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1.
BMC Pediatr ; 24(1): 123, 2024 Feb 15.
Article in English | MEDLINE | ID: mdl-38360716

ABSTRACT

There is an unmet need for phototherapy treatment in low- and middle-income countries (LMICs) to prevent disability and death of newborns with neonatal hyperbilirubinemia. Home phototherapy deployed by community health workers (CHWs) in LMICs may help increase access to essential newborn postnatal care in a more acceptable way for families and lead to an increase in indicated treatment rates for newborns with hyperbilirubinemia. We aimed to investigate the operational feasibility and acceptability of a CHW-led home phototherapy intervention in a rural sub-district of Bangladesh for families and CHWs where home delivery was common and a treatment facility for neonatal hyperbilirubinemia was often more than two hours from households. We enrolled 23 newborns who were ≥ 2 kg in weight and ≥ 35 weeks gestational age, without clinical danger signs, and met the American Academy of Pediatric treatment criteria for phototherapy for hyperbilirubinemia. We employed a mixed-method investigation to evaluate the feasibility and acceptability of home phototherapy through surveys, in-depth interviews and focus group discussions with CHWs, mothers, and grandparents. Mothers and family members found home phototherapy worked well, saved them money, and was convenient and easy to operate. CHWs found it feasible to deploy home phototherapy and identified hands-on training, mHealth job aids, a manageable workload, and prenatal education as facilitating factors for implementation. Feasibility and acceptability concerns were limited amongst parents and included: a lack of confidence in CHWs' skills, fear of putting newborn infants in a phototherapy device, and unreliable home power supply. CHW-led home phototherapy was acceptable to families and CHWs in rural Bangladesh. Further investigation should be done to determine the impact of home phototherapy on treatment rates and on preventing morbidity associated with neonatal hyperbilirubinemia. Clinical Trial (CT) registration ID: NCT03933423, full protocol can be accessed at https://doi.org/10.1186/s13102-024-00824-6 . Name of the trial registry: clinicaltrials.gov. Clinical Trial (CT) registration Date: 01/05/2019.


Subject(s)
Community Health Workers , Hyperbilirubinemia, Neonatal , Infant , Female , Pregnancy , Humans , Infant, Newborn , Child , Bangladesh , Feasibility Studies , Hyperbilirubinemia, Neonatal/therapy , Phototherapy
2.
Front Public Health ; 11: 1249614, 2023.
Article in English | MEDLINE | ID: mdl-37937074

ABSTRACT

Introduction: The SARS-CoV-2 pandemic represented a formidable scientific and technological challenge to public health due to its rapid spread and evolution. To meet these challenges and to characterize the virus over time, the State of California established the California SARS-CoV-2 Whole Genome Sequencing (WGS) Initiative, or "California COVIDNet". This initiative constituted an unprecedented multi-sector collaborative effort to achieve large-scale genomic surveillance of SARS-CoV-2 across California to monitor the spread of variants within the state, to detect new and emerging variants, and to characterize outbreaks in congregate, workplace, and other settings. Methods: California COVIDNet consists of 50 laboratory partners that include public health laboratories, private clinical diagnostic laboratories, and academic sequencing facilities as well as expert advisors, scientists, consultants, and contractors. Data management, sample sourcing and processing, and computational infrastructure were major challenges that had to be resolved in the midst of the pandemic chaos in order to conduct SARS-CoV-2 genomic surveillance. Data management, storage, and analytics needs were addressed with both conventional database applications and newer cloud-based data solutions, which also fulfilled computational requirements. Results: Representative and randomly selected samples were sourced from state-sponsored community testing sites. Since March of 2021, California COVIDNet partners have contributed more than 450,000 SARS-CoV-2 genomes sequenced from remnant samples from both molecular and antigen tests. Combined with genomes from CDC-contracted WGS labs, there are currently nearly 800,000 genomes from all 61 local health jurisdictions (LHJs) in California in the COVIDNet sequence database. More than 5% of all reported positive tests in the state have been sequenced, with similar rates of sequencing across 5 major geographic regions in the state. Discussion: Implementation of California COVIDNet revealed challenges and limitations in the public health system. These were overcome by engaging in novel partnerships that established a successful genomic surveillance program which provided valuable data to inform the COVID-19 public health response in California. Significantly, California COVIDNet has provided a foundational data framework and computational infrastructure needed to respond to future public health crises.


Subject(s)
COVID-19 , SARS-CoV-2 , Humans , SARS-CoV-2/genetics , COVID-19/epidemiology , Genomics , California/epidemiology , Data Management
3.
BMC Pediatr ; 23(1): 155, 2023 04 03.
Article in English | MEDLINE | ID: mdl-37009866

ABSTRACT

BACKGROUND: Universal screening for neonatal hyperbilirubinemia risk assessment is recommended by the American Academy of Pediatrics to reduce related morbidity. In Bangladesh and in many low- and middle-income countries, there is no screening for neonatal hyperbilirubinemia. Furthermore, neonatal hyperbilirubinemia may not be recognized as a medically significant condition by caregivers and community members. We aimed to evaluate the acceptability and operational feasibility of community health worker (CHW)-led, home-based, non-invasive neonatal hyperbilirubinemia screening using a transcutaneous bilimeter in Shakhipur, a rural subdistrict in Bangladesh. METHODS: We employed a two-step process. In the formative phase, we conducted eight focus group discussions with parents and grandparents of infants and eight key informant interviews with public and private healthcare providers and managers to explore their current knowledge, perceptions, practices, and challenges regarding identification and management of neonatal hyperbilirubinemia. Next, we piloted a prenatal sensitization intervention and home-based screening by CHWs using transcutaneous bilimeters and evaluated the acceptability and operational feasibility of this approach through focus group discussions and key informant interviews with parents, grandparents and CHWs. RESULTS: Formative findings identified misconceptions regarding neonatal hyperbilirubinemia causes and health risks among caregivers in rural Bangladesh. CHWs were comfortable with adoption, maintenance and use of the device in routine home visits. Transcutaneous bilimeter-based screening was also widely accepted by caregivers and family members due to its noninvasive technique and immediate display of findings at home. Prenatal sensitization of caregivers and family members helped to create a supportive environment in the family and empowered mothers as primary caregivers. CONCLUSION: Adopting household neonatal hyperbilirubinemia screening in the postnatal period by CHWs using a transcutaneous bilimeter is an acceptable approach by both CHWs and families and may increase rates of screening to prevent morbidity and mortality.


Subject(s)
Community Health Workers , Hyperbilirubinemia, Neonatal , Infant , Infant, Newborn , Female , Pregnancy , Humans , Child , Bangladesh , Feasibility Studies , Hyperbilirubinemia, Neonatal/diagnosis , Neonatal Screening/methods , Mothers
4.
Gates Open Res ; 7: 58, 2023.
Article in English | MEDLINE | ID: mdl-39015822

ABSTRACT

Background: Extreme hyperbilirubinemia leading to neurologic disability and death is disproportionately higher in low- and middle-income countries (LMIC) such as Bangladesh, and is largely preventable through timely treatment. In LMICs, an estimated half of all newborns are born at home and few receive screening or treatment for hyperbilirubinemia, leading to 6 million newborns per year who need phototherapy treatment for hyperbilirubinemia but are untreated. Household screening and treatment for neonatal hyperbilirubinemia with phototherapy administered by a trained community health worker (CHW) may increase indicated treatment for neonatal hyperbilirubinemia in comparison to the existing care system in Bangladesh. Methods: 530 Bangladeshi women in their second or third trimester of pregnancy from the rural community of Sakhipur, Bangladesh will be recruited for a cluster randomized trial and randomized to the intervention arm - home screening and treatment for neonatal hyperbilirubinemia - or the comparison arm to receive usual care. In the intervention arm, CHWs will provide mothers with two prenatal visits, visit newborns by 2 days of age and then daily for 3 days to measure transcutaneous bilirubin (TcB) and monitor for clinical danger signs. Newborns without danger signs but with a TcB above the treatment threshold, but >15 mg/dL will be treated with light-emitting diode (LED) phototherapy at home. Newborns with danger signs or TcB ≥15 mg/dL will be referred to a hospital for treatment. Treatment rates for neonatal hyperbilirubinemia in each arm will be compared. Conclusion: This study will evaluate the effectiveness of CHW-led home phototherapy to increase neonatal hyperbilirubinemia treatment rates in rural Bangladesh. LMICs are expanding access to postnatal care by using CHWs, and our work will give CHWs a curative treatment option for neonatal hyperbilirubinemia. Similar projects in other LMICs can be pursued to dramatically extend healthcare access to vulnerable newborns with hyperbilirubinemia.


Subject(s)
Community Health Workers , Hyperbilirubinemia, Neonatal , Neonatal Screening , Rural Population , Humans , Hyperbilirubinemia, Neonatal/therapy , Hyperbilirubinemia, Neonatal/diagnosis , Hyperbilirubinemia, Neonatal/epidemiology , Bangladesh/epidemiology , Infant, Newborn , Community Health Workers/education , Female , Neonatal Screening/methods , Phototherapy/methods , Pregnancy , Randomized Controlled Trials as Topic
5.
BMC Pediatr ; 22(1): 218, 2022 04 22.
Article in English | MEDLINE | ID: mdl-35459113

ABSTRACT

BACKGROUND: In low to middle-income countries where home births are common and neonatal postnatal care is limited, community health worker (CHW) home visits can extend the capability of health systems to reach vulnerable newborns in the postnatal period. CHW assessment of newborn danger signs supported by mHealth have the potential to improve the quality of danger sign assessments and reduce CHW training requirements. We aim to estimate the validity (sensitivity, specificity, positive and negative predictive value) of CHW assessment of newborn infants aided by mHealth compared to physician assessment. METHODS: In this prospective study, ten CHWs received five days of theoretical and hands-on training on the physical assessment of newborns including ten danger signs. CHWs assessed 273 newborn infants for danger signs within 48 h of birth and then consecutively for three days. A physician repeated 20% (n = 148) of the assessments conducted by CHWs. Both CHWs and the physician evaluated newborns for ten danger signs and decided on referral. We used the physician's danger sign identification and referral decision as the gold standard to validate CHWs' identification of danger signs and referral decisions. RESULTS: The referrals made by the CHWs had high sensitivity (93.3%), specificity (96.2%), and almost perfect agreement (K = 0.80) with the referrals made by the physician. CHW identification of all the danger signs except hypothermia showed moderate to high sensitivity (66.7-100%) compared to physician assessments. All the danger signs assessments except hypothermia showed moderate to high positive predictive value (PPV) (50-100%) and excellent negative predictive value (NPV) (99-100%). Specificity was high (99-100%) for all ten danger signs. CONCLUSION: CHW's identification of neonatal danger signs aided by mHealth showed moderate to high validity in comparison to physician assessments. mHealth platforms may reduce CHW training requirements and while maintaining quality CHW physical assessment performance extending the ability of health systems to provide neonatal postnatal care in low-resource communities. TRIAL REGISTRATION: clinicaltrials.gov NCT03933423 , January 05, 2019.


Subject(s)
Hypothermia , Telemedicine , Bangladesh , Community Health Workers , Humans , Infant , Infant, Newborn , Prospective Studies
6.
Am J Public Health ; 112(3): 467-471, 2022 03.
Article in English | MEDLINE | ID: mdl-35196037

ABSTRACT

Objectives. To evaluate a daily antigen testing program for health care personnel. Methods. We examined antigen testing results between December 13, 2020, and April 30, 2021, from 5 forensic psychiatric inpatient hospitals throughout California. Results. Among 471 023 antigen tests administered, 449 positives (0.0036% false positives) were detected. Conclusions. Antigen tests had low false-positive rates, high positive predictive value, and high levels of acceptability, important characteristics when considering their application in the community. Public Health Implications. Daily antigen testing was feasible and should be considered to reduce COVID-19 transmission. (Am J Public Health. 2022;112(3):467-471. https://doi.org/10.2105/AJPH.2021.306588).


Subject(s)
COVID-19 Serological Testing/statistics & numerical data , COVID-19/diagnosis , California , False Positive Reactions , Humans , SARS-CoV-2 , Sensitivity and Specificity
7.
BMJ Open ; 11(12): e048145, 2021 12 31.
Article in English | MEDLINE | ID: mdl-34972760

ABSTRACT

OBJECTIVE: Determine the sensitivity and specificity of neonatal jaundice visual estimation by primary healthcare workers (PHWs) and physicians as predictors of hyperbilirubinaemia. DESIGN: Multicentre observational cohort study. SETTING: Hospitals in Chandigarh and Delhi, India; Dhaka, Bangladesh; Durban, South Africa; Kumasi, Ghana; La Paz, Bolivia. PARTICIPANTS: Neonates aged 1-20 days (n=2642) who presented to hospitals for evaluation of acute illness. Infants referred for any reason from another health facility or those needing immediate cardiopulmonary resuscitation were excluded. OUTCOME MEASURES: Infants were evaluated for distribution (head, trunk, distal extremities) and degree (mild, moderate, severe) of jaundice by PHWs and physicians. Serum bilirubin level was determined for infants with jaundice, and analyses of sensitivity and specificity of visual estimations of jaundice used bilirubin thresholds of >260 µmol/L (need for phototherapy) and >340 µmol/L (need for emergency intervention in at-risk and preterm babies). RESULTS: 1241 (47.0%) neonates had jaundice. High sensitivity for detecting neonates with serum bilirubin >340 µmol/L was found for 'any jaundice of the distal extremities (palms or soles) OR deep jaundice of the trunk or head' for both PHWs (89%-100%) and physicians (81%-100%) across study sites; specificity was more variable. 'Any jaundice of the distal extremities' identified by PHWs and physicians had sensitivity of 71%-100% and specificity of 55%-95%, excluding La Paz. For the bilirubin threshold >260 µmol/L, 'any jaundice of the distal extremities OR deep jaundice of the trunk or head' had the highest sensitivity across sites (PHWs: 58%-93%, physicians: 55%-98%). CONCLUSIONS: In settings where serum bilirubin cannot be measured, neonates with any jaundice on the distal extremities should be referred to a hospital for evaluation and management, where delays in serum bilirubin measurement and appropriate treatment are anticipated following referral, the higher sensitivity sign, any jaundice on the distal extremities or deep jaundice of the trunk or head, may be preferred.


Subject(s)
Jaundice, Neonatal , Adolescent , Adult , Bangladesh , Child , Child, Preschool , Cohort Studies , Developing Countries , Humans , Infant , Infant, Newborn , Jaundice, Neonatal/diagnosis , South Africa , Young Adult
8.
Am J Trop Med Hyg ; 103(1): 465-471, 2020 07.
Article in English | MEDLINE | ID: mdl-32274986

ABSTRACT

Diarrheal illness remains a leading cause of morbidity and mortality in children < 5 years in developing countries, and contaminated water contributes to diarrhea risk. To address this problem, a novel hollow fiber ultrafilter (HFU) was developed for household water treatment. To test its impact on water quality and infant health, we conducted a cluster-randomized longitudinal evaluation in 10 intervention and 10 comparison villages in Kenya, attempting to enroll all households with infants (< 12 months old). We conducted a baseline survey, distributed HFUs to intervention households, made biweekly home visits for 1 year to assess water treatment practices and diarrhea in infants, and tested water samples from both groups every 2 months for Escherichia coli. We enrolled 92 infants from intervention households and 74 from comparison households. During the 1-year study period, 45.7% of intervention households and 97.3% of comparison households had at least one stored water sample test positive for E. coli. Compared with comparison households, the odds of E. coli contamination in stored water was lower for intervention households (odds ratio [OR]: 0.42, 95% CI: 0.24, 0.74), but there was no difference in the odds of reported diarrhea in infants, adjusting for covariates (OR: 1.19, 95% CI: 0.74, 1.90). Although nearly all water samples obtained from unprotected sources and filtered by the HFU were free of E. coli contamination, HFUs alone were not effective at reducing diarrhea in infants.


Subject(s)
Drinking Water/microbiology , Dysentery/epidemiology , Escherichia coli/isolation & purification , Water Microbiology , Water Purification/instrumentation , Adolescent , Adult , Aged , Female , Humans , Infant , Kenya/epidemiology , Male , Middle Aged , Odds Ratio , Patient Acceptance of Health Care , Rural Population , Water Purification/methods , Young Adult
9.
Int J Circumpolar Health ; 74: 29256, 2015.
Article in English | MEDLINE | ID: mdl-26547082

ABSTRACT

BACKGROUND: The lower respiratory tract infection (LRTI)-associated hospitalization rate in American Indian and Alaska Native (AI/AN) children aged <5 years declined during 1998-2008, yet remained 1.6 times higher than the general US child population in 2006-2008. PURPOSE: Describe the change in LRTI-associated hospitalization rates for AI/AN children and for the general US child population aged <5 years. METHODS: A retrospective analysis of hospitalizations with discharge ICD-9-CM codes for LRTI for AI/AN children and for the general US child population <5 years during 2009-2011 was conducted using Indian Health Service direct and contract care inpatient data and the Nationwide Inpatient Sample, respectively. We calculated hospitalization rates and made comparisons to previously published 1998-1999 rates prior to pneumococcal conjugate vaccine introduction. RESULTS: The average annual LRTI-associated hospitalization rate declined from 1998-1999 to 2009-2011 in AI/AN (35%, p<0.01) and the general US child population (19%, SE: 4.5%, p<0.01). The 2009-2011 AI/AN child average annual LRTI-associated hospitalization rate was 20.7 per 1,000, 1.5 times higher than the US child rate (13.7 95% CI: 12.6-14.8). The Alaska (38.9) and Southwest regions (27.3) had the highest rates. The disparity was greatest for infant (<1 year) pneumonia-associated and 2009-2010 H1N1 influenza-associated hospitalizations. CONCLUSIONS: Although the LRTI-associated hospitalization rate declined, the 2009-2011 AI/AN child rate remained higher than the US child rate, especially in the Alaska and Southwest regions. The residual disparity is likely multi-factorial and partly related to household crowding, indoor smoke exposure, lack of piped water and poverty. Implementation of interventions proven to reduce LRTI is needed among AI/AN children.


Subject(s)
/statistics & numerical data , Hospitalization/statistics & numerical data , Indians, North American/statistics & numerical data , Respiratory Tract Infections/ethnology , Age Factors , Alaska/epidemiology , Child, Preschool , Female , Humans , Infant , Male , Retrospective Studies , Sex Factors , United States/epidemiology , United States Indian Health Service/statistics & numerical data
10.
Am J Trop Med Hyg ; 88(4): 757-64, 2013 Apr.
Article in English | MEDLINE | ID: mdl-23382166

ABSTRACT

Although anemia in preschool children is most often attributed to iron deficiency, other nutritional, infectious, and genetic contributors are rarely concurrently measured. In a population-based, cross-sectional survey of 858 children 6-35 months of age in western Kenya, we measured hemoglobin, malaria, inflammation, sickle cell, α-thalassemia, iron deficiency, vitamin A deficiency, anthropometry, and socio-demographic characteristics. Anemia (Hb < 11 g/dL) and severe anemia (Hb < 7 g/dL) prevalence ratios (PRs) for each exposure were determined using multivariable modeling. Anemia (71.8%) and severe anemia (8.4%) were common. Characteristics most strongly associated with anemia were malaria (PR: 1.7; 95% confidence interval [CI] = 1.5-1.9), iron deficiency (1.3; 1.2-1.4), and homozygous α-thalassemia (1.3; 1.1-1.4). Characteristics associated with severe anemia were malaria (10.2; 3.5-29.3), inflammation (6.7; 2.3-19.4), and stunting (1.6; 1.0-2.4). Overall 16.8% of anemia cases were associated with malaria, 8.3% with iron deficiency, and 6.1% with inflammation. Interventions should address malaria, iron deficiency, and non-malarial infections to decrease the burden of anemia in this population.


Subject(s)
Anemia/etiology , Malaria/complications , Anemia/epidemiology , Anemia, Iron-Deficiency/diagnosis , Child, Preschool , Confidence Intervals , Cross-Sectional Studies , Female , Humans , Infant , Inflammation/complications , Kenya/epidemiology , Malaria/parasitology , Male , Multivariate Analysis , Nutritional Status , Prevalence , Rural Population , Severity of Illness Index , Socioeconomic Factors , alpha-Thalassemia/complications
11.
Am J Trop Med Hyg ; 88(1): 132-7, 2013 Jan.
Article in English | MEDLINE | ID: mdl-23243108

ABSTRACT

Household air pollution is a risk factor for pneumonia, the leading cause of death among children < 5 years of age. From 2008 to 2010, a Kenyan organization sold ≈ 2,500 ceramic cookstoves (upesi jiko) that produce less visible household smoke than 3-stone firepits. During a year-long observational study, we made 25 biweekly visits to 200 homes to determine stove use and observe signs of acute respiratory infection in children < 3 years of age. Reported stove use included 3-stone firepit only (81.8%), upesi jiko only (15.7%), and both (2.3%). Lower, but not statistically significant, percentages of children in upesi jiko-using households than 3-stone firepit-using households had observed cough (1.3% versus 2.9%, rate ratio [RR] 0.48, 95% confidence interval [CI]: 0.22-1.03), pneumonia (0.9% versus 1.7%, RR 0.60, 95% CI: 0.24-1.48), and severe pneumonia (0.3% versus 0.6%, RR 0.66, 95% CI: 0.17-2.62). Upesi jiko use did not result in significantly lower pneumonia rates. Further research on the health impact of improved cookstoves is warranted.


Subject(s)
Ceramics , Cooking , Respiratory Tract Diseases/epidemiology , Rural Population , Adult , Child , Female , Humans , Kenya/epidemiology , Male , Respiratory Tract Diseases/etiology
12.
Environ Sci Technol ; 39(10): 3538-47, 2005 May 15.
Article in English | MEDLINE | ID: mdl-15952356

ABSTRACT

Under anaerobic conditions, such as those typically found in buried sediments, the primary metabolic pathway for polychlorinated biphenyls (PCBs) is reductive dechlorination in which chlorine removal and substitution with hydrogen by bacteria result in a reduced organic compound with fewer chlorines. Vertical sediment cores were collected from Lake Hartwell (Pickens County, SC) and analyzed in 5-cm intervals for 107 PCB congeners in a total of more than 280 samples from 18 sediment cores and surface samples. This paper reports on extensive PCB dechlorination measured in Lake Hartwell sediments and the characterization of dechlorination end-member (EM) patterns using chemical forensic methods. PCB congener fingerprinting and a multivariate receptor modeling method, polytopic vector analysis (PVA), were used for identification and characterization of weathered and dechlorinated PCB congener patterns. Dechlorination resulted in a substantial shift in buried sediments from tetra- through decachlorobiphenyl congeners to mono- through trichlorobiphenyl congeners. Mono- through trichlorobiphenyls comprised approximately 80% of the PCBs in buried sediments that underwent maximum dechlorination as compared to approximately 20% in surface sediments. The major concentration decreases were seen in the tetra- through hexachlorobiphenyl homologues, which accounted for over 90% of the dechlorination. Octa- through decachlorobiphenyl congeners also were dechlorinated, but their overall contribution to dechlorination was relatively small due to their low initial concentrations (< 5%). The net accumulation of 2-CB, 2,2'/2,6-DCBs, 2,4'-DCB, 2,2',4-TCB, and 2,2',6-TCB at Lake Hartwell matched characteristic PCB dechlorination products reported in the literature, such as those for Processes M, Q, and C; and the persistence of tetrachlorobiphenyls (TeCBs) that contained 24- and 25-congener groups resembled dechlorination Processes H or H'. Although dechlorination tended to be very extensive in most of the cores, it was not always consistent from core to core or at various depth intervals within a single core. The reason for this variability in dechlorination extent could not be determined from the existing data and did not appear to correlate with such factors as PCB concentration, total organic carbon, or age. The authors used fingerprinting analysis and a PVA multivariate receptor model as exploratory data analysis tools to characterize PCB sources and their alteration patterns. Dominant sources and alteration patterns were determined in this large data set by comparing PVA EM patterns with known source patterns (i.e., Aroclors or Aroclor mixtures) and literature-reported alteration patterns. PVA also afforded an opportunity to characterize the vertical and lateral distributions of the weathered and unweathered PCB source patterns and dechlorination patterns, a task that would have been much more difficult to accomplish through comparison of chromatograms alone.


Subject(s)
Chlorine/chemistry , Environmental Monitoring/methods , Polychlorinated Biphenyls/chemistry , Polychlorinated Biphenyls/metabolism , Water Pollutants, Chemical/metabolism , Bacteria, Anaerobic/metabolism , Biodegradation, Environmental , Forensic Sciences , Fresh Water , Geologic Sediments/chemistry , Geologic Sediments/microbiology , Hazardous Waste , Models, Theoretical , Oxidation-Reduction , Polychlorinated Biphenyls/analysis , South Carolina , Water Pollutants, Chemical/analysis
13.
Environ Sci Technol ; 38(8): 2328-37, 2004 Apr 15.
Article in English | MEDLINE | ID: mdl-15116837

ABSTRACT

Natural recovery of contaminated sediments relies on burial of contaminated sediments with increasingly clean sediments over time (i.e., natural capping). Natural capping reduces the risk of resuspension of contaminated surface sediments, and it reduces the potential for contaminant transport into the food chain by limiting bioturbation of contaminated surface or near-surface sediments. This study evaluated the natural recovery of surface sediments contaminated with polychlorinated biphenyls (PCBs) at the Sangamo-Weston/Twelvemile Creek/Lake Hartwell Superfund Site (Lake Hartwell), Pickens County, SC. The primary focus was on sediment recovery resulting from natural capping processes. Total PCB (t-PCB), lead-210 (210Pb), and cesium-137 (137Cs) sediment core profiles were used to establish vertical t-PCB concentration profiles, age date sediments, and determine surface sedimentation and surface sediment recovery rates in 18 cores collected along 10 transects. Four upgradient transects in the headwaters of Lake Hartwell were impacted by historical sediment releases from three upgradient sediment impoundments. These transects were characterized by silt/ clay and sand layering. The highest PCB concentrations were associated with silt/clay layers (1.8-3.5% total organic carbon (TOC)), while sand layers (0.05-0.32% TOC) contained much lower PCB concentrations. The historical sediment releases resulted in substantial burial of PCB-contaminated sediment in the vicinity of these four cores; each core contained less than 1 mg/kg t-PCBs in the surface sand layers. Cores collected from six downgradient Lake Hartwell transects consisted primarily of silt and clay (0.91-5.1% TOC) and were less noticeably impacted by the release of sand from the impoundments. Vertical t-PCB concentration profiles in these cores began with relatively low PCB concentrations at the sediment-water interface and increased in concentration with depth until maximum PCB concentrations were measured at approximately 30-60 cm below the sediment-water interface, ca. 1960-1980. Maximum t-PCB concentrations were followed by progressively decreasing concentrations with depth until the t-PCB concentrations approached the detection limit, where sediments were likely deposited before the onset of PCB use at the Sangamo-Weston plant. The sediments containing the maximum PCB concentrations are associated with the period of maximum PCB release into the watershed. Sedimentation rates averaged 2.1 +/- 1.5 g/(cm2 yr) for 12 of 18 cores collected. The 1994 Record of Decision cleanup requirement is 1.0 mg/kg; two more goals (0.4 and 0.05 mg/kg t-PCBs) also were identified. Average surface sedimentation requirements to meet the three goals were 1.4 +/- 3.7, 11 +/- 4.2, and 33 +/- 11 cm, respectively. Using the age dating results, the average recovery dates to meet these goals were 2000.6 +/- 2.7, 2007.4 +/- 3.5, and 2022.7 +/- 11 yr, respectively. (The 95% prediction limits for these values also are provided.) Despite the reduction in surface sediment PCB concentrations, PCB concentrations measured in largemouth bass and hybrid bass filets continue to exceed the 2.0 mg/kg FDA fish tolerance level.


Subject(s)
Environmental Pollutants/analysis , Geologic Sediments/chemistry , Polychlorinated Biphenyls/analysis , Aluminum Silicates , Animals , Bass , Biological Availability , Clay , Environmental Monitoring , Environmental Pollutants/pharmacokinetics , Food Chain , Polychlorinated Biphenyls/pharmacokinetics , Refuse Disposal , Silicon Dioxide , Tissue Distribution , Water Pollution/prevention & control
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