Mercury in fur of Daubenton’s bat (<Emphasis Type="Italic">Myotis daubentonii</Emphasis>) in Southern Sweden and Comparison to Ecotoxicological Thresholds

To characterise mercury (Hg) exposure in Daubenton’s bat (Myotis daubentonii, Kuhl 1817) in southern Sweden, 17 specimens were captured in 2013 and back fur samples were taken for analysis to determine Hg concentrations. The fur Hg levels determined [1.15?±?0.27 (mean?±?standard deviation, n?=?17) µg Hg g^?1 fresh weight (fw)] represent a baseline for comparison in future assessments of Hg exposure in bat populations in northern Europe. Mercury concentrations were close to those reported in fur from other bat species, but were lower than proposed toxicological thresholds in bats (>?30 µg Hg g^?1 fw) and mice (5 µg Hg g^?1 fw). This is the first study to examine Hg exposure in bats in Scandinavia.     

Bioecological Aspects and Heavy Metal Contamination of the Mollusk <Emphasis Type="Italic">Donax denticulatus</Emphasis> in the Colombian Caribbean Coastline

Donax denticulatus is a key mollusk for the ecology of sandy beaches, serving as a controller of organic matter, microorganisms, and as bioindicator of heavy metals pollution. The goal of this study was to characterize some ecological aspects of D. denticulatus and its relationship with the content of heavy metals in their tissue, in three beaches of the Caribbean coast of Colombia. The results showed the study populations were different in terms of morphological characteristics and density (Berrugas-Sucre?<?Cartagena-Bolívar?<?Riohacha-Guajira), but not in sexual proportion; although density was clearly related to beach occupancy by tourists. Analysis of metals revealed tissue concentrations varied depending on the location (Greater means: Hg?=?0.018?±?0.004 in Riohacha; Pb?=?0.110?±?0.060 in Berrugas and Cd?=?0.040?±?0.010 µg/g in Cartagena). No relationships were found between morphometric variables and heavy metals content. Principal components analysis highlighted Riohacha for presenting differences respecting to Bocagrande and Berrugas in terms of physicochemical water parameters such as pH, temperature, salinity, dissolved oxygen and conductivity. Results suggest tourism rather than environmental pollution could be a sensitive factor for biota survival in Caribbean beaches.     

Uptake of Urea Nitrogen by <Emphasis Type="Italic">Oocystis borgei</Emphasis> in Prawn <Emphasis Type="Italic">(Litopenaeus vannamei)</Emphasis> Aquaculture Ponds

The goal of this study was to assess the rate of urea nitrogen uptake (ρ) by Oocystis borgei and the relationship between environmental factors and ρ. Light intensity, temperature, pH, salinity, and algal concentration, were used to construct an empirical model. The results showed that light intensity, algal concentration, pH and salinity had significant effects on ρ, and the optimal combination of environmental conditions for ρ was a temperature of 25°C, pH of 7.0, light intensity of 81 µmol m^?2 s^?1, salinity of 15‰, and algal concentration of 4.5?×?10⁸ cell L^?1–5.5?×?10⁸ cell L^?1. The model equation was ρ?=?2?×?10^?5?×?(A^0.363B^0.783C^0.045D^?0.503E)?+?0.0017, with a coefficient of determination (R²) of 0.83. No significant difference in variance was observed between the model-predicted values and the measured values (F?=?0.238, p?>?0.05), which demonstrated the high fitting degree of the simulation equation. This study provided valuable insight into the reduction of urea nitrogen levels in aquaculture water by O. borgei.     

Growth Recovery of <Emphasis Type="Italic">Lemna gibba</Emphasis> and <Emphasis Type="Italic">Lemna minor</Emphasis> Following a 7-Day Exposure to the Herbicide Diuron

In agricultural catchments, aquatic ecosystems can experience a pulse exposure to pesticides. Following such exposure, non-target organisms that are not extirpated may recover. This paper investigates the potential of two duckweed species (Lemna minor and Lemna gibba) to recover from a 7-day exposure to different concentrations (0.4–208 µg L^?1) of the herbicide diuron. There was significant inhibition in the growth and biomass after the initial 7-day exposure (e.g. frond number EC₅₀ = 59.2 and 52.2 µg L^?1 for L. minor and L. gibba, respectively). Following transfer to clean media, recovery (the highest concentration yielding no significant difference in the effect endpoint from the control) was observed for all effects endpoints at concentrations ranging 60–111 µg L^?1 for L. minor and 60–208 µg L^?1 for L. gibba. These results suggest that recovery is possible for primary producers at environmentally relevant concentrations considered significant in ecological risk assessment.     

Analysis and Occurrence of Bisphenol A in Mediterranean Mussels (<Emphasis Type="Italic">Mytilus galloprovincialis</Emphasis>) Sampled from the Slovenian Coastal Waters of the North Adriatic Sea

During 2015, a selection of Mediterranean mussels (Mytilus galloprovincialis) and seawater were sampled along the Slovenian coast, which is part of the North Adriatic Sea, in order to test for the presence of bisphenol A (BPA). The concentration of the BPA in the tissues of mussels sampled from the farms and open sea was from <?0.03 to 0.55 µg kg^?1 of w.w. and from <?0.03 to 0.46 µg kg^?1 of w.w., respectively. The mussel shells from the farms and open sea contained from 0.01 to 0.3 µg BPA kg^?1 of w.w. and from 0.04 to 0.27 µg BPA kg^?1 of w.w., respectively. In a harbour, mussel tissue and shell concentration of BPA was 0.21 and 0.18 µg BPA kg^?1 of w.w., respectively. The seawater in the shellfish farms and the open sea was contaminated with an average of 0.007 µg l^?1 of BPA.     

Heavy Metal Concentration in Largehead Hairtail (<Emphasis Type="Italic">Trichiurus lepturus</Emphasis> Linneaus, 1758) and Savalai Hairtail (<Emphasis Type="Italic">Lepturacanthus savala</Emphasis> (Cuvier, 1829)) Obtained from Karachi Fish Harbour,Pakistan

In this study, muscle samples gathered from Largehead hairtail (Trichiurus lepturus Linneaus, 1758) and Savali hairtail [Lepturacanthus savala (Cuvier, 1829)] from the Karachi Fish Harbour, Pakistan were analyzed to determine heavy metal concentrations (iron [Fe], zinc [Zn], copper [Cu], manganese [Mn], lead [Pb] and cadmium [Cd]) between January and December 2016. All samples were analyzed using the AAnalyst 700 Flame Atomic Absorption Spectrophotometer. It was observed that the average measured level of Fe, Zn, Cu, Mn, Pb and Cd in muscle were 77.72?±?47.84 µg/g, 20.34?±?8.49 µg/g, 2.23?±?1.16 µg/g, 0.57?±?0.36 µg/g, 0.20?±?0.16 µg/g and 0.42?±?0.19 µg/g for T. lepturus, respectively. Besides, the average level of the same metal concentrations in muscle for L. savala were 85.11?±?57.64 µg/g, 16.63?±?9.25 µg/g, 2.53?±?1.90 µg/g, 0.47?±?0.27 µg/g, 0.23?±?0.18 µg/g and 0.47?±?0.20 µg/g, respectively. The correlation between size groups and metal accumulation in muscle tissues were investigated for both fish. In terms of public risk assessment, the provisional tolerable weekly intake’s of various heavy metals were compared with the consumption of both fish. As a result of the analysis, Fe, Zn, Cu, Mn, Pb and Cd accumulations in muscle tissues of T. lepturus and L. savala collected from Karachi Fish Harbour Pakistan did not exceed limit values.     

Contamination Profile of DDTs in the Shark <Emphasis Type="Italic">Somniosus microcephalus</Emphasis> from Greenland Seawaters

DDT isomers were detected in all the liver and muscle samples of Greenland sharks Somniosus microcephalus (n?=?15) caught in Greenland seawaters. The mean concentrations of ΣDDTs (sum of o,p’ and p,p’ DDT, DDD, and DDE isomers) were 1094?±?818 ng/g lipid weight (lw) in the muscle and 761?±?416 ng/g lw in the liver. The p,p’-DDE accounted for 48%?±?41% and 53%?±?54% of the total DDT residue in the white muscle and liver, respectively. The lipid content was 48%?±?10% in the muscle and 43%?±?17% in the liver. Female sharks showed the highest concentrations of ΣDDTs. The youngest shark showed higher concentrations of ΣDDTs in the liver than the older sharks. To our knowledge, this is one of the few investigations on DDT levels in S. microcephalus where concentrations were correlated to lipid content and sex/size.     

Persistent Organochlorine Contaminant Residues in Tissues of Hedgehogs from Turkey

The residues of persistent organochlorinated pollutants (POPs), namely polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) (HCHs, CHLs, HCCPs, DDTs, and dicofol congeners) were investigated in the hair and muscle of road-killed Erinaceus roumanicus and E. concolor in Turkey. Mean residue levels were as follows: in hair, PCBs?=?7.43?±?4.88 ng/g and OCPs?=?9.21?±?1.27 ng/g; in muscle, PCBs?=?30.73?±?2.51 ng/g and OCPs?=?145.04?±?16.59 ng/g. There was no significant difference between species and sex, while there was significant difference between habitats and regions in terms of either total PCB and OCP levels, or POP levels (p?<?0.05). Age was a determinative factor for the bio-accumulation of POPs. The contaminant levels were high in the species, sample areas, and habitats. The data also showed that tissues of hedgehogs are suitable for monitoring and evaluating the bioaccumulation of POP levels in Turkey.     

Toxicity of Nickel on the Selected Species of Marine Diatoms and Copepods

Toxicity values for nickel on marine diatoms and copepods were derived based on bioassay tests. The 96 h IC₅₀ of nickel on diatoms, Odontella mobiliensis and Coscinodiscus centralis were 0.31?±?0.01 and 0.62?±?0.02 mg/L and LC₅₀ values on copepods, Oithona similis and Acartia danae were 2.78?±?0.14 and 2.34?±?0.32 mg/L, respectively. The species mean chronic values of nickel were 0.016, 0.17, 0.57 and 0.42 mg/L for O. mobiliensis, C. centralis, O. similis and A. danae, respectively. A hazardous concentration was derived and evaluated using the species sensitivity distribution (SSD) method. SSD indicated that 13 µg Ni/L is the maximum allowable concentration for protection of 95% plankton species in coastal and marine ecosystem of India. Diatoms are more sensitive to nickel than copepods by almost an order of magnitude. The toxicity values derived in the present study may be useful to calculate ambient water quality criteria/standard for nickel.     

Heavy Metal Contamination in Fish (<Emphasis Type="Italic">Callinectis amnicola</Emphasis>) From an Estuarine Creek in the Niger Delta,Nigeria and Health Risk Evaluation

Heavy metal bioconcentration in crabs from an estuarine creek in the Niger Delta was examined using atomic absorption spectrophotometry. Health risk via human exposure to metal toxicity was evaluated. Mean metal levels (µg/g) were Cr 2.32?±?0.71, Ni 2.76?±?0.48, Cu 12.94?±?3.53, Pb 5.67?±?1.03, Ag 1.83?±?0.71 and Cd 0.73?±?0.14 with significant difference (p?<?0.001) between periods. Ni, Pb and Cd had values above FAO/WHO recommended limits. Estimated daily intake values were below the reference oral doses and the target hazard quotient was <1 for each metal examined while hazard index for all metals was also <1. The target carcinogenic risk value for Ni was 3.4?×?10^?3. Based on the evaluations, the study concluded that consumers of crabs from the study area had minimal/moderate metal toxicity exposures of no significant health concern but recommended continuous monitoring to detect anomalies.     

Toxicity and Genotoxicity of Three Antimicrobials Commonly Used in Veterinary Medicine

The toxicity of chlortetracycline (CTC), oxytetracycline (OTC) and enrofloxacin (ENF) was tested on two green algal species: the international standard Pseudokirchneriella subcapitata and the native Argentine species Ankistrodesmus fusiformis. All three antibiotics inhibited the algal growth. The most sensitive species was P. subcapitata, for which the EC₅₀ for CTC, OTC and ENF were 1.19?±?0.53, 0.92?±?0.30 and 5.18?±?3.80 mg L^?1, respectively. The EC₅₀ for A. fusiformis, were 3.23?±?0.53, 7.15?±?2.69 and 10.6?±?1.28 mg L^?1, respectively. The genotoxicity of these veterinary antibiotics was also assessed using chromosome aberration (CA) and micronuclei (MN) induction in Allium cepa roots. Three concentrations were tested (0.1, 1 and 10 mg L^?1). Only ENF at 1 and 10 mg L^?1 showed any significant MN induction. These data revealed that CTC, OTC and ENF could cause toxicity on green algae, whereas ENF could cause genotoxicity on A. cepa plants.     

Genotoxic Assessment of Some Inorganic Compounds in Desert Pupfish (<Emphasis Type="Italic">Cyprinodon macularius</Emphasis>) in the Evaporation Pond from a Geothermal Plant

The frequency of micro nucleated erythrocytes in peripheral blood of the desert pupfish (Cyprinodon macularius) from a geothermal effluent pond is determined and compared to organisms kept in an aquarium. The frequency of micronucleated erythrocytes found in pupfish from the geothermal pond is 2.75 (±2.09) and only 0.44 (±0.52) in captivity organisms. Dissolved As in the ponds doubles the 340 µg L^?1 US-EPA acute quality criteria for aquatic life and Hg equals the 1.77 µg L^?1 chronic criteria. The organisms with high MNE also have significantly high Se, As and Hg concentrations in muscle and liver. Compared to international maximum allowable limits for fish consumption, there is 81× enrichment for Se, 6× for As and 5× for Hg. Although Se is not significantly enriched in water, it is likely that its bioaccumulation occurs via feeding of detritus. The desert pupfish has a significant resistance to extreme metal accumulations and to recover under unpolluted conditions.     

Bismuth(III) Volatilization and Immobilization by Filamentous Fungus <Emphasis Type="Italic">Aspergillus clavatus</Emphasis> During Aerobic Incubation

As with many metals, bismuth can be accumulated or transformed by microorganisms. These interactions affect microbial consortia and bismuth environmental behaviour, mobility, and toxicity. Recent research focused specifically on bismuth anaerobic transformation by bacteria and archaea has inspired the evaluation of the mutual interactions between bismuth and filamentous fungi as presented in this article. The Aspergillus clavatus fungus proved resistant to adverse effects from bismuth contamination in culture medium with up to a concentration of 195 µmol L^?1 during static 15- and 30-day cultivation. The examined resistance mechanism includes biosorption to the fungal surface and biovolatilization. Pelletized fungal biomass has shown high affinity for dissolved bismuth(III). Bismuth biosorption was rapid, reaching equilibrium after 50 min with a 0.35 mmol g^?1 maximum sorption capacity as calculated from the Langmuir isotherm. A. clavatus accumulated ≤70 µmol g^?1 of bismuth after 30 days. Preceding isotherm study implications that most accumulated bismuth binds to cell wall suggests that biosorption is the main detoxification mechanism. Accumulated bismuth was also partly volatilized (≤1 µmol) or sequestrated in the cytosol or vacuoles. Concurrently, ≤1.6 µmol of bismuth remaining in solution was precipitated by fungal activity. These observations indicate that complex mutual interactions between bismuth and filamentous fungi are environmentally significant regarding bismuth mobility and transformation.     

Practicalities of mapping PM<Subscript>10</Subscript> and PM<Subscript>2.5</Subscript> concentrations on city-wide scales using a portable particulate monitor

Fine particulate matter is considered to be the most significant ambient air pollutant in terms of potential health impacts. Therefore, it is important that regulators are able to accurately assess the exposure of populations to PM₁₀ and PM_2.5 across municipal areas. We report on the practicalities of using a laser light scattering portable particulate monitor (Turnkey Instruments DustMate), in combination with a GPS, to map PM₁₀ and PM_2.5 concentrations on city-wide scales in Newcastle upon Tyne/Gateshead (UK), during a series of walking surveys. A heated inlet is necessary to remove moisture droplets from the sampled air prior to analysis by the instrument, though this also results in the loss of volatile particulate components, particularly from the PM_2.5 fraction. A co-location calibration study was carried out with a reference urban background Tapered Element Oscillating Micro-Balance/Filter Dynamics Measuring System (TEOM-FDMS) system in Newcastle that is part of the UK’s Automatic Urban and Rural Network (AURN) of air quality monitoring stations. For PM₁₀, orthogonal regression of the DustMate against TEOM-FDMS data gave a slope and intercept of 1.02?±?0.06 and ?3.7?±?1.2, respectively (R ²?=?0.73), whereas for PM_2.5, the respective values were 0.78?±?0.06 and ?0.63?±?0.55 (R ²?=?0.79). These parameters are comparable to literature calibration studies using this technology. There was good agreement between simultaneous samples taken using two DustMate instruments: for PM₁₀, a slope and intercept of 1.05?±?0.03 and 0.36?±?0.5, respectively (R ²?=?0.73), were obtained, whereas for the PM_2.5, the respective values were 0.79?±?0.01 and 0.19?±?0.06 (R ²?=?0.86). Correction factors based on the slope and intercepts obtained from the calibration exercise were applied to raw data collected from the DustMate. An annually-normalised correction procedure was then used to account for different background particulate concentrations on different sampling days. These corrected PM₁₀ and PM_2.5 concentrations and corresponding GPS coordinates were displayed on a base map using Google Fusion Tables and Google Earth Professional. Almost all areas surveyed in Newcastle/Gateshead were well below the EU Air Quality Standards for PM₁₀ and PM_2.5.     

A Novel Zebrafish (<Emphasis Type="Italic">Danio rerio</Emphasis>) Assay for Assessing Musk Ambrette-Induced Toxicity

Musk ambrette (4-tert-butyl-3-methoxy-2,6-dinitrotoluene) is a nitro musk, a cheap substitute for natural musk and a potential environmental pollutant based on its persistence, accumulation in human organisms. We investigated the acute toxicity of musk ambrette using wild-type AB and transgenic Tg(fli1a:EGFP)^y1 zebrafish. Different concentrations were delivered to zebrafish by direct soaking from 6 to 72 h post-fertilization (hpf). The LC₅₀ of musk ambrette was 76.4 µg mL^?1. As musk ambrette concentration increased, zebrafish embryos showed developmental delays (50 µg mL^?1, 22 hpf), pericardial edema (5 µg mL^?1, 48 hpf), circulatory disturbances, curved body axis (1 µg mL^?1, 72 hpf) and death (100 µg mL^?1, 22 hpf). Target organ toxicity was evaluated by a zebrafish angiogenesis model. Musk ambrette induced cardiovascular morphological changes, vessel permeability variation, angiogenic changes and cardiotoxicity (10 µg mL^?1, 48 hpf). The disappearance of caudal vein plexus confirmed the vascular development toxicity. Musk ambrette negatively affects early life-stage survival and demonstrates various toxicities in zebrafish.     

Impact of Long-Term Application of Sewage on Soil and Crop Quality in Vertisols of Central India

Shortfall of rain and the decreased groundwater level force farmers to use poor quality water for crop production in developing countries. In this study, the quality of agricultural produce and soil health affected by sewage water (Patranala) irrigation was evaluated. Sewage sediment, soil and crop samples were analyzed for physico-chemical properties. Sewage water found to contain trace concentration of heavy metals. However, long-term application of this water for crop production could build up a significant amount of trace metals in both soil and sediments. The DTPA extractable heavy metals ranged Cu 2.7–7.59, Cd 0.04–0.06, Pb 1.29–2.05, Cr 0.01–0.04, Ni 0.24–1.03 and Zn 0.63–2.59 mg kg^?1 soil. The heavy metal risk assessment (hazard quotient, HQ) was calculated and found that HQ for these metals in the crops under study was in safe limits. From the study, it is concluded that growing vegetables using sewage water of Patranala is safe, but periodic monitoring to be carried out to avoid food chain contamination.     

Soil Enzymatic Activities as Influenced by Lead and Nickel Concentrations in a Vertisol of Central India

A pot-culture was conducted in Completely Randomized Design with three replicates to study the effect of Pb and Ni on enzymatic activities in a Vertisols. Results indicated that increasing in the levels of Pb from 0, 100, 150 and 300 mg kg^?1 soil significantly reduced the dehydrogenase activity (DHA) 38.9, 32.1, 30.9, 18.1 µg triphenylformazan g^?1 soil 24 h^?1; acid phosphatase activities 73, 61, 58, 55 µg PNP g^?1 soil h^?1 and alkaline phosphatase activities 80.7, 69.4, 66.2 and 64.0 µg PNP g^?1 soil h^?1, respectively. Application of Ni up to 100 mg kg^?1 had significantly improved the soil enzymatic activities and thereafter there was no such change up to the highest level (300 mg Ni kg^?1). Among soil enzymatic activities, DHA was more sensitive to Pb application. The findings generated through this study can be useful for managing waste water for safe disposal as well as sustainable crop production.     

Concentrations of Mercury and Other Inorganic Ions in Wet Precipitation Collected from a Mountain Mining Zone and an Urban Area in Central Mexico

We measured and compared mercury (Hg) and other ions in rainwater collected in San Joaquin (mining zone) and Juriquilla (urban area), central Mexico, from 2009 to 2012. A total of 274 rainwater samples were collected and analyzed for pH, electrical conductivity, \({\text{NO}}_{3}^{ - },\;{\text{SO}}_{4}^{{2 - }},\) Cl^?, \({\text{NH}}_{4}^{+},\) Na⁺, K⁺, Ca²⁺, Mg²⁺ and Hg. Mercury concentrations in rainwater varied from 24.21 to 248.89 (x-bar?=?86.97?±?10.77)?µg?L^??1 in San Joaquin (mining zone) and 11.26 to 176.91 (x-bar?=?81.51?±?10.24)?µg?L^??1 in Juriquilla (urban area). Rainwater sample were collected over periods 1–3?days, depending upon precipitation frequency. Significant correlations (p?<?0.05) were found between \({\text{SO}}_{4}^{{2 - }},\) Cl^?, \({\text{NO}}_{3}^{ - },\) Na⁺, K⁺, Ca²⁺, Mg²⁺ and Hg at the San Joaquin site. Significant correlations were obtained between \({\text{SO}}_{4}^{{2 - }},{\text{NO}}_{3}^{ - },\;{\text{NH}}_{4}^{+},\) Na⁺, K⁺, Ca²⁺, Mg²⁺ and Hg at the Juriquilla site. In order to determine if there were significant differences among each measured parameter in rainwater collected in San Joaquin and Juriquilla, Kruskal–Wallis test was applied to data. We emphasized that the distribution and concentrations of Hg and the studied ions in rainwater samples were affected by atmospheric dust and local meteorological conditions of wind-speed and direction.     

Associations of the <Emphasis Type="Italic">PON1</Emphasis> rs662 polymorphism with circulating oxidized low-density lipoprotein and lipid levels: a systematic review and meta-analysis

Background

Several meta-analyses have demonstrated that the rs662 polymorphism in Paraoxonase 1 gene (PON1) gene is associated with coronary heart disease (CHD). However, it is still uncertain whether this polymorphism is associated with the plasma levels of oxidized low-density lipoprotein (Ox-LDL) and lipids. This meta-analysis is aimed to clarify the relationships between the rs662 polymorphism and plasma levels of Ox-LDL and lipids.

Methods

By searching in PubMed, Google Scholar, Web of Science, Cochrane Library, Wanfang, VIP and CNKI databases, 5 studies (1369 subjects) and 85 studies (46,740 subjects) were respectively identified for Ox-LDL association analysis and lipid association analysis. Standardized mean difference (SMD) was used to estimate the effects of the rs662 polymorphism on plasma Ox-LDL and lipid levels.

Results

The carriers of the variant R allele had higher levels of Ox-LDL (SMD?=?0.23, 95% CI?=?0.10–0.36, P?<? 0.01), triglyceride (TG) (SMD?=?0.06, 95% CI?=?0.01–0.11, P?=?0.02), total cholesterol (TC) (SMD?=?0.04, 95% CI?=?0.00–0.07, P?=?0.05) and low-density lipoprotein cholesterol (LDL-C) (SMD?=?0.04, 95% CI?=?0.00–0.08, P?=?0.04) than the non-carriers.

Conclusions

This meta-analysis suggests that the association between the PON1 rs662 polymorphism and CHD may partly be mediated by abnormal Ox-LDL and lipid levels caused by the R allele.

     

Atmospheric CO<Subscript>2</Subscript> Level and Temperature Affect Degradation of Pretilachlor and Butachlor in Indian Soil

This study was conducted at ambient (398?±?10 µmol mol^?1), elevated (450?±?10 µmol mol^?1) and elevated (550?±?10 µmol mol^?1) atmospheric CO₂ under three moisture regime and also three level of temperature (4, 25, and 40°C) to assess the degradation of pretilachlor and butachlor. Under dry condition at 398?±?10 µmol mol^?1, T_1/2 was 28.5 and 59.4 days for pretilachlor and butachlor, respectively; slowly decreased to 18.2 and 44.5 days at 550?±?10 µmol mol^?1 indicated that elevated condition enhanced degradation than ambient condition. Under field capacity with increasing CO₂ levels from ambient to elevated, T_1/2 decreased from 18.9 to 11.6 days and 39.4 to 16.2 days for of pretilachlor and butachlor, respectively. Similarly, under submerged conditions with increasing CO₂ levels T_1/2 decreased 14.7–7.1 and 26.3–11.8 days for pretilachlor and butachlor, respectively. Study also revealed that both pretilachlor and butachlor dissipated faster at 40°C (T_1/2, 9.7 and 19.4 days) than 25°C (T_1/2, 16.2 and 36.7 days). Slower dissipation was recorded at 4°C (T_1/2, 87.6 and 182.4 days).