.10 and £2.06 kg⁻¹ of carp harvested. The resultant cost/benefit ratios per kilogram harvested were 1:1.9 for extensive production (without feeding) and 1:1.34–1.43 when intensive cultivation employing artificial foods was used.     

Toxicity of cadmium, cobalt, uranium and zinc to Zoogloea ramigera

The toxic effects of cadmium, cobalt, uranium and zinc to the bacterium Zoogloea ramigera have been studied. This organism, which is abundant in sewage-treatment plants, responded to media supplemented with heavy metals by showing a prolonged lag phase and by decreasing its growth rate. The length of the lag phase was proportional to the metal concentration when Z. ramigera was exposed to cadmium, cobalt and zinc. When exposed to uranium (uranyl ions) the organism altered its growth behavior by showing an extended lag phase almost independent of the metal concentration. The order of toxicity of the metals to Z. ramigera was Cd²⁺ = Zn²⁺ > Co²⁺ > UO₂²⁺.     

Bioconcentration potential of polydimethylsiloxane (PDMS) fluids by fish

The water solubilities (S), octanol/water partition coefficients (K_ow) and bioconcentration factors (BCF) of four polydimethylsiloxane (PDMS) fluids covering a wide range of molecular weight were measured. It is shown that a previously described correlation between S and K_ow for organic chemicals may be invalid for PDMS fluids; an alternative correlation is proposed. Some PDMS fluids tend to have a bioconcentration potential in silver carp.     

Toxic effects of disyston and furadan on the bimodal pattern of oxygen consumption in the climbing perch, Anabas testudineus (Bloch)

A significant change was noted in the aquatic (vO₂), aerial (VO₂) and total [(v + V)O₂] consumption of Anabas testudineus (Bloch) exposed to 4.0 and 10.5 mg l⁻¹ disyston and 0.56 and 1.56 mg l⁻¹ furadan. After 1 h of exposure to all the concentrations significant decreases were noticed in the (v + V)O₂. Though significant increases were noted in all the measures of respiration after 3 h of exposure in both the pesticides, their effects vary from one exposure period to another. The fish held in 4.0 mg l⁻¹ disyston and 0.56 mg l⁻¹ furadan concentrations resumed normal pattern of bimodal respiration after 120 and 96 h respectively. Further the pattern of changes in (v + V)O₂ closely followed the changes observed in VO₂ rather than vO₂ indicating that the fish held in pesticide medium predominantly relied on aerial respiration. A direct correlation was noticed between the VO₂ consumption and the surfacing frequency of the fish exposed to disyston and furadan. Relatively furadan is more toxic than disyston to Anabas testudineus if their effects on O₂ consumption are taken into consideration.     

Toxicological effects of dehydroabietic acid (DHAA) on the trout, Salmo gairdneri Richardson, in fresh water

Toxicological and physiological effects of dehydroabietic acid (DHAA), a major poison to fishes in pulp and paper mill effluents, were studied by two experiments with rainbow trout, Salmo gairdneri Richardson: in the first, fish were acutely exposed for 4 days to an average DHAA concentration of 1.2 mg l⁻¹ (Exp. I) and in the second for 30 days to an average of 20 μg DHAA l⁻¹ (Exp. II).Compared to the controls, fish of Exp. I displayed a decreased relative weight of liver, an increased blood haematocrit, and increased haemoglobin as well as plasma protein concentrations. The aspartate aminotransferase activity of heart muscle was significantly elevated, as was also the lactate dehydrogenase (LDH) of white muscle tissue. In the blood plasma, the proportion of muscle type LDH activity was simultaneously increased. UDP-glucuronyl-transferase activities of liver and kidney were strongly decreased. Results suggest an increased and altered use of body energy reserves, decreased plasma volume and impaired liver function.Fish of Exp. II showed an increased relative weight of spleen. In addition, liver and gill LDH shifted towards heart-type. We conclude that 20 μg l⁻¹ is close to the “minimum effective concentration” of DHAA to rainbow trout.     

Restoration of heavily polluted branches of the Shatt Al-Arab river, Iraq

In view of the desire to improve the water quality of the heavily polluted branches of the Shatt al-Arab River at the City of Basrah, it was proposed to maintain effective flushing as well as contracting sewerage system. The present study was conducted in order to examine the water quality of these branches in an attempt to evaluate the effectiveness of the proposed flushing system. It has been found that their waters contained very low levels of dissolved oxygen and relatively high amounts of both COD and BOD₅. The annual average water quality parameters for Basrah Branches were: dissolved oxygen 3.4 ppm; pH 7.67; hydrogen sulphide 1.4 ppm; ammonia 97 μg-at. N l⁻¹; COD 15.9 mg l⁻¹; BOD₅ 12.7 mg l⁻¹; dissolved silicates 202 μg-at. Si l⁻¹; dissolved reactive phosphate 13.4 μg-at. P-PO₄³⁻ l⁻¹; nitrate 10.4 μg-at. N-NO₃⁻ l⁻¹; nitrite 2.1 μg-at. N-NO₂⁻ l⁻¹ and chlorophyll-α 14.3 mg m⁻³. Based on our calculations, it has been concluded that the proposed system is effective, thus within a flushing cycle all of the above mentioned parameters will become within the acceptable values of the Shatt al-Arab water quality. Moreover, this system has no appreciable effect upon the water quality characteristics of the Shatt al-Arab River due to the fact that it discharges a high volume of water annually. However, It has been recommended to dredge the deposited sludge to a minimum depth of 50 cm.     

Long-term changes of mercury levels in ringed seal (Phoca hispida) from Amundsen Gulf, and beluga (Delphinapterus leucas) from the Beaufort Sea, western Canadian Arctic

Mercury (Hg) concentrations were determined in the canine teeth of ringed seals (Phoca hispida) harvested during the 13th–14th, late 19th and early 21st Centuries in Amundsen Gulf, Northwest Territories, Canada. Most historical and pre-industrial teeth contained undetectable Hg levels (i.e. < 1.0 ng/g DW), whereas samples from 2001–03 contained up to 12 ng/g DW in an age-dependent pattern. Assuming a median [Hg] value in 13th–14th Century teeth of half the detection limit (i.e. 0.5 ng/g DW), geometric means of Hg in modern teeth were 9–17 times those of seals in the 14th Century, equivalent to an anthropogenic input of 89–94% of total Hg in modern seals. These results corroborate a previous study of beluga (Delphinapterus leucas) in the nearby Beaufort Sea. While the seals' trophic position (inferred from δ¹⁵N values) did not change over time, modern δ¹³C values were lower by about 2‰ than in the 14th and 19th Centuries. This could be due to increased dissolution of anthropogenically derived CO₂ in the ocean from the atmosphere, but could also indicate more offshore pelagic feeding by modern seals, which might be a factor in their Hg exposure. New tooth [Hg] data are also presented for the Beaufort Sea beluga, using recently-discovered museum samples collected in 1960/61, which showed that most of the anthropogenic contribution to beluga Hg had already taken effect by 1960 (reaching  75% of total Hg). Taken together, the long-term seal and beluga data indicate that whereas Hg levels in the marine ecosystems of the western Canadian Arctic were probably unchanged from pre-industrial times up to the late 19th Century, there was a significant, many-fold increase in the early to mid-20th Century, but little or no change after about the early 1960s.     

Enhancement of Nitrobacter activity by heterotrophic bacteria

The present work shows that a supply which is not sterile and which contains organic matter does not interfere with the performance of a column filled with a support previously inoculated with Nitrobacter winogradskyi serotype agilis.Measurements of oxidation rates give results higher than those obtained under axenic conditions (maximum oxidation rate: 220 mg NO₂⁻ h⁻¹ l⁻¹ of reactor volume under non-sterile conditions: 160 mg NO₂⁻ h⁻¹ l⁻¹ of reactor volume under axenic conditions).This finding has concentrated our work on the effect of heterotrophic bacteria and of organic matter on the growth of Nitrobacter. We show that a fermentation filtrate of a heterotrophic bacterium (Pseudomonas sp.) added to a fermenter culture of Nitrobacter produces an increase of activity. Experimental results indicate an appreciable reduction in the latence period (15-0 h) and a considerable increase in the rate of growth of Nitrobacter. (Maximum growth rate with 10% of heterotrophic filtrate: 0.044 h⁻¹; without filtrate: 0.032 h⁻¹.)     

Role of aquatic plants in wastewater treatment by artificial wetlands

This report describes investigations using artificial wetlands which quantitatively assess the role of each of three higher aquatic plant types, Scirpus validus (bulrush), Phragmites communis (common reed) and Typha latifola (cattail), in the removal of nitrogen (via sequential nitrification-denitrification), BOD and TSS from primary municipal wastewaters. During the period August 1983–December 1984, the mean ammonia concentration of 24.7 mg l⁻¹ in the primary wastewater inflow (hydraulic application rate = 4.7 cm day⁻¹) was reduced to mean effluent levels of 1.4 mg l⁻¹ for the bulrush bed, 5.3 mg l⁻¹ for the reed bed and 17.7 mg l⁻¹ for the cattail bed, as compared to a mean value of 22.1 mg l⁻¹ for the unvegetated (control) bed. For all three vegetated beds, the mean effluent ammonia values were significantly below that for the unvegetated bed and for the inflow. The bulrushes and reeds (in that order) proved to be superior at removing ammonia, both with mean effluent levels significantly below that for the cattail bed. The high ammonia-N (and total N) removal efficiencies shown by the bulrush and reed beds are attributed to the ability of these plants to translocate O₂ from the shoots to the roots. The oxidized rhizosphere so formed stimulates sequential nitrification-denitrification. Similarly BOD removal efficiencies were highest in the bulrush and reed beds, both with mean effluent BOD levels (5.3 and 22.2 mg l⁻¹, respectively) significantly below that for the unvegetated bed (36.4 mg l⁻¹) and equal to or better than secondary treatment quality (30 mg l⁻¹). Our results demonstrate that higher aquatic plants can indeed play a significant role in secondary and advanced (N removal) wastewater treatment by wetland systems, a role that is completely distinct from that associated with their pollutant uptake capacity.     

Hyperconcentrated cultures of Scenedesmus obliquus: A new approach for wastewater biological tertiary treatment?

Algal cultures of Scenedesmus obliquus at low concentrations (0.1–0.2 g dry wt l⁻¹) provide adequate biological tertiary treatment of wastewaters. This research was aimed at studying the possibility of increasing the system performance by using hyperconcentrated cultures of S. obliquus (up to 2.6 g dry wt l⁻¹) at the laboratory scale. The algal culture grown on secondary effluent was first chemically flocculated with chitosan (30 mg l⁻¹) and decanted; the sedimented culture (5 g dry wt l⁻¹) was then resuspended in secondary effluent to obtain algal suspensions at various concentrations, the performance of which was compared to that of a control culture (0.13 g dry wt l⁻¹). The rate of exhaustion of nitrogen (N-NH₄⁺) was proportional to the algal concentration and a complete removal could be obtained within 15 min (at 2.6 g dry wt algae l⁻¹); this result compares favorably to the 2.5 h or so required by the control culture. The unit uptake rate for nitrogen (N-NH₄⁺) had a tendency to increase with the algal concentration, whereas that of phosphorus (P-PO₄³⁻) showed the opposite relationship. Considering the results obtained, it appears that hyperconcentrated algal cultures have a high potential for the tertiary treatment of wastewaters; a significant reduction of pond surface for large scale operations can be anticipated.     

The crayfish as a “biological indicator” of aquatic contamination by heavy metals

Cu, Cd. Mg, Mn and Ni concentrations in whole Cambarus bartoni, trapped from Nepahwin Lake, Joe Lake and Wizard Lake, lying at distances of 10, 30 and 150 km, respectively, from the Sudbury smelters in Northeastern Ontario, showed an inverse relationship with the distance of the habitat from the emission site. Highest concentrations of Cu were observed in the hepatopancreas, Cd in the hepatopancreas and the gut, Fe and Mn in the gut, and Mg in the exoskeleton. Tissue concentrations of Ni and Zn were highly variable. Differences between males and females at each sampling site were not significant at the 5% level. The general relationship between crayfish tissue metal concentrations at the three sites was Cu > Mg > Mn > Zn > Ni > Cd. This observed relationship, except for Mg and Mn, agreed with the concentration relationship of these metals in the water and the sediments (top 10–20 cm) in the three lakes. In laboratory studies, Cu concentrations in the hepatopancreas, gills, exoskeleton and the viscera increased significantly over the control during the 4-weeks exposure to 125,250 and 500 μg Cu 1⁻¹. Hepatopancreas, in general, had the highest Cu concentration, and the exoskeleton, the lowest. Relationship between Ni exposure and the tissue Ni concentrations in the four treatments was 800 μg Ni l⁻¹ > 400 μg Ni l⁻¹ = 200 μg Ni l⁻¹ > control, while between the exposure periods and the tissue Ni concentrations was week 4 > week 1 > week 3 = week 2. Highest Ni concentrations at the end of the 4-week exposure to Ni were observed in the gut, gills and the hepatopancreas, and the lowest in the viscera. The present study suggests that Cambarus bartoni is a reliable indicator of the presence of class B and borderline elements with specific gravity > 5 in the aquatic environment. However, their value as biomonitors of variations in Cu and Ni concentrations in freshwater ecosystems is debatable.     

Azolla–Anabaena's behaviour in urban wastewater and artificial media – Influence of combined nitrogen

The results of using the nitrogen fixing symbiotic system Azolla–Anabaena to improve the quality of treated urban wastewater, particularly on what concerns phosphorus removal efficiencies (40–65%), obtained in continuous assays performed during the past few years and presented earlier, were very promising. Nevertheless, the presence of combined nitrogen in some wastewaters can compromise the treatment efficiency. The main goal of this work was to compare plants behaviour in wastewater and in mineral media with and without added nitrogen.Azolla filiculoides's specific growth rates in wastewater and in mineral media without added nitrogen or with low nitrate concentration were very similar (0.122 d⁻¹–0.126 d⁻¹), but decreased in the presence of ammonium (0.100 d⁻¹). The orthophosphate removal rate coefficients were similar in all the growth media (0.210 d⁻¹–0.232 d⁻¹), but ammonium removal rate coefficient in wastewater was higher (0.117 d⁻¹) than in mineral medium using that source of nitrogen (0.077 d⁻¹).The ammonium present in wastewater, despite its high concentration (34 mg N L⁻¹), didn't seem to inhibit growth and nitrogen fixation, however, in mineral media, ammonium (40 mg N L⁻¹) was found to induce, respectively, 18% and 46% of inhibition.     

Sorption of ionized and neutral emerging trace organic compounds onto activated sludge from different wastewater treatment configurations

The objective of this study was to examine sorption of a suite of 19 trace organic contaminants (TOrCs) to activated sludge. Compounds examined in this study included neutral, nonionized TOrCs as well as acidic TOrCs which may carry a negative charge and basic TOrCs which may carry a positive charge at the pH of wastewater. These TOrCs were evaluated to examine how sorptive behavior might differ for TOrCs in different states of charge. Additionally, multiple sludges from geographically and operationally different wastewater treatment plants were studied to elicit how solid-phase characteristics influence TOrC sorption. Characterization of sludge solids from 6 full scale treatment facilities and 3 bench-scale reactors showed no significant difference in fraction organic carbon (f_oc) and cation exchange capacity (CEC). Sorption experiments demonstrated that sorption of TOrCs also exhibits little variation between these different sludges. Organic carbon normalized partition coefficients (log K_oc) were determined as a measure of sorption, and were found to correlate well with octanol-water partition coefficients (log K_ow) for nonionized TOrCs, and log D_ow for anionic TOrCs where log D_ow is greater than 2. These data were used to construct a linear free energy relationship (LFER), which was comparable to existing LFERs for sorption onto sludge. No trend in sorption was apparent for the remaining anionic TOrCs or for the cationic TOrCs. These data suggest that predicting sorption to activated sludge based on K_ow values is a reasonable approach for neutral TOrCs using existing LFERs, but electrostatic (and likely other) interactions may govern the sorptive behavior of the charged organic chemicals to sludge.     

The sulfide electrode in bacterial studies

The applicability of a glass/Ag, Ag₂S (silver sulfide coated silver) electrode, which is capable of selectively detecting the H₂S fraction of total reduced inorganic sulfur (S_tot) concentration in biological systems is demonstrated. This electrode was used to monitor photosynthetic sulfide oxidation by Chlorobium phaeobacteroides. The electrode was resistant to Pfennig's medium and bacterial attack and after five months of use showed a potential drift within ±2 mV corresponding to ±13% maximum. The results obtained in a batch type experiment of growth of Chlorobium at different pH values suggest that Chlorobium cells preferentially take up the HS⁻ ion rather than H₂S.     

Atmospheric NH3 and NO2 concentration and nitrogen deposition in an agricultural catchment of Eastern China

To assess the atmospheric environmental impacts of anthropogenic reactive nitrogen in the fast-developing Eastern China region, we measured atmospheric concentrations of nitrogen dioxide (NO₂) and ammonia (NH₃) as well as the wet deposition of inorganic nitrogen (NO₃⁻ and NH₄⁺) and dissolved organic nitrogen (DON) levels in a typical agricultural catchment in Jiangsu Province, China, from October 2007 to September 2008_. The annual average gaseous concentrations of NO₂ and NH₃ were 42.2 μg m⁻³ and 4.5 μg m⁻³ (0 °C, 760 mm Hg), respectively, whereas those of NO₃⁻, NH₄⁺, and DON in the rainwater within the study catchment were 1.3, 1.3, and 0.5 mg N L⁻¹, respectively. No clear difference in gaseous NO₂ concentrations and nitrogen concentrations in collected rainwater was found between the crop field and residential sites, but the average NH₃ concentration of 5.4 μg m⁻³ in residential sites was significantly higher than that in field sites (4.1 μg m⁻³). Total depositions were 40 kg N ha⁻¹ yr⁻¹ for crop field sites and 30 kg N ha⁻¹ yr⁻¹ for residential sites, in which dry depositions (NO₂ and NH₃) were 7.6 kg N ha⁻¹ yr⁻¹ for crop field sites and 1.9 kg N ha⁻¹ yr⁻¹ for residential sites. The DON in the rainwater accounted for 16% of the total wet nitrogen deposition. Oxidized N (NO₃⁻ in the precipitation and gaseous NO₂) was the dominant form of nitrogen deposition in the studied region, indicating that reactive forms of nitrogen created from urban areas contribute greatly to N deposition in the rural area evaluated in this study.     

Sorption of organics by Selenastrum capricornutum

The sorption of eight organic compounds by a representative green alga, Selenastrum capricornutum, was determined by gas-liquid chromatography using a series of linear model experiments. The log₁₀ bioconcentration factors (BCF), defined as the ratio of the concentration on in the algae to the concentration in the aqueous medium, are as follows: benzene, 3.32; toluene, 3.18; chlorobenzene, 3.69; 1,2-dichlorobenzene, 4.17; naphthalene, 4.10; phenanthrene, 4.38; di-n-butylphthalate, 4.36 and pyrene, 4.56. The relation of log₁₀ BCF correlation with log₁₀ octanol-water partition coefficient was determined as log₁₀ BCF = 0.46 log₁₀ P + 2.36.