New and legacy pesticidal persistent organic pollutants in the agricultural region of the Sultanate of Oman.

Comprehensive air and surface soil monitoring was conducted for new and legacy organochlorine pesticides (OCPs) to fill the knowledge and data gap on the sources and fate of pesticidal persistent organic pollutants (POPs) in the Sultanate of Oman. DDTs in agricultural soil samples ranged from 0.013 to 95.80 ng/g (mean: 8.4 ± 25.06 ng/g), with a median value of 0.07 ng/g. The highest concentration was observed at Shinas, where intensive agricultural practice is prevalent. The dominance of p,p'-DDT in soil and air reflected technical DDT formulation usage in Oman. Among newly enlisted POPs, pentachlorobenzene had the maximum detection frequency in air (47%) and soil (41%). Over 90% of sites reflected extensive past use of hexachlorobenzene. Major OCP isomers and metabolites showed net volatilisation from the agricultural soil, thereby indicating concurrent emission and re-emission processes from the soil of Oman. However, the cleansing effect of oceanic air mass is the possible reason for relatively lower atmospheric OCP levels from a previous study. Although DDT displayed maximum cancer risk, the level is below the permissible limit. DDT primarily stemmed from obsolete stock and inadequate management practices. Hence, we suggest there is a need for DDT regulation in Oman.

Perennial Existence of Organochlorine Pesticides in the Soils of Amghara, Kuwait.

A comprehensive study from the surface soil samples of 14 locations from Amghara, Kuwait were assessed for the investigation of organochlorine pesticides (OCPs). There is limited information regarding the distribution pattern of OCPs in the soil samples of Kuwait. The total concentration of OCPs was in the range of 209.39 pg/g -7449.18 pg/g with an average value of 1313.04 pg/g. DDT had higher concentrations in soil samples (969.52 pg/g) than the other pesticides, according to the findings. The distribution pattern of OCPs in the Amghara soils revealed their origin as both historical and recent applications of pesticides. The study extended, how residual quantities could be used to determine health risks of both children and adults. Children and adults in all the locations were subject to negligible cancer risk, according to the health risk evaluation.

Past, present and future trends of selected pesticidal and industrial POPs in Kuwait.

Given the background of current global initiatives for controlling persistent organic pollutants (POPs), an overview of the scientific knowledge about the POPs issues in Kuwait is presented in this study. Both acute and chronic exposure to POPs can be associated with a wide range of deleterious health effects, including illness and death. POPs have drawn significant political and scientific interest in their fate and actions, particularly where local releases have resulted in dispersed contamination far from the source regions. These concerns inevitably led to the establishment of the Stockholm Convention (SC) on POPs. In recent years, Kuwait has carried out a wide variety of environmental research, in particular, on the monitoring of POPs in different matrices. The technological development facilitated to achieve the opposite monitoring of pesticidal and industrial POPs. The majority of these POPs are from a point source. Kuwait does not have pesticide manufacturing facilities and has not produced pesticides for POPs in the past. In the agriculture sector, Kuwait primarily imports pesticides for pest and disease control. This review encompasses the historical presence and current status of (pesticidal) organochlorine pesticides (OCPs) and (industrial POPs) PCBs and PBDEs in Kuwait based on the export, import, consumption and usage. This research also contrasts pesticide and industrial POP data from various Kuwaiti environmental matrices with data from other parts of Asia, the EU, the USA and Africa.

Pesticides driven pollution in Kuwait: The first evidence of environmental exposure to pesticides in soils and human health risk assessment.

Soil pollution from pesticide residues is a key concern due to the high soil accumulation of pesticides and their human toxicity. Pesticide concentration of surface soil samples from the Sulaibiya agricultural field located in Kuwait was assessed in the present study. The study also investigated health risk assessment for both children and adults based on the residual concentrations. The average concentration of Æ©OCPs (sum of organochlorine pesticides) along the present study was 3062 pg/g. The residual concentration of Æ©OCPs was comparatively lower as compared to other locations around the world. Out of the 11 observed locations, A, B, and D locations indicated higher concentrations of Æ©OCPs. The results indicated that DDT showed higher concentrations 692.87 pg/g in soil samples as compared to the other pesticides. Cancer risks of OCP via ingestion, dermal contact and inhalation of soil particles suggested that all stations were in a safe zone. However, locations A, B and D were closer to the low-risk band. The distribution pattern for each form of organochlorine pesticides (OCP) was different in Sulaibiya, indicating the non-simultaneous use of different groups of OCPs in this region. Multivariate statistical analysis based on cluster analysis identified three classes, 1, 2 and 3 of pesticides, suggesting these are from the same sources. Principle component analysis (PCA) showed that soil physicochemical properties influence the pesticides in soil samples. The results provides the baseline data of pesticides in soils from Kuwait.

Spatial and temporal variations in the atmospheric concentrations of "Stockholm Convention" organochlorine pesticides in Kuwait.

The study reports fortnightly atmospheric concentrations of organochlorine pesticides concomitantly measured at an urban, "industrial" and a remote location over a twelve month period in Kuwait to examine seasonal variability and urban-rural concentration gradients. The average±SD (and range) of the ΣOC concentrations measured throughout the study period in decreasing order were urban, 505±305 (range, 33-1352) pgm-3, remote, 204±124 (4.5-556) pgm-3, and "industrial" 155±103 (8.8-533) pgm-3. The concentrations of most OCs measured in this study, except for DDT and its metabolites, were higher at urban locations relative to their concentrations at remote location, in line with the literature on POPs regarding urban conurbations being sources of industrial chemicals. The most abundant pesticides measured throughout this study were dieldrin, pentachlorobenzene, hexachlorobenzene, ΣDDTs, ΣHCHs, and oxychlordane. Hexachlorobenzene concentrations were generally higher than those of pentachlorobenzene and are both strongly negatively correlated with temperature (p<0.05) at all sampling locations. Mean summertime concentrations were higher for hexachlorocyclohexanes, chlordanes, dieldrin, and DDT isomers, except for pp-DDT. This may suggest that concentrations of these compounds may be driven by temperature.

Seasonal variations in the atmospheric concentrations of polychlorinated biphenyls in Kuwait.

The spatial and temporal variations in the atmospheric concentrations of PCBs were concomitantly measured at several sites over a twelve-month period in Kuwait to examine seasonal variability and urban-rural concentration gradients using two sampling methods. The annual mean (and range) of ∑PCB concentrations measured using high volume samplers was 10.8 (1.2-32) pg m-3 at the remote site and 39.4 (1.1-128) pg m-3 at the urban site. The median concentrations of ΣPCBs at the urban location (30.3 pg m-3) was significantly higher (p < 0.001) than that measured at the remote location (8.6 pg m-3) consistent with the view that urban centers are an important net source of these compounds to the environment. Passive sampler derived concentrations across the country showed a uniform distribution except at a few locations in the vicinity of suspected sources where elevated concentrations were measured. As with active sampling data, the concentrations measured using passive samplers were higher in urban areas (range, 4-78 pg/m3) compared to remote sites (range, 2.2-17 pg/m3). The concentrations measured at some urban sites correlated extremely well with mean temperature during the deployment period whereas temperature correlations with measured concentrations were negative at remote and semi-rural sites suggesting that air-surface exchange maybe a key driving mechanism of the current levels of PCBs in Kuwait.

Polybrominated diphenyl ether concentrations in sediments from the Northern Arabian Gulf: spatial and temporal trends.

Surficial sediment samples were obtained from 25 locations within Kuwait Bay and outside the Bay, in the Northwestern Arabian Gulf, to access recent pollution in Kuwait. The historical deposition of PBDEs to this portion of the Arabian Gulf was reconstructed by collecting a sediment core at the entrance of Kuwait Bay. The mean (and range) in concentrations of ∑11PBDEs in surficial sediments was 0.164±0.09 (0.06-0.44) pg/g dw. The concentrations measured in Kuwait Bay were generally higher than those measured in the open Gulf. When the concentrations were normalized to organic carbon, the average ∑11PBDEs concentrations measured in Kuwait Bay were seven times higher than average concentrations outside the Bay. The historical record, reconstructed from a sediment core collected at the entrance of Kuwait Bay, showed that Σ11PBDE concentrations were generally low in deeper sediment sections. The concentrations started to increase above background in the mid-1950s and increased sharply to a maximum Σ11PBDE concentration of ca 1,100 pg/g in the late 1980s. Concentrations decreased thereafter until another pulse in concentrations was observed around the early 2000 followed by a decrease in subsequent years. It is likely that the initial pulse in concentration recorded in sediments is related to inputs from the Gulf war of 1991. The penta congeners were observed throughout the length of the core although the concentrations were low. The congeners present in the Deca-PBDE technical mixture, particularly BDE 209 which is the main congener in the Deca-BDE mixture, occurred in sediment cores around the 1980s, and the concentrations increased rapidly thereafter being the most dominant congener since their first detection in sediments. The presence of nona-BDE congeners in proportions exceeding those in commercial mixtures may be suggestive of debromination of BDE 209 in sediments.