IntroductionCoral reefs as key ecosystems in Zanzibar are exposed to several anthropogenic and natural stressors.MethodsThe benthic composition and coverage of coral reefs were investigated on three data sets involving ten coral reefs monitored from 1992 to 2016. Firstly, we investigated differences in the reef composition using data from seven reefs in 2015. Secondly, we analyzed communities on three distinctive reefs (2010 to 2012) to understand the importance of seasons and reef zones (slope, crest and flat) on species abundance. Finally, we investigated long-term changes (1992 to 2016) of five reefs.ResultsBranching Porites and Acropora, and soft coral order Corallimorpharia, characterized sheltered reef communities. Soft corals and algal species characterized the reef communities exposed to strong hydrodynamic conditions, which also displayed greater cover of rocks and rubbles. The average dissimilarity between reefs ranged between 60% and 75%. The seasonal changes in community structure for reefs near Stone Town were mostly associated with soft coral Corallimorpharia. Indeed, the bare rock and algae distinguished the northern exposed reef from more sheltered reefs. Acropora was a key genus for the sheltered Chumbe reef, which explained between 14% and 18% of the dissimilarities among the three reefs. Hard corals covered between 40% and 70% in most years, with severe declines following El Niño events in 1998 and 2016. The dominating genus Acropora showed a strong decline from the late 1990s’ with signs of recovery at remote reefs compared to reefs closer to human residence.DiscussionOur results highlight the importance of seasonality and spatial differences, reflecting differences in human impact and physical exposure and significant long-term changes in coral communities. Continued monitoring of reef health is essential to evaluate the success of ongoing management to sustain the reef services.

A coastal area is an area that is very exposed to sea level changes for a long period, especially during the Holocene. Three marine sediment cores (TRC 3 and TER16-GC13C) in the offshore area were analysed for radiocarbon (14C) and some geochemical elements (Na, Al, Ca, Fe, Li, Pb, Zn, and Ba) in response to the terrigenous-and marine-originated sediment changes of in East Coast Peninsula Malaysia (ECPM) during the Holocene epoch. Across three Holocene stages, geochemical elements show a distinct temporal pattern. The average concentrations of the studied metals were marine origin was captured by the ratio Ca/Al and Ca/Fe in the early Holocene/late Holocene. The present study suggests that sea level transgression is the primary factor controlling the shifting of terrigenous- and marine-originated sediments in the ECPM.

Milk is one of the very important nutrients of human diet. The presence of toxic elements in milk may threaten the public health. This study reports the levels of Cadmium (Cd), Cobalt (Co) and Lead (Pb) in raw cow's milk collected from different areas of Zanzibar Island during March - May 2016. The samples of raw milk were analyzed by Thermo Scientific-Atomic Absorption Spectrophotometer for quantitative determination of the metals in the matrix. The concentration of Co in this study ranged from ND at Mwanakwerekwe (MK1 and MK2) to a maximum of 0.004 mg/L at Mshelishelini (MS5) and Fuoni (F5) sites with mean concentration of 0.020 ± 0.003 mg/L for all sites. Concentration of Pb ranged between 0.05 - 0.51 mg/L at Fuoni (F7) and Mwanakwerekwe (MK1) respectively, with mean concentration of 0.263 ± 0.031 mg/L for all sites. However, Cd was only detected in one sample collected at Fuoni (F3) with a concentration of 0.001 mg/L. The results revealed that cow's milk is contaminated with toxic metals, particularly Pb which exceeded the WHO maximum permissible level of 0.02 mg/L. The study furthermore sheds light on possible consequences to public health. It is recommended that, stakeholders especially in Zanzibar such as Zanzibar Food and Drug Authorities (ZFDA) and Zanzibar Bureau of Standards (ZBS) as well as researchers, use the findings of this study for policy making, future study plans, formulation of technical strategies to control milk contamination, risk assessment and develop new alternative methods to measure milk contamination even at a low detection limit for the sake of the consumers' welfare before posing any serious effects to their health.

Irgarol 1051 and diuron are photosystem II inhibitors in agricultural activities and antifouling paints in the shipping sector. This study focused on three major ports (western, southern, and eastern) surrounding Peninsular Malaysia to construct the distribution of both biocides on the basis of the seasonal and geographical changes. Surface seawater samples were collected from November 2011 to April 2012 and pretreated using the solid-phase extraction technique followed by quantification with GC-MS and LC-MS-MS for Irgarol 1051 and diuron, respectively. Generally, the distribution of Irgarol 1051 was lowest during November 2011 and highest during April 2012, and similar patterns were observed at all ports, whereas the distribution of diuron was rather vague. The increasing pattern of Irgarol 1051 from time to time is probably related to its accumulation in the seawater as a result of its half-life and consistent utilization. On the basis of the discriminant analysis, the temporal distribution of Irgarol 1051 varied at Klang North Port, Klang South Port, and Pasir Gudang Port, whereas diuron was temporally varied only at Kemaman Port. Furthermore, Irgarol 1051 was spatially varied during November 2011, whereas diuron did not show any significant changes throughout all sampling periods. Ecological risk assessment exhibited a high risk for diuron and Irgarol 1051, but Irgarol 1051 should be of greater concern because of its higher risk compared to that of diuron. Thus, it is recommended that the current Malaysian guidelines and regulations of biocide application should be reevaluated and improved to protect the ecosystem, as well as to prevent ecological risks to the aquatic environment.

Coral reefs are important ecosystems in terms of their biodiversity and ecosystem functions. Particularly at local scales, coral reefs are vulnerable to natural and anthropogenic disturbances, leading to the degradation of reef health. Here, we employed two different methods to monitor reef health. First, we conducted line transect surveys to record the benthic community structure to infer ecological reef health. Secondly, trace metal concentrations in sediment samples and a bioindicator sponge species, Haliclona fascigera, were compared among sites to detect cryptic degradation and unknown sources of pollution. The study area comprised six reefs situated along the coast of Zanzibar's main agglomeration, Stone Town, and subject to different types of disturbances and conservation management schemes. Overall, coral reef health was found to decrease with increasing proximity to Stone Town, with living hard coral cover being particularly low on reefs closest to Stone Town, which coincided with greater fishing, tourism, and pollution pressures. Reef assessments based on trace metal analyses differed from the community structure surveys. All sites showed high levels of arsenic and cadmium contamination, with some samples revealing concerning levels of chromium, copper and zinc. The reefs differed significantly between each other in terms of trace metal concentration for both sediments (p = 0.031, PERMANOVA) and sponge samples (p = 0.001, PERMANOVA). Trace metal concentrations were not correlated with distance to Stone Town, highlighting the downstream effects of industrial and urban sewage on even remote reefs. Coral reef health assessment was found to be dependent on the survey method employed, which is why we recommend the combination of complementary methods. (C) 2021 The Author(s). Published by Elsevier B.V.

Abstract Background Research from Western populations describes abdominal obesity as a low‐grade inflammatory disease; less is known from tropical areas with high pathogen burden. Objectives This cross‐sectional study investigated whether obesity contributes to low‐grade inflammation in 587 individuals from randomly selected households in Zanzibar. Materials and Methods The Association between obesity indices (body mass index [BMI], waist circumference [WC], and percentage body fat [%BF]), leptin, and inflammatory markers (C‐reactive protein [CRP], interleukin‐6 [IL‐6] and tumor‐necrosis factor‐α [TNF‐α]) was investigated using multinomial logistic regression analysis, accounting for ordinal outcome variables with four categories; 1st–4th quartile. Results Study participants were between 5 and 95 years; 49.6% were male. Mean serum levels were; leptin: 4.3 ± 5.2 ng/ml, CRP: 0.19 ± 0.42 µg/ml, IL‐6: 2.8 ± 5 pg/ml, and TNF‐α: 5.3 ± 5.2 pg/ml. Obesity indices were associated with leptin and CRP in the third and fourth quartiles in single models. In combined models, associations were observed between BMI (OR = 6.36 [95% CI, 1.09; 34.12]); WC (OR = 4.87 [95% CI, 1.59; 14.94]); and %BF (OR = 19.23 [95% CI, 4.70; 78.66]) and leptin in the fourth quartile; also between %BF and CRP in the third quartile (OR = 3.49 [95% CI 1.31; 9.31]). Conclusion Total body fat was associated with low‐grade inflammation in this tropical population rather than body fat distribution such as abdominal obesity. This may increase the risk of insulin resistance and other obesity‐related metabolic and cardiovascular health endpoints.

Tributyltin (TBT) is a potent toxic chemical deliberately introduced to marine environments for combating biofoulings in marine structures. Several methods have been developed and used for TBT analysis in marine ecosystems. The main aim of this study was to evaluate the potential of the silicone sheet passive sampler (SSPS) for organotin species tributyltin (TBT), dibutyltin (DBT) and monobutyltin (MBT) from tropical waters. The study was conducted under laboratory based experiments and then applied to field trials for natural tropical coastal waters. The sampler showed good recovery for TBT (106%) compared to DBT (55%) and MBT (11%) under laboratory conditions. The maximum level of TBT 0.9 ng (Sn)/L was detected at the Zanzibar port using SSPS. The results of this study demonstrate that SSPS is more effective and promising for TBT detection in the tropical water column in comparison to its metabolites i.e DBT and MBT. This study suggests that the silicone sheet is a robust diagnostic tool for monitoring for TBT in tropical aquatic systems. (C) 2020 The Authors. Published by Elsevier B.V.

Objectives To determine the prevalence of obesity indices (body mass index (BMI), waist circumference (WC), body fat per cent (BF%)) and cardiometabolic risk factors. To investigate the association between obesity indices and cardiometabolic risk factors in a Zanzibari population. Designs Cross-sectional study. Settings Participants randomly selected from 80 Shehias (wards) in Unguja, Zanzibar in 2013. Participants A total of 470 participants between 5 and 95 years were examined. Data on socioeconomic status, area of residence, anthropometry and venous blood were collected. Associations between obesity indices and cardiometabolic risk factors were investigated using multilevel logistic regression analyses in two steps: first, each obesity indicator was tested independently; second, all indicators combined in one model were tested for their association with cardiometabolic risk factors. Results The proportion of overweight/obese individuals was 26.4%, high WC (24.9%) and high BF% (31.1%). Cardiometabolic risk factors with highest prevalence of abnormal values included hypertension (24.5%), low high-density lipoprotein cholesterol (HDL-C) (29.4%), high low-density lipoprotein cholesterol (LDL-C) (21.3%) and high glycated haemoglobin (HbA1c) (19.1%). Obesity and hypertension increased with age, and were most prevalent in participants aged 45 years and above. Low HDL-C was most prevalent among participants aged ≥18 to <45 years, while high LDL-C was more prevalent in those above 45 years. High WC and high BF% were associated with high levels of LDL-C (OR=2.52 (95% CI 1.24 to 5.13), OR=1.91 (95% CI 1.02 to 3.58), respectively). Additionally, BMI and WC were associated with high levels of HbA1c (OR=2.08 (95% CI 1.15 to 3.79), OR=3.01 (95% CI 1.51 to 6.03), respectively). In the combined regression model, WC was associated with higher chances for hypertension (OR=2.62 (95% CI 1.14 to 6.06)) and for high levels of HbA1c (OR=2.62 (95% CI 1.12 to 6.15)). Conclusion High BMI, WC and BF% were strongly associated with hypertension, with individuals with high WC being twice more likely to have hypertension; this calls for early and effective screening strategies for this study population.

Water quality is one among the most important environmental issues these decades. Heavy metals receive a particular concern among the wide diversity of chemicals causing environmental degradation including groundwater. Nitrate, as well, is an indicator of human-induced groundwater contamination. This study investigated the levels of toxic heavy metals such as Cd, Cu, Pb, Co and Cr, and nitrate (NO3) contained in the water from 116 openwells in rural and peri-urban areas of Unguja Island, Zanzibar. The average values of the heavy metals were as follows: 1.359 ± 3.419 μg L–1 for Cr; 0.052 ± 0.109 μg L–1 for Co; 0.238 ± 0.533 μg L–1 for Cu, 0.001 ± 0.004 μg L–1 for Cd; and 0.003 ± 0.026 μg L–1 for Pb. Referring to Water quality standard in Japan (MHLW), Water quality guideline by WHO and Quality of Drinking Water Supplies (EWURA), the results suggest no serious acute problem of heavy metal contamination so far. The average value of the nitrate (NO3) was 36.1 ± 58.85 mg L–1. The nitrate contamination, some of which exceeded the values of permissible standards for safe drinking waters by MHLW and WHO, however, should not be underestimated.

Polycyclic Aromatic Hydrocarbons (PAHs) are ubiquitous class of toxic organic compounds in coastal waters. The aim of this study was to assess the potential of goby fish (Periophthalmus sobrinus) and rabbit fish (Siganus sutor) as bioindicators for PAH pollution in Zanzibar coastal waters. The fish samples were collected from four sites along the coasts of Zanzibar between February to July, 2016. The analysis of PAH metabolites from bile was conducted using Synchronous Fluorescence Scanning (SFS) spectroscopy. The parent PAH compounds (naphthalene; fluorene; phenanthrene; pyrene; fluoranthene; anthracene; benzo (a) pyrene) in the fish muscle tissues were analyzed using Gas Chromatography with Mass Spectrometric detection (GC/MS). The levels of PAH metabolites in bile of goby fish (P. sobrinus) ranged from 100 ng mL(-1) to 690 ng mL(-1). The PAH contents in goby tissues fish ranged from 0.028 +/- 0.008 ng g(-1) ww to 0.037 +/- 0.005 ng g(-1) ww with the average of 0.032 +/- 0.005 ng g(-1) ww. PAH metabolites were not detected in the bile samples from rabbit fish (S. sutor) in any sampled areas. The results suggest that the goby fish (P. sobrinus) could be promising PAH biondicator in coastal waters of tropical regions including Zanzibar islands. This is the first study applying biliary PAH metabolites in bioindicator fish species to trace PAH pollution conducted in West Indian Ocean region that can serve as a baseline information of biliary PAH metabolites as biomarkers of fish PAH pollution in the regional waters. (C) 2017 Elsevier B.V. All rights reserved.

Background Data on nutritional status and correlates of noncommunicable diseases are scarce for resource-poor settings in sub-Saharan countries. With the scope of a project, “Access to Food and Nutrition Status of the Zanzibari Population,” data for investigating public health questions were collected using proven measurement and laboratory standards. Objective The present study aims at providing a descriptive overview of recruitment approaches, standardization, quality control measures, and data collection, with special attention to the design, responses, and participant characteristics of the overall project. Methods A cross-sectional study across 80 randomly selected Shehias (wards) was conducted in 2013 in Unguja Island, Zanzibar. Examinations included all members living in 1 household, face-to-face interviews and anthropometric measurements (weight, height, mid-upper arm circumference, waist and hip circumference, and body composition) were assessed for all household members, blood pressure was taken from participants older than 2 years, and biosamples (urine and blood) from eligible household members were collected. Data collected from the core sample included sociodemographic data, nutritional status, and medical history (hypertension). Physical activity data was collected from a subsample of children between 3 and 16 years of age. Results A total of 1314 participants (mean age 23.6 ± 18.9 years, 54.54% female) completed all anthropometric measurements and were included in the analysis. Out of which, 98.40% (1293/1314) completed the household member’s questionnaire, 93.32% (1229/1314) participants older than 2 years completed blood pressure measurements, and 64.31% (845/1314) blood samples were collected from participants older than 5 years. Underweight prevalence for the total study population was 36.53% (480/1314) with the highest prevalence in children under 14 years. Overweight and obesity was highest among females with the prevalence of 7.61% (100/1314) and 6.62% (87/1314), respectively; obesity was rare among male participants. Conclusions The study provides valuable data to investigate the interplay of socioeconomic, demographic, environmental, physiological, and behavioral factors in the development of diet-related disorders in a representative sample of the Zanzibari population.

2-methythiol-4-tert-butylamino-6-cyclopropylamino-s-triazine (Irgarol-1051) has been widely used as effective alternative antifouling paint in marine structures including ships. However, it has been causing deleterious effects to marine organisms including reef building corals. The main objective of this study was to establish baseline levels of Irgarol-1051 around coral reefs and nearby ecosystems along coastline of Zanzibar Island. The levels of Irgarol-1051 ranged from 1.35ng/L around coral reefs to 15.44ng/L around harbor with average concentration of 4.11 (mean)±0.57 (SD) ng/L. This is below Environmental Risk Limit of 24ng/L as proposed by Dutch Authorities which suggests that the contamination is not alarming especially for coral reef ecosystem health. The main possible sources of the contamination are from shipping activities. This paper provides important baseline information of Irgarol-1051 around the coral reef ecosystems within the Western Indian Ocean (WIO) region and may be useful for formulation of marine conservation strategies and policies.

The herbicides Irgarol 1051 (2-(tert-butylamino)-4-cyclopropylamino)-6-(methylthio)-1,3,5-triazine) is commonly used as an antifouling paint to the boats and ships however its toxicity on marine organisms using fatty acid composition as indicator has not been fully investigated. Previous investigations have identified environmental concentrations of these herbicides as being a threat to non-target organisms, such as coral-reef and fishes. Their individual toxicity has been assessed, but they can co-occur and interact, potentially increasing their toxicity and the threat posed to marine organism. For example in Malaysia coastal water, we reported the concentration up to 2021 ng/L at Klang port. This is more than 84-fold a maximum permissible concentration in water proposed by the Dutch National Institute of Public Health and the Environment which is 24 ng/L for Irgarol-1051.

The use of antifouling paints to the boats and ships is one among the threats facing coastal resources including coral reefs in recent decades. This study reports the current contamination status of diuron and its behaviour in the coastal waters of Malaysia. The maximum concentration of diuron was 285 ng/L detected at Johor port. All samples from Redang and Bidong coral reef islands were contaminated with diuron. Temporal variation showed relatively high concentrations but no significant difference (P>0.05) during November and January (North-East monsoon) in Klang ports (North, South and West), while higher levels of diuron were detected during April, 2012 (Inter monsoon) in Kemaman, and Johor port. Although no site has shown concentration above maximum permissible concentration (430 ng/L) as restricted by the Dutch Authorities, however, long term exposure studies for environmental relevance levels of diuron around coastal areas should be given a priority in the future.

Contamination of heavy metals in coral reefs and coastal areas is a serious ecotoxicological and environmental problem due to direct runoff from anthropogenic wastes, commercial vessels and discharge from industrial effluents which may accumulate in the suspended particulate matter and settle on the bottom sediment.Surface sediment samples were collected from Samoa's commercial and fishing port and studied for the concentration and distribution of heavy metals.Two heavy metals (Cu, Pb) were detected from each port with some concentration below the permissible maximum concentration of environment quality standard set by the World Health Organization.

The world today has a population of over 7 billion people, with more than half of that number living in coastal areas, which accounts for only 5% of the inhabited land. This aspect is clearly reflected when one realises that of the 33 biggest megacities in the world, 22 are on the coast (UNEP, 2011). Especially in developing states such as Zanzibar, sewage still flows untreated into the sea, causing pollution of coastal habitats. The Zanzibar Archipelago, consists of two main islands – Unguja and Pemba with a combined population of nearly one million, while the urban population which is concentrated in Stone Town is around 200,000 (National Bureau of Statistics, 2002). The study focuses on the impact of trace metal pollution derived from dumping of household and industrial sewage, on the benthic communities found in the intertidal zone along the coast of Zanzibar. This study also serves as an extension to the paper by Rumisha et al. (2012) which assessed the influence of trace metal pollution on the community structure of soft bottom molluscs at the Dar es Salaam coast, across the Zanzibar Channel.

Emerging booster biocides contamination raises particular attention in the marine ecosystem health. This study provides the baseline data on the occurrence of Irgarol-1051 (2-methylthio-4-tert-butylamino-6-cyclopropylamiono-s-triazine) in the selected coastal water around Malaysia. The maximum detected concentration of Irgarol was 2021 ng/L at Klang West, commercial and cargo port. Coral reef Islands (Redang and Bidong) were relatively less contaminated compared to other coastal areas. The temporal variation revealed that only 1% of 28 stations sampled on November, 2011 was above the environmental risk limit of 24 ng/L as suggested by Dutch Authorities, while in January and April, 2012; 46% and 92% of the stations were above the limit respectively. The present findings demonstrate the wide detection of novel antifouling materials Irgarol-1051 which advocates the need for proper monitoring and conservation strategies for the coastal resources.