Bioaccumulation surveillance in Milford Haven Waterway

Biomonitoring of contaminants (metals, organotins, polyaromatic hydrocarbons (PAHs), PCBs) was undertaken in Milford Haven Waterway (MHW) and a reference site in the Tywi Estuary (St Ishmael/Ferryside) during 2007–2008. Bioindicator species encompassed various uptake routes—Fucus vesiculosus (dissolved contaminants); Littorina littorea (grazer); Mytilus edulis and Cerastoderma edule (suspension feeders); and Hediste (=Nereis) diversicolor (sediments). Differences in feeding and habitat preference have subtle implications for bioaccumulation trends though, with few exceptions, contaminant burdens in MHW were higher than the Tywi reference site, reflecting inputs. Elevated metal concentrations were observed at some MHW sites, whilst As and Se (molluscs and seaweed) were consistently at the higher end of the UK range. However, for most metals, distributions in MH biota were not exceptional. Several metal-species combinations indicated increases in bioavailability upstream, which may reflect the influence of geogenic/land-based sources—perhaps enhanced by lower salinity. TBT levels in MH mussels were below OSPAR toxicity thresholds and in the Tywi were close to zero. Phenyltins were not accumulated appreciably in M. edulis, whereas some H. diversicolor populations appear subjected to localized (historical) sources. PAHs in H. diversicolor were distributed evenly across most of MHW, although acenaphthene, fluoranthene, pyrene, benzo(a)anthracene and chrysene were highest at one site near the mouth; naphthalenes in H. diversicolor were enriched in the mid-upper Haven (a pattern seen in M. edulis for most PAHs). Whilst PAH (and PCB) concentrations in MH mussels were mostly above reference and OSPAR backgrounds, they are unlikely to exceed ecotoxicological thresholds. Bivalve Condition indices (CI) were highest at the Tywi reference site and at the seaward end of MH, decreasing upstream—giving rise to several significant (negative) relationships between CI and body burdens. Despite the possible influence of salinity gradient as a complicating factor, multivariate analysis indicated that a combination of contaminants could influence the pattern in condition (and the biomarkers metallothionein and TOSC). Integrating bioaccumulation data with biological and biochemical endpoints is seen as a useful way to discriminate environmental quality of moderately contaminated areas such as MHW and to prioritise cause and effect investigations.     

Organochlorine pesticide residues in drinking water in the rural areas of Haryana,India

Drinking water samples collected from rural areas of three districts of Haryana during pre-monsoon and post-monsoon periods were analysed for the presence of organochlorine pesticide residues. The main source of drinking water in rural areas, i.e. groundwater in Ambala and Gurgaon districts and surface water supply in Hisar district, was found to be contaminated with isomers of HCH and endosulfan and metabolites of DDT, whereas dieldrin remained below detection limits. During the study period, the mean values observed for total HCH, DDT and endosulfan were 87.6, 848.2, and 27.4 ng/L and 99.8, 275.3 and 164.2 ng/L, respectively, for Ambala and Gurgaon districts. In the case of Hisar district, the values were 78.5, 115.9, and 53.0 ng/L, respectively. During the study period, 37% of the samples exceeded the total pesticide level of 500 ng/L indicated in the EECD directive for drinking water. Seasonal variations of pesticide residues were also observed during the study period.     

Occupational and environmental aerosol exposure assessment: a scientific journey from the past, through the present and into the future

This paper reviews how aerosol exposure assessment, for people in both working and living environments, has evolved over the years. It charts the main scientific developments that led to progressively improved ways of thinking and methods to assess exposure to airborne particulate matter in a manner more relevant to human health. It has been a long scientific journey as one generation of pioneering contributors has handed off to the next. In the process a consistent rationale has emerged, producing aerosol sampling criteria--and in turn exposure standards--which have been increasingly relevant to actual human exposures. The journey continues as a new generation of scientists steps up to deal with the new challenges that are emerging. An appreciation of the history of what went before is essential to charting the most effective path looking forward.     

Organochlorine pesticide residue levels in blood serum of inhabitants from Veracruz, Mexico

The objective of the present study was to monitor the levels of organochlorine pesticides HCB; α-, β-, γ-HCH; pp'DDE; op'DDT; and pp'DDT in blood serum of Veracruz, Mexico inhabitants. Organochlorine pesticides were analyzed in 150 blood serum samples that constituted that which remained after clinical analyses, using gas chromatography-electron-capture detection (GC-ECD). The results were expressed as milligrams per kilogram on fat basis and micrograms per liter on wet weight. Only the following pesticides were detected: p,p'-DDE was the major organochlorine component, detected in 100% of samples at mean 15.8 mg/kg and 8.4 μg/L; p,p'-DDT was presented in 41.3.% of monitored samples at mean 3.1 mg/kg and 1.4 μg/L; β-HCH was found in 48.6% of the samples at mean 4.9 mg/kg and 2.7 μg/L; op'DDT was determined to be in only 3.3% of monitored samples at mean 2.7 mg/kg and 1.4 μg/L. The pooled samples divided according to sex showed significant differences of β-HCH and pp'DDE concentrations in females. The samples grouped according to age presented the third tertile as more contaminated in both sexes, indicating age as a positively associated factor with serum organochlorine pesticide levels in Veracruz inhabitants.     

Characterizing the intrinsic bioremediation potential of 1,4-dioxane and trichloroethene using innovative environmental diagnostic tools

An intrinsic biodegradation study involving the design and implementation of innovative environmental diagnostic tools was conducted to evaluate whether monitored natural attenuation (MNA) could be considered as part of the remedial strategy to treat an aerobic aquifer contaminated with 1,4-dioxane and trichloroethene (TCE). In this study, advanced molecular biological and stable isotopic tools were applied to confirm in situ intrinsic biodegradation of 1,4-dioxane and TCE. Analyses of Bio-Trap? samplers and groundwater samples collected from monitoring wells verified the abundance of bacteria and enzymes capable of aerobically degrading TCE and 1,4-dioxane. Furthermore, phospholipid fatty acid analysis with stable isotope probes (PLFA-SIP) of the microbial community validated the ability for microbial degradation of TCE and 1,4-dioxane. Compound specific isotope analysis (CSIA) of groundwater samples for TCE resulted in δ(13)C values that indicated likely biodegradation of TCE in three of the four monitoring wells sampled. Results of the MNA evaluation showed that enzymes capable of aerobically degrading TCE and 1,4-dioxane were present, abundant, and active in the aquifer. Taken together, these results provide direct evidence of the occurrence of TCE and 1,4-dioxane biodegradation at the study site, supporting the selection of MNA as part of the final remedy at some point in the future.     

Bioremediation of heavy metals using biostimulation in laboratory bioreactor

The present research study investigates bioremediation potential of biostimulated microbial culture isolated from heavy metals waste disposal contaminated site located at Bhayander (east), Mumbai, India. The physicochemical and microbial characterization including heavy metal contaminants have been studied at waste disposal site. The microorganisms adapted at heavy metal-contaminated environment were isolated, cultured, and biostimulated in minimal salt medium under aerobic conditions in a designed and developed laboratory bioreactor. Heavy metals such as Fe, Cu, and Cd at a selected concentration of 25, 50, and 100?μg/ml were taken in bioreactor wherein biostimulated microbial culture was added for bioremediation of heavy metals under aerobic conditions. The remediation of heavy metals was studied at an interval of 24?h for a period of 21?days. The biostimulated microbial consortium has been found effective for remediation of Cd, Cu, and Fe at higher concentration, i.e., 100?mg/l up to 98.5%, 99.6%, and 100%, respectively. Fe being a micronutrient was remediated completely compared to Cu and Cd. During the bioaccumulation of heavy metals by microorganisms, environmental parameters such as pH, total alkalinity, electronic conductivity, biological oxygen demand, chemical oxygen demand, etc. were monitored and assessed. The pilot scale study would be applicable to remediate heavy metals from waste disposal contaminated site to clean up the environment.